# The "Plater" tab. It contains the "3D", "2D", "Preview" and "Layers" subtabs.

package Slic3r::GUI::Plater;
use strict;
use warnings;
use utf8;

use File::Basename qw(basename dirname);
use List::Util qw(sum first max);
use Slic3r::Geometry qw(X Y Z MIN MAX scale unscale deg2rad);
use threads::shared qw(shared_clone);
use Wx qw(:button :cursor :dialog :filedialog :keycode :icon :font :id :listctrl :misc 
    :panel :sizer :toolbar :window wxTheApp :notebook :combobox);
use Wx::Event qw(EVT_BUTTON EVT_COMMAND EVT_KEY_DOWN EVT_LIST_ITEM_ACTIVATED 
    EVT_LIST_ITEM_DESELECTED EVT_LIST_ITEM_SELECTED EVT_MOUSE_EVENTS EVT_PAINT EVT_TOOL 
    EVT_CHOICE EVT_COMBOBOX EVT_TIMER EVT_NOTEBOOK_PAGE_CHANGED);
use base 'Wx::Panel';

use constant TB_ADD             => &Wx::NewId;
use constant TB_REMOVE          => &Wx::NewId;
use constant TB_RESET           => &Wx::NewId;
use constant TB_ARRANGE         => &Wx::NewId;
use constant TB_EXPORT_GCODE    => &Wx::NewId;
use constant TB_EXPORT_STL      => &Wx::NewId;
use constant TB_MORE    => &Wx::NewId;
use constant TB_FEWER   => &Wx::NewId;
use constant TB_45CW    => &Wx::NewId;
use constant TB_45CCW   => &Wx::NewId;
use constant TB_SCALE   => &Wx::NewId;
use constant TB_SPLIT   => &Wx::NewId;
use constant TB_CUT     => &Wx::NewId;
use constant TB_SETTINGS => &Wx::NewId;

# package variables to avoid passing lexicals to threads
our $THUMBNAIL_DONE_EVENT    : shared = Wx::NewEventType;
our $PROGRESS_BAR_EVENT      : shared = Wx::NewEventType;
our $ERROR_EVENT             : shared = Wx::NewEventType;
# Emitted from the worker thread when the G-code export is finished.
our $EXPORT_COMPLETED_EVENT  : shared = Wx::NewEventType;
our $PROCESS_COMPLETED_EVENT : shared = Wx::NewEventType;

use constant FILAMENT_CHOOSERS_SPACING => 0;
use constant PROCESS_DELAY => 0.5 * 1000; # milliseconds

my $PreventListEvents = 0;

sub new {
    my $class = shift;
    my ($parent) = @_;
    my $self = $class->SUPER::new($parent, -1, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL);
    $self->{config} = Slic3r::Config->new_from_defaults(qw(
        bed_shape complete_objects extruder_clearance_radius skirts skirt_distance brim_width
        serial_port serial_speed octoprint_host octoprint_apikey
    ));
    $self->{model} = Slic3r::Model->new;
    $self->{print} = Slic3r::Print->new;
    # List of Perl objects Slic3r::GUI::Plater::Object, representing a 2D preview of the platter.
    $self->{objects} = [];
    
    $self->{print}->set_status_cb(sub {
        my ($percent, $message) = @_;
        
        if ($Slic3r::have_threads) {
            Wx::PostEvent($self, Wx::PlThreadEvent->new(-1, $PROGRESS_BAR_EVENT, shared_clone([$percent, $message])));
        } else {
            $self->on_progress_event($percent, $message);
        }
    });
    
    # Initialize preview notebook
    $self->{preview_notebook} = Wx::Notebook->new($self, -1, wxDefaultPosition, [335,335], wxNB_BOTTOM);
    
    # Initialize handlers for canvases
    my $on_select_object = sub {
        my ($obj_idx) = @_;
        $self->select_object($obj_idx);
    };
    my $on_double_click = sub {
        $self->object_settings_dialog if $self->selected_object;
    };
    my $on_right_click = sub {
        my ($canvas, $click_pos) = @_;
        
        my ($obj_idx, $object) = $self->selected_object;
        return if !defined $obj_idx;
        
        my $menu = $self->object_menu;
        $canvas->PopupMenu($menu, $click_pos);
        $menu->Destroy;
    };
    my $on_instances_moved = sub {
        $self->update;
    };
    
    # Initialize 3D plater
    if ($Slic3r::GUI::have_OpenGL) {
        $self->{canvas3D} = Slic3r::GUI::Plater::3D->new($self->{preview_notebook}, $self->{objects}, $self->{model}, $self->{config});
        $self->{preview_notebook}->AddPage($self->{canvas3D}, '3D');
        $self->{canvas3D}->set_on_select_object($on_select_object);
        $self->{canvas3D}->set_on_double_click($on_double_click);
        $self->{canvas3D}->set_on_right_click(sub { $on_right_click->($self->{canvas3D}, @_); });
        $self->{canvas3D}->set_on_instances_moved($on_instances_moved);
        $self->{canvas3D}->on_viewport_changed(sub {
            $self->{preview3D}->canvas->set_viewport_from_scene($self->{canvas3D});
        });
    }
    
    # Initialize 2D preview canvas
    $self->{canvas} = Slic3r::GUI::Plater::2D->new($self->{preview_notebook}, wxDefaultSize, $self->{objects}, $self->{model}, $self->{config});
    $self->{preview_notebook}->AddPage($self->{canvas}, '2D');
    $self->{canvas}->on_select_object($on_select_object);
    $self->{canvas}->on_double_click($on_double_click);
    $self->{canvas}->on_right_click(sub { $on_right_click->($self->{canvas}, @_); });
    $self->{canvas}->on_instances_moved($on_instances_moved);
    
    # Initialize 3D toolpaths preview
    if ($Slic3r::GUI::have_OpenGL) {
        $self->{preview3D} = Slic3r::GUI::Plater::3DPreview->new($self->{preview_notebook}, $self->{print});
        $self->{preview3D}->canvas->on_viewport_changed(sub {
            $self->{canvas3D}->set_viewport_from_scene($self->{preview3D}->canvas);
        });
        $self->{preview_notebook}->AddPage($self->{preview3D}, 'Preview');
        $self->{preview3D_page_idx} = $self->{preview_notebook}->GetPageCount-1;
    }
    
    # Initialize toolpaths preview
    if ($Slic3r::GUI::have_OpenGL) {
        $self->{toolpaths2D} = Slic3r::GUI::Plater::2DToolpaths->new($self->{preview_notebook}, $self->{print});
        $self->{preview_notebook}->AddPage($self->{toolpaths2D}, 'Layers');
    }
    
    EVT_NOTEBOOK_PAGE_CHANGED($self, $self->{preview_notebook}, sub {
        if ($self->{preview_notebook}->GetSelection == $self->{preview3D_page_idx}) {
            $self->{preview3D}->load_print;
        }
    });
    
    # toolbar for object manipulation
    if (!&Wx::wxMSW) {
        Wx::ToolTip::Enable(1);
        $self->{htoolbar} = Wx::ToolBar->new($self, -1, wxDefaultPosition, wxDefaultSize, wxTB_HORIZONTAL | wxTB_TEXT | wxBORDER_SIMPLE | wxTAB_TRAVERSAL);
        $self->{htoolbar}->AddTool(TB_ADD, "Add…", Wx::Bitmap->new($Slic3r::var->("brick_add.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_REMOVE, "Delete", Wx::Bitmap->new($Slic3r::var->("brick_delete.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_RESET, "Delete All", Wx::Bitmap->new($Slic3r::var->("cross.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_ARRANGE, "Arrange", Wx::Bitmap->new($Slic3r::var->("bricks.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddSeparator;
        $self->{htoolbar}->AddTool(TB_MORE, "More", Wx::Bitmap->new($Slic3r::var->("add.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_FEWER, "Fewer", Wx::Bitmap->new($Slic3r::var->("delete.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddSeparator;
        $self->{htoolbar}->AddTool(TB_45CCW, "45° ccw", Wx::Bitmap->new($Slic3r::var->("arrow_rotate_anticlockwise.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_45CW, "45° cw", Wx::Bitmap->new($Slic3r::var->("arrow_rotate_clockwise.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_SCALE, "Scale…", Wx::Bitmap->new($Slic3r::var->("arrow_out.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_SPLIT, "Split", Wx::Bitmap->new($Slic3r::var->("shape_ungroup.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddTool(TB_CUT, "Cut…", Wx::Bitmap->new($Slic3r::var->("package.png"), wxBITMAP_TYPE_PNG), '');
        $self->{htoolbar}->AddSeparator;
        $self->{htoolbar}->AddTool(TB_SETTINGS, "Settings…", Wx::Bitmap->new($Slic3r::var->("cog.png"), wxBITMAP_TYPE_PNG), '');
    } else {
        my %tbar_buttons = (
            add             => "Add…",
            remove          => "Delete",
            reset           => "Delete All",
            arrange         => "Arrange",
            increase        => "",
            decrease        => "",
            rotate45ccw     => "",
            rotate45cw      => "",
            changescale     => "Scale…",
            split           => "Split",
            cut             => "Cut…",
            settings        => "Settings…",
        );
        $self->{btoolbar} = Wx::BoxSizer->new(wxHORIZONTAL);
        for (qw(add remove reset arrange increase decrease rotate45ccw rotate45cw changescale split cut settings)) {
            $self->{"btn_$_"} = Wx::Button->new($self, -1, $tbar_buttons{$_}, wxDefaultPosition, wxDefaultSize, wxBU_EXACTFIT);
            $self->{btoolbar}->Add($self->{"btn_$_"});
        }
    }

    $self->{list} = Wx::ListView->new($self, -1, wxDefaultPosition, wxDefaultSize,
        wxLC_SINGLE_SEL | wxLC_REPORT | wxBORDER_SUNKEN | wxTAB_TRAVERSAL | wxWANTS_CHARS );
    $self->{list}->InsertColumn(0, "Name", wxLIST_FORMAT_LEFT, 145);
    $self->{list}->InsertColumn(1, "Copies", wxLIST_FORMAT_CENTER, 45);
    $self->{list}->InsertColumn(2, "Scale", wxLIST_FORMAT_CENTER, wxLIST_AUTOSIZE_USEHEADER);
    EVT_LIST_ITEM_SELECTED($self, $self->{list}, \&list_item_selected);
    EVT_LIST_ITEM_DESELECTED($self, $self->{list}, \&list_item_deselected);
    EVT_LIST_ITEM_ACTIVATED($self, $self->{list}, \&list_item_activated);
    EVT_KEY_DOWN($self->{list}, sub {
        my ($list, $event) = @_;
        if ($event->GetKeyCode == WXK_TAB) {
            $list->Navigate($event->ShiftDown ? &Wx::wxNavigateBackward : &Wx::wxNavigateForward);
        } else {
            $event->Skip;
        }
    });
    
    # right pane buttons
    $self->{btn_export_gcode} = Wx::Button->new($self, -1, "Export G-code…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
    $self->{btn_reslice} = Wx::Button->new($self, -1, "Slice now", wxDefaultPosition, [-1, 30], wxBU_LEFT);
    $self->{btn_print} = Wx::Button->new($self, -1, "Print…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
    $self->{btn_send_gcode} = Wx::Button->new($self, -1, "Send to printer", wxDefaultPosition, [-1, 30], wxBU_LEFT);
    $self->{btn_export_stl} = Wx::Button->new($self, -1, "Export STL…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
    #$self->{btn_export_gcode}->SetFont($Slic3r::GUI::small_font);
    #$self->{btn_export_stl}->SetFont($Slic3r::GUI::small_font);
    $self->{btn_print}->Hide;
    $self->{btn_send_gcode}->Hide;
    
    if ($Slic3r::GUI::have_button_icons) {
        my %icons = qw(
            add             brick_add.png
            remove          brick_delete.png
            reset           cross.png
            arrange         bricks.png
            export_gcode    cog_go.png
            print           arrow_up.png
            send_gcode      arrow_up.png
            reslice         reslice.png
            export_stl      brick_go.png
            
            increase        add.png
            decrease        delete.png
            rotate45cw      arrow_rotate_clockwise.png
            rotate45ccw     arrow_rotate_anticlockwise.png
            changescale     arrow_out.png
            split           shape_ungroup.png
            cut             package.png
            settings        cog.png
        );
        for (grep $self->{"btn_$_"}, keys %icons) {
            $self->{"btn_$_"}->SetBitmap(Wx::Bitmap->new($Slic3r::var->($icons{$_}), wxBITMAP_TYPE_PNG));
        }
    }
    $self->selection_changed(0);
    $self->object_list_changed;
    EVT_BUTTON($self, $self->{btn_export_gcode}, sub {
        $self->export_gcode;
    });
    EVT_BUTTON($self, $self->{btn_print}, sub {
        $self->{print_file} = $self->export_gcode(Wx::StandardPaths::Get->GetTempDir());
    });
    EVT_BUTTON($self, $self->{btn_send_gcode}, sub {
        $self->{send_gcode_file} = $self->export_gcode(Wx::StandardPaths::Get->GetTempDir());
    });
    EVT_BUTTON($self, $self->{btn_reslice}, \&reslice);
    EVT_BUTTON($self, $self->{btn_export_stl}, \&export_stl);
    
    if ($self->{htoolbar}) {
        EVT_TOOL($self, TB_ADD, sub { $self->add; });
        EVT_TOOL($self, TB_REMOVE, sub { $self->remove() }); # explicitly pass no argument to remove
        EVT_TOOL($self, TB_RESET, sub { $self->reset; });
        EVT_TOOL($self, TB_ARRANGE, sub { $self->arrange; });
        EVT_TOOL($self, TB_MORE, sub { $self->increase; });
        EVT_TOOL($self, TB_FEWER, sub { $self->decrease; });
        EVT_TOOL($self, TB_45CW, sub { $_[0]->rotate(-45) });
        EVT_TOOL($self, TB_45CCW, sub { $_[0]->rotate(45) });
        EVT_TOOL($self, TB_SCALE, sub { $self->changescale(undef); });
        EVT_TOOL($self, TB_SPLIT, sub { $self->split_object; });
        EVT_TOOL($self, TB_CUT, sub { $_[0]->object_cut_dialog });
        EVT_TOOL($self, TB_SETTINGS, sub { $_[0]->object_settings_dialog });
    } else {
        EVT_BUTTON($self, $self->{btn_add}, sub { $self->add; });
        EVT_BUTTON($self, $self->{btn_remove}, sub { $self->remove() }); # explicitly pass no argument to remove
        EVT_BUTTON($self, $self->{btn_reset}, sub { $self->reset; });
        EVT_BUTTON($self, $self->{btn_arrange}, sub { $self->arrange; });
        EVT_BUTTON($self, $self->{btn_increase}, sub { $self->increase; });
        EVT_BUTTON($self, $self->{btn_decrease}, sub { $self->decrease; });
        EVT_BUTTON($self, $self->{btn_rotate45cw}, sub { $_[0]->rotate(-45) });
        EVT_BUTTON($self, $self->{btn_rotate45ccw}, sub { $_[0]->rotate(45) });
        EVT_BUTTON($self, $self->{btn_changescale}, sub { $self->changescale(undef); });
        EVT_BUTTON($self, $self->{btn_split}, sub { $self->split_object; });
        EVT_BUTTON($self, $self->{btn_cut}, sub { $_[0]->object_cut_dialog });
        EVT_BUTTON($self, $self->{btn_settings}, sub { $_[0]->object_settings_dialog });
    }
    
    $_->SetDropTarget(Slic3r::GUI::Plater::DropTarget->new($self))
        for grep defined($_),
            $self, $self->{canvas}, $self->{canvas3D}, $self->{preview3D}, $self->{list};
    
    EVT_COMMAND($self, -1, $THUMBNAIL_DONE_EVENT, sub {
        my ($self, $event) = @_;
        my ($obj_idx) = @{$event->GetData};
        return if !$self->{objects}[$obj_idx];  # object was deleted before thumbnail generation completed
        
        $self->on_thumbnail_made($obj_idx);
    });
    
    EVT_COMMAND($self, -1, $PROGRESS_BAR_EVENT, sub {
        my ($self, $event) = @_;
        my ($percent, $message) = @{$event->GetData};
        $self->on_progress_event($percent, $message);
    });
    
    EVT_COMMAND($self, -1, $ERROR_EVENT, sub {
        my ($self, $event) = @_;
        Slic3r::GUI::show_error($self, @{$event->GetData});
    });
    
    EVT_COMMAND($self, -1, $EXPORT_COMPLETED_EVENT, sub {
        my ($self, $event) = @_;
        $self->on_export_completed($event->GetData);
    });
    
    EVT_COMMAND($self, -1, $PROCESS_COMPLETED_EVENT, sub {
        my ($self, $event) = @_;
        $self->on_process_completed($event->GetData);
    });
    
    if ($Slic3r::have_threads) {
        my $timer_id = Wx::NewId();
        $self->{apply_config_timer} = Wx::Timer->new($self, $timer_id);
        EVT_TIMER($self, $timer_id, sub {
            my ($self, $event) = @_;
            $self->async_apply_config;
        });
    }
    
    $self->{canvas}->update_bed_size;
    if ($self->{canvas3D}) {
        $self->{canvas3D}->update_bed_size;
        $self->{canvas3D}->zoom_to_bed;
    }
    if ($self->{preview3D}) {
        $self->{preview3D}->set_bed_shape($self->{config}->bed_shape);
    }
    $self->update;
    
    {
        my $presets;
        if ($self->GetFrame->{mode} eq 'expert') {
            $presets = $self->{presets_sizer} = Wx::FlexGridSizer->new(3, 2, 1, 2);
            $presets->AddGrowableCol(1, 1);
            $presets->SetFlexibleDirection(wxHORIZONTAL);
            my %group_labels = (
                print       => 'Print settings',
                filament    => 'Filament',
                printer     => 'Printer',
            );
            # UI Combo boxes for a print, multiple filaments, and a printer.
            # Initially a single filament combo box is created, but the number of combo boxes for the filament selection may increase,
            # once a printer preset with multiple extruders is activated.
            # $self->{preset_choosers}{$group}[$idx]
            $self->{preset_choosers} = {};
            # Boolean indicating whether the '- default -' preset is shown by the combo box.
            $self->{preset_choosers_default_suppressed} = {};
            for my $group (qw(print filament printer)) {
                my $text = Wx::StaticText->new($self, -1, "$group_labels{$group}:", wxDefaultPosition, wxDefaultSize, wxALIGN_RIGHT);
                $text->SetFont($Slic3r::GUI::small_font);
                my $choice = Wx::BitmapComboBox->new($self, -1, "", wxDefaultPosition, wxDefaultSize, [], wxCB_READONLY);
                $self->{preset_choosers}{$group} = [$choice];
                $self->{preset_choosers_default_suppressed}{$group} = 0;
                # setup the listener
                EVT_COMBOBOX($choice, $choice, sub {
                    my ($choice) = @_;
                    wxTheApp->CallAfter(sub {
                        $self->_on_select_preset($group, $choice);
                    });
                });
                $presets->Add($text, 0, wxALIGN_RIGHT | wxALIGN_CENTER_VERTICAL | wxRIGHT, 4);
                $presets->Add($choice, 1, wxALIGN_CENTER_VERTICAL | wxEXPAND | wxBOTTOM, 0);
            }
        }
        
        my $object_info_sizer;
        {
            my $box = Wx::StaticBox->new($self, -1, "Info");
            $object_info_sizer = Wx::StaticBoxSizer->new($box, wxVERTICAL);
            $object_info_sizer->SetMinSize([350,-1]);
            my $grid_sizer = Wx::FlexGridSizer->new(3, 4, 5, 5);
            $grid_sizer->SetFlexibleDirection(wxHORIZONTAL);
            $grid_sizer->AddGrowableCol(1, 1);
            $grid_sizer->AddGrowableCol(3, 1);
            $object_info_sizer->Add($grid_sizer, 0, wxEXPAND);
            
            my @info = (
                size        => "Size",
                volume      => "Volume",
                facets      => "Facets",
                materials   => "Materials",
                manifold    => "Manifold",
            );
            while (my $field = shift @info) {
                my $label = shift @info;
                my $text = Wx::StaticText->new($self, -1, "$label:", wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
                $text->SetFont($Slic3r::GUI::small_font);
                $grid_sizer->Add($text, 0);
                
                $self->{"object_info_$field"} = Wx::StaticText->new($self, -1, "", wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
                $self->{"object_info_$field"}->SetFont($Slic3r::GUI::small_font);
                if ($field eq 'manifold') {
                    $self->{object_info_manifold_warning_icon} = Wx::StaticBitmap->new($self, -1, Wx::Bitmap->new($Slic3r::var->("error.png"), wxBITMAP_TYPE_PNG));
                    $self->{object_info_manifold_warning_icon}->Hide;
                    
                    my $h_sizer = Wx::BoxSizer->new(wxHORIZONTAL);
                    $h_sizer->Add($self->{object_info_manifold_warning_icon}, 0);
                    $h_sizer->Add($self->{"object_info_$field"}, 0);
                    $grid_sizer->Add($h_sizer, 0, wxEXPAND);
                } else {
                    $grid_sizer->Add($self->{"object_info_$field"}, 0);
                }
            }
        }
        
        my $buttons_sizer = Wx::BoxSizer->new(wxHORIZONTAL);
        $self->{buttons_sizer} = $buttons_sizer;
        $buttons_sizer->AddStretchSpacer(1);
        $buttons_sizer->Add($self->{btn_export_stl}, 0, wxALIGN_RIGHT, 0);
        $buttons_sizer->Add($self->{btn_reslice}, 0, wxALIGN_RIGHT, 0);
        $buttons_sizer->Add($self->{btn_print}, 0, wxALIGN_RIGHT, 0);
        $buttons_sizer->Add($self->{btn_send_gcode}, 0, wxALIGN_RIGHT, 0);
        $buttons_sizer->Add($self->{btn_export_gcode}, 0, wxALIGN_RIGHT, 0);
        
        my $right_sizer = Wx::BoxSizer->new(wxVERTICAL);
        $right_sizer->Add($presets, 0, wxEXPAND | wxTOP, 10) if defined $presets;
        $right_sizer->Add($buttons_sizer, 0, wxEXPAND | wxBOTTOM, 5);
        $right_sizer->Add($self->{list}, 1, wxEXPAND, 5);
        $right_sizer->Add($object_info_sizer, 0, wxEXPAND, 0);
        
        my $hsizer = Wx::BoxSizer->new(wxHORIZONTAL);
        $hsizer->Add($self->{preview_notebook}, 1, wxEXPAND | wxTOP, 1);
        $hsizer->Add($right_sizer, 0, wxEXPAND | wxLEFT | wxRIGHT, 3);
        
        my $sizer = Wx::BoxSizer->new(wxVERTICAL);
        $sizer->Add($self->{htoolbar}, 0, wxEXPAND, 0) if $self->{htoolbar};
        $sizer->Add($self->{btoolbar}, 0, wxEXPAND, 0) if $self->{btoolbar};
        $sizer->Add($hsizer, 1, wxEXPAND, 0);
        
        $sizer->SetSizeHints($self);
        $self->SetSizer($sizer);
    }

    $self->update_ui_from_settings();
    
    return $self;
}

# sets the callback
sub on_select_preset {
    my ($self, $cb) = @_;
    $self->{on_select_preset} = $cb;
}

sub _on_select_preset {
	my $self = shift;
	my ($group, $choice) = @_;
	
	# If user changed a filament preset and the selected machine is equipped with multiple extruders,
    # there are multiple filament selection combo boxes shown at the platter. In that case
    # don't propagate the filament selection changes to the tab.
    my $default_suppressed = $self->{preset_choosers_default_suppressed}{$group};
	if ($group eq 'filament' && @{$self->{preset_choosers}{filament}} > 1) {
        # Indices of the filaments selected.
		my @filament_presets = $self->filament_presets;
		$Slic3r::GUI::Settings->{presets}{filament} = $choice->GetString($filament_presets[0] - $default_suppressed) . ".ini";
		$Slic3r::GUI::Settings->{presets}{"filament_${_}"} = $choice->GetString($filament_presets[$_] - $default_suppressed)
			for 1 .. $#filament_presets;
		wxTheApp->save_settings;
		return;
	}
	
	# call GetSelection() in scalar context as it's context-aware
	$self->{on_select_preset}->($group, scalar($choice->GetSelection) + $default_suppressed)
	    if $self->{on_select_preset};
	
	# get new config and generate on_config_change() event for updating plater and other things
	$self->on_config_change($self->GetFrame->config);
}

sub GetFrame {
    my ($self) = @_;
    return &Wx::GetTopLevelParent($self);
}

# Called after the Preferences dialog is closed and the program settings are saved.
# Update the UI based on the current preferences.
sub update_ui_from_settings
{
    my ($self) = @_;
    if (defined($self->{btn_reslice}) && $self->{buttons_sizer}->IsShown($self->{btn_reslice}) != (! $Slic3r::GUI::Settings->{_}{background_processing})) {
        $self->{buttons_sizer}->Show($self->{btn_reslice}, ! $Slic3r::GUI::Settings->{_}{background_processing});
        $self->{buttons_sizer}->Layout;
    }
}

# Update presets (Print settings, Filament, Printer) from their respective tabs.
# Called by 
#       Slic3r::GUI::Tab::Print::_on_presets_changed
#       Slic3r::GUI::Tab::Filament::_on_presets_changed
#       Slic3r::GUI::Tab::Printer::_on_presets_changed
# when the presets are loaded or the user selects another preset.
# For Print settings and Printer, synchronize the selection index with their tabs.
# For Filament, synchronize the selection index for a single extruder printer only, otherwise keep the selection.
sub update_presets {
    my $self = shift;
    # $presets: one of qw(print filament printer)
    # $selected: index of the selected preset in the array. This may not correspond
    # with the index of selection in the UI element, where not all items are displayed.
    my ($group, $presets, $default_suppressed, $selected, $is_dirty) = @_;
    
    my @choosers = @{ $self->{preset_choosers}{$group} };
    foreach my $choice (@choosers) {
        if ($group eq 'filament' && @choosers > 1) {
            # if we have more than one filament chooser, keep our selection
            # instead of importing the one from the tab
            $selected = $choice->GetSelection + $self->{preset_choosers_default_suppressed}{$group};
            $is_dirty = 0;
        }
        $choice->Clear;
        foreach my $preset (@$presets) {
            next if ($preset->default && $default_suppressed);
            my $bitmap;
            if ($group eq 'filament') {
                my $config = $preset->config(['filament_colour']);
                my $rgb_hex = $config->filament_colour->[0];
                if ($preset->default) {
                    $bitmap = Wx::Bitmap->new($Slic3r::var->("spool.png"), wxBITMAP_TYPE_PNG);
                } else {
                    $rgb_hex =~ s/^#//;
                    my @rgb = unpack 'C*', pack 'H*', $rgb_hex;
                    my $image = Wx::Image->new(16,16);
                    $image->SetRGB(Wx::Rect->new(0,0,16,16), @rgb);
                    $bitmap = Wx::Bitmap->new($image);
                }
            } elsif ($group eq 'print') {
                $bitmap = Wx::Bitmap->new($Slic3r::var->("cog.png"), wxBITMAP_TYPE_PNG);
            } elsif ($group eq 'printer') {
                $bitmap = Wx::Bitmap->new($Slic3r::var->("printer_empty.png"), wxBITMAP_TYPE_PNG);
            }
            $choice->AppendString($preset->name, $bitmap);
        }
        
        if ($selected <= $#$presets) {
            my $idx = $selected - $default_suppressed;
            if ($idx >= 0) {
                if ($is_dirty) {
                    $choice->SetString($idx, $choice->GetString($idx) . " (modified)");
                }
                # call SetSelection() only after SetString() otherwise the new string
                # won't be picked up as the visible string
                $choice->SetSelection($idx);
            }
        }
    }

    $self->{preset_choosers_default_suppressed}{$group} = $default_suppressed;
}

# Return a vector of indices of filaments selected by the $self->{preset_choosers}{filament} combo boxes.
sub filament_presets {
    my $self = shift;
    # force scalar context for GetSelection() as it's context-aware
    return map scalar($_->GetSelection) + $self->{preset_choosers_default_suppressed}{filament}, @{ $self->{preset_choosers}{filament} };
}

sub add {
    my $self = shift;
    
    my @input_files = wxTheApp->open_model($self);
    $self->load_file($_) for @input_files;
}

sub load_file {
    my $self = shift;
    my ($input_file) = @_;
    
    $Slic3r::GUI::Settings->{recent}{skein_directory} = dirname($input_file);
    wxTheApp->save_settings;
    
    my $process_dialog = Wx::ProgressDialog->new('Loading…', "Processing input file…", 100, $self, 0);
    $process_dialog->Pulse;
    
    local $SIG{__WARN__} = Slic3r::GUI::warning_catcher($self);
    
    my $model = eval { Slic3r::Model->read_from_file($input_file) };
    Slic3r::GUI::show_error($self, $@) if $@;
    
    if (defined $model) {
        if ($model->looks_like_multipart_object) {
            my $dialog = Wx::MessageDialog->new($self,
                "This file contains several objects positioned at multiple heights. "
                . "Instead of considering them as multiple objects, should I consider\n"
                . "this file as a single object having multiple parts?\n",
                'Multi-part object detected', wxICON_WARNING | wxYES | wxNO);
            if ($dialog->ShowModal() == wxID_YES) {
                $model->convert_multipart_object;
            }
        }
        $self->load_model_objects(@{$model->objects});
        $self->statusbar->SetStatusText("Loaded " . basename($input_file));
    }
    
    $process_dialog->Destroy;
}

sub load_model_objects {
    my ($self, @model_objects) = @_;
    
    my $bed_centerf = $self->bed_centerf;
    my $bed_shape = Slic3r::Polygon->new_scale(@{$self->{config}->bed_shape});
    my $bed_size = $bed_shape->bounding_box->size;
    
    my $need_arrange = 0;
    my $scaled_down = 0;
    my @obj_idx = ();
    foreach my $model_object (@model_objects) {
        my $o = $self->{model}->add_object($model_object);
        
        push @{ $self->{objects} }, Slic3r::GUI::Plater::Object->new(
            name => basename($model_object->input_file),
        );
        push @obj_idx, $#{ $self->{objects} };
    
        if ($model_object->instances_count == 0) {
            # if object has no defined position(s) we need to rearrange everything after loading
            $need_arrange = 1;
        
            # add a default instance and center object around origin
            $o->center_around_origin;  # also aligns object to Z = 0
            $o->add_instance(offset => $bed_centerf);
        }
        
        {
            # if the object is too large (more than 5 times the bed), scale it down
            my $size = $o->bounding_box->size;
            my $ratio = max(@$size[X,Y]) / unscale(max(@$bed_size[X,Y]));
            if ($ratio > 5) {
                $_->set_scaling_factor(1/$ratio) for @{$o->instances};
                $scaled_down = 1;
            }
        }
    
        $self->{print}->auto_assign_extruders($o);
        $self->{print}->add_model_object($o);
    }
    
    # if user turned autocentering off, automatic arranging would disappoint them
    if (!$Slic3r::GUI::Settings->{_}{autocenter}) {
        $need_arrange = 0;
    }
    
    if ($scaled_down) {
        Slic3r::GUI::show_info(
            $self,
            'Your object appears to be too large, so it was automatically scaled down to fit your print bed.',
            'Object too large?',
        );
    }
    
    foreach my $obj_idx (@obj_idx) {
        my $object = $self->{objects}[$obj_idx];
        my $model_object = $self->{model}->objects->[$obj_idx];
        $self->{list}->InsertStringItem($obj_idx, $object->name);
        $self->{list}->SetItemFont($obj_idx, Wx::Font->new(10, wxDEFAULT, wxNORMAL, wxNORMAL))
            if $self->{list}->can('SetItemFont');  # legacy code for wxPerl < 0.9918 not supporting SetItemFont()
    
        $self->{list}->SetItem($obj_idx, 1, $model_object->instances_count);
        $self->{list}->SetItem($obj_idx, 2, ($model_object->instances->[0]->scaling_factor * 100) . "%");
    
        $self->make_thumbnail($obj_idx);
    }
    $self->arrange if $need_arrange;
    $self->update;
    
    # zoom to objects
    $self->{canvas3D}->zoom_to_volumes
        if $self->{canvas3D};
    
    $self->{list}->Update;
    $self->{list}->Select($obj_idx[-1], 1);
    $self->object_list_changed;
    
    $self->schedule_background_process;
}

sub bed_centerf {
    my ($self) = @_;
    
    my $bed_shape = Slic3r::Polygon->new_scale(@{$self->{config}->bed_shape});
    my $bed_center = $bed_shape->bounding_box->center;
    return Slic3r::Pointf->new(unscale($bed_center->x), unscale($bed_center->y)); #)
}

sub remove {
    my $self = shift;
    my ($obj_idx) = @_;
    
    $self->stop_background_process;
    
    # Prevent toolpaths preview from rendering while we modify the Print object
    $self->{toolpaths2D}->enabled(0) if $self->{toolpaths2D};
    $self->{preview3D}->enabled(0) if $self->{preview3D};
    
    # if no object index is supplied, remove the selected one
    if (!defined $obj_idx) {
        ($obj_idx, undef) = $self->selected_object;
    }
    
    splice @{$self->{objects}}, $obj_idx, 1;
    $self->{model}->delete_object($obj_idx);
    $self->{print}->delete_object($obj_idx);
    $self->{list}->DeleteItem($obj_idx);
    $self->object_list_changed;
    
    $self->select_object(undef);
    $self->update;
    $self->schedule_background_process;
}

sub reset {
    my $self = shift;
    
    $self->stop_background_process;
    
    # Prevent toolpaths preview from rendering while we modify the Print object
    $self->{toolpaths2D}->enabled(0) if $self->{toolpaths2D};
    $self->{preview3D}->enabled(0) if $self->{preview3D};
    
    @{$self->{objects}} = ();
    $self->{model}->clear_objects;
    $self->{print}->clear_objects;
    $self->{list}->DeleteAllItems;
    $self->object_list_changed;
    
    $self->select_object(undef);
    $self->update;
}

sub increase {
    my ($self, $copies) = @_;
    
    $copies //= 1;
    my ($obj_idx, $object) = $self->selected_object;
    my $model_object = $self->{model}->objects->[$obj_idx];
    my $instance = $model_object->instances->[-1];
    for my $i (1..$copies) {
        $instance = $model_object->add_instance(
            offset          => Slic3r::Pointf->new(map 10+$_, @{$instance->offset}),
            scaling_factor  => $instance->scaling_factor,
            rotation        => $instance->rotation,
        );
        $self->{print}->objects->[$obj_idx]->add_copy($instance->offset);
    }
    $self->{list}->SetItem($obj_idx, 1, $model_object->instances_count);
    
    # only autoarrange if user has autocentering enabled
    $self->stop_background_process;
    if ($Slic3r::GUI::Settings->{_}{autocenter}) {
        $self->arrange;
    } else {
        $self->update;
    }
    $self->schedule_background_process;
}

sub decrease {
    my ($self, $copies) = @_;
    
    $copies //= 1;
    $self->stop_background_process;
    
    my ($obj_idx, $object) = $self->selected_object;
    my $model_object = $self->{model}->objects->[$obj_idx];
    if ($model_object->instances_count > $copies) {
        for my $i (1..$copies) {
            $model_object->delete_last_instance;
            $self->{print}->objects->[$obj_idx]->delete_last_copy;
        }
        $self->{list}->SetItem($obj_idx, 1, $model_object->instances_count);
    } else {
        $self->remove;
    }
    
    if ($self->{objects}[$obj_idx]) {
        $self->{list}->Select($obj_idx, 0);
        $self->{list}->Select($obj_idx, 1);
    }
    $self->update;
    $self->schedule_background_process;
}

sub set_number_of_copies {
    my ($self) = @_;
    
    $self->pause_background_process;
    
    # get current number of copies
    my ($obj_idx, $object) = $self->selected_object;
    my $model_object = $self->{model}->objects->[$obj_idx];
    
    # prompt user
    my $copies = Wx::GetNumberFromUser("", "Enter the number of copies of the selected object:", "Copies", $model_object->instances_count, 0, 1000, $self);
    my $diff = $copies - $model_object->instances_count;
    if ($diff == 0) {
        # no variation
        $self->resume_background_process;
    } elsif ($diff > 0) {
        $self->increase($diff);
    } elsif ($diff < 0) {
        $self->decrease(-$diff);
    }
}

sub rotate {
    my $self = shift;
    my ($angle, $axis) = @_;
    
    # angle is in degrees
    $axis //= Z;
    
    my ($obj_idx, $object) = $self->selected_object;
    return if !defined $obj_idx;
    
    my $model_object = $self->{model}->objects->[$obj_idx];
    my $model_instance = $model_object->instances->[0];
    
    # we need thumbnail to be computed before allowing rotation
    return if !$object->thumbnail;
    
    if (!defined $angle) {
        my $axis_name = $axis == X ? 'X' : $axis == Y ? 'Y' : 'Z';
        $angle = Wx::GetNumberFromUser("", "Enter the rotation angle:", "Rotate around $axis_name axis", $model_instance->rotation, -364, 364, $self);
        return if !$angle || $angle == -1;
        $angle = 0 - $angle;  # rotate clockwise (be consistent with button icon)
    }
    
    $self->stop_background_process;
    
    if ($axis == Z) {
        my $new_angle = $model_instance->rotation + deg2rad($angle);
        $_->set_rotation($new_angle) for @{ $model_object->instances };
        $object->transform_thumbnail($self->{model}, $obj_idx);
    } else {
        # rotation around X and Y needs to be performed on mesh
        # so we first apply any Z rotation
        if ($model_instance->rotation != 0) {
            $model_object->rotate($model_instance->rotation, Z);
            $_->set_rotation(0) for @{ $model_object->instances };
        }
        $model_object->rotate(deg2rad($angle), $axis);
        
        # realign object to Z = 0
        $model_object->center_around_origin;
        $self->make_thumbnail($obj_idx);
    }
    
    $model_object->update_bounding_box;
    # update print and start background processing
    $self->{print}->add_model_object($model_object, $obj_idx);
    
    $self->selection_changed;  # refresh info (size etc.)
    $self->update;
    $self->schedule_background_process;
}

sub mirror {
    my ($self, $axis) = @_;
    
    my ($obj_idx, $object) = $self->selected_object;
    return if !defined $obj_idx;
    
    my $model_object = $self->{model}->objects->[$obj_idx];
    my $model_instance = $model_object->instances->[0];
    
    # apply Z rotation before mirroring
    if ($model_instance->rotation != 0) {
        $model_object->rotate($model_instance->rotation, Z);
        $_->set_rotation(0) for @{ $model_object->instances };
    }
    
    $model_object->mirror($axis);
    $model_object->update_bounding_box;
    
    # realign object to Z = 0
    $model_object->center_around_origin;
    $self->make_thumbnail($obj_idx);
        
    # update print and start background processing
    $self->stop_background_process;
    $self->{print}->add_model_object($model_object, $obj_idx);
    
    $self->selection_changed;  # refresh info (size etc.)
    $self->update;
    $self->schedule_background_process;
}

sub changescale {
    my ($self, $axis, $tosize) = @_;
    
    my ($obj_idx, $object) = $self->selected_object;
    return if !defined $obj_idx;
    
    my $model_object = $self->{model}->objects->[$obj_idx];
    my $model_instance = $model_object->instances->[0];
    
    # we need thumbnail to be computed before allowing scaling
    return if !$object->thumbnail;
    
    my $object_size = $model_object->bounding_box->size;
    my $bed_size = Slic3r::Polygon->new_scale(@{$self->{config}->bed_shape})->bounding_box->size;
    
    if (defined $axis) {
        my $axis_name = $axis == X ? 'X' : $axis == Y ? 'Y' : 'Z';
        my $scale;
        if ($tosize) {
            my $cursize = $object_size->[$axis];
            my $newsize = Wx::GetNumberFromUser("", "Enter the new size for the selected object:", "Scale along $axis_name",
                $cursize, 0, $bed_size->[$axis], $self);
            return if !$newsize || $newsize < 0;
            $scale = $newsize / $cursize * 100;
        } else {
            $scale = Wx::GetNumberFromUser("", "Enter the scale % for the selected object:", "Scale along $axis_name",
                100, 0, 100000, $self);
        }
        return if !$scale || $scale < 0;
        
        # apply Z rotation before scaling
        if ($model_instance->rotation != 0) {
            $model_object->rotate($model_instance->rotation, Z);
            $_->set_rotation(0) for @{ $model_object->instances };
        }
        
        my $versor = [1,1,1];
        $versor->[$axis] = $scale/100;
        $model_object->scale_xyz(Slic3r::Pointf3->new(@$versor));
        # object was already aligned to Z = 0, so no need to realign it
        $self->make_thumbnail($obj_idx);
    } else {
        my $scale;
        if ($tosize) {
            my $cursize = max(@$object_size);
            my $newsize = Wx::GetNumberFromUser("", "Enter the new max size for the selected object:", "Scale",
                $cursize, 0, max(@$bed_size), $self);
            return if !$newsize || $newsize < 0;
            $scale = $newsize / $cursize * 100;
        } else {
            # max scale factor should be above 2540 to allow importing files exported in inches
            $scale = Wx::GetNumberFromUser("", "Enter the scale % for the selected object:", 'Scale',
                $model_instance->scaling_factor*100, 0, 100000, $self);
        }
        return if !$scale || $scale < 0;
    
        $self->{list}->SetItem($obj_idx, 2, "$scale%");
        $scale /= 100;  # turn percent into factor
        
        my $variation = $scale / $model_instance->scaling_factor;
        foreach my $range (@{ $model_object->layer_height_ranges }) {
            $range->[0] *= $variation;
            $range->[1] *= $variation;
        }
        $_->set_scaling_factor($scale) for @{ $model_object->instances };
        $object->transform_thumbnail($self->{model}, $obj_idx);
    }
    $model_object->update_bounding_box;
    
    # update print and start background processing
    $self->stop_background_process;
    $self->{print}->add_model_object($model_object, $obj_idx);
    
    $self->selection_changed(1);  # refresh info (size, volume etc.)
    $self->update;
    $self->schedule_background_process;
}

sub arrange {
    my $self = shift;
    
    $self->pause_background_process;
    
    my $bb = Slic3r::Geometry::BoundingBoxf->new_from_points($self->{config}->bed_shape);
    my $success = $self->{model}->arrange_objects($self->GetFrame->config->min_object_distance, $bb);
    # ignore arrange failures on purpose: user has visual feedback and we don't need to warn him
    # when parts don't fit in print bed
    
    $self->update(1);
}

sub split_object {
    my $self = shift;
    
    my ($obj_idx, $current_object)  = $self->selected_object;
    
    # we clone model object because split_object() adds the split volumes
    # into the same model object, thus causing duplicates when we call load_model_objects()
    my $new_model = $self->{model}->clone;  # store this before calling get_object()
    my $current_model_object = $new_model->get_object($obj_idx);
    
    if ($current_model_object->volumes_count > 1) {
        Slic3r::GUI::warning_catcher($self)->("The selected object can't be split because it contains more than one volume/material.");
        return;
    }
    
    $self->pause_background_process;
    
    my @model_objects = @{$current_model_object->split_object};
    if (@model_objects == 1) {
        $self->resume_background_process;
        Slic3r::GUI::warning_catcher($self)->("The selected object couldn't be split because it contains only one part.");
        $self->resume_background_process;
        return;
    }
    
    foreach my $object (@model_objects) {
        $object->instances->[$_]->offset->translate($_ * 10, $_ * 10)
            for 1..$#{ $object->instances };
        
        # we need to center this single object around origin
        $object->center_around_origin;
    }

    # remove the original object before spawning the object_loaded event, otherwise 
    # we'll pass the wrong $obj_idx to it (which won't be recognized after the
    # thumbnail thread returns)
    $self->remove($obj_idx);
    $current_object = $obj_idx = undef;
    
    # load all model objects at once, otherwise the plate would be rearranged after each one
    # causing original positions not to be kept
    $self->load_model_objects(@model_objects);
}

sub schedule_background_process {
    my ($self) = @_;
    
    if (defined $self->{apply_config_timer}) {
        $self->{apply_config_timer}->Start(PROCESS_DELAY, 1);  # 1 = one shot
    }
}

# Executed asynchronously by a timer every PROCESS_DELAY (0.5 second).
# The timer is started by schedule_background_process(), 
sub async_apply_config {
    my ($self) = @_;
    
    # reset preview canvases
    $self->{toolpaths2D}->reload_print if $self->{toolpaths2D};
    $self->{preview3D}->reload_print if $self->{preview3D};
    
    # pause process thread before applying new config
    # since we don't want to touch data that is being used by the threads
    $self->pause_background_process;
    
    # apply new config
    my $invalidated = $self->{print}->apply_config($self->GetFrame->config);
    
    return if !$Slic3r::GUI::Settings->{_}{background_processing};
    
    if ($invalidated) {
        # kill current thread if any
        $self->stop_background_process;
    } else {
        $self->resume_background_process;
    }
    
    # schedule a new process thread in case it wasn't running
    $self->start_background_process;
}

sub start_background_process {
    my ($self) = @_;
    
    return if !$Slic3r::have_threads;
    return if !@{$self->{objects}};
    return if $self->{process_thread};
    
    # It looks like declaring a local $SIG{__WARN__} prevents the ugly
    # "Attempt to free unreferenced scalar" warning...
    local $SIG{__WARN__} = Slic3r::GUI::warning_catcher($self);
    
    # don't start process thread if config is not valid
    eval {
        # this will throw errors if config is not valid
        $self->GetFrame->config->validate;
        $self->{print}->validate;
    };
    if ($@) {
        $self->statusbar->SetStatusText($@);
        return;
    }
    
    # apply extra variables
    {
        my $extra = $self->GetFrame->extra_variables;
        $self->{print}->placeholder_parser->set($_, $extra->{$_}) for keys %$extra;
    }
    
    # start thread
    @_ = ();
    $self->{process_thread} = Slic3r::spawn_thread(sub {
        eval {
            $self->{print}->process;
        };
        if ($@) {
            Slic3r::debugf "Background process error: $@\n";
            Wx::PostEvent($self, Wx::PlThreadEvent->new(-1, $PROCESS_COMPLETED_EVENT, $@));
        } else {
            Wx::PostEvent($self, Wx::PlThreadEvent->new(-1, $PROCESS_COMPLETED_EVENT, undef));
        }
        Slic3r::thread_cleanup();
    });
    Slic3r::debugf "Background processing started.\n";
}

sub stop_background_process {
    my ($self) = @_;
    
    $self->{apply_config_timer}->Stop if defined $self->{apply_config_timer};
    $self->statusbar->SetCancelCallback(undef);
    $self->statusbar->StopBusy;
    $self->statusbar->SetStatusText("");
    $self->{toolpaths2D}->reload_print if $self->{toolpaths2D};
    $self->{preview3D}->reload_print if $self->{preview3D};
    
    if ($self->{process_thread}) {
        Slic3r::debugf "Killing background process.\n";
        Slic3r::kill_all_threads();
        $self->{process_thread} = undef;
    } else {
        Slic3r::debugf "No background process running.\n";
    }
    
    # if there's an export process, kill that one as well
    if ($self->{export_thread}) {
        Slic3r::debugf "Killing background export process.\n";
        Slic3r::kill_all_threads();
        $self->{export_thread} = undef;
    }
}

sub pause_background_process {
    my ($self) = @_;
    
    if ($self->{process_thread} || $self->{export_thread}) {
        Slic3r::pause_all_threads();
        return 1;
    } elsif (defined $self->{apply_config_timer} && $self->{apply_config_timer}->IsRunning) {
        $self->{apply_config_timer}->Stop;
        return 1;
    }
    
    return 0;
}

sub resume_background_process {
    my ($self) = @_;
    
    if ($self->{process_thread} || $self->{export_thread}) {
        Slic3r::resume_all_threads();
    }
}

sub reslice {
    # explicitly cancel a previous thread and start a new one.
    my ($self) = @_;
    # Don't reslice if export of G-code or sending to OctoPrint is running.
    if ($Slic3r::have_threads && ! defined($self->{export_gcode_output_file}) && ! defined($self->{send_gcode_file})) {
        $self->stop_background_process;
        $self->statusbar->SetCancelCallback(sub {
            $self->stop_background_process;
            $self->statusbar->SetStatusText("Slicing cancelled");
            # this updates buttons status
            $self->object_list_changed;
        });
        $self->start_background_process;
    }
}

sub export_gcode {
    my ($self, $output_file) = @_;
    
    return if !@{$self->{objects}};
    
    if ($self->{export_gcode_output_file}) {
        Wx::MessageDialog->new($self, "Another export job is currently running.", 'Error', wxOK | wxICON_ERROR)->ShowModal;
        return;
    }
    
    # if process is not running, validate config
    # (we assume that if it is running, config is valid)
    eval {
        # this will throw errors if config is not valid
        $self->GetFrame->config->validate;
        $self->{print}->validate;
    };
    Slic3r::GUI::catch_error($self) and return;
    
    
    # apply config and validate print
    my $config = $self->GetFrame->config;
    eval {
        # this will throw errors if config is not valid
        $config->validate;
        $self->{print}->apply_config($config);
        $self->{print}->validate;
    };
    if (!$Slic3r::have_threads) {
        Slic3r::GUI::catch_error($self) and return;
    }
    
    # select output file
    if ($output_file) {
        $self->{export_gcode_output_file} = $self->{print}->expanded_output_filepath($output_file);
    } else {
        my $default_output_file = $self->{print}->expanded_output_filepath($main::opt{output});
        my $dlg = Wx::FileDialog->new($self, 'Save G-code file as:', wxTheApp->output_path(dirname($default_output_file)),
            basename($default_output_file), &Slic3r::GUI::FILE_WILDCARDS->{gcode}, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
        if ($dlg->ShowModal != wxID_OK) {
            $dlg->Destroy;
            return;
        }
        my $path = Slic3r::decode_path($dlg->GetPath);
        $Slic3r::GUI::Settings->{_}{last_output_path} = dirname($path);
        wxTheApp->save_settings;
        $self->{export_gcode_output_file} = $path;
        $dlg->Destroy;
    }
    
    $self->statusbar->StartBusy;
    
    if ($Slic3r::have_threads) {
        $self->statusbar->SetCancelCallback(sub {
            $self->stop_background_process;
            $self->statusbar->SetStatusText("Export cancelled");
            $self->{export_gcode_output_file} = undef;
            $self->{send_gcode_file} = undef;
            
            # this updates buttons status
            $self->object_list_changed;
        });
        
        # start background process, whose completion event handler
        # will detect $self->{export_gcode_output_file} and proceed with export
        $self->start_background_process;
    } else {
        eval {
            $self->{print}->process;
            $self->{print}->export_gcode(output_file => $self->{export_gcode_output_file});
        };
        my $result = !Slic3r::GUI::catch_error($self);
        $self->on_export_completed($result);
    }
    
    # this updates buttons status
    $self->object_list_changed;
    
    return $self->{export_gcode_output_file};
}

# This gets called only if we have threads.
sub on_process_completed {
    my ($self, $error) = @_;
    
    $self->statusbar->SetCancelCallback(undef);
    $self->statusbar->StopBusy;
    $self->statusbar->SetStatusText($error // "");
    
    Slic3r::debugf "Background processing completed.\n";
    $self->{process_thread}->detach if $self->{process_thread};
    $self->{process_thread} = undef;
    
    # if we're supposed to perform an explicit export let's display the error in a dialog
    if ($error && $self->{export_gcode_output_file}) {
        $self->{export_gcode_output_file} = undef;
        Slic3r::GUI::show_error($self, $error);
    }
    
    return if $error;
    $self->{toolpaths2D}->reload_print if $self->{toolpaths2D};
    $self->{preview3D}->reload_print if $self->{preview3D};
    
    # if we have an export filename, start a new thread for exporting G-code
    if ($self->{export_gcode_output_file}) {
        @_ = ();
        
        # workaround for "Attempt to free un referenced scalar..."
        our $_thread_self = $self;
        
        $self->{export_thread} = Slic3r::spawn_thread(sub {
            eval {
                $_thread_self->{print}->export_gcode(output_file => $_thread_self->{export_gcode_output_file});
            };
            if ($@) {
                Wx::PostEvent($_thread_self, Wx::PlThreadEvent->new(-1, $ERROR_EVENT, shared_clone([ $@ ])));
                Wx::PostEvent($_thread_self, Wx::PlThreadEvent->new(-1, $EXPORT_COMPLETED_EVENT, 0));
            } else {
                Wx::PostEvent($_thread_self, Wx::PlThreadEvent->new(-1, $EXPORT_COMPLETED_EVENT, 1));
            }
            Slic3r::thread_cleanup();
        });
        Slic3r::debugf "Background G-code export started.\n";
    }
}

# This gets called also if we have no threads.
sub on_progress_event {
    my ($self, $percent, $message) = @_;
    
    $self->statusbar->SetProgress($percent);
    $self->statusbar->SetStatusText("$message…");
}

# Called when the G-code export finishes, either successfully or with an error.
# This gets called also if we don't have threads.
sub on_export_completed {
    my ($self, $result) = @_;
    
    $self->statusbar->SetCancelCallback(undef);
    $self->statusbar->StopBusy;
    $self->statusbar->SetStatusText("");
    
    Slic3r::debugf "Background export process completed.\n";
    $self->{export_thread}->detach if $self->{export_thread};
    $self->{export_thread} = undef;
    
    my $message;
    my $send_gcode = 0;
    my $do_print = 0;
    if ($result) {
        # G-code file exported successfully.
        if ($self->{print_file}) {
            $message = "File added to print queue";
            $do_print = 1;
        } elsif ($self->{send_gcode_file}) {
            $message = "Sending G-code file to the OctoPrint server...";
            $send_gcode = 1;
        } else {
            $message = "G-code file exported to " . $self->{export_gcode_output_file};
        }
    } else {
        $message = "Export failed";
    }
    $self->{export_gcode_output_file} = undef;
    $self->statusbar->SetStatusText($message);
    wxTheApp->notify($message);
    
    $self->do_print if $do_print;
    # Send $self->{send_gcode_file} to OctoPrint.
    $self->send_gcode if $send_gcode;
    $self->{print_file} = undef;
    $self->{send_gcode_file} = undef;
    
    # this updates buttons status
    $self->object_list_changed;
}

sub do_print {
    my ($self) = @_;
    
    my $printer_tab = $self->GetFrame->{options_tabs}{printer};
    my $printer_name = $printer_tab->get_current_preset->name;
    
    my $controller = $self->GetFrame->{controller};
    my $printer_panel = $controller->add_printer($printer_name, $printer_tab->config);
    
    my $filament_stats = $self->{print}->filament_stats;
    my @filament_names = $self->GetFrame->filament_preset_names;
    $filament_stats = { map { $filament_names[$_] => $filament_stats->{$_} } keys %$filament_stats };
    $printer_panel->load_print_job($self->{print_file}, $filament_stats);
    
    $self->GetFrame->select_tab(1);
}

# Send $self->{send_gcode_file} to OctoPrint.
#FIXME Currently this call blocks the UI. Make it asynchronous.
sub send_gcode {
    my ($self) = @_;
    
    $self->statusbar->StartBusy;
    
    my $ua = LWP::UserAgent->new;
    $ua->timeout(180);
    
    my $path = Slic3r::encode_path($self->{send_gcode_file});
    my $res = $ua->post(
        "http://" . $self->{config}->octoprint_host . "/api/files/local",
        Content_Type => 'form-data',
        'X-Api-Key' => $self->{config}->octoprint_apikey,
        Content => [
            # OctoPrint doesn't like Windows paths so we use basename()
            # Also, since we need to read from filesystem we process it through encode_path()
            file => [ $path, basename($path) ],
        ],
    );
    
    $self->statusbar->StopBusy;
    
    if ($res->is_success) {
        $self->statusbar->SetStatusText("G-code file successfully uploaded to the OctoPrint server");
    } else {
        my $message = "Error while uploading to the OctoPrint server: " . $res->status_line;
        Slic3r::GUI::show_error($self, $message);
        $self->statusbar->SetStatusText($message);
    }
}

sub export_stl {
    my $self = shift;
    
    return if !@{$self->{objects}};
        
    my $output_file = $self->_get_export_file('STL') or return;
    Slic3r::Format::STL->write_file($output_file, $self->{model}, binary => 1);
    $self->statusbar->SetStatusText("STL file exported to $output_file");
}

sub export_object_stl {
    my $self = shift;
    
    my ($obj_idx, $object) = $self->selected_object;
    return if !defined $obj_idx;
    
    my $model_object = $self->{model}->objects->[$obj_idx];
        
    my $output_file = $self->_get_export_file('STL') or return;
    Slic3r::Format::STL->write_file($output_file, $model_object->mesh, binary => 1);
    $self->statusbar->SetStatusText("STL file exported to $output_file");
}

sub export_amf {
    my $self = shift;
    
    return if !@{$self->{objects}};
        
    my $output_file = $self->_get_export_file('AMF') or return;
    Slic3r::Format::AMF->write_file($output_file, $self->{model});
    $self->statusbar->SetStatusText("AMF file exported to $output_file");
}

sub _get_export_file {
    my $self = shift;
    my ($format) = @_;
    
    my $suffix = $format eq 'STL' ? '.stl' : '.amf.xml';
    
    my $output_file = $main::opt{output};
    {
        $output_file = $self->{print}->expanded_output_filepath($output_file);
        $output_file =~ s/\.gcode$/$suffix/i;
        my $dlg = Wx::FileDialog->new($self, "Save $format file as:", dirname($output_file),
            basename($output_file), &Slic3r::GUI::MODEL_WILDCARD, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
        if ($dlg->ShowModal != wxID_OK) {
            $dlg->Destroy;
            return undef;
        }
        $output_file = Slic3r::decode_path($dlg->GetPath);
        $dlg->Destroy;
    }
    return $output_file;
}

sub make_thumbnail {
    my $self = shift;
    my ($obj_idx) = @_;
    
    my $plater_object = $self->{objects}[$obj_idx];
    $plater_object->thumbnail(Slic3r::ExPolygon::Collection->new);
    my $cb = sub {
        $plater_object->make_thumbnail($self->{model}, $obj_idx);
        
        if ($Slic3r::have_threads) {
            Wx::PostEvent($self, Wx::PlThreadEvent->new(-1, $THUMBNAIL_DONE_EVENT, shared_clone([ $obj_idx ])));
            Slic3r::thread_cleanup();
            threads->exit;
        } else {
            $self->on_thumbnail_made($obj_idx);
        }
    };
    
    @_ = ();
    $Slic3r::have_threads
        ? threads->create(sub { $cb->(); Slic3r::thread_cleanup(); })->detach
        : $cb->();
}

sub on_thumbnail_made {
    my $self = shift;
    my ($obj_idx) = @_;
    
    $self->{objects}[$obj_idx]->transform_thumbnail($self->{model}, $obj_idx);
    $self->refresh_canvases;
}

# this method gets called whenever print center is changed or the objects' bounding box changes
# (i.e. when an object is added/removed/moved/rotated/scaled)
sub update {
    my ($self, $force_autocenter) = @_;
    
    if ($Slic3r::GUI::Settings->{_}{autocenter} || $force_autocenter) {
        $self->{model}->center_instances_around_point($self->bed_centerf);
    }
    
    my $running = $self->pause_background_process;
    my $invalidated = $self->{print}->reload_model_instances();
    
    # The mere fact that no steps were invalidated when reloading model instances 
    # doesn't mean that all steps were done: for example, validation might have 
    # failed upon previous instance move, so we have no running thread and no steps
    # are invalidated on this move, thus we need to schedule a new run.
    if ($invalidated || !$running) {
        $self->schedule_background_process;
    } else {
        $self->resume_background_process;
    }
    
    $self->refresh_canvases;
}

# When a number of extruders changes, the UI needs to be updated to show a single filament selection combo box per extruder.
sub on_extruders_change {
    my ($self, $num_extruders) = @_;
    
    my $choices = $self->{preset_choosers}{filament};
    while (@$choices < $num_extruders) {
        # copy strings from first choice
        my @presets = $choices->[0]->GetStrings;
        
        # initialize new choice
        my $choice = Wx::BitmapComboBox->new($self, -1, "", wxDefaultPosition, wxDefaultSize, [@presets], wxCB_READONLY);
        push @$choices, $choice;
        
        # copy icons from first choice
        $choice->SetItemBitmap($_, $choices->[0]->GetItemBitmap($_)) for 0..$#presets;
        
        # insert new choice into sizer
        $self->{presets_sizer}->Insert(4 + ($#$choices-1)*2, 0, 0);
        $self->{presets_sizer}->Insert(5 + ($#$choices-1)*2, $choice, 0, wxEXPAND | wxBOTTOM, FILAMENT_CHOOSERS_SPACING);
        
        # setup the listener
        EVT_COMBOBOX($choice, $choice, sub {
            my ($choice) = @_;
            wxTheApp->CallAfter(sub {
                $self->_on_select_preset('filament', $choice);
            });
        });
        
        # initialize selection
        my $i = first { $choice->GetString($_) eq ($Slic3r::GUI::Settings->{presets}{"filament_" . $#$choices} || '') } 0 .. $#presets;
        $choice->SetSelection($i || 0);
    }
    
    # remove unused choices if any
    while (@$choices > $num_extruders) {
        $self->{presets_sizer}->Remove(4 + ($#$choices-1)*2);  # label
        $self->{presets_sizer}->Remove(4 + ($#$choices-1)*2);  # wxChoice
        $choices->[-1]->Destroy;
        pop @$choices;
    }
    $self->Layout;
}

sub on_config_change {
    my $self = shift;
    my ($config) = @_;
    
    foreach my $opt_key (@{$self->{config}->diff($config)}) {
        $self->{config}->set($opt_key, $config->get($opt_key));
        if ($opt_key eq 'bed_shape') {
            $self->{canvas}->update_bed_size;
            $self->{canvas3D}->update_bed_size if $self->{canvas3D};
            $self->{preview3D}->set_bed_shape($self->{config}->bed_shape)
                if $self->{preview3D};
            $self->update;
        } elsif ($opt_key eq 'serial_port') {
            if ($config->get('serial_port')) {
                $self->{btn_print}->Show;
            } else {
                $self->{btn_print}->Hide;
            }
            $self->Layout;
        } elsif ($opt_key eq 'octoprint_host') {
            if ($config->get('octoprint_host')) {
                $self->{btn_send_gcode}->Show;
            } else {
                $self->{btn_send_gcode}->Hide;
            }
            $self->Layout;
        }
    }
    
    return if !$self->GetFrame->is_loaded;
    
    # (re)start timer
    $self->schedule_background_process;
}

sub list_item_deselected {
    my ($self, $event) = @_;
    return if $PreventListEvents;
    
    if ($self->{list}->GetFirstSelected == -1) {
        $self->select_object(undef);
        $self->refresh_canvases;
    }
}

sub list_item_selected {
    my ($self, $event) = @_;
    return if $PreventListEvents;
    
    my $obj_idx = $event->GetIndex;
    $self->select_object($obj_idx);
    $self->refresh_canvases;
}

sub list_item_activated {
    my ($self, $event, $obj_idx) = @_;
    
    $obj_idx //= $event->GetIndex;
	$self->object_settings_dialog($obj_idx);
}

sub object_cut_dialog {
    my $self = shift;
    my ($obj_idx) = @_;
    
    if (!defined $obj_idx) {
        ($obj_idx, undef) = $self->selected_object;
    }
    
    if (!$Slic3r::GUI::have_OpenGL) {
        Slic3r::GUI::show_error($self, "Please install the OpenGL modules to use this feature (see build instructions).");
        return;
    }
    
    my $dlg = Slic3r::GUI::Plater::ObjectCutDialog->new($self,
		object              => $self->{objects}[$obj_idx],
		model_object        => $self->{model}->objects->[$obj_idx],
	);
	return unless $dlg->ShowModal == wxID_OK;
	
	if (my @new_objects = $dlg->NewModelObjects) {
	    $self->remove($obj_idx);
	    $self->load_model_objects(grep defined($_), @new_objects);
	    $self->arrange;
	}
}

sub object_settings_dialog {
    my $self = shift;
    my ($obj_idx) = @_;
    
    if (!defined $obj_idx) {
        ($obj_idx, undef) = $self->selected_object;
    }
    my $model_object = $self->{model}->objects->[$obj_idx];
    
    # validate config before opening the settings dialog because
    # that dialog can't be closed if validation fails, but user
    # can't fix any error which is outside that dialog
    return unless $self->validate_config;
    
    my $dlg = Slic3r::GUI::Plater::ObjectSettingsDialog->new($self,
		object          => $self->{objects}[$obj_idx],
		model_object    => $model_object,
	);
	$self->pause_background_process;
	$dlg->ShowModal;
	
    # update thumbnail since parts may have changed
    if ($dlg->PartsChanged) {
	    # recenter and re-align to Z = 0
	    $model_object->center_around_origin;
        $self->make_thumbnail($obj_idx);
    }
	
	# update print
	if ($dlg->PartsChanged || $dlg->PartSettingsChanged) {
	    $self->stop_background_process;
        $self->{print}->reload_object($obj_idx);
        $self->schedule_background_process;
    } else {
        $self->resume_background_process;
    }
}

# Called to update various buttons depending on whether there are any objects or
# whether background processing (export of a G-code, sending to Octoprint, forced background re-slicing) is active.
sub object_list_changed {
    my $self = shift;
    
    # Enable/disable buttons depending on whether there are any objects on the platter.
    my $have_objects = @{$self->{objects}} ? 1 : 0;
    my $method = $have_objects ? 'Enable' : 'Disable';
    $self->{"btn_$_"}->$method
        for grep $self->{"btn_$_"}, qw(reset arrange reslice export_gcode export_stl print send_gcode);
    
    if ($self->{export_gcode_output_file} || $self->{send_gcode_file}) {
        $self->{btn_reslice}->Disable;
        $self->{btn_export_gcode}->Disable;
        $self->{btn_print}->Disable;
        $self->{btn_send_gcode}->Disable;
    }
    
    if ($self->{htoolbar}) {
        $self->{htoolbar}->EnableTool($_, $have_objects)
            for (TB_RESET, TB_ARRANGE);
    }
}

sub selection_changed {
    my $self = shift;
    
    my ($obj_idx, $object) = $self->selected_object;
    my $have_sel = defined $obj_idx;
    
    my $method = $have_sel ? 'Enable' : 'Disable';
    $self->{"btn_$_"}->$method
        for grep $self->{"btn_$_"}, qw(remove increase decrease rotate45cw rotate45ccw changescale split cut settings);
    
    if ($self->{htoolbar}) {
        $self->{htoolbar}->EnableTool($_, $have_sel)
            for (TB_REMOVE, TB_MORE, TB_FEWER, TB_45CW, TB_45CCW, TB_SCALE, TB_SPLIT, TB_CUT, TB_SETTINGS);
    }
    
    if ($self->{object_info_size}) { # have we already loaded the info pane?
        if ($have_sel) {
            my $model_object = $self->{model}->objects->[$obj_idx];
            my $model_instance = $model_object->instances->[0];
            $self->{object_info_size}->SetLabel(sprintf("%.2f x %.2f x %.2f", @{$model_object->instance_bounding_box(0)->size}));
            $self->{object_info_materials}->SetLabel($model_object->materials_count);
            
            if (my $stats = $model_object->mesh_stats) {
                $self->{object_info_volume}->SetLabel(sprintf('%.2f', $stats->{volume} * ($model_instance->scaling_factor**3)));
                $self->{object_info_facets}->SetLabel(sprintf('%d (%d shells)', $model_object->facets_count, $stats->{number_of_parts}));
                if (my $errors = sum(@$stats{qw(degenerate_facets edges_fixed facets_removed facets_added facets_reversed backwards_edges)})) {
                    $self->{object_info_manifold}->SetLabel(sprintf("Auto-repaired (%d errors)", $errors));
                    $self->{object_info_manifold_warning_icon}->Show;
                    
                    # we don't show normals_fixed because we never provide normals
	                # to admesh, so it generates normals for all facets
                    my $message = sprintf '%d degenerate facets, %d edges fixed, %d facets removed, %d facets added, %d facets reversed, %d backwards edges',
                        @$stats{qw(degenerate_facets edges_fixed facets_removed facets_added facets_reversed backwards_edges)};
                    $self->{object_info_manifold}->SetToolTipString($message);
                    $self->{object_info_manifold_warning_icon}->SetToolTipString($message);
                } else {
                    $self->{object_info_manifold}->SetLabel("Yes");
                }
            } else {
                $self->{object_info_facets}->SetLabel($object->facets);
            }
        } else {
            $self->{"object_info_$_"}->SetLabel("") for qw(size volume facets materials manifold);
            $self->{object_info_manifold_warning_icon}->Hide;
            $self->{object_info_manifold}->SetToolTipString("");
        }
        $self->Layout;
    }
    
    # prepagate the event to the frame (a custom Wx event would be cleaner)
    $self->GetFrame->on_plater_selection_changed($have_sel);
}

sub select_object {
    my ($self, $obj_idx) = @_;
    
    $_->selected(0) for @{ $self->{objects} };
    if (defined $obj_idx) {
        $self->{objects}->[$obj_idx]->selected(1);
        
        # We use this flag to avoid circular event handling
        # Select() happens to fire a wxEVT_LIST_ITEM_SELECTED on Windows, 
        # whose event handler calls this method again and again and again
        $PreventListEvents = 1;
        $self->{list}->Select($obj_idx, 1);
        $PreventListEvents = 0;
    } else {
        # TODO: deselect all in list
    }
    $self->selection_changed(1);
}

sub selected_object {
    my $self = shift;
    
    my $obj_idx = first { $self->{objects}[$_]->selected } 0..$#{ $self->{objects} };
    return undef if !defined $obj_idx;
    return ($obj_idx, $self->{objects}[$obj_idx]),
}

sub refresh_canvases {
    my ($self) = @_;
    
    $self->{canvas}->Refresh;
    $self->{canvas3D}->update if $self->{canvas3D};
    $self->{preview3D}->reload_print if $self->{preview3D};
}

sub validate_config {
    my $self = shift;
    
    eval {
        $self->GetFrame->config->validate;
    };
    return 0 if Slic3r::GUI::catch_error($self);    
    return 1;
}

sub statusbar {
    my $self = shift;
    return $self->GetFrame->{statusbar};
}

sub object_menu {
    my ($self) = @_;
    
    my $frame = $self->GetFrame;
    my $menu = Wx::Menu->new;
    $frame->_append_menu_item($menu, "Delete\tCtrl+Del", 'Remove the selected object', sub {
        $self->remove;
    }, undef, 'brick_delete.png');
    $frame->_append_menu_item($menu, "Increase copies\tCtrl++", 'Place one more copy of the selected object', sub {
        $self->increase;
    }, undef, 'add.png');
    $frame->_append_menu_item($menu, "Decrease copies\tCtrl+-", 'Remove one copy of the selected object', sub {
        $self->decrease;
    }, undef, 'delete.png');
    $frame->_append_menu_item($menu, "Set number of copies…", 'Change the number of copies of the selected object', sub {
        $self->set_number_of_copies;
    }, undef, 'textfield.png');
    $menu->AppendSeparator();
    $frame->_append_menu_item($menu, "Rotate 45° clockwise", 'Rotate the selected object by 45° clockwise', sub {
        $self->rotate(-45);
    }, undef, 'arrow_rotate_clockwise.png');
    $frame->_append_menu_item($menu, "Rotate 45° counter-clockwise", 'Rotate the selected object by 45° counter-clockwise', sub {
        $self->rotate(+45);
    }, undef, 'arrow_rotate_anticlockwise.png');
    
    my $rotateMenu = Wx::Menu->new;
    my $rotateMenuItem = $menu->AppendSubMenu($rotateMenu, "Rotate", 'Rotate the selected object by an arbitrary angle');
    $frame->_set_menu_item_icon($rotateMenuItem, 'textfield.png');
    $frame->_append_menu_item($rotateMenu, "Around X axis…", 'Rotate the selected object by an arbitrary angle around X axis', sub {
        $self->rotate(undef, X);
    }, undef, 'bullet_red.png');
    $frame->_append_menu_item($rotateMenu, "Around Y axis…", 'Rotate the selected object by an arbitrary angle around Y axis', sub {
        $self->rotate(undef, Y);
    }, undef, 'bullet_green.png');
    $frame->_append_menu_item($rotateMenu, "Around Z axis…", 'Rotate the selected object by an arbitrary angle around Z axis', sub {
        $self->rotate(undef, Z);
    }, undef, 'bullet_blue.png');
    
    my $mirrorMenu = Wx::Menu->new;
    my $mirrorMenuItem = $menu->AppendSubMenu($mirrorMenu, "Mirror", 'Mirror the selected object');
    $frame->_set_menu_item_icon($mirrorMenuItem, 'shape_flip_horizontal.png');
    $frame->_append_menu_item($mirrorMenu, "Along X axis…", 'Mirror the selected object along the X axis', sub {
        $self->mirror(X);
    }, undef, 'bullet_red.png');
    $frame->_append_menu_item($mirrorMenu, "Along Y axis…", 'Mirror the selected object along the Y axis', sub {
        $self->mirror(Y);
    }, undef, 'bullet_green.png');
    $frame->_append_menu_item($mirrorMenu, "Along Z axis…", 'Mirror the selected object along the Z axis', sub {
        $self->mirror(Z);
    }, undef, 'bullet_blue.png');
    
    my $scaleMenu = Wx::Menu->new;
    my $scaleMenuItem = $menu->AppendSubMenu($scaleMenu, "Scale", 'Scale the selected object along a single axis');
    $frame->_set_menu_item_icon($scaleMenuItem, 'arrow_out.png');
    $frame->_append_menu_item($scaleMenu, "Uniformly…", 'Scale the selected object along the XYZ axes', sub {
        $self->changescale(undef);
    });
    $frame->_append_menu_item($scaleMenu, "Along X axis…", 'Scale the selected object along the X axis', sub {
        $self->changescale(X);
    }, undef, 'bullet_red.png');
    $frame->_append_menu_item($scaleMenu, "Along Y axis…", 'Scale the selected object along the Y axis', sub {
        $self->changescale(Y);
    }, undef, 'bullet_green.png');
    $frame->_append_menu_item($scaleMenu, "Along Z axis…", 'Scale the selected object along the Z axis', sub {
        $self->changescale(Z);
    }, undef, 'bullet_blue.png');
    
    my $scaleToSizeMenu = Wx::Menu->new;
    my $scaleToSizeMenuItem = $menu->AppendSubMenu($scaleToSizeMenu, "Scale to size", 'Scale the selected object along a single axis');
    $frame->_set_menu_item_icon($scaleToSizeMenuItem, 'arrow_out.png');
    $frame->_append_menu_item($scaleToSizeMenu, "Uniformly…", 'Scale the selected object along the XYZ axes', sub {
        $self->changescale(undef, 1);
    });
    $frame->_append_menu_item($scaleToSizeMenu, "Along X axis…", 'Scale the selected object along the X axis', sub {
        $self->changescale(X, 1);
    }, undef, 'bullet_red.png');
    $frame->_append_menu_item($scaleToSizeMenu, "Along Y axis…", 'Scale the selected object along the Y axis', sub {
        $self->changescale(Y, 1);
    }, undef, 'bullet_green.png');
    $frame->_append_menu_item($scaleToSizeMenu, "Along Z axis…", 'Scale the selected object along the Z axis', sub {
        $self->changescale(Z, 1);
    }, undef, 'bullet_blue.png');
    
    $frame->_append_menu_item($menu, "Split", 'Split the selected object into individual parts', sub {
        $self->split_object;
    }, undef, 'shape_ungroup.png');
    $frame->_append_menu_item($menu, "Cut…", 'Open the 3D cutting tool', sub {
        $self->object_cut_dialog;
    }, undef, 'package.png');
    $menu->AppendSeparator();
    $frame->_append_menu_item($menu, "Settings…", 'Open the object editor dialog', sub {
        $self->object_settings_dialog;
    }, undef, 'cog.png');
    $menu->AppendSeparator();
    $frame->_append_menu_item($menu, "Export object as STL…", 'Export this single object as STL file', sub {
        $self->export_object_stl;
    }, undef, 'brick_go.png');
    
    return $menu;
}

# Set a camera direction, zoom to all objects.
sub select_view {
    my ($self, $direction) = @_;
    my $idx_page = $self->{preview_notebook}->GetSelection;
    my $page = ($idx_page == &Wx::wxNOT_FOUND) ? '3D' : $self->{preview_notebook}->GetPageText($idx_page);
    if ($page eq 'Preview') {
        $self->{preview3D}->canvas->select_view($direction);
        $self->{canvas3D}->set_viewport_from_scene($self->{preview3D}->canvas);
    } else {
        $self->{canvas3D}->select_view($direction);
        $self->{preview3D}->canvas->set_viewport_from_scene($self->{canvas3D});
    }
}

package Slic3r::GUI::Plater::DropTarget;
use Wx::DND;
use base 'Wx::FileDropTarget';

sub new {
    my $class = shift;
    my ($window) = @_;
    my $self = $class->SUPER::new;
    $self->{window} = $window;
    return $self;
}

sub OnDropFiles {
    my $self = shift;
    my ($x, $y, $filenames) = @_;
    
    # stop scalars leaking on older perl
    # https://rt.perl.org/rt3/Public/Bug/Display.html?id=70602
    @_ = ();
    
    # only accept STL, OBJ and AMF files
    return 0 if grep !/\.(?:stl|obj|amf(?:\.xml)?)$/i, @$filenames;
    
    $self->{window}->load_file($_) for @$filenames;
}

# 2D preview of an object. Each object is previewed by its convex hull.
package Slic3r::GUI::Plater::Object;
use Moo;

use List::Util qw(first);
use Slic3r::Geometry qw(X Y Z MIN MAX deg2rad);

has 'name'                  => (is => 'rw', required => 1);
has 'thumbnail'             => (is => 'rw'); # ExPolygon::Collection in scaled model units with no transforms
has 'transformed_thumbnail' => (is => 'rw');
has 'instance_thumbnails'   => (is => 'ro', default => sub { [] });  # array of ExPolygon::Collection objects, each one representing the actual placed thumbnail of each instance in pixel units
has 'selected'              => (is => 'rw', default => sub { 0 });

sub make_thumbnail {
    my ($self, $model, $obj_idx) = @_;
    
    # make method idempotent
    $self->thumbnail->clear;
    
    my $mesh = $model->objects->[$obj_idx]->raw_mesh;
    if ($mesh->facets_count <= 5000) {
        # remove polygons with area <= 1mm
        my $area_threshold = Slic3r::Geometry::scale 1;
        $self->thumbnail->append(
            grep $_->area >= $area_threshold,
            @{ $mesh->horizontal_projection },   # horizontal_projection returns scaled expolygons
        );
        $self->thumbnail->simplify(0.5);
    } else {
        my $convex_hull = Slic3r::ExPolygon->new($mesh->convex_hull);
        $self->thumbnail->append($convex_hull);
    }
    
    return $self->thumbnail;
}

sub transform_thumbnail {
    my ($self, $model, $obj_idx) = @_;
    
    return unless defined $self->thumbnail;
    
    my $model_object = $model->objects->[$obj_idx];
    my $model_instance = $model_object->instances->[0];
    
    # the order of these transformations MUST be the same everywhere, including
    # in Slic3r::Print->add_model_object()
    my $t = $self->thumbnail->clone;
    $t->rotate($model_instance->rotation, Slic3r::Point->new(0,0));
    $t->scale($model_instance->scaling_factor);
    
    $self->transformed_thumbnail($t);
}

1;