Fixes a performance issues on Windows, where the cut is being

refreshed many times for a single move of the Z plane.

Fixes a problem on Windows, where the new wxWidgets always returned
Cancel, even if the window was closed with the "Cut" button.

Improved performance if the live preview is disabled or not needed,
because both top and bottom parts shall be displayed.

1 files changed, 84 insertions, 23 deletions

diff --git a/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm b/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
index 8b9a2ed99..a523fb085 100644
--- a/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
+++ b/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
@@ -15,6 +15,11 @@ sub new {
     $self->{model_object_idx} = $params{model_object_idx};
     $self->{model_object} = $params{model_object};
     $self->{new_model_objects} = [];
+    # Mark whether the mesh cut is valid.
+    # If not, it needs to be recalculated by _update() on wxTheApp->CallAfter() or on exit of the dialog.
+    $self->{mesh_cut_valid} = 0;
+    # Note whether the window was already closed, so a pending update is not executed.
+    $self->{already_closed} = 0;
     
     # cut options
     $self->{cut_options} = {
@@ -31,11 +36,18 @@ sub new {
         title       => 'Cut',
         on_change   => sub {
             my ($opt_id) = @_;
-            
-            $self->{cut_options}{$opt_id} = $optgroup->get_value($opt_id);
-            wxTheApp->CallAfter(sub {
-                $self->_update;
-            });
+            # There seems to be an issue with wxWidgets 3.0.2/3.0.3, where the slider
+            # genates tens of events for a single value change.
+            # Only trigger the recalculation if the value changes
+            # or a live preview was activated and the mesh cut is not valid yet.
+            if ($self->{cut_options}{$opt_id} != $optgroup->get_value($opt_id) ||
+                ! $self->{mesh_cut_valid} && $self->_life_preview_active()) {
+                $self->{cut_options}{$opt_id} = $optgroup->get_value($opt_id);
+                $self->{mesh_cut_valid} = 0;
+                wxTheApp->CallAfter(sub {
+                    $self->_update;
+                });
+            }
         },
         label_width  => 120,
     );
@@ -113,6 +125,10 @@ sub new {
     $self->{sizer}->SetSizeHints($self);
     
     EVT_BUTTON($self, $self->{btn_cut}, sub {
+        # Recalculate the cut if the preview was not active.
+        $self->_perform_cut() unless $self->{mesh_cut_valid};
+
+        # Adjust position / orientation of the split object halves.
         if ($self->{new_model_objects}{lower}) {
             if ($self->{cut_options}{rotate_lower}) {
                 $self->{new_model_objects}{lower}->rotate(PI, X);
@@ -123,41 +139,86 @@ sub new {
             $self->{new_model_objects}{upper}->center_around_origin;  # align to Z = 0
         }
         
+        # Note that the window was already closed, so a pending update will not be executed.
+        $self->{already_closed} = 1;
         $self->EndModal(wxID_OK);
-        $self->Close;
+        $self->Destroy();
     });
-    
+
+    EVT_CLOSE($self, sub {
+        # Note that the window was already closed, so a pending update will not be executed.
+        $self->{already_closed} = 1;
+        $self->EndModal(wxID_CANCEL);
+        $self->Destroy();
+    });
+
     $self->_update;
     
     return $self;
 }
 
+# scale Z down to original size since we're using the transformed mesh for 3D preview
+# and cut dialog but ModelObject::cut() needs Z without any instance transformation
+sub _mesh_slice_z_pos
+{
+    my ($self) = @_;
+    return $self->{cut_options}{z} / $self->{model_object}->instances->[0]->scaling_factor;
+}
+
+# Only perform live preview if just a single part of the object shall survive.
+sub _life_preview_active
+{
+    my ($self) = @_;
+    return $self->{cut_options}{preview} && ($self->{cut_options}{keep_upper} != $self->{cut_options}{keep_lower});
+}
+
+# Slice the mesh, keep the top / bottom part.
+sub _perform_cut 
+{
+    my ($self) = @_;
+
+    # Early exit. If the cut is valid, don't recalculate it.
+    return if $self->{mesh_cut_valid};
+
+    my $z = $self->_mesh_slice_z_pos();
+
+    my ($new_model) = $self->{model_object}->cut($z);
+    my ($upper_object, $lower_object) = @{$new_model->objects};
+    $self->{new_model} = $new_model;
+    $self->{new_model_objects} = {};
+    if ($self->{cut_options}{keep_upper} && $upper_object->volumes_count > 0) {
+        $self->{new_model_objects}{upper} = $upper_object;
+    }
+    if ($self->{cut_options}{keep_lower} && $lower_object->volumes_count > 0) {
+        $self->{new_model_objects}{lower} = $lower_object;
+    }
+
+    $self->{mesh_cut_valid} = 1;
+}
+
 sub _update {
     my ($self) = @_;
-    
+
+    # Don't update if the window was already closed.
+    # We are not sure whether the action planned by wxTheApp->CallAfter() may be triggered after the window is closed.
+    # Probably not, but better be safe than sorry, which is espetially true on multiple platforms.
+    return if $self->{already_closed};
+
+    # Only recalculate the cut, if the live cut preview is active.
+    my $life_preview_active = $self->_life_preview_active();
+    $self->_perform_cut() if $life_preview_active;
+
     {
         # scale Z down to original size since we're using the transformed mesh for 3D preview
         # and cut dialog but ModelObject::cut() needs Z without any instance transformation
-        my $z = $self->{cut_options}{z} / $self->{model_object}->instances->[0]->scaling_factor;
-        
-        {
-            my ($new_model) = $self->{model_object}->cut($z);
-            my ($upper_object, $lower_object) = @{$new_model->objects};
-            $self->{new_model} = $new_model;
-            $self->{new_model_objects} = {};
-            if ($self->{cut_options}{keep_upper} && $upper_object->volumes_count > 0) {
-                $self->{new_model_objects}{upper} = $upper_object;
-            }
-            if ($self->{cut_options}{keep_lower} && $lower_object->volumes_count > 0) {
-                $self->{new_model_objects}{lower} = $lower_object;
-            }
-        }
+        my $z = $self->_mesh_slice_z_pos();
+
         
         # update canvas
         if ($self->{canvas}) {
             # get volumes to render
             my @objects = ();
-            if ($self->{cut_options}{preview}) {
+            if ($life_preview_active) {
                 push @objects, values %{$self->{new_model_objects}};
             } else {
                 push @objects, $self->{model_object};