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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/** \file
* \ingroup editorui
*
* API for simple creation of grid UIs, supporting typically needed features.
* https://wiki.blender.org/wiki/Source/Interface/Views/Grid_Views
*/
#pragma once
#include "BLI_function_ref.hh"
#include "BLI_map.hh"
#include "BLI_vector.hh"
#include "UI_resources.h"
struct bContext;
struct PreviewImage;
struct uiBlock;
struct uiButGridTile;
struct uiLayout;
struct View2D;
struct wmNotifier;
namespace blender::ui {
class AbstractGridView;
/* ---------------------------------------------------------------------- */
/** \name Grid-View Item Type
* \{ */
class AbstractGridViewItem {
friend class AbstractGridView;
friend class GridViewLayoutBuilder;
const AbstractGridView *view_;
bool is_active_ = false;
protected:
/** Reference to a string that uniquely identifies this item in the view. */
StringRef identifier_{};
/** Every visible item gets a button of type #UI_BTYPE_GRID_TILE during the layout building. */
uiButGridTile *grid_tile_but_ = nullptr;
public:
virtual ~AbstractGridViewItem() = default;
virtual void build_grid_tile(uiLayout &layout) const = 0;
/**
* Compare this item's identifier to \a other to check if they represent the same data.
* Used to recognize an item from a previous redraw, to be able to keep its state (e.g. active,
* renaming, etc.).
*/
bool matches(const AbstractGridViewItem &other) const;
const AbstractGridView &get_view() const;
/**
* Requires the tree to have completed reconstruction, see #is_reconstructed(). Otherwise we
* can't be sure about the item state.
*/
bool is_active() const;
protected:
AbstractGridViewItem(StringRef identifier);
/** Called when the item's state changes from inactive to active. */
virtual void on_activate();
/**
* If the result is not empty, it controls whether the item should be active or not,
* usually depending on the data that the view represents.
*/
virtual std::optional<bool> should_be_active() const;
/**
* Copy persistent state (e.g. active, selection, etc.) from a matching item of
* the last redraw to this item. If sub-classes introduce more advanced state they should
* override this and make it update their state accordingly.
*/
virtual void update_from_old(const AbstractGridViewItem &old);
/**
* Activates this item, deactivates other items, and calls the
* #AbstractGridViewItem::on_activate() function.
* Requires the tree to have completed reconstruction, see #is_reconstructed(). Otherwise the
* actual item state is unknown, possibly calling state-change update functions incorrectly.
*/
void activate();
void deactivate();
private:
/** See #AbstractTreeView::change_state_delayed() */
void change_state_delayed();
static void grid_tile_click_fn(bContext *, void *but_arg1, void *);
void add_grid_tile_button(uiBlock &block);
};
/** \} */
/* ---------------------------------------------------------------------- */
/** \name Grid-View Base Class
* \{ */
struct GridViewStyle {
GridViewStyle(int width, int height);
int tile_width = 0;
int tile_height = 0;
};
class AbstractGridView {
friend class AbstractGridViewItem;
friend class GridViewBuilder;
friend class GridViewLayoutBuilder;
protected:
Vector<std::unique_ptr<AbstractGridViewItem>> items_;
/** <identifier, item> map to lookup items by identifier, used for efficient lookups in
* #update_from_old(). */
Map<StringRef, AbstractGridViewItem *> item_map_;
GridViewStyle style_;
bool is_reconstructed_ = false;
public:
AbstractGridView();
virtual ~AbstractGridView() = default;
using ItemIterFn = FunctionRef<void(AbstractGridViewItem &)>;
void foreach_item(ItemIterFn iter_fn) const;
/** Listen to a notifier, returning true if a redraw is needed. */
virtual bool listen(const wmNotifier &) const;
/**
* Convenience wrapper constructing the item by forwarding given arguments to the constructor of
* the type (\a ItemT).
*
* E.g. if your grid-item type has the following constructor:
* \code{.cpp}
* MyGridItem(std::string str, int i);
* \endcode
* You can add an item like this:
* \code
* add_item<MyGridItem>("blabla", 42);
* \endcode
*/
template<class ItemT, typename... Args> inline ItemT &add_item(Args &&...args);
const GridViewStyle &get_style() const;
int get_item_count() const;
protected:
virtual void build_items() = 0;
/**
* Check if the view is fully (re-)constructed. That means, both #build_items() and
* #update_from_old() have finished.
*/
bool is_reconstructed() const;
private:
/**
* Match the grid-view against an earlier version of itself (if any) and copy the old UI state
* (e.g. active, selected, renaming, etc.) to the new one. See
* #AbstractGridViewItem.update_from_old().
*/
void update_from_old(uiBlock &new_block);
AbstractGridViewItem *find_matching_item(const AbstractGridViewItem &item_to_match,
const AbstractGridView &view_to_search_in) const;
/**
* Items may want to do additional work when state changes. But these state changes can only be
* reliably detected after the view has completed reconstruction (see #is_reconstructed()). So
* the actual state changes are done in a delayed manner through this function.
*/
void change_state_delayed();
/**
* Add an already constructed item, moving ownership to the grid-view.
* All items must be added through this, it handles important invariants!
*/
AbstractGridViewItem &add_item(std::unique_ptr<AbstractGridViewItem> item);
};
/** \} */
/* ---------------------------------------------------------------------- */
/** \name Grid-View Builder
*
* TODO unify this with `TreeViewBuilder` and call view-specific functions via type erased view?
* \{ */
class GridViewBuilder {
uiBlock &block_;
public:
GridViewBuilder(uiBlock &block);
/** Build \a grid_view into the previously provided block, clipped by \a view_bounds (view space,
* typically `View2D.cur`). */
void build_grid_view(AbstractGridView &grid_view, const View2D &v2d);
};
/** \} */
/* ---------------------------------------------------------------------- */
/** \name Predefined Grid-View Item Types
*
* Common, Basic Grid-View Item Types.
* \{ */
/**
* A grid item that shows preview image icons at a nicely readable size (multiple of the normal UI
* unit size).
*/
class PreviewGridItem : public AbstractGridViewItem {
public:
using IsActiveFn = std::function<bool()>;
using ActivateFn = std::function<void(PreviewGridItem &new_active)>;
protected:
/** See #set_on_activate_fn() */
ActivateFn activate_fn_;
/** See #set_is_active_fn() */
IsActiveFn is_active_fn_;
public:
std::string label{};
int preview_icon_id = ICON_NONE;
PreviewGridItem(StringRef identifier, StringRef label, int preview_icon_id);
void build_grid_tile(uiLayout &layout) const override;
/**
* Set a custom callback to execute when activating this view item. This way users don't have to
* sub-class #PreviewGridItem, just to implement custom activation behavior (a common thing to
* do).
*/
void set_on_activate_fn(ActivateFn fn);
/**
* Set a custom callback to check if this item should be active.
*/
void set_is_active_fn(IsActiveFn fn);
private:
std::optional<bool> should_be_active() const override;
void on_activate() override;
};
/** \} */
/* ---------------------------------------------------------------------- */
template<class ItemT, typename... Args> inline ItemT &AbstractGridView::add_item(Args &&...args)
{
static_assert(std::is_base_of<AbstractGridViewItem, ItemT>::value,
"Type must derive from and implement the AbstractGridViewItem interface");
return dynamic_cast<ItemT &>(add_item(std::make_unique<ItemT>(std::forward<Args>(args)...)));
}
} // namespace blender::ui
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