wxArtProvider class is used to customize the look of wxWidgets application.
When wxWidgets needs to display an icon or a bitmap (e.g. in the standard file dialog), it does not use a hard-coded resource but asks wxArtProvider for it instead. This way users can plug in their own wxArtProvider class and easily replace standard art with their own version.
All that is needed is to derive a class from wxArtProvider, override either its wxArtProvider::CreateBitmap() (not implemented in wx) and/or its wxArtProvider::CreateIconBundle() (not implemented in wx) methods and register the provider with wxArtProvider::Push() (not implemented in wx):
If you need bitmap images (of the same artwork) that should be displayed at different sizes you should probably consider overriding wxArtProvider::CreateIconBundle (not implemented in wx) and supplying icon bundles that contain different bitmap sizes.
Identifying art resources
Every bitmap and icon bundle are known to wxArtProvider under an unique ID that is used when requesting a resource from it. The ID is represented by the ?wxArtID type and can have one of these predefined values (you can see bitmaps represented by these constants in the page_samples_artprov):
Additionally, any string recognized by custom art providers registered using wxArtProvider::Push (not implemented in wx) may be used.
Note: When running under GTK+ 2, GTK+ stock item IDs (e.g. "gtk-cdrom") may be used as well: For a list of the GTK+ stock items please refer to the GTK+ documentation page. It is also possible to load icons from the current icon theme by specifying their name (without extension and directory components). Icon themes recognized by GTK+ follow the freedesktop.org Icon Themes specification. Note that themes are not guaranteed to contain all icons, so wxArtProvider may return ?wxNullBitmap or ?wxNullIcon. The default theme is typically installed in /usr/share/icons/hicolor.
Client ID serve as a hint to wxArtProvider that is supposed to help it to choose the best looking bitmap. For example it is often desirable to use slightly different icons in menus and toolbars even though they represent the same action (e.g. wxART_FILE_OPEN). Remember that this is really only a hint for wxArtProvider - it is common that getBitmap/2 returns identical bitmap for different client values!
wxWidgets docs: wxArtProvider
getBitmap(Id) -> wxBitmap:wxBitmap()
getBitmap(Id, Options :: [Option]) -> wxBitmap:wxBitmap()
Query registered providers for bitmap with given ID.
Return: The bitmap if one of registered providers recognizes the ID or wxNullBitmap otherwise.