gdk.paintable
Module for [Paintable] interface
Types 2
[gdk.paintable.Paintable] is a simple interface used by GTK to represent content that can be painted.
The content of a [gdk.paintable.Paintable] can be painted anywhere at any size without requiring any sort of layout. The interface is inspired by similar concepts elsewhere, such as
ClutterContent, HTML/CSS Paint Sources,A [gdk.paintable.Paintable] can be snapshot at any time and size using [gdk.paintable.Paintable.snapshot]. How the paintable interprets that size and if it scales or centers itself into the given rectangle is implementation defined, though if you are implementing a [gdk.paintable.Paintable] and don't know what to do, it is suggested that you scale your paintable ignoring any potential aspect ratio.
The contents that a [gdk.paintable.Paintable] produces may depend on the [gdk.snapshot.Snapshot] passed to it. For example, paintables may decide to use more detailed images on higher resolution screens or when OpenGL is available. A [gdk.paintable.Paintable] will however always produce the same output for the same snapshot.
A [gdk.paintable.Paintable] may change its contents, meaning that it will now produce a different output with the same snapshot. Once that happens, it will call [gdk.paintable.Paintable.invalidateContents] which will emit the signal@Gdk.Paintable::invalidate-contents signal. If a paintable is known to never change its contents, it will set the [gdk.types.PaintableFlags.Contents] flag. If a consumer cannot deal with changing contents, it may call [gdk.paintable.Paintable.getCurrentImage] which will return a static paintable and use that.
A paintable can report an intrinsic (or preferred) size or aspect ratio it wishes to be rendered at, though it doesn't have to. Consumers of the interface can use this information to layout thepaintable appropriately. Just like the contents, the size of a paintable can change. A paintable will indicate this by calling [gdk.paintable.Paintable.invalidateSize] which will emit the signal@Gdk.Paintable::invalidate-size signal. And just like for contents, if a paintable is known to never change its size, it will set the [gdk.types.PaintableFlags.Size] flag.
Besides API for applications, there are some functions that are only useful for implementing subclasses and should not be used by applications: [gdk.paintable.Paintable.invalidateContents], [gdk.paintable.Paintable.invalidateSize], [gdk.paintable.Paintable.newEmpty].
gdk.paintable.Paintable newEmpty(int intrinsicWidth, int intrinsicHeight)Returns a paintable that has the given intrinsic size and draws nothing.void computeConcreteSize(double specifiedWidth, double specifiedHeight, double defaultWidth, double defaultHeight, out double concreteWidth, out double concreteHeight)Compute a concrete size for the [gdk.paintable.Paintable].gdk.paintable.Paintable getCurrentImage()Gets an immutable paintable for the current contents displayed by paintable.gdk.types.PaintableFlags getFlags()Get flags for the paintable.double getIntrinsicAspectRatio()Gets the preferred aspect ratio the paintable would like to be displayed at.int getIntrinsicHeight()Gets the preferred height the paintable would like to be displayed at.int getIntrinsicWidth()Gets the preferred width the paintable would like to be displayed at.void invalidateContents()Called by implementations of [gdk.paintable.Paintable] to invalidate their contents.void invalidateSize()Called by implementations of [gdk.paintable.Paintable] to invalidate their size.void snapshot(gdk.snapshot.Snapshot snapshot, double width, double height)Snapshots the given paintable with the given width and height.gulong connectInvalidateContents(T)(T callback, Flag!"After" after = No.After)Connect to `InvalidateContents` signal.gulong connectInvalidateSize(T)(T callback, Flag!"After" after = No.After)Connect to `InvalidateSize` signal.