contents of paintable
gdk.paintable_mixin
Module for [Paintable] interface mixin
Templates 2
tmplPaintableT()
[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].
Functions
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].
Applies the sizing algorithm outlined in the
CSS Image specto the given paintable. See that link for more details.
It is not necessary to call this function when both specified_width and specified_height are known, but it is useful to call this function in GtkWidget:measure implementations to compute the other dimension when only one dimension is given.
Parameters
specifiedWidth | the width paintable could be drawn into or 0.0 if unknown |
specifiedHeight | the height paintable could be drawn into or 0.0 if unknown |
defaultWidth | the width paintable would be drawn into if no other constraints were given |
defaultHeight | the height paintable would be drawn into if no other constraints were given |
concreteWidth | will be set to the concrete width computed |
concreteHeight | will be set to the concrete height computed |
gdk.paintable.Paintable getCurrentImage()
Gets an immutable paintable for the current contents displayed by paintable.
This is useful when you want to retain the current state of an animation, for example to take a screenshot of a running animation.
If the paintable is already immutable, it will return itself.
Returns
An immutable paintable for the current
gdk.types.PaintableFlags getFlags()
Get flags for the paintable.
This is oftentimes useful for optimizations.
See [gdk.types.PaintableFlags] for the flags and what they mean.
Returns
The [gdk.types.PaintableFlags] for this paintable
double getIntrinsicAspectRatio()
Gets the preferred aspect ratio the paintable would like to be displayed at.
The aspect ratio is the width divided by the height, so a value of 0.5 means that the paintable prefers to be displayed twice as high as it is wide. Consumers of this interface can use this to preserve aspect ratio when displaying the paintable.
This is a purely informational value and does not in any way limit the values that may be passed to [gdk.paintable.Paintable.snapshot].
Usually when a paintable returns nonzero values from [gdk.paintable.Paintable.getIntrinsicWidth] and [gdk.paintable.Paintable.getIntrinsicHeight] the aspect ratio should conform to those values, though that is not required.
If the paintable does not have a preferred aspect ratio, it returns 0. Negative values are never returned.
Returns
the intrinsic aspect ratio of paintable or 0 if none.
int getIntrinsicHeight()
Gets the preferred height the paintable would like to be displayed at.
Consumers of this interface can use this to reserve enough space to draw the paintable.
This is a purely informational value and does not in any way limit the values that may be passed to [gdk.paintable.Paintable.snapshot].
If the paintable does not have a preferred height, it returns 0. Negative values are never returned.
Returns
the intrinsic height of paintable or 0 if none.
int getIntrinsicWidth()
Gets the preferred width the paintable would like to be displayed at.
Consumers of this interface can use this to reserve enough space to draw the paintable.
This is a purely informational value and does not in any way limit the values that may be passed to [gdk.paintable.Paintable.snapshot].
If the paintable does not have a preferred width, it returns 0. Negative values are never returned.
Returns
the intrinsic width of paintable or 0 if none.
void invalidateContents()
Called by implementations of [gdk.paintable.Paintable] to invalidate their contents.
Unless the contents are invalidated, implementations must guarantee that multiple calls of [gdk.paintable.Paintable.snapshot] produce the same output.
This function will emit the signalGdk.Paintable::invalidate-contents signal.
If a paintable reports the [gdk.types.PaintableFlags.Contents] flag, it must not call this function.
void invalidateSize()
Called by implementations of [gdk.paintable.Paintable] to invalidate their size.
As long as the size is not invalidated, paintable must return the same values for its intrinsic width, height and aspect ratio.
This function will emit the signalGdk.Paintable::invalidate-size signal.
If a paintable reports the [gdk.types.PaintableFlags.Size] flag, it must not call this function.
void snapshot(gdk.snapshot.Snapshot snapshot, double width, double height)
Snapshots the given paintable with the given width and height.
The paintable is drawn at the current (0,0) offset of the snapshot. If width and height are not larger than zero, this function will do nothing.
Parameters
snapshot | a [gdk.snapshot.Snapshot] to snapshot to |
width | width to snapshot in |
height | height to snapshot in |
gulong connectInvalidateContents(T)(T callback, Flag!"After" after = No.After) if (isCallable!T
&& is(ReturnType!T == void)
&& (Parameters!T.length < 1 || (ParameterStorageClassTuple!T[0] == ParameterStorageClass.none && is(Parameters!T[0] : gdk.paintable.Paintable)))
&& Parameters!T.length < 2)
Connect to InvalidateContents signal.
Emitted when the contents of the paintable change.
Examples for such an event would be videos changing to the next frame or the icon theme for an icon changing.
Parameters
callback | signal callback delegate or function to connect void callback(gdk.paintable.Paintable paintable) paintable the instance the signal is connected to (optional) |
after | Yes.After to execute callback after default handler, No.After to execute before (default) |
Returns
Signal ID
gulong connectInvalidateSize(T)(T callback, Flag!"After" after = No.After) if (isCallable!T
&& is(ReturnType!T == void)
&& (Parameters!T.length < 1 || (ParameterStorageClassTuple!T[0] == ParameterStorageClass.none && is(Parameters!T[0] : gdk.paintable.Paintable)))
&& Parameters!T.length < 2)
Connect to InvalidateSize signal.
Emitted when the intrinsic size of the paintable changes.
This means the values reported by at least one of [gdk.paintable.Paintable.getIntrinsicWidth], [gdk.paintable.Paintable.getIntrinsicHeight] or [gdk.paintable.Paintable.getIntrinsicAspectRatio] has changed.
Examples for such an event would be a paintable displaying the contents of a toplevel surface being resized.
Parameters
callback | signal callback delegate or function to connect void callback(gdk.paintable.Paintable paintable) paintable the instance the signal is connected to (optional) |
after | Yes.After to execute callback after default handler, No.After to execute before (default) |
Returns
Signal ID
tmplPaintableGidBuilderT()