Description

Gnome::Gtk4::Snapshot assists in creating Gnome::Gsk4::RenderNodes for widgets.

It functions in a similar way to a cairo context, and maintains a stack of render nodes and their associated transformations.

The node at the top of the stack is the one that gtk_snapshot_append_…()` functions operate on. Use the gtk_snapshot_push_…()` functions and [method $Snapshot.pop] to change the current node.

The typical way to obtain a Gnome::Gtk4::Snapshot object is as an argument to the [vfunc $Gtk.Widget.snapshot] vfunc. If you need to create your own Gnome::Gtk4::Snapshot, use .newsnapshot().

Class initialization

new

:native-object

Create an object using a native object from elsewhere. See also Gnome::N::TopLevelSupportClass.

multi method new ( N-Object :$native-object! )

new-snapshot

Creates a new Gnome::Gtk4::Snapshot.

method new-snapshot ( --> Gnome::Gtk4::Snapshot \)

Methods

append-border

Appends a stroked border rectangle inside the given $outline.

The four sides of the border can have different widths and colors.

method append-border ( N-Object $outline, Num() $border-width, N-Object $border-color )

• $outline; the outline of the border

• $border-width; the stroke width of the border on the top, right, bottom and left side respectively..

• $border-color; the color used on the top, right, bottom and left side.

append-cairo

Creates a new Gnome::Gsk4::CairoNode and appends it to the current render node of $snapshot, without changing the current node.

method append-cairo ( N-Object $bounds --> UInt )

• $bounds; the bounds for the new node

Return value; a Gnome::Cairo::N-Context suitable for drawing the contents of the newly created render node.

append-color

Creates a new render node drawing the $color into the given $bounds and appends it to the current render node of $snapshot.

You should try to avoid calling this function if $color is transparent.

method append-color ( N-Object $color, N-Object $bounds )

• $color; the color to draw

• $bounds; the bounds for the new node

append-conic-gradient

Appends a conic gradient node with the given stops to $snapshot.

method append-conic-gradient ( N-Object $bounds, N-Object $center, Num() $rotation, N-Object $stops, Int() $n-stops )

• $bounds; the rectangle to render the gradient into

• $center; the center point of the conic gradient

• $rotation; the clockwise rotation in degrees of the starting angle. 0 means the starting angle is the top..

• $stops; the color stops defining the gradient

• $n-stops; the number of elements in $stops.

append-fill

A convenience method to fill a path with a color.

See .push-fill() if you need to fill a path with more complex content than a color.

method append-fill ( N-Object $path, GskFillRule $fill-rule, N-Object $color )

• $path; The path describing the area to fill

• $fill-rule; The fill rule to use.

• $color; the color to fill the path with

append-inset-shadow

Appends an inset shadow into the box given by $outline.

method append-inset-shadow ( N-Object $outline, N-Object $color, Num() $dx, Num() $dy, Num() $spread, Num() $blur-radius )

• $outline; outline of the region surrounded by shadow

• $color; color of the shadow

• $dx; horizontal offset of shadow.

• $dy; vertical offset of shadow.

• $spread; how far the shadow spreads towards the inside.

• $blur-radius; how much blur to apply to the shadow.

append-layout

No documentation of method.

method append-layout ( N-Object() $layout, N-Object $color )

• $layout; .

• $color;

append-linear-gradient

Appends a linear gradient node with the given stops to $snapshot.

method append-linear-gradient ( N-Object $bounds, N-Object $start-point, N-Object $end-point, N-Object $stops, Int() $n-stops )

• $bounds; the rectangle to render the linear gradient into

• $start-point; the point at which the linear gradient will begin

• $end-point; the point at which the linear gradient will finish

• $stops; the color stops defining the gradient

• $n-stops; the number of elements in $stops.

append-node

Appends $node to the current render node of $snapshot, without changing the current node.

If $snapshot does not have a current node yet, $node will become the initial node.

method append-node ( N-Object() $node )

• $node; a Gnome::Gsk4::RenderNode.

append-outset-shadow

Appends an outset shadow node around the box given by $outline.

method append-outset-shadow ( N-Object $outline, N-Object $color, Num() $dx, Num() $dy, Num() $spread, Num() $blur-radius )

• $outline; outline of the region surrounded by shadow

• $color; color of the shadow

• $dx; horizontal offset of shadow.

• $dy; vertical offset of shadow.

• $spread; how far the shadow spreads towards the outside.

• $blur-radius; how much blur to apply to the shadow.

append-radial-gradient

Appends a radial gradient node with the given stops to $snapshot.

method append-radial-gradient ( N-Object $bounds, N-Object $center, Num() $hradius, Num() $vradius, Num() $start, Num() $end, N-Object $stops, Int() $n-stops )

• $bounds; the rectangle to render the readial gradient into

• $center; the center point for the radial gradient

• $hradius; the horizontal radius.

• $vradius; the vertical radius.

• $start; the start position (on the horizontal axis).

• $end; the end position (on the horizontal axis).

• $stops; the color stops defining the gradient

• $n-stops; the number of elements in $stops.

append-repeating-linear-gradient

Appends a repeating linear gradient node with the given stops to $snapshot.

method append-repeating-linear-gradient ( N-Object $bounds, N-Object $start-point, N-Object $end-point, N-Object $stops, Int() $n-stops )

• $bounds; the rectangle to render the linear gradient into

• $start-point; the point at which the linear gradient will begin

• $end-point; the point at which the linear gradient will finish

• $stops; the color stops defining the gradient

• $n-stops; the number of elements in $stops.

append-repeating-radial-gradient

Appends a repeating radial gradient node with the given stops to $snapshot.

method append-repeating-radial-gradient ( N-Object $bounds, N-Object $center, Num() $hradius, Num() $vradius, Num() $start, Num() $end, N-Object $stops, Int() $n-stops )

• $bounds; the rectangle to render the readial gradient into

• $center; the center point for the radial gradient

• $hradius; the horizontal radius.

• $vradius; the vertical radius.

• $start; the start position (on the horizontal axis).

• $end; the end position (on the horizontal axis).

• $stops; the color stops defining the gradient

• $n-stops; the number of elements in $stops.

append-scaled-texture

Creates a new render node drawing the $texture into the given $bounds and appends it to the current render node of $snapshot.

In contrast to .append-texture(), this function provides control about how the filter that is used when scaling.

method append-scaled-texture ( N-Object() $texture, GskScalingFilter $filter, N-Object $bounds )

• $texture; the texture to render.

• $filter; the filter to use.

• $bounds; the bounds for the new node

append-stroke

A convenience method to stroke a path with a color.

See .push-stroke() if you need to stroke a path with more complex content than a color.

method append-stroke ( N-Object $path, N-Object $stroke, N-Object $color )

• $path; The path describing the area to fill

• $stroke; The stroke attributes

• $color; the color to fill the path with

append-texture

Creates a new render node drawing the $texture into the given $bounds and appends it to the current render node of $snapshot.

If the texture needs to be scaled to fill $bounds, linear filtering is used. See .append-scaled-texture() if you need other filtering, such as nearest-neighbour.

method append-texture ( N-Object() $texture, N-Object $bounds )

• $texture; the texture to render.

• $bounds; the bounds for the new node

free-to-node

Returns the node that was constructed by $snapshot and frees $snapshot.

See also .to-node().

method free-to-node (--> N-Object )

Return value; a newly-created Gnome::Gsk4::RenderNode.

free-to-paintable

Returns a paintable for the node that was constructed by $snapshot and frees $snapshot.

method free-to-paintable ( N-Object $size --> N-Object )

• $size; The size of the resulting paintable or undefined to use the bounds of the snapshot

Return value; a newly-created Gnome::Gdk4::R-Paintable.

gl-shader-pop-texture

Removes the top element from the stack of render nodes and adds it to the nearest Gnome::Gsk4::GLShaderNode below it.

This must be called the same number of times as the number of textures is needed for the shader in .push-gl-shader().

method gl-shader-pop-texture ( )

perspective

Applies a perspective projection transform.

See .perspective() in class Gnome::Gsk4::N-Transform for a discussion on the details.

method perspective ( Num() $depth )

• $depth; distance of the z=0 plane.

pop

Removes the top element from the stack of render nodes, and appends it to the node underneath it.

method pop ( )

push-blend

Blends together two images with the given blend mode.

Until the first call to .pop(), the bottom image for the blend operation will be recorded. After that call, the top image to be blended will be recorded until the second call to .pop().

Calling this function requires two subsequent calls to .pop().

method push-blend ( GskBlendMode $blend-mode )

• $blend-mode; blend mode to use.

push-blur

Blurs an image.

The image is recorded until the next call to .pop().

method push-blur ( Num() $radius )

• $radius; the blur radius to use. Must be positive.

push-clip

Clips an image to a rectangle.

The image is recorded until the next call to .pop().

method push-clip ( N-Object $bounds )

• $bounds; the rectangle to clip to

push-color-matrix

Modifies the colors of an image by applying an affine transformation in RGB space.

In particular, the colors will be transformed by applying

pixel = transpose(color_matrix) * pixel + color_offset

for every pixel. The transformation operates on unpremultiplied colors, with color components ordered R, G, B, A.

The image is recorded until the next call to .pop().

method push-color-matrix ( N-Object $color-matrix, N-Object $color-offset )

• $color-matrix; the color matrix to use

• $color-offset; the color offset to use

push-cross-fade

Snapshots a cross-fade operation between two images with the given $progress.

Until the first call to .pop(), the start image will be snapshot. After that call, the end image will be recorded until the second call to .pop().

Calling this function requires two subsequent calls to .pop().

method push-cross-fade ( Num() $progress )

• $progress; progress between 0.0 and 1.0.

push-debug This function is not yet available

Inserts a debug node with a message.

Debug nodes don't affect the rendering at all, but can be helpful in identifying parts of a render node tree dump, for example in the GTK inspector.

method push-debug ( Str $message, … )

• $message; a printf-style format string.

• …; …. Note that each argument must be specified as a type followed by its value!

push-fill

Fills the area given by $path and $fill-rule with an image and discards everything outside of it.

The image is recorded until the next call to .pop().

If you want to fill the path with a color, .append-fill() may be more convenient.

method push-fill ( N-Object $path, GskFillRule $fill-rule )

• $path; The path describing the area to fill

• $fill-rule; The fill rule to use.

push-gl-shader

Push a Gnome::Gsk4::GLShaderNode.

The node uses the given Gnome::Gsk4::GLShader and uniform values Additionally this takes a list of $n-children other nodes which will be passed to the Gnome::Gsk4::GLShaderNode.

The $take-args argument is a block of data to use for uniform arguments, as per types and offsets defined by the $shader. Normally this is generated by .format-args() in class Gnome::Gsk4::GLShader or Gnome::Gsk4::N-ShaderArgsBuilder .

The snapshotter takes ownership of $take-args, so the caller should not free it after this.

If the renderer doesn't support GL shaders, or if there is any problem when compiling the shader, then the node will draw pink. You should use .compile() in class Gnome::Gsk4::GLShader to ensure the $shader will work for the renderer before using it.

If the shader requires textures (see .get-n-textures() in class Gnome::Gsk4::GLShader), then it is expected that you call .gl-shader-pop-texture() the number of times that are required. Each of these calls will generate a node that is added as a child to the Gnome::Gsk4::GLShaderNode, which in turn will render these offscreen and pass as a texture to the shader.

Once all textures (if any) are pop:ed, you must call the regular .pop().

If you want to use pre-existing textures as input to the shader rather than rendering new ones, use .append-texture() to push a texture node. These will be used directly rather than being re-rendered.

For details on how to write shaders, see Gnome::Gsk4::GLShader.

method push-gl-shader ( N-Object() $shader, N-Object $bounds, N-Object $take-args )

• $shader; The code to run.

• $bounds; the rectangle to render into

• $take-args; (transfer ownership: full) Data block with arguments for the shader.

push-mask

Until the first call to .pop(), the mask image for the mask operation will be recorded.

After that call, the source image will be recorded until the second call to .pop().

Calling this function requires 2 subsequent calls to .pop().

method push-mask ( GskMaskMode $mask-mode )

• $mask-mode; mask mode to use.

push-opacity

Modifies the opacity of an image.

The image is recorded until the next call to .pop().

method push-opacity ( Num() $opacity )

• $opacity; the opacity to use.

push-repeat

Creates a node that repeats the child node.

The child is recorded until the next call to .pop().

method push-repeat ( N-Object $bounds, N-Object $child-bounds )

• $bounds; the bounds within which to repeat

• $child-bounds; the bounds of the child or undefined to use the full size of the collected child node

push-rounded-clip

Clips an image to a rounded rectangle.

The image is recorded until the next call to .pop().

method push-rounded-clip ( N-Object $bounds )

• $bounds; the rounded rectangle to clip to

push-shadow

Applies a shadow to an image.

The image is recorded until the next call to .pop().

method push-shadow ( N-Object $shadow, Int() $n-shadows )

• $shadow; the first shadow specification

• $n-shadows; number of shadow specifications.

push-stroke

Strokes the given $path with the attributes given by $stroke and an image.

The image is recorded until the next call to .pop().

Note that the strokes are subject to the same transformation as everything else, so uneven scaling will cause horizontal and vertical strokes to have different widths.

If you want to stroke the path with a color, .append-stroke() may be more convenient.

method push-stroke ( N-Object $path, N-Object $stroke )

• $path; The path to stroke

• $stroke; The stroke attributes

render-background

Note: The native version of this routine is deprecated in gtk4-lib() since version 4.10

Creates a render node for the CSS background according to $context, and appends it to the current node of $snapshot, without changing the current node.

method render-background ( N-Object() $context, Num() $x, Num() $y, Num() $width, Num() $height )

• $context; the style context that defines the background.

• $x; X origin of the rectangle.

• $y; Y origin of the rectangle.

• $width; rectangle width.

• $height; rectangle height.

render-focus

Note: The native version of this routine is deprecated in gtk4-lib() since version 4.10

Creates a render node for the focus outline according to $context, and appends it to the current node of $snapshot, without changing the current node.

method render-focus ( N-Object() $context, Num() $x, Num() $y, Num() $width, Num() $height )

• $context; the style context that defines the focus ring.

• $x; X origin of the rectangle.

• $y; Y origin of the rectangle.

• $width; rectangle width.

• $height; rectangle height.

render-frame

Note: The native version of this routine is deprecated in gtk4-lib() since version 4.10

Creates a render node for the CSS border according to $context, and appends it to the current node of $snapshot, without changing the current node.

method render-frame ( N-Object() $context, Num() $x, Num() $y, Num() $width, Num() $height )

• $context; the style context that defines the frame.

• $x; X origin of the rectangle.

• $y; Y origin of the rectangle.

• $width; rectangle width.

• $height; rectangle height.

render-insertion-cursor

Note: The native version of this routine is deprecated in gtk4-lib() since version 4.10

Draws a text caret using $snapshot at the specified index of $layout.

method render-insertion-cursor ( N-Object() $context, Num() $x, Num() $y, N-Object() $layout, Int() $index, PangoDirection $direction )

• $context; a Gnome::Gtk4::StyleContext.

• $x; X origin.

• $y; Y origin.

• $layout; the Gnome::Pango::Layout of the text.

• $index; the index in the Gnome::Pango::Layout.

• $direction; the enumeration PangoDirection defined in Gnome::Pango::T-direction of the text.

render-layout

Note: The native version of this routine is deprecated in gtk4-lib() since version 4.10

Creates a render node for rendering $layout according to the style information in $context, and appends it to the current node of $snapshot, without changing the current node.

method render-layout ( N-Object() $context, Num() $x, Num() $y, N-Object() $layout )

• $context; the style context that defines the text.

• $x; X origin of the rectangle.

• $y; Y origin of the rectangle.

• $layout; the Gnome::Pango::Layout to render.

restore

Restores $snapshot to the state saved by a preceding call to [method $Snapshot.save] and removes that state from the stack of saved states.

method restore ( )

rotate

Rotates @ $snapshot's coordinate system by $angle degrees in 2D space - or in 3D speak, rotates around the Z axis. The rotation happens around the origin point of (0, 0) in the $snapshot's current coordinate system.

To rotate around axes other than the Z axis, use .rotate3d() in class Gnome::Gsk4::N-Transform.

method rotate ( Num() $angle )

• $angle; the rotation angle, in degrees (clockwise).

rotate3d

Rotates $snapshot's coordinate system by $angle degrees around $axis.

For a rotation in 2D space, use .rotate() in class Gnome::Gsk4::N-Transform.

method rotate3d ( Num() $angle, N-Object $axis )

• $angle; the rotation angle, in degrees (clockwise).

• $axis; The rotation axis

save

Makes a copy of the current state of $snapshot and saves it on an internal stack.

When .restore() is called, $snapshot will be restored to the saved state.

Multiple calls to .save() and .restore() can be nested; each call to C<.restore()>` restores the state from the matching paired C<.save()>`.

It is necessary to clear all saved states with corresponding calls to C<.restore()>`.

method save ( )

scale

Scales $snapshot's coordinate system in 2-dimensional space by the given factors.

Use .scale3d() to scale in all 3 dimensions.

method scale ( Num() $factor-x, Num() $factor-y )

• $factor-x; scaling factor on the X axis.

• $factor-y; scaling factor on the Y axis.

scale3d

Scales $snapshot's coordinate system by the given factors.

method scale3d ( Num() $factor-x, Num() $factor-y, Num() $factor-z )

• $factor-x; scaling factor on the X axis.

• $factor-y; scaling factor on the Y axis.

• $factor-z; scaling factor on the Z axis.

to-node

Returns the render node that was constructed by $snapshot.

Note that this function may return undefined if nothing has been added to the snapshot or if its content does not produce pixels to be rendered.

After calling this function, it is no longer possible to add more nodes to $snapshot. The only function that should be called after this is .unref() in class Gnome::GObject::Object.

method to-node (--> N-Object )

Return value; the constructed Gnome::Gsk4::RenderNode or undefined if there are no nodes to render..

to-paintable

Returns a paintable encapsulating the render node that was constructed by $snapshot.

After calling this function, it is no longer possible to add more nodes to $snapshot. The only function that should be called after this is .unref() in class Gnome::GObject::Object.

method to-paintable ( N-Object $size --> N-Object )

• $size; The size of the resulting paintable or undefined to use the bounds of the snapshot

Return value; a new Gnome::Gdk4::R-Paintable.

transform

Transforms $snapshot's coordinate system with the given $transform.

method transform ( N-Object $transform )

• $transform; the transform to apply

transform-matrix

Transforms $snapshot's coordinate system with the given $matrix.

method transform-matrix ( N-Object $matrix )

• $matrix; the matrix to multiply the transform with

translate

Translates $snapshot's coordinate system by $point in 2-dimensional space.

method translate ( N-Object $point )

• $point; the point to translate the snapshot by

translate3d

Translates $snapshot's coordinate system by $point.

method translate3d ( N-Object $point )

• $point; the point to translate the snapshot by