class Gtk::Snapshot

Overview

Gtk::Snapshot assists in creating Gsk::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 Snapshot::pop to change the current node.

The typical way to obtain a Gtk::Snapshot object is as an argument to the Gtk::Widget#snapshot vfunc. If you need to create your own Gtk::Snapshot, use Gtk::Snapshot.new.

Defined in:

lib/gi-crystal/src/auto/gtk-4.0/snapshot.cr
lib/gtk4/src/bindings/gtk/snapshot.cr

Constructors

Class Method Summary

Instance Method Summary

Constructor methods inherited from class Gdk::Snapshot

new new

Class methods inherited from class Gdk::Snapshot

g_type : UInt64 g_type

Instance methods inherited from class GObject::Object

bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void)? data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void)? qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void)?) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void)? steal_data, steal_qdata(quark : UInt32) : Pointer(Void)? steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, cast?(obj : GObject::Object) : self? cast?, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new new, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

compat_control(what : UInt64, data : Pointer(Void)?) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new : self #

Creates a new Gtk::Snapshot.


Class Method Detail

def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.


Instance Method Detail

def append_border(outline : Gsk::RoundedRect, border_width : Enumerable(Float32), border_color : Enumerable(Gdk::RGBA)) : Nil #

Appends a stroked border rectangle inside the given @outline.

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


def append_cairo(bounds : Graphene::Rect) : Cairo::Context #

Creates a new Gsk::CairoNode and appends it to the current render node of @snapshot, without changing the current node.


def append_color(color : Gdk::RGBA, bounds : Graphene::Rect) : Nil #

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.


def append_conic_gradient(bounds : Graphene::Rect, center : Graphene::Point, rotation : Float32, stops : Enumerable(Gsk::ColorStop)) : Nil #

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


def append_inset_shadow(outline : Gsk::RoundedRect, color : Gdk::RGBA, dx : Float32, dy : Float32, spread : Float32, blur_radius : Float32) : Nil #

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


def append_layout(layout : Pango::Layout, color : Gdk::RGBA) : Nil #

def append_linear_gradient(bounds : Graphene::Rect, start_point : Graphene::Point, end_point : Graphene::Point, stops : Enumerable(Gsk::ColorStop)) : Nil #

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


def append_node(node : Gsk::RenderNode) : Nil #

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.


def append_outset_shadow(outline : Gsk::RoundedRect, color : Gdk::RGBA, dx : Float32, dy : Float32, spread : Float32, blur_radius : Float32) : Nil #

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


def append_radial_gradient(bounds : Graphene::Rect, center : Graphene::Point, hradius : Float32, vradius : Float32, start : Float32, end _end : Float32, stops : Enumerable(Gsk::ColorStop)) : Nil #

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


def append_repeating_linear_gradient(bounds : Graphene::Rect, start_point : Graphene::Point, end_point : Graphene::Point, stops : Enumerable(Gsk::ColorStop)) : Nil #

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


def append_repeating_radial_gradient(bounds : Graphene::Rect, center : Graphene::Point, hradius : Float32, vradius : Float32, start : Float32, end _end : Float32, stops : Enumerable(Gsk::ColorStop)) : Nil #

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


def append_texture(texture : Gdk::Texture, bounds : Graphene::Rect) : Nil #

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


def gl_shader_pop_texture : Nil #

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

This must be called the same number of times as the number of textures is needed for the shader in Gtk::Snapshot#push_gl_shader.


def perspective(depth : Float32) : Nil #

Applies a perspective projection transform.

See Gsk::Transform#perspective for a discussion on the details.


def pop : Nil #

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


def push_blend(blend_mode : Gsk::BlendMode) : Nil #

Blends together two images with the given blend mode.

Until the first call to Gtk::Snapshot#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 Gtk::Snapshot#pop.

Calling this function requires two subsequent calls to Gtk::Snapshot#pop.


def push_blur(radius : Float64) : Nil #

Blurs an image.

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_clip(bounds : Graphene::Rect) : Nil #

Clips an image to a rectangle.

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_color_matrix(color_matrix : Graphene::Matrix, color_offset : Graphene::Vec4) : Nil #

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

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_cross_fade(progress : Float64) : Nil #

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

Until the first call to Gtk::Snapshot#pop, the start image will be snapshot. After that call, the end image will be recorded until the second call to Gtk::Snapshot#pop.

Calling this function requires two subsequent calls to Gtk::Snapshot#pop.


def push_gl_shader(shader : Gsk::GLShader, bounds : Graphene::Rect, take_args : GLib::Bytes) : Nil #

Push a Gsk::GLShaderNode.

The node uses the given Gsk::GLShader and uniform values Additionally this takes a list of @n_children other nodes which will be passed to the Gsk::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 Gsk::GLShader#format_args or Gsk::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 Gsk::GLShader#compile to ensure the @shader will work for the renderer before using it.

If the shader requires textures (see Gsk::GLShader#n_textures), then it is expected that you call Gtk::Snapshot#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 Gsk::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 Gtk::Snapshot#pop.

If you want to use pre-existing textures as input to the shader rather than rendering new ones, use Gtk::Snapshot#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 Gsk::GLShader.


def push_opacity(opacity : Float64) : Nil #

Modifies the opacity of an image.

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_repeat(bounds : Graphene::Rect, child_bounds : Graphene::Rect?) : Nil #

Creates a node that repeats the child node.

The child is recorded until the next call to Gtk::Snapshot#pop.


def push_rounded_clip(bounds : Gsk::RoundedRect) : Nil #

Clips an image to a rounded rectangle.

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_shadow(shadow : Enumerable(Gsk::Shadow)) : Nil #

Applies a shadow to an image.

The image is recorded until the next call to Gtk::Snapshot#pop.


def push_shadow(*shadow : Gsk::Shadow) #

def render_background(context : Gtk::StyleContext, x : Float64, y : Float64, width : Float64, height : Float64) : Nil #

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.


def render_focus(context : Gtk::StyleContext, x : Float64, y : Float64, width : Float64, height : Float64) : Nil #

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.


def render_frame(context : Gtk::StyleContext, x : Float64, y : Float64, width : Float64, height : Float64) : Nil #

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.


def render_insertion_cursor(context : Gtk::StyleContext, x : Float64, y : Float64, layout : Pango::Layout, index : Int32, direction : Pango::Direction) : Nil #

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


def render_layout(context : Gtk::StyleContext, x : Float64, y : Float64, layout : Pango::Layout) : Nil #

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.


def restore : Nil #

Restores @snapshot to the state saved by a preceding call to Snapshot::save and removes that state from the stack of saved states.


def rotate(angle : Float32) : Nil #

Rotates @@snapshot's coordinate system by @angle degrees in 2D space - or in 3D speak, rotates around the Z axis.

To rotate around other axes, use [method@Gsk.Transform.rotate_3d].


def rotate_3d(angle : Float32, axis : Graphene::Vec3) : Nil #

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

For a rotation in 2D space, use Gsk::Transform#rotate.


def save : Nil #

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

When Gtk::Snapshot#restore is called, @snapshot will be restored to the saved state. Multiple calls to Snapshot::save and Snapshot::restore can be nested; each call to gtk_snapshot_restore() restores the state from the matching paired gtk_snapshot_save().

It is necessary to clear all saved states with corresponding calls to gtk_snapshot_restore().


def scale(factor_x : Float32, factor_y : Float32) : Nil #

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

Use [method@Gtk.Snapshot.scale_3d] to scale in all 3 dimensions.


def scale_3d(factor_x : Float32, factor_y : Float32, factor_z : Float32) : Nil #

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


def to_node : Gsk::RenderNode? #

Returns 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 GObject::Object#unref.


def to_paintable(size : Graphene::Size?) : Gdk::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 GObject::Object#unref.


def transform(transform : Gsk::Transform?) : Nil #

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


def transform_matrix(matrix : Graphene::Matrix) : Nil #

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


def translate(point : Graphene::Point) : Nil #

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


def translate_3d(point : Graphene::Point3D) : Nil #

Translates @snapshot's coordinate system by @point.