Struct RenderReplay 

pub struct RenderReplay(/* private fields */);

Available on crate feature v4_22 only.

A facility to replay a RenderNode and its children, potentially modifying them.

This is a utility tool to walk a rendernode tree. The most powerful way is to provide a function via set_node_filter() to filter each individual node and then run filter_node() on the nodes you want to filter.

An easier method exists to just walk the node tree and extract information without any modifications. If you want to do that, the functions set_node_foreach() exists. You can also call foreach_node() to run that function. Note that the previously mentioned complex functionality will still be invoked if you have set up a function for it, but its result will not be returned.

Here is an example that combines both approaches to print the whole tree:

⚠️ The following code is in c ⚠️

#include <gtk/gtk.h>

static GskRenderNode *
print_nodes (GskRenderReplay *replay,
             GskRenderNode   *node,
             gpointer         user_data)
{
  int *depth = user_data;
  GskRenderNode *result;

  g_print ("%*s%s\n", 2 * *depth, "", g_type_name_from_instance ((GTypeInstance *) node));

  *depth += 1;
  result = gsk_render_replay_default (replay, node);
  *depth -= 1;

  return result;
}

int
main (int argc, char *argv[])
{
  GFile *file;
  GBytes *bytes;
  GskRenderNode *node;
  GskRenderReplay *replay;
  int depth = 0;

  gtk_init ();

  if (argc < 2)
    {
      g_print ("usage: %s NODEFILE\n", argv[0]);
      return 0;
    }

  file = g_file_new_for_commandline_arg (argv[1]);
  bytes = g_file_load_bytes (file, NULL, NULL, NULL);
  g_object_unref (file);
  if (bytes == NULL)
    return 1;

  node = gsk_render_node_deserialize (bytes, NULL, NULL);
  g_bytes_unref (bytes);
  if (node == NULL)
    return 1;

  replay = gsk_render_replay_new ();
  gsk_render_replay_set_node_filter (replay, print_nodes, &depth, NULL);
  gsk_render_node_foreach_node (replay, node);
  gsk_render_node_unref (node);

  return 0;
}

Implementations

impl RenderReplay

pub fn default(&self, node: impl AsRef<RenderNode>) -> Option<RenderNode>

Replays the node using the default method.

The default method calls filter_node() on all its child nodes and the filter functions for all its proeprties. If none of them are changed, it returns the passed in node. Otherwise it constructs a new node with the changed children and properties.

It may not be possible to construct a new node when any of the callbacks return NULL. In that case, this function will return NULL, too.

node

the node to replay

Returns

The replayed node

pub fn filter_font(&self, font: &impl IsA<Font>) -> Font

Filters a font using the current filter function.

font

The font to filter

Returns

the filtered font

pub fn filter_node(&self, node: impl AsRef<RenderNode>) -> Option<RenderNode>

Replays a node using the replay’s filter function.

After the replay the node may be unchanged, or it may be removed, which will result in None being returned.

This function calls the registered callback in the following order:

1. If a foreach function is set, it is called first. If it returns false, this function immediately exits and returns the passed in node.

2. If a node filter is set, it is called and its result is returned.

3. default() is called and its result is returned.

node

the node to replay

Returns

The replayed node

pub fn filter_texture(&self, texture: &impl IsA<Texture>) -> Texture

Filters a texture using the current filter function.

texture

The texture to filter

Returns

the filtered texture

pub fn foreach_node(&self, node: impl AsRef<RenderNode>)

Calls the filter and foreach functions for each node.

This function calls filter_node() internally, but discards the result assuming no changes were made.

node

the node to replay

pub fn set_font_filter<P: Fn(&RenderReplay, &Font) -> Font + 'static>( &mut self, filter: P, )

Sets a filter function to be called by default() for nodes that contain fonts.

You can call GskRenderReplay::filter_font() to filter a font yourself.

filter

the font filter function

pub fn unset_font_filter(&mut self)

pub fn set_node_filter<P: Fn(&RenderReplay, &RenderNode) -> Option<RenderNode> + 'static>( &mut self, filter: P, )

Sets the function to use as a node filter.

This is the most complex function to use for replaying nodes. It can either:

• keep the node and just return it unchanged

• create a replacement node and return that

• discard the node by returning None

• call default() to have the default handler run for this node, which calls your function on its children

filter

The function to call to replay nodes

pub fn unset_node_filter(&mut self)

pub fn set_node_foreach<P: Fn(&RenderReplay, &RenderNode) -> ControlFlow + 'static>( &mut self, foreach: P, )

Sets the function to call for every node.

This function is called before the node filter, so if it returns FALSE, the node filter will never be called.

foreach

the function to call for all nodes

pub fn unset_foreach_node(&mut self)

pub fn set_texture_filter<P: Fn(&RenderReplay, &Texture) -> Texture + 'static>( &mut self, filter: P, )

Sets a filter function to be called by default() for nodes that contain textures.

You can call GskRenderReplay::filter_texture() to filter a texture yourself.

filter

the texture filter function

pub fn unset_texture_filter(&mut self)

pub fn new() -> RenderReplay

Creates a new replay object to replay nodes.

Returns

A new replay object to replay nodes

Trait Implementations

impl Default for RenderReplay

fn default() -> Self

Returns the “default value” for a type.

impl Drop for RenderReplay

fn drop(&mut self)

Executes the destructor for this type.