Class (GI Struct)

Gsk-4.0 ▶ Gsk ▶ RenderReplaySince 4.22

A facility to replay a Gsk.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 Gsk.RenderReplay.set_node_filter to filter each individual node and then run Gsk.RenderReplay.filter_node on the nodes you want to filter.

If you want to just walk the node tree and extract information without any modifications, you can also use Gsk.RenderNode.get_children.

Here is a little example application that redacts text in a node file:

#include <gtk/gtk.h>

static GskRenderNode *
redact_nodes (GskRenderReplay *replay,
              GskRenderNode   *node,
              gpointer         user_data)
{
  GskRenderNode *result;

  if (gsk_render_node_get_node_type (node) == GSK_TEXT_NODE)
    {
      graphene_rect_t bounds;
      const GdkRGBA *color;

      gsk_render_node_get_bounds (node, &bounds);
      color = gsk_text_node_get_color (node);

      result = gsk_color_node_new (color, &bounds);
    }
  else
    {
      result = gsk_render_replay_default (replay, node);
    }

  return result;
}

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

  gtk_init ();

  if (argc != 3)
    {
      g_print ("usage: %s INFILE OUTFILE\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, redact_nodes, NULL, NULL);
  result = gsk_render_replay_filter_node (replay, node);
  gsk_render_replay_free (replay);

  if (!gsk_render_node_write_to_file (result, argv[2], NULL))
    return 1;

  gsk_render_node_unref (result);
  gsk_render_node_unref (node);

  return 0;
}

4.22

Index
constructor
$gtype
default filter_font filter_node filter_texture free set_font_filter set_node_filter set_texture_filter new
$gtype: GType<RenderReplay>

  • Replays the node using the default method.

    The default method calls Gsk.RenderReplay.filter_node on all its child nodes and the filter functions for all its properties. 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.

    Parameters

    Returns Gsk.RenderNode

    The replayed node

    4.22

  • 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 NULL

    • call Gsk.RenderReplay.default to have the default handler run for this node, which calls your function on its children

    Parameters

    Returns void

    4.22