DisplayList

DisplayList is the finished recording produced by DisplayListBuilder.build(). It is GPU-free, nestable, and cheap to keep. Later edits to the builder that produced it do not affect the list.

Replay it every frame, nest it inside another list, or keep a retained list for content that does not change and build a smaller list for live overlays.

builder.draw_display_list(&background);
builder.draw_display_list(&overlay);

builder.drawDisplayList(background);
builder.drawDisplayListCached(overlay); // reuse a GPU raster of this list

The scene records one cell, then replays it. Change the gap, count, or cell size.

draw_display_list_cached (JavaScript drawDisplayListCached) rasterizes the nested list into a texture and reuses it while the scale is stable. During a zoom gesture call set_raster_hold (JavaScript setGestureHold) and clear it when the view settles — see Context.

A list does not own GPU resources of its own. Images and paragraphs it refers to must outlive the render that uses the list.

In JavaScript, call list.free() when you no longer need it. Free the list before freeing images or the renderer it was drawn with.

Next: Context.