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Performance

YAUI is fast by default. This page explains what costs time, and how to keep it low. For measurements against uGUI and UI Toolkit, see Benchmarks.

Draw calls​

A panel is drawn in one draw call, except where:

  • the material changes between elements in the draw order (custom materials),
  • a mask starts or ends (YauiMask),
  • more than 8 textures are used by consecutive elements. Font atlases, sprite textures, dynamic atlas pages and raw image textures all count.

To keep draw calls low:

  • Use the uber shader (box style, text effects, image types) instead of custom materials.
  • Use ClipChildren instead of YauiMask when a rectangle or a single rounded rectangle is enough.
  • Keep small sprites in the dynamic atlas, and put larger sprites that are shown together in the same sprite atlas.
  • Use few fonts in one panel.

CPU​

WorkTips
Text generation is the most expensive operation.Set texts only when they change. Keep the number of texts that change in the same frame low.
Layout runs for the boundaries that contain changes.Give fixed Width and Height to containers whose size does not depend on their content, to make them layout boundaries. Animate with the render transform, not with layout properties.
Hierarchy changes rebuild the draw order of the panel.Reuse elements instead of creating and destroying them each frame. Enabling and disabling a GameObject is also a hierarchy change.
YauiPanel.ForceUpdate() completes all the work at once on the main thread.Call it only when you need the result in the same frame.

Colors, render transforms and opacity are nearly free to change, and a frame without changes costs almost nothing.

GPU​

The uber shader has a cost for its many features: the GPU time of YAUI is about 1.7 to 2.3 times uGUI's, and about the same as UI Toolkit's or lower (see Benchmarks). To keep it low:

  • Avoid large overlapping transparent areas (overdraw), as with any UI.
  • Large shadow blurs enlarge the quads that are drawn.
  • YAUI_PIXEL_CLIP in custom shaders costs GPU time on mobile. Enable it only when needed.

Scroll views​

YauiScrollView moves its content with the render transform, so scrolling never runs the layout. It does not virtualize its items: all items are drawn and laid out. For very long lists, reuse a small set of items in a higher layer.