By default, WPF does not cache the rendered contents of TileBrush objects, such as DrawingBrush and VisualBrush. In static scenarios where neither the contents nor use of the TileBrush in the scene is changing, this makes sense, since it conserves video memory. It does not make as much sense when a TileBrush with static content is used in a non-static way—for example, when a static DrawingBrush or VisualBrush is mapped to the surface of a rotating 3D object. The default behavior of WPF is to re-render the entire content of the DrawingBrush or VisualBrush every frame, even though the content is unchanging.

By setting the CachingHint property of the RenderOptions object to Cache you can increase performance by using cached versions of the tiled brush objects.

The CacheInvalidationThresholdMinimum and CacheInvalidationThresholdMaximum property values are relative size values that determine when the TileBrush object should be regenerated due to changes in scale. For example, by setting the CacheInvalidationThresholdMaximum property to 2.0, the cache for the TileBrush only needs to be regenerated when its size exceeds twice the size of the current cache.

The following example shows how to use the caching hint option for a DrawingBrush.

// Set the minimum and maximum relative sizes for regenerating the tiled brush.
RenderOptions.SetCacheInvalidationThresholdMinimum(drawingBrush, 0.5);
RenderOptions.SetCacheInvalidationThresholdMaximum(drawingBrush, 2.0);

// The tiled brush will be regenerated when the size is
//   0.5x, 0.25x (and so forth)
// and
//   2x, 4x, 8x (and so forth)
// of the original size.

// Set the caching hint option for the brush.
RenderOptions.SetCachingHint(drawingBrush, CachingHint.Cache);

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference

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