QwtSymbol.CachePolicy 枚举类型参考

成员变量

详细描述

Depending on the render engine and the complexity of the symbol shape it might be faster to render the symbol to a pixmap and to paint this pixmap.

F.e. the raster paint engine is a pure software renderer where in cache mode a draw operation usually ends in raster operation with the the backing store, that are usually faster, than the algorithms for rendering polygons. But the opposite can be expected for graphic pipelines that can make use of hardware acceleration.

The default setting is AutoCache

参见

setCachePolicy(), cachePolicy()

注解

The policy has no effect, when the symbol is painted to a vector graphics format ( PDF, SVG ).

警告

Since Qt 4.8 raster is the default backend on X11

在文件 QwtSymbol.x 第 117 行定义.

结构体成员变量说明

AutoCache

AutoCache

Use a cache when one of the following conditions is true:

• The symbol is rendered with the software renderer ( QPaintEngine::Raster )

在文件 QwtSymbol.x 第 132 行定义.

Cache

Cache

Always use a pixmap cache

在文件 QwtSymbol.x 第 123 行定义.

NoCache

NoCache

Don't use a pixmap cache

在文件 QwtSymbol.x 第 120 行定义.