| 摘要 |
A screen capture tool reduces information transfer when capturing a series of screen areas. For example, the screen capture tool reduces usage of Bit Block Transfer operations from a display card frame buffer to system memory. The screen capture tool scans pixel values in portions of a screen area to detect changes relative to a previously captured screen area, identifying portions to be updated by BitBlt operation. Or, the screen capture tool analyzes display driver commands to identify portions of a screen area to be updated by BitBlt operation. The screen capture tool then constructs a representation of the screen area. For example, the screen capture tool provides portions of the screen area that do not require a BitBlt operation (which may involve copying or other use of pixel information already in system memory) and then captures other portions of the screen area by BitBlt operation.
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