Paint Using Custom Callbacks
Some advanced display adapters offer non-standard paint functions that give you the ability to access a card's more advanced features. For example, a medical display adapter might give users the ability to display more than 256 shades of gray (more than 8 bits per component). One such card comes from Barco (www.barco.com) and it can display up to 8192 shades of gray (13-bits per pixel). These adapters require you to use different functions for displaying such data, rather than standard GDI functions like StretchDIBits.
LEADTOOLS makes it possible to use such advanced functions by allowing you to use custom callbacks during the paint process. We allow you to replace some of the standard GDI functions (like StretchDIBits) with the specialized function for the particular capture device.You do that by filling a PAINTCALLBACKDATA structure with the callbacks you wish to replace and then calling one of the paint functions that use this structure:
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Paints the whole image using custom callbacks. | |
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Paints only the bitmap portion inside a region using custom callbacks. | |
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Paints a buffer using custom callbacks (use this to implement paint while load effect). | |
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Paints only the buffer portion inside a region using custom callbacks | |
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Paints a bitmap overlay using custom callbacks. |
You override only the paint functions that you need. The default GDI function equivalents will be used for the functions you do not override. Please see the PAINTCALLBACKDATA documentation for a list of functions you can override.