TQARenderEnd
A drawing engine must define a method to signal the end of any rendering into a draw context.
typedef TQAError (*TQARenderEnd) ( const TQADrawContext *drawContext, const TQARect *modifiedRect);
drawContext- A draw context.
modifiedRect- The minimum area of the back buffer of the specified draw context to display, or the value
NULL.DESCRIPTION
YourTQARenderEndfunction should perform any operations necessary to display an image rendered into the draw context specified by thedrawContextparameter. If the draw context is double buffered, your function should display the back buffer. If the draw context is single buffered, your function should callQAFlush. In either case, your drawing engine should unlock any frame buffers or other memory that is locked, remove any cursor shields, and so forth.The
modifiedRectparameter indicates the minimum area of the back buffer of the specified draw context that should be displayed. If the value of themodifiedRectparameter isNULL, the entire back buffer is displayed. If the value of themodifiedRectparameter is notNULL, it indicates the rectangle in the back buffer to display. Some drawing engines may exhibit improved performance when an area that is smaller than the entire draw context rectangle is passed (to avoid unnecessary pixel copying). However, the interpretation of themodifiedRectparameter is dependent on the drawing engine, which may choose to draw the entire back buffer.Your
TQARenderEndfunction should return a result code (of typeTQAError) indicating whether any errors have occurred since the previous call to yourTQARenderStartfunction. If all rendering commands completed successfully, you should return the valuekQANoErr. If you return any other value, the code that calledQARenderEndshould assume that the rendered image is incorrect.SPECIAL CONSIDERATIONS
Applications should callQARenderStartbefore performing any rendering operations in the specified draw context, and they should call eitherQARenderEndto signal the end of rendering operations orQARenderAbortto cancel rendering operations. Once an application has calledQARenderEnd, it should not submit any drawing requests until it has calledQARenderStartagain.
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