References ▼
#include "l_bitmap.h"
L_INT pEXT_CALLBACK YourFunction(pDisplay, pBitmap, prcDestClip, pUserData)
This callback is used perform memory initialization or device initialization.
Handle of the device context passed to the paint function.
Pointer to the bitmap handle structure holding the input data.
Pointer to the destination clipping rectangle.
Void pointer that you can use to access a variable or structure containing data that your callback function needs. This gives you a way to receive data indirectly from the function that uses this callback function. (This is the same pointer that you pass in the pUserData parameter of the PAINTCALLBACKDATA structure.)
| Value | Meaning |
|---|---|
| SUCCESS | The function was successful. |
| < 1 | An error occurred. Refer to Return Codes. |
pDisplay is the pDisplay member from the PAINTCALLBACKDATA structure that you passed to the paint function. The default callbacks expect it to be a HDC handle. But, if you override all the paint callbacks, it can be a pointer of any type you want.
This callback is called after PAINTCALLBACK_ISCOMPATIBLEDC and before any other paint callbacks. This callback will be called exactly once for a paint operation.
You can use this callback to perform any device initialization or memory allocation needed for the current paint operation.
You can perform the device resetting or memory freeing in PAINTCALLBACK_POSTPAINT callback.
Required DLLs and Libraries
For an example, refer to L_PaintDCCallback.
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