PAINTCALLBACK_SETVIEWPORTORGEX Function

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#include "l_bitmap.h"

L_BOOL pEXT_CALLBACK YourFunction(pDisplay, nX, nY, lpPoint, pUserData)

L_VOID *pDisplay;	/* device context handle */
L_INT nX;	/* new x-coordinate of viewport origin */
L_INT nY;	/* new y-coordinate of viewport origin */
LPPOINT lpPoint;	/* original viewport origin */
L_VOID *pUserData;	/* pointer to additional data */

This is the callback that replaces the SetViewportOrgEx GDI function.

Parameter	Description
pDisplay	Handle of the device context passed to the paint function.
nX	Specifies the x-coordinate, in device units, of the new viewport origin.
nY	Specifies the y-coordinate, in device units, of the new viewport origin.
lpPoint	Pointer to a POINT structure that receives the previous viewport origin, in device coordinates. If lpPoint is NULL, this parameter is not used.
pUserData	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.)

Returns

The return values are the same as the return values for the corresponding GDI function.

Comments

The internal display engine calls your callback function if you override the corresponding GDI function in the PAINTCALLBACKDATA structure.

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.

Please see the Microsoft documentation for the values you are expected to return and for the meaning of the parameters before pUserData.

Required DLLs and Libraries

LTDIS

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application

Example

For an example, refer to L_PaintDCCallback.