HDC就是TCanvas.Handle
BOOL SetViewportOrgEx(
HDC hdc, // handle of device context
int X, // new x-coordinate of viewport origin
int Y, // new y-coordinate of viewport origin
LPPOINT lpPoint // address of structure receiving original origin
);
Parameters
hdc
Identifies the device context.
X
Specifies the x-coordinate, in device units, of the new viewport origin.
Y
Specifies the y-coordinate, in device units, of the new viewport origin.
lpPoint
Points to a POINT structure. The previous viewport origin (in device coordinates) is placed in this structure. If lpPoint is NULL, nothing is returned.
Return Values
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero.
