## Presentation Device Driver Reference for OS/2

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### GreNotifyTransformChange - Remarks

This function is called by the graphics engine to provide sufficient information to allow the device to optimize its calling of the GreConvert function or, where possible, to make all point transformations itself. The minimum requirement is for the handling routine to update the current position and pattern origin, and then call back to the GreNotifyTransformChange routine in the graphics engine. Note that the handling routine must:

Check that the new current position is valid.
Check that the change will not cause an overflow of the 16-bit coordinates for the device space.
Fail safe. If an error is detected or the call back to the graphics engine fails, the routine must restore the initial values before returning FALSE.