These flags determine the region returned in prclBounds:
SETUPDC_VISRGN
Replace the contents of the visible
region of hdc with the contents of hrgnVis.
SETUPDC_ORIGIN
Set the DC origin to (xOrg, yOrg).
SETUPDC_ACCUMBOUNDSON
Turn on bounds accumulation. This only affects the
COM_ALT_BOUND flag. If COM_ALT_BOUND (see page Calling
Conventions) is not set, the bounds rectangle is reset to an empty rectangle.
If COM_ALT_BOUND is already set, the bounds rectangle is not changed.
SETUPDC_ACCUMBOUNDSOFF
Turn off bounds accumulation.
SETUPDC_REALCLIP
Recalculate the true device clipping region. This
bit is normally set, but can be 0 when immediate recalculation is not required.
SETUPDC_SETOWNER
When this
bit is set, the DC must belong to the current process.
SETUPDC_CLEANDC
When this bit is set, the simulation marks the visible
regions as valid and calls GreNotifyClipChange in the presentation driver.