SetPort
into the active GrafPort. It stores whichPort into the global variable thePort. whichPort is a pointer to a previously opened 108-byte GrafPort structure you now want to activate.
Notes: All Quickdraw activities are performed based upon values in the current
active GrafPort and use its local coordinate system. All drawing is performed on the BitMap . thePort->portBits. This function is typically used to restore a previously-active GrafPort after switching to an other. For instance, a window update activity may be
GrafPtr savePort; /* temporary storage */ SetPort ( myWindow ); [TOKEN:12074] select local one */ .
. ... do some updating on the local window ...
.