Previously, during the spring, we had added the basic region operations, which already allow us to do a bunch of cool stuff, but next up on the list was implementing region recording. This neat feature QuickDraw allows the program to open a new output region for “recording”, to which certain QuickDraw “FrameXXX” operations will output inversion points into. This includes StdLine, StdOval, StdRect, StdRgn, and RoundRects.
The article on MacGUI, which was mentioned earlier when discussing regions, also contained a neat screenshot of results of OpenRgn/CloseRgn operation with accompanying Pascal source code. We made adaption of this code for the C Toolbox testbed, so we could have a picture to compare to, to see that the results would match ones expected on a real Mac.
At the same time, we were working on adding “source” transfer mode support to the region-clipping blitter, as transferring text to screen uses those to handle moving the text from offscreen buffer to the screen (previously we only implemented the non-clipped blitter). After getting this to work, there was also a nice benefit that non-scaled CopyBits can also be implemented easily soon, although only for cases where source and destination bitmaps are different (ScrollRect and window manager will use same source and destination, forcing inverted blitting direction depending on their locations).