Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cbmvax!vu-vlsi!swatsun!jackiw From: jackiw@cs.swarthmore.edu (Nick Jackiw) Newsgroups: comp.sys.mac.programmer Subject: Re: Bitmap --> region code needed Message-ID: <3139@carthage.cs.swarthmore.edu> Date: 28 Sep 89 15:09:33 GMT References: <8909261258.AA01237@cscwam.UMD.EDU> Reply-To: jackiw@carthage (Nick Jackiw) Distribution: usa Organization: Visual Geometry Project, Swarthmore College, PA Lines: 39 In article <8909261258.AA01237@cscwam.UMD.EDU> rick@wam.UMD.EDU writes: > I hope someone can point me in the right direction. I'm looking for code > (C, asm, or Pascal) that will convert a bitmap into a region (ie black pixels > included in region or vice versa for white pixels). > Public domain source would be nice but commercial source will also do. Apple licenses a subroutine called _BitmapRgn, of the form: FUNCTION BitMapRgn(region:RgnHandle; bMap:BitMap):OSErr; "The region will be built so that all one bits in bMap are inside the region and all zero bits are outside of it." - Technote #193 The subroutine is available in the 32-bit Quickdraw init (I dunno the trap number, but the MacDTS would); or separately, from: Apple Software Licensing / Apple Computer, Inc. 20525 Mariani Ave MS 38-I / Cupertino, CA 95014 Also take a look at CalcMask and CopyMask, described in Inside Mac #IV. You may be able to accomplish your desired effect without ever needing to go to the region stage. -Nick > I need to use a bitmap to mask a region while > drawing in much the same way that X uses bitmaps as clipping regions while > drawing. Any help would be greatly appreciated. I think I may have seen some > discussion on this topic a while back in this newsgroup. Thanx. > > rick@wam.umd.edu -- _ _|\____ Nick Jackiw | Visual Geometry Project | Math Department / /_/ O> \ ------------+-------------------------+ Swarthmore College | O> | 215-328-8225| jackiw@cs.swarthmore.edu| Swarthmore PA 19081 \_Guernica_/ ------------+-------------------------+ USA