home *** CD-ROM | disk | FTP | other *** search
- Xref: sparky comp.sys.mac.programmer:13211 comp.sys.mac.hardware:14470 comp.sys.mac.system:10527
- Path: sparky!uunet!dtix!darwin.sura.net!paladin.american.edu!auvm!alijku11!k360171
- From: K360171@ALIJKU11.BITNET (Norbert Mueller)
- Newsgroups: comp.sys.mac.programmer,comp.sys.mac.hardware,comp.sys.mac.system
- Subject: Quadra (950?) Color QuickDraw bug ???
- Message-ID: <92212.180146K360171@ALIJKU11.BITNET>
- Date: 30 Jul 92 23:01:46 GMT
- Organization: Johannes Kepler University Linz - Computing Center
- Lines: 39
-
- I just discovered a very unusual behavior in a program I am writing.
- I have only been able to reproduce it on the Q950, the bug (?) does
- not occur on a IIci. No other machines have been tested so far.
-
- The scenario: In my application I create a (large) picture consisting
- of mainly MoveTo, LineTo, FrameOval, TextSize, RGBForeColor,
- and DrawString. (TextMode is SrcOr)
- This picture is scaled to an offscreen pixmap via DrawPicture, to
- achieve zooming. The pixmap (belonging to a GWorld) is copied to
- the window GrafPort. Everything works fine except:
- At some combinations of color/font/font-size and the zooming ratio
- used in the DrawPicture command the text disappears on the screen.
- It is in the original picture, which I can verify via exporting to
- the clipboard.
- This never happens for black text. The loss occurs during the
- DrawPicture call. The picture prints Ok (DrawPicture to the printer
- GrafPort). The problem occur only in 8-bit mode, lower resolutions
- and 16-bit are Ok (screen depth = offscreen depth).
- Only for the text some colors seem to map to
- black or white exclusively, when a small reduction is requested.
- (i.e. the destrect is less then 1/4 of the srcrect in DrawPicture)
- Well maybe its a feature - something like dithering scaled text.
- But the way it works is pretty useless and it breaks my
- program.
-
- Same problem in 8bit gray.
- Ha! I just noticed another "feature" switching to Thousands (i.e.
- 16-bit) Grays - does not change the monitor to grays. The colors
- change a little, but even the Finder icons remain colored! Only
- the menubar is b/w.
-
- Additional info: I am using an Apple 21" monitor on the Q950.
-
- Has anybody seen a similar behavior? Is it a known bug?
- Whom should I tell to get a fix?
-
-
- N. Mueller
- Institute of Chemistry, Johannes Kepler University, A-4040 Linz, Austria
-