GNOME Bugzilla – Bug 90969
Blending modes (other than normal) fail
Last modified: 2002-11-02 23:39:22 UTC
When I use other blending modes than normal it happens sometimes (very often) that the result is not correct and shows several vertical lines. Here is an example: start the Gimp File / New Ok. select the Bucket Fill Choose Multiply mode Click in the image. The result is attached here. This phenomenon does not appear when the blending is done between two layers. It happens when using a tool or between a layer and a floating object. AirBete.
Created attachment 10539 [details] The resulting GIMP image
I can reproduce this. It seems to be a bug in the MMX routines since it doesn't happen when GIMP is started with the --no-mmx command-line option.
This might be a duplicate of bug #86290.
CVS as of November 01 2002 11:00 GMT I can reproduce this. (mmx enabled) Furthermore, it appears only with a background layer lacking an alpha channel. Following 'Layer->Alpha->Add Alpha Channel' the miscreant behavior goes away.
This is good news as it seems to imply that the bug is not in the MMX code but in the code that decides which routines to apply. Garry, do you plan to investigate this further? Would be nice to get this fixed soon.
Confirm it is a duplicate of #86290. Both bugs exhibit same maligned rendering condition, which arises from invocation of layer_multiply_mode_mmx () via combine_sub_region ( ) in paint_func.c, which is a common control flow to both bugs. Suspect layer_multiply_mode_mmx () is not correctly handling the 2 sources when such has three and four byte pixel depths, respectively. Issue disappears when both sources are at same depth; and, of course, the issue disappears with mmx disabled, as observed in separate ways in both bugs. *** This bug has been marked as a duplicate of 86290 ***