Opened 19 years ago
Closed 13 years ago
#1561 closed defect (fixed)
Implement context-sensitive alpha blending for 24 or 32-bit images
Reported by: | sdlime | Owned by: | sdlime |
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Priority: | high | Milestone: | |
Component: | MapServer C Library | Version: | 4.8 |
Severity: | normal | Keywords: | |
Cc: |
Description (last modified by )
This is sort of the next step beyond Sean's work with bug 926. The problem with that approach is that using TRANSPARENCY ALPHA precludes using the general layer transparency. It is easy enough to change the code in mapgd.h so that alpha blending is turned on with 24-bit symbols and in that case you no longer need the ALPHA setting. I *think* our approach should be to only turn on blending when necessary and turn off again when done. That actually simplifies the code a bit since you don't have to save the blending state when entering the drawing or labeling functions. My initial tests work ok although I have to try many more symbol output image combinations. Ideas how to automate? So now I can draw markers with alpha channels and also make them even more transparent. I did uncover a bug in in our image merging code that doesn't seem to deal with alpha channels quite right, but when fixed the results are great. Steve
Change History (1)
comment:1 by , 13 years ago
Description: | modified (diff) |
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Resolution: | → fixed |
Status: | new → closed |
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we don't use transparency alpha anymore