Opened 20 years ago
Closed 16 years ago
#1155 closed enhancement (fixed)
transparency at the STYLE level
Reported by: | Owned by: | sdlime | |
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Priority: | high | Milestone: | 5.2 release |
Component: | MapServer C Library | Version: | 4.4 |
Severity: | minor | Keywords: | |
Cc: | sgillies@…, dmorissette |
Description (last modified by )
Until there is a support of transparency at feature level in Mapserver, the SLD won't be able to support this feature. Later, Bart van den Eijnden wrote: > Hi list, > > is it possible using Mapserver to have a transparent polygon fill through > SLD? > > E.g.: > > <Fill> > <CssParameter name="fill">#ff0000</CssParameter> > <CssParameter name="fill-opacity">0.5</CssParameter> > </Fill> > > If not, is there a work-around to accomplish this using SLD? > > Thanks in advance. > > Best regards, > Bart >
Attachments (1)
Change History (11)
comment:2 by , 20 years ago
Summary: | transparency at the CLASS level → transparency at the STYLE level |
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You're absolutely right Sean, I have changed the bug summary accordingly.
comment:3 by , 20 years ago
Support at style level will likely be expensive, is it really necessary? Would feature level transparency be good enough? That is, moving transparency from msDrawMap to msDrawShape. Even then it may slow things down a good bit. Steve
comment:4 by , 20 years ago
My purpose as a user would be to get a whole layer of polygons transparent using SLD. SLD specifies transparency at the Symbolizer level, so users could theoretically request maps which have different transparency for different styles, but I think this will rather be exception then rule. Just my opinion though.
comment:5 by , 20 years ago
One place you might want transparency at CLASS level (or lower) is to have transparent polygons in one class and opaque polygons in another class, or to do a classification that has continuously varying transparency. Also, now, if you want to have a polygon with a transparent fill and solid (100% opaque boundary) you need two layers -- at double the cost. With transparency in a style, you could have a solid stroke style and a transparent fill style. I'm not sure which is faster/slower: two iterations over a layer for separate stroke/fill opacity or a few extra statements within msDrawShape.
comment:6 by , 20 years ago
Cc: | added; removed |
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To be exactly consistent with the SLD, we need to have the transparency at the STYLE level as decribed by Sean's comments. Steve : I understand the cost associated with doing tranceparency at style level, but Is it correct to assume that if no transparency is set (which is the general case), the user won't see any diffrence ? If that is the case, those who needs it should be prepared to pay the price for this feature. Steve : do you intend to keep the transparency at the layer level as well as adding it at a class (or style) level ?
comment:8 by , 16 years ago
Description: | modified (diff) |
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AGG support for style level opacity has been added in r7476, for all symbol types *except* PIXMAP symbols.
known issue: rendering lineworks with multiple styles (eg to create outlined roads) will produce unwanted results (intersections appear at (more or less)twice the desired opacity, and the caching of the bottommost style is ineffective). see attached image for an example.
by , 16 years ago
Attachment: | style-opacity.png added |
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style level opacity rendering glitches on multi-style lineworks
comment:9 by , 16 years ago
Cc: | added |
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Milestone: | FUTURE → 5.2 release |
comment:10 by , 16 years ago
Resolution: | → fixed |
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Status: | new → closed |
Thomas has addressed this in the AGG code for 5.2 so I'm going to close this in favor of tracking specific to that work should it be necessary.
Steve