[mapserver-users] Using IMAGECOLOR to create a transparency mask

[Glenn Waldron]

Thanks Thomas, I believe this answers my question. Sounds like I will not be
able to do what I want inside MapServer and still do 24-bit color.

Thanks again for your (and everyone's) help.


Glenn Waldron : Pelican Mapping : http://pelicanmapping.com :
+1.703.652.4791


On Thu, Feb 5, 2009 at 3:16 PM, thomas bonfort <thomas.bonfort at gmail.com>wrote:

> this is meant to be applied with paletted images, ie
> IMAGEMODE PC256
> which is only supported with the gd driver. having a single fully
> transparent color is not compatible with antialiasing, so you're
> better off sticking with gd anyways if you have this transparency
> requirement.
>
> regards,
> thomas
>
> On Thu, Feb 5, 2009 at 21:03, Glenn Waldron <gwaldron at gmail.com> wrote:
> > Hi Steve,
> >
> > I am trying to achieve the transparency effect as described in the
> > documentation:
> > "IMAGECOLOR [r] [g] [b]Color to initialize the map with (i.e. background
> > color). When transparency is enabled (TRANSPARENT ON) for the typical
> case
> > of 8-bit pseudocolored map generation, this color will be marked as
> > transparent in the output file palette. Any other map components drawn in
> > this color will also be transparent, so for map generation with
> transparency
> > it is best to use an otherwise unused color as the background
> color."Perhaps
> > I'm not clear on what constitutes "8-bit pseudocolored map generation". I
> am
> > using the AGG/PNG driver with TRANSPARENT ON.
> >
> >
> > Glenn Waldron : Pelican Mapping : http://pelicanmapping.com :
> > +1.703.652.4791
> >
> >
> > On Thu, Feb 5, 2009 at 2:04 PM, Steve Lime <Steve.Lime at dnr.state.mn.us>
> > wrote:
> >>
> >> IMAGECOLOR just sets the background color for an image.
> >>
> >> Steve
> >>
> >> >>> On 2/5/2009 at 1:02 PM, in message
> >> <70fbea790902051102p52a8067ar643666f0562642f3 at mail.gmail.com>, Glenn
> >> Waldron
> >> <gwaldron at gmail.com> wrote:
> >> > Hi Thomas,
> >> >
> >> > In that case maybe I am misunderstanding the purpose of IMAGECOLOR.
> What
> >> > is
> >> > it supposed to do, if not make all pixels of the specified color
> >> > transparent?
> >> >
> >> >
> >> > Glenn Waldron : Pelican Mapping : http://pelicanmapping.com :
> >> > +1.703.652.4791
> >> >
> >> >
> >> > On Thu, Feb 5, 2009 at 1:24 PM, thomas bonfort
> >> > <thomas.bonfort at gmail.com>wrote:
> >> >
> >> >> On Thu, Feb 5, 2009 at 14:43, Glenn Waldron <gwaldron at gmail.com>
> wrote:
> >> >> > Stephen,
> >> >> >
> >> >> >  However, I am trying to
> >> >> > get the pixels in the final composited image to be completely
> >> >> transparent.
> >> >> >
> >> >>
> >> >> There's no way you can set pixels to become transparent once the
> image
> >> >> is saved with the AGG outputformat.
> >> >>
> >> >> regards,
> >> >> thomas
> >> >>
> >>
> >
> >
> > _______________________________________________
> > mapserver-users mailing list
> > mapserver-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
> >
> >
>
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