<div dir="ltr">Thanks for your reply, but I should have mentioned that I have a LOT of different colors to be displayed, almost a million...<div><br></div><div>I should also have mentioned that I've already tried to filter out the anti-aliased pixels by setting all alpha bytes to 255 and then assuming that all pixels that don't have alpha=255 in the PNG can be removed, but that assumption seems to be wrong.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 16, 2017 at 2:00 PM, Lime, Steve D (MNIT) <span dir="ltr"><<a href="mailto:steve.lime@state.mn.us" target="_blank">steve.lime@state.mn.us</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hmmm… I wonder if you just could use a pre-computed palette to control quantizing to 8 bits. You can supply a palette file (RGB or RGBA) and the MapServer will
map 24/32-bit values to those in the palette. Format options are:<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> FORMATOPTION "PALETTE_FORCE=TRUE"<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> FORMATOPTION "PALETTE=palette.txt"<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">This will definitely limit the colors in your output image to those you specify. The question is whether or not the anti-aliased colors will map to the right
color and that will depend on your palette. I did write a simple test with a 5 color palette (black, white, red, green and blue) and it seems to work ok but that’s a very simple palette… Based on your application it might work though.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
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<u></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><span>-<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><a href="http://maps1.dnr.state.mn.us/cgi-bin/mapserv70?map=/usr/local/mapserver/apps/test/palette/test.map&mode=map" target="_blank">http://maps1.dnr.state.mn.us/<wbr>cgi-bin/mapserv70?map=/usr/<wbr>local/mapserver/apps/test/<wbr>palette/test.map&mode=map</a>
(24-bit)<u></u><u></u></span></p>
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<u></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><span>-<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><a href="http://maps1.dnr.state.mn.us/cgi-bin/mapserv70?map=/usr/local/mapserver/apps/test/palette/test.map&mode=map&map.imagetype=png8" target="_blank">http://maps1.dnr.state.mn.us/<wbr>cgi-bin/mapserv70?map=/usr/<wbr>local/mapserver/apps/test/<wbr>palette/test.map&mode=map&map.<wbr>imagetype=png8</a>
(8-bit w/5 colors)<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Steve<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> mapserver-users [mailto:<a href="mailto:mapserver-users-bounces@lists.osgeo.org" target="_blank">mapserver-users-<wbr>bounces@lists.osgeo.org</a>]
<b>On Behalf Of </b>Erik H<br>
<b>Sent:</b> Monday, October 16, 2017 10:58 AM<br>
<b>To:</b> <a href="mailto:mapserver-users@lists.osgeo.org" target="_blank">mapserver-users@lists.osgeo.<wbr>org</a><br>
<b>Subject:</b> [mapserver-users] Draw roads WITHOUT anti-aliasing<u></u><u></u></span></p><div><div class="h5">
<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">I'm running a tiling server that uses MapServer 7.0.4 to generate PNGs.<u></u><u></u></p>
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<p class="MsoNormal">My colleagues came up with an ingenious idea to animate traffic conditions that would require them to identify road segments based on their color. They asked me to generate tiles with a predetermined RGBA value per road segment. <u></u><u></u></p>
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<p class="MsoNormal">I configured a layer of type LINE, with a STYLE section containing 'COLOR [palette]' (palette being a field in the database query). Initially, I thought I was creating the images my colleagues needed, but it seems that the anti-aliasing
causes some pixels to have colors other than the one I specified; this prevents us from identifying the road segments.<u></u><u></u></p>
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<p class="MsoNormal">We can live without anti-aliasing, but I was unable to turn it off; I tried both the AGG/PNG and GD/PNG drivers and messed with various FORMATOPTION identifiers, but nothing seemed to make any difference.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Any suggestions?<u></u><u></u></p>
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<p class="MsoNormal">Thanks.<u></u><u></u></p>
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