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<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Ah, thanks. So the solution is to not call GDALSetRasterNoDataValue() unless we really want to set one color as transparent.<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Even Rouault <even.rouault@spatialys.com>
<br>
<b>Sent:</b> Thursday, March 26, 2020 11:24 PM<br>
<b>To:</b> Joaquim Manuel Freire Luís <jluis@ualg.pt><br>
<b>Cc:</b> gdal-dev@lists.osgeo.org<br>
<b>Subject:</b> Re: [gdal-dev] Issue with writen colortables<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:9.0pt;font-family:"Courier New"">On jeudi 26 mars 2020 23:19:47 CET Joaquim Manuel Freire Luís wrote:<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">> Funny, I made it nodata = 1 and the zero moved to second place.<o:p></o:p></span></p>
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<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">Fully determinstic behaviour: GDAL sets the alpha component of the entry in
<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">the color table whose value is nodata to 0:<o:p></o:p></span></p>
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<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New""><a href="https://github.com/OSGeo/gdal/blob/master/gdal/frmts/png/pngdataset.cpp#L1820">https://github.com/OSGeo/gdal/blob/master/gdal/frmts/png/pngdataset.cpp#L1820</a><o:p></o:p></span></p>
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<span style="font-size:9.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
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<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">Spatialys - Geospatial professional services<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New""><a href="http://www.spatialys.com">http://www.spatialys.com</a><o:p></o:p></span></p>
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