Re: [mapserver-users] Quantize and 8bit/1bit PNG problem
Hi! Could I please ask for a comment on this issue from one of the developers? paalkr wrote: Hi! I have the following output format defined in my mapfile (MapServer 5.4.2): OUTPUTFORMAT NAME png8bit DRIVER AGG/PNG MIMETYPE image/png EXTENSION png FORMATOPTION QUANTIZE_FORCE=ON FORMATOPTION QUANTIZE_COLORS=256 FORMATOPTION QUANTIZE_NEW=ON FORMATOPTION INTERLACE=OFF END This works very well most of the time, even transparency. But in situations where the GetMap request don't contain any data at all (returned image should be total transparent) the resulting PNG is 1bit in stead of 8bits. If the produced image does contain some data the produced image i 8bits, with correctly rendered transparency where there are no data. This behavior are specially troublesome when building a tile cache because there are a lot of this request without any valid data. In almost all applications I guess that this issue wouldn't do any harm, but we uses Bing Maps for some projects and Bing Maps can't handle 1bit PNGs. What can be done to overcome this issue? Regards, Pål Kristensen - Regards, Pål Kristensen -- View this message in context: http://n2.nabble.com/Quantize-and-8bit-1bit-PNG-problem-tp3641221p3930988.html Sent from the Mapserver - User mailing list archive at Nabble.com. ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Quantize and 8bit/1bit PNG problem
paalkr wrote: Hi! Could I please ask for a comment on this issue from one of the developers? Pål, One bit PNGs are a perfectly valid response. I would suggest two approaches. 1) File a ticket with Microsoft on Bing Maps, and hopefully they will roll a fix into their operational build within a couple days. (ha ha) 2) Manually produce a nice empty tile that works with Bing Maps some other way, and write a script to replace the 1bit PNG file (which should presumably have a fixed size) with the bing-safe ones. Perhaps not the sort of answer you were hoping for, but you did implore us for comment even when none of us thought we had anything particularly bright to say. Best regards, paalkr wrote: Hi! I have the following output format defined in my mapfile (MapServer 5.4.2): OUTPUTFORMAT NAME png8bit DRIVER AGG/PNG MIMETYPE image/png EXTENSION png FORMATOPTION QUANTIZE_FORCE=ON FORMATOPTION QUANTIZE_COLORS=256 FORMATOPTION QUANTIZE_NEW=ON FORMATOPTION INTERLACE=OFF END This works very well most of the time, even transparency. But in situations where the GetMap request don't contain any data at all (returned image should be total transparent) the resulting PNG is 1bit in stead of 8bits. If the produced image does contain some data the produced image i 8bits, with correctly rendered transparency where there are no data. This behavior are specially troublesome when building a tile cache because there are a lot of this request without any valid data. In almost all applications I guess that this issue wouldn't do any harm, but we uses Bing Maps for some projects and Bing Maps can't handle 1bit PNGs. What can be done to overcome this issue? -- ---+-- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush| Geospatial Programmer for Rent ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Quantize and 8bit/1bit PNG problem
You could use a Python/PHP mapscript wrapper that tests to see the number of colors in the PNG before returning it to the client. In such a case you could manipulate the PNG using GD/PAL/Cairo/Graphics-Library-of-the-Month. - Original Message From: Frank Warmerdam warmer...@pobox.com To: paalkr pal.kristen...@statkart.no Cc: mapserver-users@lists.osgeo.org Sent: Mon, November 2, 2009 8:59:13 AM Subject: Re: [mapserver-users] Quantize and 8bit/1bit PNG problem paalkr wrote: Hi! Could I please ask for a comment on this issue from one of the developers? Pål, One bit PNGs are a perfectly valid response. I would suggest two approaches. 1) File a ticket with Microsoft on Bing Maps, and hopefully they will roll a fix into their operational build within a couple days. (ha ha) 2) Manually produce a nice empty tile that works with Bing Maps some other way, and write a script to replace the 1bit PNG file (which should presumably have a fixed size) with the bing-safe ones. Perhaps not the sort of answer you were hoping for, but you did implore us for comment even when none of us thought we had anything particularly bright to say. Best regards, paalkr wrote: Hi! I have the following output format defined in my mapfile (MapServer 5.4.2): OUTPUTFORMAT NAME png8bit DRIVER AGG/PNG MIMETYPE image/png EXTENSION png FORMATOPTION QUANTIZE_FORCE=ON FORMATOPTION QUANTIZE_COLORS=256 FORMATOPTION QUANTIZE_NEW=ON FORMATOPTION INTERLACE=OFF END This works very well most of the time, even transparency. But in situations where the GetMap request don't contain any data at all (returned image should be total transparent) the resulting PNG is 1bit in stead of 8bits. If the produced image does contain some data the produced image i 8bits, with correctly rendered transparency where there are no data. This behavior are specially troublesome when building a tile cache because there are a lot of this request without any valid data. In almost all applications I guess that this issue wouldn't do any harm, but we uses Bing Maps for some projects and Bing Maps can't handle 1bit PNGs. What can be done to overcome this issue? -- ---+-- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush| Geospatial Programmer for Rent ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Quantize and 8bit/1bit PNG problem
Hi Frank! Thanks for the comment! The idea of using Bing Maps and Silverlight was not mine, I argued quite heavily against it :) The bug is in fact in Sliverlight and Microsoft has admitted it, but they don't wont to fix it, go figure! I understand that a 1bit image is a total valid output and I personally don't have any trouble with it. The request to the list was more like a documentation thing from my side, so that the Microsoft fanboys can see for them selves that the problem should be fixed in the broken software (Bing Maps and Silverlight), not vice versa. I guess that the best workaround is the suggested python mapscript wrapper, and check if the output is 1bit or not, if true then change it with a 8bits image instead. But I'm not totally sure that I really wont to fix this on the service side anyway ;) Frank Warmerdam wrote: paalkr wrote: Hi! Could I please ask for a comment on this issue from one of the developers? Pål, One bit PNGs are a perfectly valid response. I would suggest two approaches. 1) File a ticket with Microsoft on Bing Maps, and hopefully they will roll a fix into their operational build within a couple days. (ha ha) 2) Manually produce a nice empty tile that works with Bing Maps some other way, and write a script to replace the 1bit PNG file (which should presumably have a fixed size) with the bing-safe ones. Perhaps not the sort of answer you were hoping for, but you did implore us for comment even when none of us thought we had anything particularly bright to say. Best regards, paalkr wrote: Hi! I have the following output format defined in my mapfile (MapServer 5.4.2): OUTPUTFORMAT NAME png8bit DRIVER AGG/PNG MIMETYPE image/png EXTENSION png FORMATOPTION QUANTIZE_FORCE=ON FORMATOPTION QUANTIZE_COLORS=256 FORMATOPTION QUANTIZE_NEW=ON FORMATOPTION INTERLACE=OFF END This works very well most of the time, even transparency. But in situations where the GetMap request don't contain any data at all (returned image should be total transparent) the resulting PNG is 1bit in stead of 8bits. If the produced image does contain some data the produced image i 8bits, with correctly rendered transparency where there are no data. This behavior are specially troublesome when building a tile cache because there are a lot of this request without any valid data. In almost all applications I guess that this issue wouldn't do any harm, but we uses Bing Maps for some projects and Bing Maps can't handle 1bit PNGs. What can be done to overcome this issue? -- ---+-- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush| Geospatial Programmer for Rent ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users - Regards, Pål Kristensen -- View this message in context: http://n2.nabble.com/Quantize-and-8bit-1bit-PNG-problem-tp3641221p3935009.html Sent from the Mapserver - User mailing list archive at Nabble.com. ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
