Re: [GRASS-user] translucency and svg output
pete davidson wrote: The only workaround I've managed to find so far is to export each layer as an individual svg, with v.out.svg? Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] translucency and svg output
Pete, sorry if I'm off board : do you absolutely need to generate a /vector/ output ? Vincent. Le mercredi 24 mars 2010 à 20:15 -0700, pete davidson a écrit : On Wed, Mar 24, 2010 at 7:49 PM, pete davidson caiti...@gmail.com wrote: On Wed, Mar 24, 2010 at 7:42 PM, Glynn Clements gl...@gclements.plus.com wrote: pete davidson wrote: I'm producing maps in svg format using the cairo driver and d.out.file. One thing I'd really like to be able to do is set one or more of the vector layers to be partially translucent. After rummaging through this list, I'm beginning to wonder if its possible at all, since translucency in the guis seems to be handled by g.pnmcomp, but perhaps someone with more experience knows a way to do it. It isn't. The graphics API doesn't support an alpha component. Apart from anything else, it can't easily be implemented for PostScript output, as PostScript doesn't support translucency. Faking it with patterns is possible, but it starts getting complicated if you want more than one translucent layer. The only workaround I've managed to find so far is to export each layer as an individual svg, then use something like inkscape to rejoin them, setting the translucency/transparency of each layer as I do it. Which is fine for a map with only a few layers, but gets tedious when dealing with maps with dozens of layers. SVG is XML, so it shouldn't be especially hard to automate the process using generic XML-processing tools. Ohh, I hadn't thought of editing the svg/xml directly. Thanks for the suggestion, I'll see what I can achieve from there. And then we discover that the 'svg' produced by cairo using the above script is actually just a png in an svg wrapper.. At least for my particular install of Grass. That's frustrating. Ahh well, back to the drawing board. Peter ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] translucency and svg output
Thanks to all for these suggestions and comments. I will look at the options suggested by Andreas, and follow Glynn's comment to explore why Cairo dropped to rasterization - it's good to know that *that's* why I got raster output, rather than wrapping a raster being all that Cairo does! To answer Hamish, no, I was exporting each individual layer using d.vect and d.out.file. Your question gives me the idea I should try using v.out.svg for individual layers to help work out why Cairo dropped to raster output and/or to produce individual layers to stitch together later if necessary. Re Vincent's comment that holding vector format to 'the very end', unfortunately what I'm doing isn't for single-use - I'm producing maps that will be used by several end users for uses ranging from conference posters to individual papers, so I can't predict final image sizes in advance (and I'm not going to be the only end-user). Hence my desire to stick to a vector format in the hopes that they'll at least scale cleanly. Although if Vincent is willing to share an example script that uses imagemagik to compose ps layers I'd be delighted to see it. Thanks again to all for sharing your thoughts expertise. Peter ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] translucency and svg output
pete davidson wrote: I'm producing maps in svg format using the cairo driver and d.out.file. One thing I'd really like to be able to do is set one or more of the vector layers to be partially translucent. After rummaging through this list, I'm beginning to wonder if its possible at all, since translucency in the guis seems to be handled by g.pnmcomp, but perhaps someone with more experience knows a way to do it. It isn't. The graphics API doesn't support an alpha component. Apart from anything else, it can't easily be implemented for PostScript output, as PostScript doesn't support translucency. Faking it with patterns is possible, but it starts getting complicated if you want more than one translucent layer. The only workaround I've managed to find so far is to export each layer as an individual svg, then use something like inkscape to rejoin them, setting the translucency/transparency of each layer as I do it. Which is fine for a map with only a few layers, but gets tedious when dealing with maps with dozens of layers. SVG is XML, so it shouldn't be especially hard to automate the process using generic XML-processing tools. -- Glynn Clements gl...@gclements.plus.com ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] translucency and svg output
On Wed, Mar 24, 2010 at 7:42 PM, Glynn Clements gl...@gclements.plus.comwrote: pete davidson wrote: I'm producing maps in svg format using the cairo driver and d.out.file. One thing I'd really like to be able to do is set one or more of the vector layers to be partially translucent. After rummaging through this list, I'm beginning to wonder if its possible at all, since translucency in the guis seems to be handled by g.pnmcomp, but perhaps someone with more experience knows a way to do it. It isn't. The graphics API doesn't support an alpha component. Apart from anything else, it can't easily be implemented for PostScript output, as PostScript doesn't support translucency. Faking it with patterns is possible, but it starts getting complicated if you want more than one translucent layer. The only workaround I've managed to find so far is to export each layer as an individual svg, then use something like inkscape to rejoin them, setting the translucency/transparency of each layer as I do it. Which is fine for a map with only a few layers, but gets tedious when dealing with maps with dozens of layers. SVG is XML, so it shouldn't be especially hard to automate the process using generic XML-processing tools. Ohh, I hadn't thought of editing the svg/xml directly. Thanks for the suggestion, I'll see what I can achieve from there. Regards, Peter ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] translucency and svg output
On Wed, Mar 24, 2010 at 7:49 PM, pete davidson caiti...@gmail.com wrote: On Wed, Mar 24, 2010 at 7:42 PM, Glynn Clements gl...@gclements.plus.comwrote: pete davidson wrote: I'm producing maps in svg format using the cairo driver and d.out.file. One thing I'd really like to be able to do is set one or more of the vector layers to be partially translucent. After rummaging through this list, I'm beginning to wonder if its possible at all, since translucency in the guis seems to be handled by g.pnmcomp, but perhaps someone with more experience knows a way to do it. It isn't. The graphics API doesn't support an alpha component. Apart from anything else, it can't easily be implemented for PostScript output, as PostScript doesn't support translucency. Faking it with patterns is possible, but it starts getting complicated if you want more than one translucent layer. The only workaround I've managed to find so far is to export each layer as an individual svg, then use something like inkscape to rejoin them, setting the translucency/transparency of each layer as I do it. Which is fine for a map with only a few layers, but gets tedious when dealing with maps with dozens of layers. SVG is XML, so it shouldn't be especially hard to automate the process using generic XML-processing tools. Ohh, I hadn't thought of editing the svg/xml directly. Thanks for the suggestion, I'll see what I can achieve from there. And then we discover that the 'svg' produced by cairo using the above script is actually just a png in an svg wrapper.. At least for my particular install of Grass. That's frustrating. Ahh well, back to the drawing board. Peter ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
