Milton Jonathan ha scritto: > Hello Andrea > > I don't have any code around me right now, but I can tell you my > understanding of this topic: > - DPI should affect the pixels/meter ratio (map scale). > - Symbolizers given in meters should not change apparent size when DPI > varies, as the size of the map in meters also remains the same. In this > situation, when DPI increases the sizes in pixels of both the map and > the symbolizers should increase proportionately. > - Symbolizers given in pixels should have a SMALLER apparent size if DPI > increases: the same number of pixels now represent a smaller size in the > real world (more dots in the same inch) > > That said, I don't think that a new rescaling step should be necessary. > My feeling is that the DPI setting should affect the map scale > (pixels/meter) passed over to the UomRescaleStyleVisitor. > > Of course, it could be ME who is missing something :P
Right, my understanding is different than yours. Think you want to generate an image that you need to send to a printer doing 300dpi. Your screen is 100dpi or something like that instead. The dpi is just an accident of the display technology, but you want the symbolizers to have the same size. However on the screen 50 pixels are long X, whilst when printed the are long just X/3 because the priter can cram a lot more pixels in the same space. You want the output to look the same, but to do so, you need to generate a symbolizer that's 3 times larger in terms of pixel, to preserve its size in cm. So no matter if you are sizing in pixels or in meters, you need to compensate for the DPI change by rescaling everything by targetDpi/standardDpi Makes sense? Afaik this is what uDig does for printing (looking for confirmation on this one) Cheers Andrea -- Andrea Aime OpenGeo - http://opengeo.org Expert service straight from the developers. ------------------------------------------------------------------------------ ThinkGeek and WIRED's GeekDad team up for the Ultimate GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the lucky parental unit. See the prize list and enter to win: http://p.sf.net/sfu/thinkgeek-promo _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
