On 2008-10-11 17:14-0700 Alan W. Irwin wrote: > In sum, I feel I am making excellent progress on understanding the -dev svg > text positioning problems that so many people here have encountered. I have > fixed one (bad) text-positioning bug as of revision 8884, and I have a plan > to deal with the remaining one that I have found. I have some hope that > once that remaining bug is fixed we'll have a complete cure for the text > positioning problems, but we'll see.
OK, I am now finished with this as of revision 8892. To explain how I deal with the last identified issue, notice that the choice of anchor tag was perfect for justifications of 0., 0.5., and 1.0. Thus, I calculated a rough sum of the glyph sizes (this algorithm should only be correct for monospaced fonts), and applied a differential correction proportional to the difference of the justification from the nearest of 0., 0.5, or 1.0. Since these justifications are the ones chosen for all standard examples other than example 3, and the deviation from those justifications is small in that case, the standard examples don't provide much of a test of my differential correction. However, I did check the empirical proportionality constant I use with special examples with fairly long character strings like "HHHHHHH", etc., and also printed out results for sum_glyph_size, and I think the differential correction should be okay. Certainly it makes a nice looking result for example 3. I have only spot checked a few examples other than 3, but what I checked continues to look good for firefox 2 (with glyph lookup problems expecially for the exotic fonts of example 24) and konqueror (with substantially worse glyph lookup problems) so there is essentially no change in those cases except for the improvement to example 3 (the degree labels are not crammed so tightly to the circle anymore). Where the major change is expected is for other viewers and also for svg editors because of the extraneous extra spaces and newline characters that I removed from the <text> tag values produced by svg.c. Andrew, and Steve (and anybody else) could you try your tests again of svg results for revision 8892? I think the positioning results will be a lot better than before but if your applications had trouble with glyph finding before (i.e., text is missing altogether), that issue will remain unchanged. If your tests show good positioning results, then I will ascribe the remaining small positioning issues (up to a half-character width displaced from the correct position) with "display" to librsvg problems, but in any case I hope/believe I am done with my refinements to this driver. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); PLplot scientific plotting software package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
