SVN r3776 now has support for rotation of mathtext to any angle in the Agg backend (i.e. it's now supported in all backends).
Enjoy! Mike Michael Droettboom wrote: > Paul Kienzle wrote: >> On Thu, Aug 30, 2007 at 02:19:47PM -0400, Michael Droettboom wrote: >>> Paul Kienzle wrote: >>>> Hi all, >>>> Before I look to deeply into this myself, is there anyone working on it >>>> already? Is there anything I need to look out for when implementing it? >>> I've made a few excursions down that road -- >>> >>> For bitmap font rendering, the entire math expression is first laid out >>> in a greyscale bitmap buffer, which is cached and then transferred to >>> the main plot bitmap. It was already that way when I got here, and I >>> assume that's an important optimization (so the text doesn't have to be >>> re-laid-out when the plot is zoomed/panned). I say "perhaps" because I >>> have no data to back it up, and don't know if that came out of profiling >>> or not. >>> >>> There are a few key low level pieces that are missing for rotation: >>> >>> - FT2Font.draw_glyph_to_bitmap does not support rotation. This would >>> have to be added, or there may be a way to use >>> set_text/draw_glyphs_to_bitmap which does support rotation. However, >>> that would make rendering the entire expression to a single buffer much >>> more difficult. >> Adding rotation to draw_glyph_to_bitmap looks like the easier option... > > >>> - The horizontal lines are all drawn as filled rectangles aligned to the >>> pixel grid, directly into the font buffers. That will probably have to >>> be pushed upward into the Agg layer to get good line drawing at >>> arbitrary angles -- but that also makes caching the bitmap a little more >>> difficult. So maybe it makes sense to implement our own Breshenham's >>> algorithm in ft2font.cpp. >> ...but if we need to go into agg anyway, why not use Agg's font handling >> capabilities directly? > > Perhaps historical reasons. I wonder if they're still relevant. > >>> All this will be affected by John's proposed refactoring of the >>> backends, of course, which has kind of kept me off of it in a "wait and >>> see" kind of mode. Right now, each backend has a custom interface to >>> communicate with mathtext -- whereas mathtext should simply be calling >>> the same low-level methods on all backends to get its job done. That, >>> of course, would make this buffer optimization harder (or at least it >>> would have to be thought about differently). >> I haven't followed the refactoring proposal close enough to know if it >> makes more sense to implement mathtext via freetype in agg or to use >> freetype directly like you are currently doing. Once that decision is >> clear, we can certainly prototype the handling of rotated text in the Agg >> backend. >> >> Presumably this will have to be repeated for Cairo. > > Cairo already works, as of a few weeks ago, it no longer uses bitmaps > for mathtext rendering. (I should have been more clear earlier -- my > brain has it filed in with the vector backends, though obviously it has > a resterizer.) > >>> Let me know if you decide to implement this and let me know if you have >>> any questions about the code. Otherwise I'm happy to add it to my queue. >> I can get by for now with limited text rotation, at least until the >> backend refactoring has settled. > > That may be a while (re: John's latest message). In the meantime, I'm > going to explore, as he suggested, how bad doing a raster rotation would > look, as that's the easiest path forward. > > Cheers, > Mike > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
