Sascha Brawer <[EMAIL PROTECTED]> writes: > It seems there are several people with that goal, and that some > coordination would be good so we can share at least some of the effort. > Therefore, I guess I'll try to arrange a discussion session during > LinuxKongress in Saarbrücken/Germany. Jean-Daniel, are you planning to go > there, by chance? > > Graydon, where are you located? Is there a chance that either you or > someone else might be present who is familiar with what you are doing on > top of Cairo/Xr?
I am located in Canada, and it will be somewhat of a trick for me to get to Saarbrücken. I'll ask my manager, but I can't make any promises. I have had a look over the agile2d material, and while I was quite enthusiastic looking at screenshots and playing with the demo material, after reading the code I am hesitant to endorse this as a solution for classpath or gcj. it seems quite specifically an experiment in java2d *acceleration*, rather than from-scratch implementation. In particular, it relies on the existing sun java2d to perform much of the "tricky" work, such as region and scanline conversion of fonts, strokes and shapes; glyph selection, shaping and layout. moreover it does not appear to support porter/duff compositing rules or splines, nor subpixel positioning of glyphs (the latter is a common problem when using texture mosaics for hardware-assisted glyphs). in general terms -- and I don't mean to start a flamewar or anything -- what it seems to do is (elegantly) copy pixels, matrices and vectors back and forth between sun's java2d and the video card's texture buffers, matrix stack and display lists, keeping the requisite graphics states in sync and accelerating those operations it can with hardware resources. the result is a good speedup, but it's not particularly independent of sun's code. (a broader concern I have with "hardware accelerated" drawing is that there is sometimes an uncontrollable loss of precision and increase in ambiguous or unspecified behavior when using consumer graphics hardware. for example -- though you'll probably have a hard time reproducing this -- my cheapo OGL video card appears to make some creative decisions about texel coordinates, such that depending on the position of a window on the screen, glyphs in the agile2d demo are selected from one pixel further to the left or right than they should be, making small (< 24pt) text read like garbage. this is less significant with applications like games -- for which the hardware is designed -- or for large block-pixel movement commands, but can be a problem when attempting to do precise subpixel operations, for example rendering and placing glyphs.) -graydon _______________________________________________ Classpath mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/classpath