Phil Endecott wrote: > Code that does not use rotation will execute a few more instructions > since x and y values are being updated where previously only x values > were used. I anticipate that this overhead will not be measureable, > however. The important thing is that there is no trigonometry, and > only minimal additional multiplication, in the non-rotated case. If > anyone with a benchmarkable application would like to try to quantify > the effect, please do so.
I don't think it's relevant. > The Patch > --------- > > My patch is against DirectFB1.0.0 with the addition of Denis' > GetKerning patch posted yesterday. I suspect that it will apply > without much trouble to other versions (I have increased the diff > context size to make this more likely); feedback on that would be > appreciated. Download it from here: > > http://chezphil.org/tmp/dfb_rotation_1.patch Many thanks. I applied it to 1.1.x (only few conflicts). > The ++DFB patch is here: > > http://chezphil.org/tmp/++dfb_rotation_1.patch > > (Somehow, I often screw up when creating patch files. Please excuse me > if I got it wrong!) > > > Test / Demo > ----------- > > A test/demo program is here: > > http://chezphil.org/tmp/rotation_demo.cc Looks very cool. > Issues > ------ > > My test program seems to show some off-by-one errors in the bounding > box calculations, and perhaps some kerning problems. I plan to fix > this. Let me know if you spot any other problems. Only problem I saw was DSTF_BOTTOMRIGHT with 270 degree rotation. > Notes > ----- > > I am coming to the opinion that DirectFB would benefit from the use of > fractional pixel positions. This was somewhat crystalised when I read > this article, which was linked to from LWN: > > http://antigrain.com/research/font_rasterization/index.html Indeed, sub pixel positioning and text rendering would be nice. I started looking at blitting support for sub pixel rendered fonts, but thought with the current flags it's not fully possible. -- Best regards, Denis Oliver Kropp .------------------------------------------. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | "------------------------------------------" _______________________________________________ directfb-dev mailing list [email protected] http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
