Unless you decide to save the transparent view of the gui to a file so that it can later be composited over something, you are free to use subpixel-antialiasing, using the formulae from my first message.
> I am writing a GUI library So we are kind of a blood brothers :-) 2015-11-05 15:00 GMT+01:00 John Found <[email protected]>: > On Thu, 5 Nov 2015 13:05:43 +0100 > Wojciech Mamrak <[email protected]> wrote: > >> > In a result I made it first to convert the RGB glyph to grayscale and >> > then to blend it to the background. This way, the transparency is always >> > OK. >> >> You can return grayscale bitmaps from FT directly, without the >> conversion on your side. >> The transparency will be OK but remember to use the alpha channel >> blending formula this time :) > > I am writing a GUI library and the user later will choose how FT fonts to be > rendered. > So, I need to provide support for all possible formats. > > For the grayscale rendered glyphs, I am using the value as a "intensity", > multiplying > by it every component of the the drawing color: > > Crgb = Crgb * Gray and then making the standard alpha blending of so computed > color and > the background. Everything seems to work fine... > > Now I am using the same algorithm for LCD rendered glyphs, only computing the > gray value > by a little bit weird equation: Gray = (R + 2*G + B)/4 and the result is also > pretty good. > >> >> > But the big question is "Do I need subpixel antialiased fonts so badly?" :) >> >> This question holds if you intend to compose and display some images >> on the screen (which is always opaque). Then it depends on font size, >> font itself, targeted device (e.g. resolution, pixel layout), etc. If >> you intend to save images with transparency, the only versatile option >> is grayscale antialiased text. Generating SVG images, which are >> composed "at runtime", assuming rendering engine supports >> subpixel-antialiased text, is another option. >> > > It depends greatly on the use cases of the library. > > But as long as it is not finished yet, I can say only that it is intended to > be used for GUI creation on x86 computers, working under different OSes. > > > -- > http://fresh.flatassembler.net > http://asm32.info > John Found <[email protected]> _______________________________________________ Freetype mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/freetype
