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List:       freedesktop-xorg
Subject:    Re: Color bitmap support in Xft?
From:       Clément_Pit--Claudel <clement.pit () gmail ! com>
Date:       2015-12-18 12:43:11
Message-ID: 5673FF5F.7050703 () gmail ! com
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Hi Michael,

Are you thinking of the SVG in OpenType proposal from Adobe and Mozilla? Indeed, it \
would be nice to have support for that too, but it seems like a much more ambitious \
project. There are demos at \
https://people.mozilla.org/~jkew/opentype-svg/soccer.html, and a draft spec from \
Adobe at https://lists.w3.org/Archives/Public/public-svgopentype/2011Oct/0000.html.

The fonts I was thinking about are much simpler; they only embed static raster \
images. The full spec is below:

  http://www.microsoft.com/typography/otspec/cbdt.htm
  http://www.microsoft.com/typography/otspec/cblc.htm

But I imagine Xft doesn't need to be aware of the low-level details, since FreeType \
already has support for this.

Clément.

On 12/18/2015 02:16 AM, Michael Titke wrote:
> Just add a video mode font (we'll need to "typeset" videos intext
> anyway - what was layout then?) and replace user input with random
> noise where DSP would have told those smart ones ...
> 
> On 17/12/2015 21:23, Clément Pit--Claudel wrote:
> > Hi all,
> > 
> > I'm looking into adding support for color emoji to Emacs. Color
> > emoji use a new feature of OpenType fonts that allows font
> > designers to embed full-color images in a font for certain glyphs.
> > Fonts such as Google Noto Emoji or Apple Color Emoji thus have a
> > table mapping certain Unicode points to raster color images. This
> > feature is frequently used on smartphones, and was more recently
> > added to Chrome and Firefox (both get it throught Freetype).
> > 
> > Freetype has support for these multicolor glyphs since version 2.5
> > (2013). So does FontConfig (and, apparently, Skia). However, it
> > does not seem to be possible to use this feature through Xft. Has
> > there been efforts to support it?
> > 
> > IIUC, the required changes would involve extending case matches
> > that look at the FT_Pixel_Mode enumeration (it gained a new member
> > FT_PIXEL_MODE_BGRA), and passing an extra flag to Freetype. Here is
> > the relevant documentation:
> > 
> > > FT_PIXEL_MODE_BGRA
> > > 
> > > An image with four 8-bit channels per pixel, representing a
> > > color image (such as emoticons) with alpha channel. For each
> > > pixel, the format is BGRA, which means, the blue channel comes
> > > first in memory. The color channels are pre-multiplied and in the
> > > sRGB colorspace. For example, full red at half-translucent
> > > opacity will be represented as ‘00,00,80,80', not ‘00,00,FF,80'.
> > > See also FT_LOAD_COLOR. FT_LOAD_COLOR
> > > 
> > > This flag is used to request loading of color embedded-bitmap 
> > > images. The resulting color bitmaps, if available, will have the
> > > FT_PIXEL_MODE_BGRA format. When the flag is not used and color 
> > > bitmaps are found, they will be converted to 256-level gray
> > > bitmaps transparently. Those bitmaps will be in the
> > > FT_PIXEL_MODE_GRAY format
> > Has such an extension been discussed before? Or am I taking the
> > wrong approach?
> > 
> > Clément.
> > 
> > 
> > 
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> 
> 
> _______________________________________________ xorg@lists.x.org:
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