[Devel] Re: [Kannada] Re: Problem with freetype rendering of an Indic opentype font

[Arun Sharma]

On Thu, Sep 04, 2003 at 10:24:10PM +0200, Werner LEMBERG wrote:
> > I see a problem with the freetype rendering of this unicode string:
> > 
> > "0xcb7 0xccd"
> > 
> > Using Microsoft tunga.ttf (A kannada font that ships with Windows
> > XP).  In fact, the problem manifests itself with all other
> > consonants too, including 0xcb7.
> 
> I don't have time to investigate but it seems to me that some
> contextual shaping is happening.  If this is true it is not a problem
> of FreeType 2 (which doesn't support OpenType directly for the moment)
> but rather a problem one level higher where Indic scripts are handled,
> probably within the Pango library.  Owen?

ok, I did some more investigation. Here's a partial dump of the font.
According to this rule, glyph 0x62 should've been substituted by glyph
0xb0. But for some reason, it's not happening.

Does this ring a bell ?

        -Arun

   <Lookup> <!-- 36 -->
      <LookupType>SINGLE</LookupType>
      <Subtable>
         <SubstFormat>2</SubstFormat>
         <Coverage>
            <CoverageFormat>2</CoverageFormat>
            <Glyph>  42 -   64</Glyph>
            <Glyph>  75 -   75</Glyph>
            <Glyph> 10d -  10e</Glyph>
         </Coverage>
         <GlyphCount>38</GlyphCount>
         <Substitute>0x90</Substitute> <!-- 0 -->
         <Substitute>0x91</Substitute> <!-- 1 -->
         <Substitute>0x92</Substitute> <!-- 2 -->
         <Substitute>0x93</Substitute> <!-- 3 -->
         <Substitute>0x94</Substitute> <!-- 4 -->
         <Substitute>0x95</Substitute> <!-- 5 -->
         <Substitute>0x96</Substitute> <!-- 6 -->
         <Substitute>0x97</Substitute> <!-- 7 -->
         <Substitute>0x98</Substitute> <!-- 8 -->
         <Substitute>0x99</Substitute> <!-- 9 -->
         <Substitute>0x9a</Substitute> <!-- 10 -->
         <Substitute>0x9b</Substitute> <!-- 11 -->
         <Substitute>0x9c</Substitute> <!-- 12 -->
         <Substitute>0x9d</Substitute> <!-- 13 -->
         <Substitute>0x9e</Substitute> <!-- 14 -->
         <Substitute>0x9f</Substitute> <!-- 15 -->
         <Substitute>0xa0</Substitute> <!-- 16 -->
         <Substitute>0xa1</Substitute> <!-- 17 -->
         <Substitute>0xa2</Substitute> <!-- 18 -->
         <Substitute>0xa3</Substitute> <!-- 19 -->
         <Substitute>0xa4</Substitute> <!-- 20 -->
         <Substitute>0xa5</Substitute> <!-- 21 -->
         <Substitute>0xa6</Substitute> <!-- 22 -->
         <Substitute>0xa7</Substitute> <!-- 23 -->
         <Substitute>0xa8</Substitute> <!-- 24 -->
         <Substitute>0xa9</Substitute> <!-- 25 -->
         <Substitute>0xaa</Substitute> <!-- 26 -->
         <Substitute>0xab</Substitute> <!-- 27 -->
         <Substitute>0xac</Substitute> <!-- 28 -->
         <Substitute>0xad</Substitute> <!-- 29 -->
         <Substitute>0xae</Substitute> <!-- 30 -->
         <Substitute>0xaf</Substitute> <!-- 31 -->
         <Substitute>0xb0</Substitute> <!-- 32 -->
         <Substitute>0xb1</Substitute> <!-- 33 -->
         <Substitute>0xb2</Substitute> <!-- 34 -->
         <Substitute>0xb3</Substitute> <!-- 35 -->
         <Substitute>0x10f</Substitute> <!-- 36 -->
         <Substitute>0x110</Substitute> <!-- 37 -->
      </Subtable>
   </Lookup>