Bug 25018

https://sourceforge.net/projects/freetype/files/freetype2/2.10.0/

Changelog:
```
CHANGES BETWEEN 2.9.1 and 2.10

  I. IMPORTANT CHANGES

    - A bunch  of new functions has  been added to access  and process
      COLR/CPAL data of OpenType fonts with color-layered glyphs.

        FT_Palette_Data_Get
          Retrieve color palette data.
        FT_Palette_Select
          Select and activate a color palette for color-layered
          glyphs.
        FT_Palette_Set_Foreground_Color
          Set text foreground color for palette index 0xFFFF.

        FT_Get_Color_Glyph_Layer
          Get color layers for a given glyph (using an interator
          object).

        FT_Bitmap_Blend
          Blend one bitmap onto another with a given color.

    - An   experimental  feature   is   the  new   behaviour  of   the
      `FT_LOAD_COLOR' load  flag for color-layered  glyphs: Internally
      it  sets a  flag so  that  if `FT_Render_Glyph'  is called  with
      `FT_RENDER_MODE_NORMAL'      (or       `FT_Load_Glyph'      with
      `FT_LOAD_RENDER'), a default blending  of the color glyph layers
      will happen automatically for convenience.

    - As  a   GSoC  2018   project,  Nikhil   Ramakrishnan  completely
      overhauled and modernized the API reference.


  II. MISCELLANEOUS

    - The  logic for  computing  the global  ascender, descender,  and
      height  of  OpenType  fonts   has  been  slightly  adjusted  for
      consistency.

      . If the `useTypoMetrics' flag (i.e., bit 7 in the `fsSelection'
        field) in the  `OS/2' table is set, use the  `sTypo' fields in
        `OS/2' unconditionally.
      . Otherwise use  the metrics data from the `hhea'  table (if not
        zero).
      . Otherwise use the `sTypo' fields from the `OS/2' table (if not
        zero).
      . Otherwise use the `usWin' data from the `OS/2' table as a last
        resort.

      Variable fonts will apply the `MVAR' deltas to whichever metrics
      were picked.

    - `TT_Set_MM_Blend' could  fail if  call repeatedly with  the same
      arguments.

    - The precision  of handling  deltas in  Variation Fonts  has been
      increased.  The  problem did only show  up with multidimensional
      designspaces.

    - New function `FT_Library_SetLcdGeometry' to  set up the geometry
      of LCD subpixels.

    - FreeType now uses the `defaultChar' property of PCF fonts to set
      the  glyph for  the undefined  character  at glyph  index 0  (as
      FreeType already does for all other supported font formats).  As
      a consequence,  the order of  glyphs of  a PCF font  if accessed
      with  FreeType  can  be   different  now  compared  to  previous
      versions.

      This change doesn't affect PCF font access with cmaps.

    - `FT_Select_Charmap' has  been changed  to allow  parameter value
      `FT_ENCODING_NONE', which is valid for BDF, PCF, and Windows FNT
      formats to  access built-in cmaps  that don't have  a predefined
      `FT_Encoding' value.

    - A previously  reserved field in the  `FT_GlyphSlotRec' structure
      now holds the glyph index.

    - On Win32 platforms,  the use of `_DLL' to build  the library has
      been replaced with `DLL_EXPORT' and `DLL_IMPORT'.

    - The usual round  of fuzzer bug fixes to  better reject malformed
      fonts.

    - `FT_Outline_New_Internal'  and  `FT_Outline_Done_Internal'  have
      been removed.  These two functions were public by oversight only
      and were never documented.

    - A new  function `FT_Error_String' returns descriptions  of error
      codes if  configuration macro  FT_CONFIG_OPTION_ERROR_STRINGS is
      defined.

    - `FT_Set_MM_WeightVector'  and  `FT_Get_MM_WeightVector' are  new
      functions limited to Adobe MultiMaster fonts to directly set and
      get the weight vector.

    - Support for Position Independent Code as needed by  systems that
      prohibit  automatic  address  fixups,  such  as BREW,  has  been
      removed.  [Compilation with modern compilers that use flags like
      `-fPIC' or `-fPIE' is not affected.]

    - The  `ftdump' demo  program has  new  options `-c'  and `-C'  to
      display charmaps  in compact and detailed  format, respectively.
      Option `-V' has been removed.

    - The `ftview', `ftstring',  and `ftgrid' demo programs  use a new
      command line option `-d' to  specify the program window's width,
      height, and color depth.

    - The `ftview' demo program now  displays red boxes for zero-width
      glyphs.

    - `ftglyph'   has   limited   support  to   display   fonts   with
      color-layered glyphs.  This will be improved later on.

    - `ftgrid' can now display bitmap fonts also.

    - The `ttdebug'  demo program has  a new  option `-f' to  select a
      member of a TrueType collection (TTC).

    - Other various improvements to the demo programs.
```