naiveproxy/components/services/font/public/interfaces/font_service.mojom

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module font_service.mojom;

import "mojo/public/mojom/base/file.mojom";

enum TypefaceSlant {
  ROMAN = 0,
  ITALIC = 1,
  OBLIQUE = 2,
};

struct TypefaceStyle {
  uint16 weight;
  uint8 width;
  TypefaceSlant slant;
};

// A reference to specific font on the font service.
struct FontIdentity {
  uint32 id;
  int32 ttc_index;
  // TODO(erg): So the string is supposed to be a path. However, the current
  // chrome code goes out of its way to send this to the renderer process, and
  // it is passed to blink, even though the openStream() IPC in chrome uses the
  // id number instead. Do more investigation about what we need to do to plug
  // this system path leak.
  string str_representation;
};

enum RenderStyleSwitch {
    OFF = 0,
    ON = 1,
    NO_PREFERENCE = 2,
};

struct FontRenderStyle {
  RenderStyleSwitch use_bitmaps;    // use embedded bitmap strike if possible
  RenderStyleSwitch use_autohint;  // use 'auto' hinting (FreeType specific)
  RenderStyleSwitch use_hinting;    // hint glyphs to the pixel grid
  uint8 hint_style;                 // level of hinting, 0..3
  RenderStyleSwitch use_antialias;  // antialias glyph shapes
  // use subpixel rendering (partially-filled pixels)
  RenderStyleSwitch use_subpixel_rendering;
  // use subpixel positioning (fractional X positions for glyphs)
  RenderStyleSwitch use_subpixel_positioning;
};

// Loads and resolves fonts & returns additional information accessible from
// FontConfig only outside the sandbox.
//
// We still need to load fonts from within a sandboxed process. We set
// up a service to match fonts and load them. This service needs full
// filesystem access because fonts can be configured to live anywhere on the
// filesystem. The FontService takes a request for a font by family name
// and resolves it, hiding all filesystem details.
interface FontService {
  // Returns the best match for |family_name| and |style|. On error, returns a
  // null |identity|.
  MatchFamilyName(string family_name, TypefaceStyle style) =>
      (FontIdentity? identity, string family_name, TypefaceStyle style);

  // Returns a handle to the raw font specified by |id_number|.
  OpenStream(uint32 id_number) => (mojo_base.mojom.File? font_handle);

  // Returns a fallback FontIdentity and Typeface style for the given character
  // and locale. If no fallback font can be found, returns a null identity.
  FallbackFontForCharacter(uint32 character, string locale) =>
      (FontIdentity? identity,
       string family_name,
       bool is_bold,
       bool is_italic);

  // Fill out the given WebFontRenderStyle with the user's preferences for
  // rendering the given font at the given size (in pixels), given weight
  // (is_bold or not), and given slant (is_italic or not).
  FontRenderStyleForStrike(string family,
    uint32 size,
    bool is_italic,
    bool is_bold,
    float device_scale_factor) =>
    (FontRenderStyle? font_render_style);

  // Matches a font uniquely by postscript name or full font name.
  // Used in Blink for @font-face { src: local(arg) } matching.
  // Provide full_postscript_name_or_full_font_name encoded as UTF-8.
  MatchFontByPostscriptNameOrFullFontName(
      string postscript_name_or_full_font_name) =>
    (FontIdentity? identity);

  // PPAPI Specific font call to match a font family and charset.
  MatchFontWithFallback(string family, bool is_bold, bool is_italic,
      uint32 charset, uint32 fallback_family_type) =>
      (mojo_base.mojom.File? font_file_handle);
};