Backed out changeset 32689459fc62 (bug 1782731) for causing reftest failures. CLOSED TREE

gfx/thebes/gfxFcPlatformFontList.cpp

@@ -2415,8 +2415,8 @@ gfxPlatformFontList::PrefFontList* gfxFcPlatformFontList::FindGenericFamilies(
           // -- select the fonts to be used for the generic
           auto prefFonts = MakeUnique<PrefFontList>();  // can be empty but in
                                                         // practice won't happen
-          uint32_t limit = StaticPrefs::
-              gfx_font_rendering_fontconfig_max_generic_substitutions();
+          uint32_t limit =
+              gfxPlatformGtk::GetPlatform()->MaxGenericSubstitions();
           bool foundFontWithLang = false;
           for (int i = 0; i < faces->nfont; i++) {
             FcPattern* font = faces->fonts[i];

gfx/thebes/gfxPlatformGtk.cpp

@@ -72,6 +72,9 @@
 
 #define GDK_PIXMAP_SIZE_MAX 32767
 
+#define GFX_PREF_MAX_GENERIC_SUBSTITUTIONS \
+  "gfx.font_rendering.fontconfig.max_generic_substitutions"
+
 using namespace mozilla;
 using namespace mozilla::gfx;
 using namespace mozilla::unicode;
@@ -99,6 +102,7 @@ gfxPlatformGtk::gfxPlatformGtk() {
     gtk_init(nullptr, nullptr);
   }
 
+  mMaxGenericSubstitutions = UNINITIALIZED_VALUE;
   mIsX11Display = gfxPlatform::IsHeadless() ? false : GdkIsX11Display();
   if (XRE_IsParentProcess()) {
     InitX11EGLConfig();
@@ -464,11 +468,30 @@ gfxImageFormat gfxPlatformGtk::GetOffscreenFormat() {
 }
 
 void gfxPlatformGtk::FontsPrefsChanged(const char* aPref) {
+  // only checking for generic substitions, pass other changes up
+  if (strcmp(GFX_PREF_MAX_GENERIC_SUBSTITUTIONS, aPref) != 0) {
+    gfxPlatform::FontsPrefsChanged(aPref);
+    return;
+  }
+
+  mMaxGenericSubstitutions = UNINITIALIZED_VALUE;
   gfxFcPlatformFontList* pfl = gfxFcPlatformFontList::PlatformFontList();
   pfl->ClearGenericMappings();
   FlushFontAndWordCaches();
 }
 
+uint32_t gfxPlatformGtk::MaxGenericSubstitions() {
+  if (mMaxGenericSubstitutions == UNINITIALIZED_VALUE) {
+    mMaxGenericSubstitutions =
+        Preferences::GetInt(GFX_PREF_MAX_GENERIC_SUBSTITUTIONS, 3);
+    if (mMaxGenericSubstitutions < 0) {
+      mMaxGenericSubstitutions = 3;
+    }
+  }
+
+  return uint32_t(mMaxGenericSubstitutions);
+}
+
 bool gfxPlatformGtk::AccelerateLayersByDefault() { return true; }
 
 #if defined(MOZ_X11)

gfx/thebes/gfxPlatformGtk.h

@@ -50,6 +50,9 @@ class gfxPlatformGtk final : public gfxPlatform {
 
   void FontsPrefsChanged(const char* aPref) override;
 
+  // maximum number of fonts to substitute for a generic
+  uint32_t MaxGenericSubstitions();
+
   bool SupportsPluginDirectBitmapDrawing() override { return true; }
 
   bool AccelerateLayersByDefault() override;
@@ -71,6 +74,8 @@ class gfxPlatformGtk final : public gfxPlatform {
   bool CheckVariationFontSupport() override;
   void BuildContentDeviceData(mozilla::gfx::ContentDeviceData* aOut) override;
 
+  int8_t mMaxGenericSubstitutions;
+
  private:
   nsTArray<uint8_t> GetPlatformCMSOutputProfileData() override;
 

modules/libpref/init/StaticPrefList.yaml

@@ -5687,13 +5687,6 @@
   value: false
   mirror: always
 
-#ifdef MOZ_WIDGET_GTK
--   name: gfx.font_rendering.fontconfig.max_generic_substitutions
-    type: RelaxedAtomicUint32
-    value: 3
-    mirror: always
-#endif
-
 #if defined(XP_WIN)
 # Whether the DirectWrite bold simulation should be used when a bold font-weight
 # is requested but no bold face available in the family. This renders poorly with

modules/libpref/init/all.js

@@ -3277,6 +3277,11 @@ pref("font.size.monospace.x-math", 13);
   // snooper.  So, let's use true for its default value.
   pref("intl.ime.hack.uim.using_key_snooper", true);
 
+  #ifdef MOZ_WIDGET_GTK
+    // maximum number of fonts to substitute for a generic
+    pref("gfx.font_rendering.fontconfig.max_generic_substitutions", 3);
+  #endif
+
 #endif // !ANDROID && !XP_MACOSX && XP_UNIX
 
 #if defined(ANDROID)