Bug 1457103 - patch 2 - Refactor logic from gfxFontconfigFontEntry implementations of GetVariationAxes and GetVariationInstances to gfxFT2Utils, where it can be shared by the gfxFT2Fonts backend. r=jwatt

gfx/thebes/gfxFT2Utils.cpp

@@ -11,6 +11,9 @@
 #include <fontconfig/fcfreetype.h>
 #endif
 
+#include "ft2build.h"
+#include FT_MULTIPLE_MASTERS_H
+
 #include "prlink.h"
 
 uint32_t
@@ -96,3 +99,62 @@ gfxFT2LockedFace::FindCharVariantFunction()
 
     return function;
 }
+
+/*static*/
+void
+gfxFT2Utils::GetVariationAxes(const FT_MM_Var* aMMVar,
+                              nsTArray<gfxFontVariationAxis>& aAxes)
+{
+    MOZ_ASSERT(aAxes.IsEmpty());
+    if (!aMMVar) {
+        return;
+    }
+    aAxes.SetCapacity(aMMVar->num_axis);
+    for (unsigned i = 0; i < aMMVar->num_axis; i++) {
+        const auto& a = aMMVar->axis[i];
+        gfxFontVariationAxis axis;
+        axis.mMinValue = a.minimum / 65536.0;
+        axis.mMaxValue = a.maximum / 65536.0;
+        axis.mDefaultValue = a.def / 65536.0;
+        axis.mTag = a.tag;
+        axis.mName.Assign(NS_ConvertUTF8toUTF16(a.name));
+        aAxes.AppendElement(axis);
+    }
+}
+
+/*static*/
+void
+gfxFT2Utils::GetVariationInstances(
+    gfxFontEntry* aFontEntry,
+    const FT_MM_Var* aMMVar,
+    nsTArray<gfxFontVariationInstance>& aInstances)
+{
+    MOZ_ASSERT(aInstances.IsEmpty());
+    if (!aMMVar) {
+        return;
+    }
+    hb_blob_t* nameTable =
+        aFontEntry->GetFontTable(TRUETYPE_TAG('n','a','m','e'));
+    if (!nameTable) {
+        return;
+    }
+    aInstances.SetCapacity(aMMVar->num_namedstyles);
+    for (unsigned i = 0; i < aMMVar->num_namedstyles; i++) {
+        const auto& ns = aMMVar->namedstyle[i];
+        gfxFontVariationInstance inst;
+        nsresult rv =
+            gfxFontUtils::ReadCanonicalName(nameTable, ns.strid, inst.mName);
+        if (NS_FAILED(rv)) {
+            continue;
+        }
+        inst.mValues.SetCapacity(aMMVar->num_axis);
+        for (unsigned j = 0; j < aMMVar->num_axis; j++) {
+            gfxFontVariationValue value;
+            value.mAxis = aMMVar->axis[j].tag;
+            value.mValue = ns.coords[j] / 65536.0;
+            inst.mValues.AppendElement(value);
+        }
+        aInstances.AppendElement(inst);
+    }
+    hb_blob_destroy(nameTable);
+}

gfx/thebes/gfxFT2Utils.h

@@ -63,4 +63,22 @@ protected:
     FT_Face mFace;
 };
 
+
+// A couple of FreeType-based utilities shared by gfxFontconfigFontEntry
+// and FT2FontEntry.
+
+typedef struct FT_MM_Var_ FT_MM_Var;
+
+class gfxFT2Utils {
+public:
+    static void
+    GetVariationAxes(const FT_MM_Var* aMMVar,
+                     nsTArray<gfxFontVariationAxis>& aAxes);
+
+    static void
+    GetVariationInstances(gfxFontEntry* aFontEntry,
+                          const FT_MM_Var* aMMVar,
+                          nsTArray<gfxFontVariationInstance>& aInstances);
+};
+
 #endif /* GFX_FT2UTILS_H */

gfx/thebes/gfxFcPlatformFontList.cpp

@@ -1112,56 +1112,20 @@ gfxFontconfigFontEntry::GetMMVar()
 void
 gfxFontconfigFontEntry::GetVariationAxes(nsTArray<gfxFontVariationAxis>& aAxes)
 {
-    MOZ_ASSERT(aAxes.IsEmpty());
-    FT_MM_Var* mmVar = GetMMVar();
-    if (!mmVar) {
+    if (!HasVariations()) {
         return;
     }
-    aAxes.SetCapacity(mmVar->num_axis);
-    for (unsigned i = 0; i < mmVar->num_axis; i++) {
-        const auto& a = mmVar->axis[i];
-        gfxFontVariationAxis axis;
-        axis.mMinValue = a.minimum / 65536.0;
-        axis.mMaxValue = a.maximum / 65536.0;
-        axis.mDefaultValue = a.def / 65536.0;
-        axis.mTag = a.tag;
-        axis.mName.Assign(NS_ConvertUTF8toUTF16(a.name));
-        aAxes.AppendElement(axis);
-    }
+    gfxFT2Utils::GetVariationAxes(GetMMVar(), aAxes);
 }
 
 void
 gfxFontconfigFontEntry::GetVariationInstances(
     nsTArray<gfxFontVariationInstance>& aInstances)
 {
-    MOZ_ASSERT(aInstances.IsEmpty());
-    FT_MM_Var* mmVar = GetMMVar();
-    if (!mmVar) {
+    if (!HasVariations()) {
         return;
     }
-    hb_blob_t* nameTable = GetFontTable(TRUETYPE_TAG('n','a','m','e'));
-    if (!nameTable) {
-        return;
-    }
-    aInstances.SetCapacity(mmVar->num_namedstyles);
-    for (unsigned i = 0; i < mmVar->num_namedstyles; i++) {
-        const auto& ns = mmVar->namedstyle[i];
-        gfxFontVariationInstance inst;
-        nsresult rv =
-            gfxFontUtils::ReadCanonicalName(nameTable, ns.strid, inst.mName);
-        if (NS_FAILED(rv)) {
-            continue;
-        }
-        inst.mValues.SetCapacity(mmVar->num_axis);
-        for (unsigned j = 0; j < mmVar->num_axis; j++) {
-            gfxFontVariationValue value;
-            value.mAxis = mmVar->axis[j].tag;
-            value.mValue = ns.coords[j] / 65536.0;
-            inst.mValues.AppendElement(value);
-        }
-        aInstances.AppendElement(inst);
-    }
-    hb_blob_destroy(nameTable);
+    gfxFT2Utils::GetVariationInstances(this, GetMMVar(), aInstances);
 }
 
 nsresult