# HG changeset patch
# User Jonathan Kew <jkew@mozilla.com>
# Date 1518606125 -39600
# Node ID dc462be5c9a67b6f3b14cab88951c6563b327896
# Parent  cecc23e078c60fcfe8a9967a7067da877d1f2a23
Bug 1435984 - patch 6 - Apply variation settings from the font entry when instantiation fonts for DirectWrite. r=lsalzman

diff --git a/gfx/thebes/gfxDWriteFontList.cpp b/gfx/thebes/gfxDWriteFontList.cpp
--- a/gfx/thebes/gfxDWriteFontList.cpp
+++ b/gfx/thebes/gfxDWriteFontList.cpp
@@ -695,16 +695,25 @@ gfxDWriteFontEntry::CreateFontInstance(c
     return new gfxDWriteFont(unscaledFont, this, aFontStyle, aNeedsBold);
 }
 
 nsresult
 gfxDWriteFontEntry::CreateFontFace(IDWriteFontFace **aFontFace,
                                    const nsTArray<gfxFontVariation>* aVariations,
                                    DWRITE_FONT_SIMULATIONS aSimulations)
 {
+    // Convert an OpenType font tag from our uint32_t representation
+    // (as constructed by TRUETYPE_TAG(...)) to the order DWrite wants.
+    auto makeDWriteAxisTag = [](uint32_t aTag) {
+        return DWRITE_MAKE_FONT_AXIS_TAG((aTag >> 24) & 0xff,
+                                         (aTag >> 16) & 0xff,
+                                         (aTag >> 8) & 0xff,
+                                          aTag & 0xff);
+    };
+
     // initialize mFontFace if this hasn't been done before
     if (!mFontFace) {
         HRESULT hr;
         if (mFont) {
             hr = mFont->CreateFontFace(getter_AddRefs(mFontFace));
         } else if (mFontFile) {
             IDWriteFontFile *fontFile = mFontFile.get();
             hr = Factory::GetDWriteFactory()->
@@ -721,16 +730,36 @@ gfxDWriteFontEntry::CreateFontFace(IDWri
         if (FAILED(hr)) {
             return NS_ERROR_FAILURE;
         }
         // Also get the IDWriteFontFace5 interface if we're running on a
         // sufficiently new DWrite version where it is available.
         if (mFontFace) {
             mFontFace->QueryInterface(__uuidof(IDWriteFontFace5),
                 (void**)getter_AddRefs(mFontFace5));
+            if (!mVariationSettings.IsEmpty()) {
+                // If the font entry has variations specified, mFontFace5 will
+                // be a distinct face that has the variations applied.
+                RefPtr<IDWriteFontResource> resource;
+                HRESULT hr =
+                    mFontFace5->GetFontResource(getter_AddRefs(resource));
+                MOZ_ASSERT(SUCCEEDED(hr));
+                AutoTArray<DWRITE_FONT_AXIS_VALUE, 4> fontAxisValues;
+                for (const auto& v : mVariationSettings) {
+                    DWRITE_FONT_AXIS_VALUE axisValue = {
+                        makeDWriteAxisTag(v.mTag),
+                        v.mValue
+                    };
+                    fontAxisValues.AppendElement(axisValue);
+                }
+                resource->CreateFontFace(mFontFace->GetSimulations(),
+                                         fontAxisValues.Elements(),
+                                         fontAxisValues.Length(),
+                                         getter_AddRefs(mFontFace5));
+            }
         }
     }
 
     // Do we need to modify DWrite simulations from what mFontFace has?
     bool needSimulations =
         (aSimulations & DWRITE_FONT_SIMULATIONS_BOLD) &&
         !(mFontFace->GetSimulations() & DWRITE_FONT_SIMULATIONS_BOLD);
 
@@ -738,23 +767,34 @@ gfxDWriteFontEntry::CreateFontFace(IDWri
     // IDWriteFontResource to create a new modified face.
     if (mFontFace5 && (aVariations && !aVariations->IsEmpty() ||
                        needSimulations)) {
         RefPtr<IDWriteFontResource> resource;
         HRESULT hr = mFontFace5->GetFontResource(getter_AddRefs(resource));
         MOZ_ASSERT(SUCCEEDED(hr));
         AutoTArray<DWRITE_FONT_AXIS_VALUE, 4> fontAxisValues;
         if (aVariations) {
-            for (const auto& v : *aVariations) {
+            // Merge mVariationSettings and *aVariations if both present
+            const nsTArray<gfxFontVariation>* vars;
+            AutoTArray<gfxFontVariation,4> mergedSettings;
+            if (!aVariations) {
+                vars = &mVariationSettings;
+            } else  {
+                if (mVariationSettings.IsEmpty()) {
+                    vars = aVariations;
+                } else {
+                    gfxFontUtils::MergeVariations(mVariationSettings,
+                                                  *aVariations,
+                                                  &mergedSettings);
+                    vars = &mergedSettings;
+                }
+            }
+            for (const auto& v : *vars) {
                 DWRITE_FONT_AXIS_VALUE axisValue = {
-                    // let dwrite put the tag bytes in the order it wants
-                    DWRITE_MAKE_FONT_AXIS_TAG((v.mTag >> 24) & 0xff,
-                                              (v.mTag >> 16) & 0xff,
-                                              (v.mTag >> 8) & 0xff,
-                                              v.mTag & 0xff),
+                    makeDWriteAxisTag(v.mTag),
                     v.mValue
                 };
                 fontAxisValues.AppendElement(axisValue);
             }
         }
         IDWriteFontFace5* ff5;
         resource->CreateFontFace(aSimulations,
                                  fontAxisValues.Elements(),
@@ -788,18 +828,23 @@ gfxDWriteFontEntry::CreateFontFace(IDWri
                            aSimulations,
                            aFontFace);
         for (UINT32 i = 0; i < numberOfFiles; ++i) {
             files[i]->Release();
         }
         return FAILED(hr) ? NS_ERROR_FAILURE : NS_OK;
     }
 
-    // no simulation: we can just add a reference to mFontFace and return that
-    *aFontFace = mFontFace;
+    // no simulation: we can just add a reference to mFontFace5 (if present)
+    // or mFontFace (otherwise) and return that
+    if (mFontFace5) {
+        *aFontFace = mFontFace5;
+    } else {
+        *aFontFace = mFontFace;
+    }
     (*aFontFace)->AddRef();
     return NS_OK;
 }
 
 bool
 gfxDWriteFontEntry::InitLogFont(IDWriteFont *aFont, LOGFONTW *aLogFont)
 {
     HRESULT hr;