Support for fake bold and italics

This patch adds support for computing when fake bold and fake italics
are needed (because the styles are requested but not provided by the
matching FontFamily), and providing them as part of the layout result.

Part of the fix for bug 15436379 Fake bold doesn't fully work (Minikin)

Change-Id: I180c034b559837943673b5c272c8e890178dff0d

1 files changed, 18 insertions, 3 deletions

diff --git a/libs/minikin/FontFamily.cpp b/libs/minikin/FontFamily.cpp
index 0fb98ae..9106f63 100644
--- a/libs/minikin/FontFamily.cpp
+++ b/libs/minikin/FontFamily.cpp
@@ -109,7 +109,7 @@ void FontFamily::addFontLocked(MinikinFont* typeface, FontStyle style) {    type
 }
 
 // Compute a matching metric between two styles - 0 is an exact match
-int computeMatch(FontStyle style1, FontStyle style2) {
+static int computeMatch(FontStyle style1, FontStyle style2) {
     if (style1 == style2) return 0;
     int score = abs(style1.getWeight() - style2.getWeight());
     if (style1.getItalic() != style2.getItalic()) {
@@ -118,7 +118,15 @@ int computeMatch(FontStyle style1, FontStyle style2) {
     return score;
 }
 
-MinikinFont* FontFamily::getClosestMatch(FontStyle style) const {
+static FontFakery computeFakery(FontStyle wanted, FontStyle actual) {
+    // If desired weight is 2 or more grades higher than actual
+    // (for example, medium 500 -> bold 700), then select fake bold.
+    bool isFakeBold = (wanted.getWeight() - actual.getWeight()) >= 2;
+    bool isFakeItalic = wanted.getItalic() && !actual.getItalic();
+    return FontFakery(isFakeBold, isFakeItalic);
+}
+
+FakedFont FontFamily::getClosestMatch(FontStyle style) const {
     const Font* bestFont = NULL;
     int bestMatch = 0;
     for (size_t i = 0; i < mFonts.size(); i++) {
@@ -129,7 +137,14 @@ MinikinFont* FontFamily::getClosestMatch(FontStyle style) const {
             bestMatch = match;
         }
     }
-    return bestFont == NULL ? NULL : bestFont->typeface;
+    FakedFont result;
+    if (bestFont == NULL) {
+        result.font = NULL;
+    } else {
+        result.font = bestFont->typeface;
+        result.fakery = computeFakery(style, bestFont->style);
+    }
+    return result;
 }
 
 size_t FontFamily::getNumFonts() const {