Provisionally enable "palt" OpenType feature

We want to test configurations where the Noto Japanese font will have
its "palt" feature (to select tighter spacing in kana) will be enabled
for framework but not WebView or Chrome rendering of Japanese text. This
patch simply hardcodes this feature on.

This is also a first step towards more general setting of OpenType
features. The hardcoded feature list will grow into one set by
parameters which will eventually be plumbed up to Java.

Change-Id: Ie284e0487a1434155c8ac1cb68ddc4fc4b3c018a

1 files changed, 10 insertions, 1 deletions

diff --git a/libs/minikin/Layout.cpp b/libs/minikin/Layout.cpp
index 3cab673..2fdf853 100644
--- a/libs/minikin/Layout.cpp
+++ b/libs/minikin/Layout.cpp
@@ -618,6 +618,12 @@ void Layout::doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_
     cache.mCache.put(key, value);
 }
 
+static void addFeatures(vector<hb_feature_t>* features) {
+    // hardcoded features, to be repaced with more flexible configuration
+    static hb_feature_t palt = { HB_TAG('p', 'a', 'l', 't'), 1, 0, ~0u };
+    features->push_back(palt);
+}
+
 void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
         bool isRtl, LayoutContext* ctx) {
     hb_buffer_t* buffer = LayoutEngine::getInstance().hbBuffer;
@@ -627,6 +633,9 @@ void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t
         std::reverse(items.begin(), items.end());
     }
 
+    vector<hb_feature_t> features;
+    addFeatures(&features);
+
     float x = mAdvance;
     float y = 0;
     for (size_t run_ix = 0; run_ix < items.size(); run_ix++) {
@@ -663,7 +672,7 @@ void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t
                 hb_buffer_set_language(buffer, hb_language_from_string(lang.c_str(), -1));
             }
             hb_buffer_add_utf16(buffer, buf, bufSize, srunstart + start, srunend - srunstart);
-            hb_shape(hbFont, buffer, NULL, 0);
+            hb_shape(hbFont, buffer, features.empty() ? NULL : &features[0], features.size());
             unsigned int numGlyphs;
             hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, &numGlyphs);
             hb_glyph_position_t* positions = hb_buffer_get_glyph_positions(buffer, NULL);