Apply contextStart consistently in getRunAdvance

The contextStart needs to be applied to all offsets relative to the
actual start of context. The code was missing "offset", which caused
mischief especially in mixed LTR and RTL text.

Bug: 21573666
Change-Id: I47a1b6cde5862442b9c7236ee72b2ceb0df9b2e9

1 files changed, 2 insertions, 1 deletions

diff --git a/core/jni/android/graphics/Paint.cpp b/core/jni/android/graphics/Paint.cpp
index 63395ed..d14fc0f 100644
--- a/core/jni/android/graphics/Paint.cpp
+++ b/core/jni/android/graphics/Paint.cpp
@@ -1055,7 +1055,8 @@ public:
         // TODO performance: optimize JNI array access
         jchar* textArray = env->GetCharArrayElements(text, NULL);
         jfloat result = doRunAdvance(paint, typeface, textArray + contextStart,
-                start - contextStart, end - start, contextEnd - contextStart, isRtl, offset);
+                start - contextStart, end - start, contextEnd - contextStart, isRtl,
+                offset - contextStart);
         env->ReleaseCharArrayElements(text, textArray, JNI_ABORT);
         return result;
     }