expose runtime changes to gamma

1 files changed, 21 insertions, 1 deletions

diff --git a/core/jni/android/graphics/Typeface.cpp b/core/jni/android/graphics/Typeface.cpp
index 21dde63..238ece1 100644
--- a/core/jni/android/graphics/Typeface.cpp
+++ b/core/jni/android/graphics/Typeface.cpp
@@ -141,6 +141,25 @@ static SkTypeface* Typeface_createFromFile(JNIEnv* env, jobject, jstring jpath)
     return SkTypeface::CreateFromFile(str.c_str());
 }
 
+#define MIN_GAMMA   (0.1f)
+#define MAX_GAMMA   (10.0f)
+static float pinGamma(float gamma) {
+    if (gamma < MIN_GAMMA) {
+        gamma = MIN_GAMMA;
+    } else if (gamma > MAX_GAMMA) {
+        gamma = MAX_GAMMA;
+    }
+    return gamma;
+}
+
+extern void skia_set_text_gamma(float, float);
+
+static void Typeface_setGammaForText(JNIEnv* env, jobject, jfloat blackGamma,
+                                     jfloat whiteGamma) {
+    // Comment this out for release builds. This is only used during development
+    skia_set_text_gamma(pinGamma(blackGamma), pinGamma(whiteGamma));
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 static JNINativeMethod gTypefaceMethods[] = {
@@ -151,7 +170,8 @@ static JNINativeMethod gTypefaceMethods[] = {
     { "nativeCreateFromAsset",    "(Landroid/content/res/AssetManager;Ljava/lang/String;)I",
                                            (void*)Typeface_createFromAsset },
     { "nativeCreateFromFile",     "(Ljava/lang/String;)I",
-                                           (void*)Typeface_createFromFile }
+                                           (void*)Typeface_createFromFile },
+    { "setGammaForText", "(FF)V", (void*)Typeface_setGammaForText },
 };
 
 int register_android_graphics_Typeface(JNIEnv* env);