1 files changed, 85 insertions, 0 deletions
diff --git a/libs/hwui/utils/MathUtils.h b/libs/hwui/utils/MathUtils.h
new file mode 100644
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+++ b/libs/hwui/utils/MathUtils.h
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+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MATHUTILS_H
+#define MATHUTILS_H
+
+namespace android {
+namespace uirenderer {
+
+#define NON_ZERO_EPSILON (0.001f)
+#define ALPHA_EPSILON (0.001f)
+
+class MathUtils {
+public:
+    /**
+     * Check for floats that are close enough to zero.
+     */
+    inline static bool isZero(float value) {
+        return (value >= -NON_ZERO_EPSILON) && (value <= NON_ZERO_EPSILON);
+    }
+
+    inline static bool isPositive(float value) {
+        return value >= NON_ZERO_EPSILON;
+    }
+
+    /**
+     * Clamps alpha value, and snaps when very near 0 or 1
+     */
+    inline static float clampAlpha(float alpha) {
+        if (alpha <= ALPHA_EPSILON) {
+            return 0;
+        } else if (alpha >= (1 - ALPHA_EPSILON)) {
+            return 1;
+        } else {
+            return alpha;
+        }
+    }
+
+    /*
+     * Clamps positive tessellation scale values
+     */
+    inline static float clampTessellationScale(float scale) {
+        const float MIN_SCALE = 0.0001;
+        const float MAX_SCALE = 1e10;
+        if (scale < MIN_SCALE) {
+            return MIN_SCALE;
+        } else if (scale > MAX_SCALE) {
+            return MAX_SCALE;
+        }
+        return scale;
+    }
+
+    inline static bool areEqual(float valueA, float valueB) {
+        return isZero(valueA - valueB);
+    }
+
+    inline static int max(int a, int b) {
+        return a > b ? a : b;
+    }
+
+    inline static int min(int a, int b) {
+        return a < b ? a : b;
+    }
+
+    inline static float lerp(float v1, float v2, float t) {
+        return v1 + ((v2 - v1) * t);
+    }
+}; // class MathUtils
+
+} /* namespace uirenderer */
+} /* namespace android */
+
+#endif /* MATHUTILS_H */