1 files changed, 42 insertions, 0 deletions
diff --git a/src/core/SkScalar.cpp b/src/core/SkScalar.cpp
new file mode 100644
index 0000000000..c6755d1d3c
--- /dev/null
+++ b/src/core/SkScalar.cpp
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010, 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.
+*/
+
+#include "SkScalar.h"
+
+SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
+                            const SkScalar values[], int length) {
+    SkASSERT(length > 0);
+    SkASSERT(keys != NULL);
+    SkASSERT(values != NULL);
+#ifdef SK_DEBUG
+    for (int i = 1; i < length; i++)
+        SkASSERT(keys[i] >= keys[i-1]);
+#endif
+    int right = 0;
+    while (right < length && searchKey > keys[right])
+        right++;
+    // Could use sentinel values to eliminate conditionals, but since the
+    // tables are taken as input, a simpler format is better.
+    if (length == right)
+        return values[length-1];
+    if (0 == right)
+        return values[0];
+    // Otherwise, interpolate between right - 1 and right.
+    SkScalar rightKey = keys[right];
+    SkScalar leftKey = keys[right-1];
+    SkScalar fract = SkScalarDiv(searchKey-leftKey,rightKey-leftKey);
+    return SkScalarInterp(values[right-1], values[right], fract);
+}