1 files changed, 85 insertions, 0 deletions
diff --git a/src/com/android/camera/ui/motion/LinearScale.java b/src/com/android/camera/ui/motion/LinearScale.java
new file mode 100644
index 000000000..5886f6882
--- /dev/null
+++ b/src/com/android/camera/ui/motion/LinearScale.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+package com.android.camera.ui.motion;
+
+/**
+ * Represents a discrete linear scale function.
+ */
+public final class LinearScale {
+    private final float mDomainA;
+    private final float mDomainB;
+    private final float mRangeA;
+    private final float mRangeB;
+
+    private final float mScale;
+
+    public LinearScale(float domainA, float domainB, float rangeA, float rangeB) {
+        mDomainA = domainA;
+        mDomainB = domainB;
+        mRangeA = rangeA;
+        mRangeB = rangeB;
+
+        // Precomputed ratio between input domain and output range.
+        float scale = (mRangeB - mRangeA) / (mDomainB - mDomainA);
+        mScale = Float.isNaN(scale) ? 0.0f : scale;
+    }
+
+    /**
+     * Clamp a given domain value to the given domain.
+     */
+    public float clamp(float domainValue) {
+        if (mDomainA > mDomainB) {
+            return Math.max(mDomainB, Math.min(mDomainA, domainValue));
+        }
+
+        return Math.max(mDomainA, Math.min(mDomainB, domainValue));
+    }
+
+    /**
+     * Returns true if the value is within the domain.
+     */
+    public boolean isInDomain(float domainValue) {
+        if (mDomainA > mDomainB) {
+            return domainValue <= mDomainA && domainValue >= mDomainB;
+        }
+        return domainValue >= mDomainA && domainValue <= mDomainB;
+    }
+
+    /**
+     * Linearly scale a given domain value into the output range.
+     */
+    public float scale(float domainValue) {
+        return mRangeA + (domainValue - mDomainA) * mScale;
+    }
+
+    /**
+     * For the current domain and range parameters produce a new scale function
+     * that is the inverse of the current scale function.
+     */
+    public LinearScale inverse() {
+        return new LinearScale(mRangeA, mRangeB, mDomainA, mDomainB);
+    }
+
+    @Override
+    public String toString() {
+        return "LinearScale{" +
+              "mDomainA=" + mDomainA +
+              ", mDomainB=" + mDomainB +
+              ", mRangeA=" + mRangeA +
+              ", mRangeB=" + mRangeB + "}";
+    }
+}
+\ No newline at end of file