1 files changed, 109 insertions, 0 deletions
diff --git a/src/com/android/camera/ui/focus/CameraCoordinateTransformer.java b/src/com/android/camera/ui/focus/CameraCoordinateTransformer.java
new file mode 100644
index 000000000..809503c9a
--- /dev/null
+++ b/src/com/android/camera/ui/focus/CameraCoordinateTransformer.java
@@ -0,0 +1,109 @@
+/*
+ * 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.
+ */
+
+package com.android.camera.ui.focus;
+
+import android.graphics.Matrix;
+import android.graphics.RectF;
+
+/**
+ * Transform coordinates to and from preview coordinate space and camera driver
+ * coordinate space.
+ */
+public class CameraCoordinateTransformer {
+    // http://developer.android.com/guide/topics/media/camera.html#metering-focus-areas
+    private static final RectF CAMERA_DRIVER_RECT = new RectF(-1000, -1000, 1000, 1000);
+
+    private final Matrix mCameraToPreviewTransform;
+    private final Matrix mPreviewToCameraTransform;
+
+    /**
+     * Convert rectangles to / from camera coordinate and preview coordinate space.
+     *
+     * @param mirrorX if the preview is mirrored along the X axis.
+     * @param displayOrientation orientation in degrees.
+     * @param previewRect the preview rectangle size and position.
+     */
+    public CameraCoordinateTransformer(boolean mirrorX, int displayOrientation,
+          RectF previewRect) {
+        if (!hasNonZeroArea(previewRect)) {
+            throw new IllegalArgumentException("previewRect");
+        }
+
+        mCameraToPreviewTransform = cameraToPreviewTransform(mirrorX, displayOrientation,
+              previewRect);
+        mPreviewToCameraTransform = inverse(mCameraToPreviewTransform);
+    }
+
+    /**
+     * Transform a rectangle in camera space into a new rectangle in preview
+     * view space.
+     *
+     * @param source the rectangle in camera space
+     * @return the rectangle in preview view space.
+     */
+    public RectF toPreviewSpace(RectF source) {
+        RectF result = new RectF();
+        mCameraToPreviewTransform.mapRect(result, source);
+        return result;
+    }
+
+    /**
+     * Transform a rectangle in preview view space into a new rectangle in
+     * camera view space.
+     *
+     * @param source the rectangle in preview view space
+     * @return the rectangle in camera view space.
+     */
+    public RectF toCameraSpace(RectF source) {
+        RectF result = new RectF();
+        mPreviewToCameraTransform.mapRect(result, source);
+        return result;
+    }
+
+    private Matrix cameraToPreviewTransform(boolean mirrorX, int displayOrientation,
+          RectF previewRect) {
+        Matrix transform = new Matrix();
+
+        // Need mirror for front camera.
+        transform.setScale(mirrorX ? -1 : 1, 1);
+
+        // Apply a rotate transform.
+        // This is the value for android.hardware.Camera.setDisplayOrientation.
+        transform.postRotate(displayOrientation);
+
+        // Map camera driver coordinates to preview rect coordinates
+        Matrix fill = new Matrix();
+        fill.setRectToRect(CAMERA_DRIVER_RECT,
+              previewRect,
+              Matrix.ScaleToFit.FILL);
+
+        // Concat the previous transform on top of the fill behavior.
+        transform.setConcat(fill, transform);
+
+        return transform;
+    }
+
+    private Matrix inverse(Matrix source) {
+        Matrix newMatrix = new Matrix();
+        source.invert(newMatrix);
+        return newMatrix;
+    }
+
+    private boolean hasNonZeroArea(RectF rect) {
+        return rect.width() != 0 && rect.height() != 0;
+    }
+}