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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.
*/
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;
}
}
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