/*
* Copyright 2022 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 androidx.camera.viewfinder.internal.utils;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.Size;
import android.view.Display;
import android.view.Surface;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.camera.viewfinder.CameraViewfinder;
import androidx.camera.viewfinder.internal.transform.TransformationInfo;
/**
* Utility class for transform.
*
* <p> The vertices representation uses a float array to represent a rectangle with arbitrary
* rotation and rotation-direction. It could be otherwise represented by a triple of a
* {@link RectF}, a rotation degrees integer and a boolean flag for the rotation-direction
* (clockwise v.s. counter-clockwise).
*
* TODO(b/179827713): merge this with {@link androidx.camera.core.internal.utils.ImageUtil}.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public class TransformUtils {
// Normalized space (-1, -1) - (1, 1).
public static final RectF NORMALIZED_RECT = new RectF(-1, -1, 1, 1);
private TransformUtils() {
}
/**
* Converts {@link Surface} rotation to rotation degrees: 90, 180, 270 or 0.
*/
public static int surfaceRotationToRotationDegrees(int rotationValue) {
switch (rotationValue) {
case Surface.ROTATION_0:
return 0;
case Surface.ROTATION_90:
return 90;
case Surface.ROTATION_180:
return 180;
case Surface.ROTATION_270:
return 270;
default:
throw new IllegalStateException("Unexpected rotation value " + rotationValue);
}
}
/**
* Returns true if the rotation degrees is 90 or 270.
*/
public static boolean is90or270(int rotationDegrees) {
if (rotationDegrees == 90 || rotationDegrees == 270) {
return true;
}
if (rotationDegrees == 0 || rotationDegrees == 180) {
return false;
}
throw new IllegalArgumentException("Invalid rotation degrees: " + rotationDegrees);
}
/**
* Converts a {@link Size} to a float array of vertices.
*/
@NonNull
public static float[] sizeToVertices(@NonNull Size size) {
return new float[]{0, 0, size.getWidth(), 0, size.getWidth(), size.getHeight(), 0,
size.getHeight()};
}
/**
* Checks if aspect ratio matches while tolerating rounding error.
*
* <p> One example of the usage is comparing the viewport-based crop rect from different use
* cases. The crop rect is rounded because pixels are integers, which may introduce an error
* when we check if the aspect ratio matches. For example, when {@link CameraViewfinder}'s
* width/height are prime numbers 601x797, the crop rect from other use cases cannot have a
* matching aspect ratio even if they are based on the same viewport. This method checks the
* aspect ratio while tolerating a rounding error.
*
* @param size1 the rounded size1
* @param isAccurate1 if size1 is accurate. e.g. it's true if it's the PreviewView's
* dimension which viewport is based on
* @param size2 the rounded size2
* @param isAccurate2 if size2 is accurate.
*/
public static boolean isAspectRatioMatchingWithRoundingError(
@NonNull Size size1, boolean isAccurate1, @NonNull Size size2, boolean isAccurate2) {
// The crop rect coordinates are rounded values. Each value is at most .5 away from their
// true values. So the width/height, which is the difference of 2 coordinates, are at most
// 1.0 away from their true value.
// First figure out the possible range of the aspect ratio's true value.
float ratio1UpperBound;
float ratio1LowerBound;
if (isAccurate1) {
ratio1UpperBound = (float) size1.getWidth() / size1.getHeight();
ratio1LowerBound = ratio1UpperBound;
} else {
ratio1UpperBound = (size1.getWidth() + 1F) / (size1.getHeight() - 1F);
ratio1LowerBound = (size1.getWidth() - 1F) / (size1.getHeight() + 1F);
}
float ratio2UpperBound;
float ratio2LowerBound;
if (isAccurate2) {
ratio2UpperBound = (float) size2.getWidth() / size2.getHeight();
ratio2LowerBound = ratio2UpperBound;
} else {
ratio2UpperBound = (size2.getWidth() + 1F) / (size2.getHeight() - 1F);
ratio2LowerBound = (size2.getWidth() - 1F) / (size2.getHeight() + 1F);
}
// Then we check if the true value range overlaps.
return ratio1UpperBound >= ratio2LowerBound && ratio2UpperBound >= ratio1LowerBound;
}
/**
* Gets the transform from one {@link Rect} to another with rotation degrees.
*
* <p> Following is how the source is mapped to the target with a 90° rotation. The rect
* <a, b, c, d> is mapped to <a', b', c', d'>.
*
* <pre>
* a----------b d'-----------a'
* | source | -90°-> | |
* d----------c | target |
* | |
* c'-----------b'
* </pre>
*/
@NonNull
public static Matrix getRectToRect(
@NonNull RectF source, @NonNull RectF target, int rotationDegrees) {
// Map source to normalized space.
Matrix matrix = new Matrix();
matrix.setRectToRect(source, NORMALIZED_RECT, Matrix.ScaleToFit.FILL);
// Add rotation.
matrix.postRotate(rotationDegrees);
// Restore the normalized space to target's coordinates.
matrix.postConcat(getNormalizedToBuffer(target));
return matrix;
}
/**
* Creates {@link TransformationInfo} by resolution, display, front camera and sensor
* orientation.
*
* @param surfaceResolution The surface resolution.
* @param display The view {@link Display}.
* @param isFrontCamera The front or rear camera information.
* @param sensorOrientation THe sensor orientation.
* @return {@link TransformationInfo}.
*/
@NonNull
public static TransformationInfo createTransformInfo(
@NonNull Size surfaceResolution,
@NonNull Display display,
boolean isFrontCamera,
int sensorOrientation) {
// For Camera2, cropRect is equal to full size of surface and targetRotation is default
// display rotation.
// For CameraX, targetRotation can be set by the user.
Rect cropRect = new Rect(0, 0,
surfaceResolution.getWidth(), surfaceResolution.getHeight());
// TODO: verify the viewfinder working correctly when not in a locked portrait orientation,
// for both the PERFORMANCE and the COMPATIBLE mode
int relativeRotationDegrees =
CameraOrientationUtil.surfaceRotationToDegrees(display.getRotation());
return TransformationInfo.of(cropRect,
CameraOrientationUtil.getRelativeImageRotation(
relativeRotationDegrees,
sensorOrientation,
!isFrontCamera),
display.getRotation());
}
/**
* Gets the transform from a normalized space (-1, -1) - (1, 1) to the given rect.
*/
@NonNull
private static Matrix getNormalizedToBuffer(@NonNull RectF viewPortRect) {
Matrix normalizedToBuffer = new Matrix();
normalizedToBuffer.setRectToRect(NORMALIZED_RECT, viewPortRect, Matrix.ScaleToFit.FILL);
return normalizedToBuffer;
}
}