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/*
* Copyright (C) 2012 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.contacts.common.util;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.BitmapDrawable;
/**
* Provides static functions to decode bitmaps at the optimal size
*/
public class BitmapUtil {
private BitmapUtil() {}
/**
* Returns Width or Height of the picture, depending on which size is smaller. Doesn't actually
* decode the picture, so it is pretty efficient to run.
*/
public static int getSmallerExtentFromBytes(byte[] bytes) {
final BitmapFactory.Options options = new BitmapFactory.Options();
// don't actually decode the picture, just return its bounds
options.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(bytes, 0, bytes.length, options);
// test what the best sample size is
return Math.min(options.outWidth, options.outHeight);
}
/**
* Finds the optimal sampleSize for loading the picture
* @param originalSmallerExtent Width or height of the picture, whichever is smaller
* @param targetExtent Width or height of the target view, whichever is bigger.
*
* If either one of the parameters is 0 or smaller, no sampling is applied
*/
public static int findOptimalSampleSize(int originalSmallerExtent, int targetExtent) {
// If we don't know sizes, we can't do sampling.
if (targetExtent < 1) return 1;
if (originalSmallerExtent < 1) return 1;
// Test what the best sample size is. To do that, we find the sample size that gives us
// the best trade-off between resulting image size and memory requirement. We allow
// the down-sampled image to be 20% smaller than the target size. That way we can get around
// unfortunate cases where e.g. a 720 picture is requested for 362 and not down-sampled at
// all. Why 20%? Why not. Prove me wrong.
int extent = originalSmallerExtent;
int sampleSize = 1;
while ((extent >> 1) >= targetExtent * 0.8f) {
sampleSize <<= 1;
extent >>= 1;
}
return sampleSize;
}
/**
* Decodes the bitmap with the given sample size
*/
public static Bitmap decodeBitmapFromBytes(byte[] bytes, int sampleSize) {
final BitmapFactory.Options options;
if (sampleSize <= 1) {
options = null;
} else {
options = new BitmapFactory.Options();
options.inSampleSize = sampleSize;
}
return BitmapFactory.decodeByteArray(bytes, 0, bytes.length, options);
}
/**
* Retrieves a copy of the specified drawable resource, rotated by a specified angle.
*
* @param resources The current resources.
* @param resourceId The resource ID of the drawable to rotate.
* @param angle The angle of rotation.
* @return Rotated drawable.
*/
public static Drawable getRotatedDrawable(
android.content.res.Resources resources, int resourceId, float angle) {
// Get the original drawable and make a copy which will be rotated.
Bitmap original = BitmapFactory.decodeResource(resources, resourceId);
Bitmap rotated = Bitmap.createBitmap(
original.getWidth(), original.getHeight(), Bitmap.Config.ARGB_8888);
// Perform the rotation.
Canvas tempCanvas = new Canvas(rotated);
tempCanvas.rotate(angle, original.getWidth()/2, original.getHeight()/2);
tempCanvas.drawBitmap(original, 0, 0, null);
return new BitmapDrawable(resources,rotated);
}
}
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