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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.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
/** 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.
* <p>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);
}
/**
* Given an input bitmap, scales it to the given width/height and makes it round.
*
* @param input {@link Bitmap} to scale and crop
* @param targetWidth desired output width
* @param targetHeight desired output height
* @return output bitmap scaled to the target width/height and cropped to an oval. The cropping
* algorithm will try to fit as much of the input into the output as possible, while
* preserving the target width/height ratio.
*/
public static Bitmap getRoundedBitmap(Bitmap input, int targetWidth, int targetHeight) {
if (input == null) {
return null;
}
final Bitmap.Config inputConfig = input.getConfig();
final Bitmap result =
Bitmap.createBitmap(
targetWidth, targetHeight, inputConfig != null ? inputConfig : Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(result);
final Paint paint = new Paint();
canvas.drawARGB(0, 0, 0, 0);
paint.setAntiAlias(true);
final RectF dst = new RectF(0, 0, targetWidth, targetHeight);
canvas.drawOval(dst, paint);
// Specifies that only pixels present in the destination (i.e. the drawn oval) should
// be overwritten with pixels from the input bitmap.
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
final int inputWidth = input.getWidth();
final int inputHeight = input.getHeight();
// Choose the largest scale factor that will fit inside the dimensions of the
// input bitmap.
final float scaleBy =
Math.min((float) inputWidth / targetWidth, (float) inputHeight / targetHeight);
final int xCropAmountHalved = (int) (scaleBy * targetWidth / 2);
final int yCropAmountHalved = (int) (scaleBy * targetHeight / 2);
final Rect src =
new Rect(
inputWidth / 2 - xCropAmountHalved,
inputHeight / 2 - yCropAmountHalved,
inputWidth / 2 + xCropAmountHalved,
inputHeight / 2 + yCropAmountHalved);
canvas.drawBitmap(input, src, dst, paint);
return result;
}
}
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