Rotate, transform Bitmap
/*
* Copyright (C) 2010 Stewart Gateley <birbeck@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//package com.birbeck.wallpaperslideshow;
import java.io.File;
import java.io.FileFilter;
import java.util.Collection;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.util.Log;
/**
* Collection of utility functions used in this package.
*/
public class BitmapUtil {
public static final int UNCONSTRAINED = -1;
private static final String TAG = "BitmapUtil";
public BitmapUtil() {
}
// Rotates the bitmap by the specified degree.
// If a new bitmap is created, the original bitmap is recycled.
public static Bitmap rotate(Bitmap b, int degrees, Matrix m) {
if (degrees != 0 && b != null) {
if (m == null) {
m = new Matrix();
}
m.setRotate(degrees,
(float) b.getWidth() / 2, (float) b.getHeight() / 2);
try {
Bitmap b2 = Bitmap.createBitmap(
b, 0, 0, b.getWidth(), b.getHeight(), m, true);
if (b != b2) {
b.recycle();
b = b2;
}
} catch (OutOfMemoryError ex) {
// We have no memory to rotate. Return the original bitmap.
Log.e(TAG, "Got oom exception ", ex);
}
}
return b;
}
/*
* Compute the sample size as a function of minSideLength
* and maxNumOfPixels.
* minSideLength is used to specify that minimal width or height of a
* bitmap.
* maxNumOfPixels is used to specify the maximal size in pixels that is
* tolerable in terms of memory usage.
*
* The function returns a sample size based on the constraints.
* Both size and minSideLength can be passed in as IImage.UNCONSTRAINED,
* which indicates no care of the corresponding constraint.
* The functions prefers returning a sample size that
* generates a smaller bitmap, unless minSideLength = IImage.UNCONSTRAINED.
*
* Also, the function rounds up the sample size to a power of 2 or multiple
* of 8 because BitmapFactory only honors sample size this way.
* For example, BitmapFactory downsamples an image by 2 even though the
* request is 3. So we round up the sample size to avoid OOM.
*/
public static int computeSampleSize(BitmapFactory.Options options,
int minSideLength, int maxNumOfPixels) {
int initialSize = computeInitialSampleSize(options, minSideLength,
maxNumOfPixels);
int roundedSize;
if (initialSize <= 8) {
roundedSize = 1;
while (roundedSize < initialSize) {
roundedSize <<= 1;
}
} else {
roundedSize = (initialSize + 7) / 8 * 8;
}
return roundedSize;
}
private static int computeInitialSampleSize(BitmapFactory.Options options,
int minSideLength, int maxNumOfPixels) {
double w = options.outWidth;
double h = options.outHeight;
int lowerBound = (maxNumOfPixels == UNCONSTRAINED) ? 1 :
(int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));
int upperBound = (minSideLength == UNCONSTRAINED) ? 128 :
(int) Math.min(Math.floor(w / minSideLength),
Math.floor(h / minSideLength));
if (upperBound < lowerBound) {
// return the larger one when there is no overlapping zone.
return lowerBound;
}
if ((maxNumOfPixels == UNCONSTRAINED) &&
(minSideLength == UNCONSTRAINED)) {
return 1;
} else if (minSideLength == UNCONSTRAINED) {
return lowerBound;
} else {
return upperBound;
}
}
public static Bitmap transform(Matrix scaler,
Bitmap source,
int targetWidth,
int targetHeight,
boolean scaleUp,
boolean recycle) {
int deltaX = source.getWidth() - targetWidth;
int deltaY = source.getHeight() - targetHeight;
if (!scaleUp && (deltaX < 0 || deltaY < 0)) {
/*
* In this case the bitmap is smaller, at least in one dimension,
* than the target. Transform it by placing as much of the image
* as possible into the target and leaving the top/bottom or
* left/right (or both) black.
*/
Bitmap b2 = Bitmap.createBitmap(targetWidth, targetHeight,
Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b2);
int deltaXHalf = Math.max(0, deltaX / 2);
int deltaYHalf = Math.max(0, deltaY / 2);
Rect src = new Rect(
deltaXHalf,
deltaYHalf,
deltaXHalf + Math.min(targetWidth, source.getWidth()),
deltaYHalf + Math.min(targetHeight, source.getHeight()));
int dstX = (targetWidth - src.width()) / 2;
int dstY = (targetHeight - src.height()) / 2;
Rect dst = new Rect(
dstX,
dstY,
targetWidth - dstX,
targetHeight - dstY);
c.drawBitmap(source, src, dst, null);
if (recycle) {
source.recycle();
}
return b2;
}
float bitmapWidthF = source.getWidth();
float bitmapHeightF = source.getHeight();
float bitmapAspect = bitmapWidthF / bitmapHeightF;
float viewAspect = (float) targetWidth / targetHeight;
if (bitmapAspect > viewAspect) {
float scale = targetHeight / bitmapHeightF;
if (scale < .9F || scale > 1F) {
scaler.setScale(scale, scale);
} else {
scaler = null;
}
} else {
float scale = targetWidth / bitmapWidthF;
if (scale < .9F || scale > 1F) {
scaler.setScale(scale, scale);
} else {
scaler = null;
}
}
Bitmap b1;
if (scaler != null) {
// this is used for minithumb and crop, so we want to filter here.
b1 = Bitmap.createBitmap(source, 0, 0,
source.getWidth(), source.getHeight(), scaler, true);
} else {
b1 = source;
}
if (recycle && b1 != source) {
source.recycle();
}
int dx1 = Math.max(0, b1.getWidth() - targetWidth);
int dy1 = Math.max(0, b1.getHeight() - targetHeight);
Bitmap b2 = Bitmap.createBitmap(
b1,
dx1 / 2,
dy1 / 2,
targetWidth,
targetHeight);
if (b2 != b1) {
if (recycle || b1 != source) {
b1.recycle();
}
}
return b2;
}
/**
* Make a bitmap from a given Uri.
*
* @param uri
*/
public static Bitmap makeBitmap(int minSideLength, int maxNumOfPixels,
String pathName, BitmapFactory.Options options) {
try {
if (options == null) options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(pathName, options);
if (options.mCancel || options.outWidth == -1
|| options.outHeight == -1) {
return null;
}
options.inSampleSize = computeSampleSize(
options, minSideLength, maxNumOfPixels);
options.inJustDecodeBounds = false;
//options.inDither = false;
//options.inPreferredConfig = Bitmap.Config.ARGB_8888;
return BitmapFactory.decodeFile(pathName, options);
} catch (OutOfMemoryError ex) {
Log.e(TAG, "Got oom exception ", ex);
return null;
}
}
public static String getExtension(String name) {
String ext = null;
int i = name.lastIndexOf('.');
if (i > 0 && i < name.length() - 1) {
ext = name.substring(i+1).toLowerCase();
}
return ext;
}
public static File[] listFiles(File directory, boolean recurse, FileFilter filter) {
if (!recurse) {
return directory.listFiles(filter);
} else {
Collection<File> mFiles = new java.util.LinkedList<File>();
innerListFiles(mFiles, directory, filter);
return (File[]) mFiles.toArray(new File[mFiles.size()]);
}
}
public static void innerListFiles(Collection<File> files, File directory,
FileFilter filter) {
File[] found = directory.listFiles();
if (found != null) {
for (int i = 0; i < found.length; i++) {
if (found[i].isDirectory()) {
innerListFiles(files, found[i], filter);
} else {
File[] found2 = directory.listFiles((FileFilter) filter);
for (int j = 0; j < found2.length; j++) {
files.add(found2[j]);
}
}
}
}
}
}
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