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Diffstat (limited to 'java/com/android/contacts/common/util/BitmapUtil.java')
-rw-r--r-- | java/com/android/contacts/common/util/BitmapUtil.java | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/java/com/android/contacts/common/util/BitmapUtil.java b/java/com/android/contacts/common/util/BitmapUtil.java new file mode 100644 index 000000000..20f916a3f --- /dev/null +++ b/java/com/android/contacts/common/util/BitmapUtil.java @@ -0,0 +1,167 @@ +/* + * 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; +import android.graphics.drawable.BitmapDrawable; +import android.graphics.drawable.Drawable; + +/** 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); + } + + /** + * 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); + } + + /** + * 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; + } +} |