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Apache License
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package com.example.android.bitmapfun.util; /*from w ww . j a v a 2 s .c o m*/ import java.io.FileDescriptor; import com.example.android.bitampfun.BuildConfig; import android.annotation.TargetApi; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Build; import android.util.Log; public class BitmapUtils { private final static String TAG="BitmapUtils"; /** * Decode and sample down a bitmap from resources to the requested width and height. * * @param res The resources object containing the image data * @param resId The resource id of the image data * @param reqWidth The requested width of the resulting bitmap * @param reqHeight The requested height of the resulting bitmap * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap * @return A bitmap sampled down from the original with the same aspect ratio and dimensions * that are equal to or greater than the requested width and height */ public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, int reqWidth, int reqHeight, ImageCache cache) { // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resId, options); // Calculate inSampleSize if( reqWidth <= 0 || reqHeight <= 0){ options.inSampleSize = 1; }else{ options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); } // If we're running on Honeycomb or newer, try to use inBitmap if (Utils.hasHoneycomb()) { addInBitmapOptions(options, cache); } // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, resId, options); } /** * Decode and sample down a bitmap from a file to the requested width and height. * * @param filename The full path of the file to decode * @param reqWidth The requested width of the resulting bitmap * @param reqHeight The requested height of the resulting bitmap * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap * @return A bitmap sampled down from the original with the same aspect ratio and dimensions * that are equal to or greater than the requested width and height */ public static Bitmap decodeSampledBitmapFromFile(String filename, int reqWidth, int reqHeight, ImageCache cache) { // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(filename, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); // If we're running on Honeycomb or newer, try to use inBitmap if (Utils.hasHoneycomb()) { addInBitmapOptions(options, cache); } // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; return BitmapFactory.decodeFile(filename, options); } /** * Decode and sample down a bitmap from a file input stream to the requested width and height. * * @param fileDescriptor The file descriptor to read from * @param reqWidth The requested width of the resulting bitmap * @param reqHeight The requested height of the resulting bitmap * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap * @return A bitmap sampled down from the original with the same aspect ratio and dimensions * that are equal to or greater than the requested width and height */ public static Bitmap decodeSampledBitmapFromDescriptor( FileDescriptor fileDescriptor, int reqWidth, int reqHeight, ImageCache cache) { // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; // If we're running on Honeycomb or newer, try to use inBitmap if (Utils.hasHoneycomb() && cache != null) { addInBitmapOptions(options, cache); } Bitmap bitmap = null; try{ bitmap = BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options); }catch(Exception e){ Log.e(TAG, e.getMessage()); if(options.inBitmap != null){ Log.d(TAG, "retry to decode without inBitmap"); options.inBitmap = null; bitmap = BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options); } } return bitmap; } public static Bitmap decodeSampledBitmapFromRes(Resources resources, int ResId, int reqWidth, int reqHeight, ImageCache cache) { // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(resources, ResId, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; // If we're running on Honeycomb or newer, try to use inBitmap if (Utils.hasHoneycomb()) { addInBitmapOptions(options, cache); } return BitmapFactory.decodeResource(resources, ResId, options); } @TargetApi(Build.VERSION_CODES.HONEYCOMB) private static void addInBitmapOptions(BitmapFactory.Options options, ImageCache cache) { // inBitmap only works with mutable bitmaps so force the decoder to // return mutable bitmaps. options.inMutable = true; if (cache != null) { // Try and find a bitmap to use for inBitmap Bitmap inBitmap = cache.getBitmapFromReusableSet(options); if (inBitmap != null) { if (BuildConfig.DEBUG) { Log.d(TAG, "Found bitmap to use for inBitmap"); } options.inBitmap = inBitmap; } } } /** * Calculate an inSampleSize for use in a {@link BitmapFactory.Options} object when decoding * bitmaps using the decode* methods from {@link BitmapFactory}. This implementation calculates * the closest inSampleSize that will result in the final decoded bitmap having a width and * height equal to or larger than the requested width and height. This implementation does not * ensure a power of 2 is returned for inSampleSize which can be faster when decoding but * results in a larger bitmap which isn't as useful for caching purposes. * * @param options An options object with out* params already populated (run through a decode* * method with inJustDecodeBounds==true * @param reqWidth The requested width of the resulting bitmap * @param reqHeight The requested height of the resulting bitmap * @return The value to be used for inSampleSize */ public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { // Calculate ratios of height and width to requested height and width final int heightRatio = Math.round((float) height / (float) reqHeight); final int widthRatio = Math.round((float) width / (float) reqWidth); // Choose the smallest ratio as inSampleSize value, this will guarantee a final image // with both dimensions larger than or equal to the requested height and width. inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; // This offers some additional logic in case the image has a strange // aspect ratio. For example, a panorama may have a much larger // width than height. In these cases the total pixels might still // end up being too large to fit comfortably in memory, so we should // be more aggressive with sample down the image (=larger inSampleSize). final float totalPixels = width * height; // Anything more than 2x the requested pixels we'll sample down further final float totalReqPixelsCap = reqWidth * reqHeight * 2; while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) { inSampleSize++; } } return inSampleSize; } }