BitmapUtils.java 文件源码

/**
 * Decode bitmap from stream using sampling to get bitmap with the requested limit.
 */
static BitmapSampled decodeSampledBitmap(Context context, Uri uri, int reqWidth, int reqHeight) {

    try {
        ContentResolver resolver = context.getContentResolver();

        // First decode with inJustDecodeBounds=true to check dimensions
        BitmapFactory.Options options = decodeImageForOption(resolver, uri);

        // Calculate inSampleSize
        options.inSampleSize = Math.max(
                calculateInSampleSizeByReqestedSize(options.outWidth, options.outHeight, reqWidth, reqHeight),
                calculateInSampleSizeByMaxTextureSize(options.outWidth, options.outHeight));

        // Decode bitmap with inSampleSize set
        Bitmap bitmap = decodeImage(resolver, uri, options);

        return new BitmapSampled(bitmap, options.inSampleSize);

    } catch (Exception e) {
        throw new RuntimeException("Failed to load sampled bitmap: " + uri + "\r\n" + e.getMessage(), e);
    }
}