BitmapFactory.decodeFile内存不足,图像为2400x2400

Question

我需要将文件从文件发送到服务器.服务器以2400x2400的分辨率请求图像.

我想要做的是:

1)使用正确的inSampleSize使用BitmapFactory.decodeFile获取位图.

2)以JPEG格式压缩图像,质量为40%

3)在base64中对图像进行编码

4)发送到服务器

我无法实现第一步,它抛出一个内存不足的异常.我确信inSampleSize是正确的,但我想即使使用inSampleSize,Bitmap也很大(在DDMS中大约30 MB).

任何想法怎么办呢？我可以在不创建位图对象的情况下执行这些步骤吗？我的意思是在文件系统而不是RAM内存上进行.

这是当前的代码:

// The following function calculate the correct inSampleSize
Bitmap image = Util.decodeSampledBitmapFromFile(imagePath, width,height);   
// compressing the image
ByteArrayOutputStream baos = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.JPEG, 40, baos);
// encode image
String encodedImage = Base64.encodeToString(baos.toByteArray(),Base64.DEFAULT));


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;
    }

    return inSampleSize;
}

public static Bitmap decodeSampledBitmapFromFile(String path,int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(path, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(path,options);
}

Answer 1

您可以跳过ARGB_8888,然后使用RGB_565,然后抖动然后图像以保持良好的质量

 BitmapFactory.Options options = new BitmapFactory.Options();
 options.inJustDecodeBounds = false;
 options.inPreferredConfig = Config.RGB_565;
 options.inDither = true;