Question

我从服务器获取图像，缩放后图像质量不保留。以下是我的代码，请帮助我保持图像质量。

private Bitmap decodeFile1(File f){
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            o.inScaled = false;
            o.inDither = false;
            o.inPreferredConfig = Bitmap.Config.ARGB_8888;
            BitmapFactory.decodeStream(new FileInputStream(f),null,o);              
            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE=70;
            int width_tmp=o.outWidth, height_tmp=o.outHeight;
            int scale=1;
            while(true){
                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
                    break;
                width_tmp/=2;
                height_tmp/=2;
                scale++;
            }


            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inPreferredConfig = Bitmap.Config.ARGB_8888;
            o2.inSampleSize=scale;
            o2.inScaled = false;
            o2.inDither = false;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {}
        return null;
    }

Answer 1

您可以使用以下代码

//decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f){
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            FileInputStream stream1=new FileInputStream(f);
            BitmapFactory.decodeStream(stream1,null,o);
            stream1.close();

            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE=1024;
            int width_tmp=o.outWidth, height_tmp=o.outHeight;
            int scale=1;
            while(true){
                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
                    break;
                width_tmp/=2;
                height_tmp/=2;
                scale*=2;
            }

            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize=scale;
            FileInputStream stream2=new FileInputStream(f);
            Bitmap bitmap=BitmapFactory.decodeStream(stream2, null, o2);
            stream2.close();
            return bitmap;
        } catch (FileNotFoundException e) {
        } 
        catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

在您的代码中，您还可以更改以下代码

final int REQUIRED_SIZE=1024; //Increase its value to get quality image but remember it should be the power of 2.

缩放后，Android图像质量无法保留

1 个答案: