android开发 缩放到指定比例的尺寸

一种通过matrix矩阵缩放：

//使用Bitmap加Matrix来缩放
    public static Drawable resizeImage(Bitmap bitmap, int w, int h) 
    {  
        Bitmap BitmapOrg = bitmap;  
        int width = BitmapOrg.getWidth();  
        int height = BitmapOrg.getHeight();  
        int newWidth = w;  
        int newHeight = h;  
 
        float scaleWidth = ((float) newWidth) / width;  
        float scaleHeight = ((float) newHeight) / height;  
 
        Matrix matrix = new Matrix();  
        matrix.postScale(scaleWidth, scaleHeight);  
        // if you want to rotate the Bitmap   
        // matrix.postRotate(45);   
        Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,  
                        height, matrix, true);  
        return new BitmapDrawable(resizedBitmap);  
    }

另一种，通过设置BitmapFactory.Options的inSampleSize参数来缩放

//使用BitmapFactory.Options的inSampleSize参数来缩放
    public static Drawable resizeImage2(String path,
            int width,int height) 
    {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;//不加载bitmap到内存中
        BitmapFactory.decodeFile(path,options); 
        int outWidth = options.outWidth;
        int outHeight = options.outHeight;
        options.inDither = false;
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        options.inSampleSize = 1;
         
        if (outWidth != 0 && outHeight != 0 && width != 0 && height != 0) 
        {
            int sampleSize=(outWidth/width+outHeight/height)/2;
            Log.d(tag, "sampleSize = " + sampleSize);
            options.inSampleSize = sampleSize;
        }
     
        options.inJustDecodeBounds = false;
        return new BitmapDrawable(BitmapFactory.decodeFile(path, options));     
    }