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  • 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));     
        }
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  • 原文地址:https://www.cnblogs.com/feijian/p/4739017.html
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