android:Bitmap 居中按照宽高比例进行剪裁

最新推荐文章于 2024-08-12 04:02:34 发布

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本文介绍了一种用于调整图片尺寸的算法实现，该算法能够按指定的比例调整图片的宽度和高度，并确保图片的内容完整且不失真。通过计算新的宽度和高度，并使用Bitmap.createBitmap方法创建新的位图。

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public static Bitmap scaleBitmap(Bitmap bitmap,float w,float h){
        float width = bitmap.getWidth();
        float height = bitmap.getHeight();
        float x = 0,y = 0,scaleWidth = width,scaleHeight = height;
        Bitmap newbmp;
        //Log.e("gacmy","width:"+width+" height:"+height);
        if(w > h){//比例宽度大于高度的情况
            float scale = w/h;
            float tempH = width/scale;
            if(height > tempH){//
                x = 0;
                y=(height-tempH)/2;
                scaleWidth = width;
                scaleHeight = tempH;
            }else{
                scaleWidth = height*scale;
                x = (width - scaleWidth)/2;
                y= 0;
            }


            Log.e("gacmy","scale:"+scale+" scaleWidth:"+scaleWidth+" scaleHeight:"+scaleHeight);
        }else if(w < h){//比例宽度小于高度的情况
            float scale = h/w;
            float tempW = height/scale;
            if(width > tempW){
                y = 0;
                x = (width -tempW)/2;
                scaleWidth = tempW;
                scaleHeight = height;
            }else{
                scaleHeight = width*scale;
                y = (height - scaleHeight)/2;
                x = 0;
                scaleWidth = width;
            }

        }else{//比例宽高相等的情况
            if(width > height){
                x= (width-height)/2;
                y = 0;
                scaleHeight = height;
                scaleWidth = height;
            }else {
                y=(height - width)/2;
                x = 0;
                scaleHeight = width;
                scaleWidth = width;
            }
        }
        try {
            newbmp = Bitmap.createBitmap(bitmap, (int) x, (int) y, (int) scaleWidth, (int) scaleHeight, null, false);// createBitmap()方法中定义的参数x+width要小于或等于bitmap.getWidth()，y+height要小于或等于bitmap.getHeight()
            //bitmap.recycle();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        return newbmp;
    }