标签：style blog http io color ar sp div on
我们都知道Imageview中有不同的拉伸比率，比如fitStart，centCrop这样的，所以imageview中的drawable不一定和imageview占有相同的位置和大小，那么怎么计算呢？
思路：
1.得到imageview现在的宽高
2.得到imageview现在显示的区域(Rect)
3.得到drawable本身图片的宽高
4.得到drawable显示时的缩放比例
5.计算得到drawable现在显示的宽高
6.通过drawable显示的宽高和imageview显示的宽高来计算出imageview距离内部drawable的内边距
7.通过imageview的显示区域和內边距计算出drawable的显示区域
// view的实际宽高 float vWidth = v.getWidth(); float vHeight = v.getHeight(); // 得到imageview中的矩阵，准备得到drawable的拉伸比率 Matrix m = v.getImageMatrix(); float[] values = new float[10]; m.getValues(values); // drawable的本身宽高 float dOriginalWidth = drawable.getIntrinsicWidth(); float dOriginalHeight = drawable.getIntrinsicHeight(); float dRatio = dOriginalWidth / dOriginalHeight;//如果大于1，表示drawable宽>高 drawable = null; //Image在绘制过程中的变换矩阵，从中获得x和y方向的缩放系数 value[0],[4] //得到drawable的实际显示时的宽高 int dWidth = (int)(dOriginalWidth * values[0]); int dHeight = (int)(dOriginalHeight * values[4]); //得到imageview的宽高和drawable的宽高的差值 float w = vWidth - dWidth; float h = vHeight - dHeight; Rect startBounds = new Rect(); v.getGlobalVisibleRect(startBounds);
之后通过对startBounds进行修改，就可以求出drawable实际显示的范围了。因为拉伸模式不同，所以计算方式也不同，下面给出几种模式的计算方式
if (originalType == ScaleType.CENTER_INSIDE) { //finalBounds = getCentInside_originalPic_finalBounds(v, dRatio, startBounds); finalBounds.left = (int) (startBounds.left + (w / 2) + 0.5f); finalBounds.top = (int) (startBounds.top + (h / 2) +0.5f); finalBounds.right = (int) (startBounds.right - (w / 2) + 0.5f); finalBounds.bottom = (int) (startBounds.bottom - (h / 2) + 0.5f); } else if (originalType == ScaleType.FIT_START) { //finalBounds = getFitStart_originalPic_finalBounds(dRatio, startBounds); finalBounds.right = (int) (startBounds.right - w + 0.5f); finalBounds.top = startBounds.top; finalBounds.left = startBounds.left; finalBounds.bottom = (int) (startBounds.bottom - h + 0.5f); } else if (originalType == ScaleType.FIT_CENTER) { //finalBounds = getFitCenter_originalPic_finalBounds(dRatio, startBounds); finalBounds.left = (int) (startBounds.left + (w / 2) + 0.5f); finalBounds.top = (int) (startBounds.top + (h / 2) +0.5f); finalBounds.right = (int) (startBounds.right - (w / 2) + 0.5f); finalBounds.bottom = (int) (startBounds.bottom - (h / 2) + 0.5f); } else if (originalType == ScaleType.FIT_END) { //finalBounds = getFitEnd_originalPic_finalBounds(dRatio, startBounds); finalBounds.left = (int) (startBounds.left + w + 0.5f); finalBounds.top = (int) (startBounds.top + h + 0.5f); finalBounds.right = startBounds.right; finalBounds.bottom = startBounds.bottom; }
参考自：http://blog.csdn.net/liu_zhen_wei/article/details/8349400
得到ImageView中drawable显示的区域的计算方法
标签：style blog http io color ar sp div on
原文地址：http://www.cnblogs.com/tianzhijiexian/p/4104836.html
