我已经设置了prescaled位图的ImageView源。然后，我读过的矩阵的ImageView 并通过 matrix.postTranslate（shiftX，缩骨）转向了ImageView的位图

I have set a prescaled Bitmap as ImageView's source. Then I've read Matrix of an ImageView and shift Bitmap of an ImageView via matrix.postTranslate(shiftX, shiftY).

现在我要放大/缩小和形象，同时保持的ImageView 的中心位图的相同点是规模之前。

Now I want to zoom in / out and image while maintaining center of ImageView at the same point of Bitmap that was before scale.

如果我尝试在图片放大与 matrix.postScale（变焦，变焦），点，我想保持（蓝点）转移到其他地方（紫点）。

If I try to zoom in an image with matrix.postScale(zoom, zoom), point that I want to maintain (blue dot) shifts to other place (purple dot).

我已经尝试了几种不同的方法来移位图回来，但我不能让它正常工作。我知道，最初的位图大小，ImageView的大小，特点是点线的距离。试图计算需要移位，并使用 matrix.postTranslate（-zoomshiftX，-zoomshiftY）之后，但它不能正常移动。

I have tried several different ways to shift Bitmap back, but I cant get it to work correctly. I know initial Bitmap size, ImageView size, distances marked by doted line. Tried to calculate needed shift and use matrix.postTranslate(-zoomshiftX, -zoomshiftY) afterwards, but it doesn't shift correctly.

即使发现了，matrix.postScale（）函数后潜在的位图的像素数并没有改变，并试图matrix.postTranslate（-zoomshiftX /变焦，-zoomshiftY /缩放） - 但仍没有运气

Even found out, that underlying Bitmap's pixel count doesnt change after matrix.postScale() function and tried matrix.postTranslate(-zoomshiftX/zoom, -zoomshiftY/zoom) - but still no luck.

我如何实现这种放大？

推荐答案

看看我的问题就在这里建立一个可缩放的ViewGroup。我所描述的code段从我的端到端解决方案，以及它的一些可能会有所帮助。

Take a look at my question here regarding creating a zoomable ViewGroup. I've described code snippets from my end solution, and some of it might be helpful.

Extending RelativeLayout的，并覆盖dispatchDraw（）创建一个可缩放的ViewGroup