图像的可见部分的Andr​​oid寄存器触摸事件？ [英] Android register touch events on visible portion of image?

问题描述

我目前在思考如何我可以注册只是触及一个PNG图片中可以看到（不透明）的部分活动。

I've currently been thinking about how I could register only touch events on the visible (non-transparent) parts of a .PNG image.

-I've一直在测试与周围AndEngine，似乎他们有多种选择：我已经试过所有我能找到也没有用

-I've been testing around with AndEngine and it seems they have multiple options: I've tried any I could find to no avail.

- 我可以很可能创建自己的检查一个给定的触摸区域的透明度，我想的方法，但不知道有多少工作/这可能与屏幕上的物体15-20能够被感动创建开销..

-I could very possibly create my own method of checking a given touched area's transparency I suppose, but not sure how much work/overhead that might create with 15-20 objects on screen being able to be touched..

任何帮助很多AP preciated！

Any help is much appreciated!

推荐答案

一个简单的方法来做到这将是抢在触摸位置的像素颜色。然后，你可以检查像素是透明的：

One simple way to do it would be to grab the the pixel color at the touch location. Then you can check if the pixel is transparent:

int color = Bitmap.getPixel(x,y); // x and y are the location of the touch event in Bitmap space
int alpha = Color.getAlpha(color);
boolean isTransparent = (alpha==0);

注：根据您实现您的触摸监听器将可能需要到X转换，触摸事件的x的y位置，图像视图的y坐标

Note: Depending on how you implement your touch listener will might need to convert the x,y location of the touch event to the x,y coordinates of the image view.

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