Android:如何获取绘制路径的区域大小? [英] Android: How to get the area size of a drawn path?

问题描述

我的问题是测量路径的表面积.
我生成一个随机路径并将其绘制在画布上.触摸这个封闭路径后，我想获得这个绘制路径的区域大小.

我怎样才能得到这条路径的实际面积大小?

路径(形状)在此处如下所示:
图片链接

My problem is to measure the surface area of a path.
I generate a random Path and draw it on a canvas. After touching on this closen path, i want to get the area size of this drawn path.

How can i get the real area size of this path?

The pathes (shapes) looks like this here:
link to the image

推荐答案

我找到了解决方案.我从路径生成一个区域并使用 RegionIterator 来获取区域内的 Rects.使用这个 Rects，我可以计算路径的整个区域.

I found a solution. I generate a Region from the path and use a RegionIterator to get Rects inside the Region. With this Rects i can calculate the whole area of the path.

private void calculateArea(Region region) {

        RegionIterator regionIterator = new RegionIterator(region);

        int size = 0; // amount of Rects
        float area = 0; // units of area

        Rect tmpRect= new Rect(); 

        while (regionIterator.next(tmpRect)) {
            size++;
            area += tmpRect.width() * tmpRect.height();
        }

        log.d("Rect amount=" + size);
        log.d("Area Size / units of area=" + area);
}

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