在Android中对图片进行徒手裁剪 [英] Freehand cropping on the image in android

问题描述

我正在android中对图像进行徒手裁剪。我能够使用触摸在图像上绘制任意形状，并收集数组列表中路径上的所有点。但是我无法提取任意形状内的图像部分。

I am implementing the freehand cropping on the image in android. I am able to draw the arbitrary shape on the image using touch and collect all the points on the path in the array list. But I am not able to extract the part of image inside the arbitrary shape.

我搜索了很多内容，但找不到合适的答案。没有人有这样的可行示例。

I searched quite a lot but was not able to find the appropriate answer. Does any body have a working example of this.

编辑：我可以使用位图上的以下代码创建任意形状。

I am able to create a arbitrary shape using the below code on the bitmap.

@Override
protected void onDraw(Canvas canvas) {


    canvas.drawBitmap(scaledBitmap, 0, 0,null);
    path.reset();


    boolean firstTouchPoint = true;

    for (int i = 0; i < lastPath.size(); i += 2) {
        Point point = lastPath.get(i);

        if (firstTouchPoint) {
            firstTouchPoint = false;
            path.moveTo(point.fXPosition, point.fYPosition);
        } else if (i < lastPath.size() - 1) {
            Point next = lastPath.get(i + 1);
            path.quadTo(point.fXPosition, point.fYPosition, next.fXPosition, next.fYPosition);
        } else {
            path.lineTo(point.fXPosition, point.fYPosition);
        }
    }

    canvas.drawPath(path, paint); 


}

，但我无法提取

推荐答案

您应该尝试以下操作：

//the image should support transparency.
Bitmap scaledBitmap = Bitmap.createBitmap(width, height,Bitmap.Config.ARGB_8888);
// fill the area around the path with alpha
Canvas c = new Canvas(scaledBitmap);
c.clipPath(path, Region.Op.DIFFERENCE);
c.drawColor(0x00000000, PorterDuff.Mode.CLEAR);

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