android 按多边形区域裁剪图像

ru9i0ody 于 2023-06-20 发布在 Android

关注(0)|答案(3)|浏览(262)

我想裁剪图像的多边形面积，但找不到任何库，这可以使它。OpenCV对于这个小东西来说太大了。JJIL [enter link description here]仅裁剪矩形区域。也许你有什么想法，我如何才能实现它？谢谢你的帮助！

对于Nidhi：尝试这样的东西，如果不工作-创建另一个画布的路径，然后从它得到位图（掩码），并应用此掩码位图到您的初始画布，而不是drawPath。

Bitmap obmp = BitmapFactory.decodeResource(getResources(), R.drawable.image1);
Bitmap resultImg = Bitmap.createBitmap(obmp.getWidth(), obmp.getHeight(), Bitmap.Config.ARGB_8888);
Bitmap maskImg = Bitmap.createBitmap(obmp.getWidth(), obmp.getHeight(), Bitmap.Config.ARGB_8888);
Canvas mCanvas = new Canvas(resultImg);
Canvas maskCanvas = new Canvas(maskImg);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setAntiAlias(true);
paint.setStyle(Paint.Style.FILL);;
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
Path path = new Path();
path.moveTo(view.mx,view.my);
path.lineTo(view.x1,view.y1);
path.lineTo(view.x2,view.y2 );
path.lineTo(view.x3,view.y3);
path.lineTo(view.x4,view.y4);
path.close();
maskCanvas.drawPath(path, paint);   
mCanvas.drawBitmap(obmp, 0, 0, null);
mCanvas.drawBitmap(maskImg, 0, 0, paint);

android

来源：https://stackoverflow.com/questions/15969028/crop-image-by-polygon-area

3条答案

按热度按时间

monwx1rj1#

感谢Eddy_Em，我通过使用PorterDuffXfermode实现了这一点。Good example

赞(0）回复(0）举报 2023-06-20

gg0vcinb2#

这是一个可以工作的Kotlin示例，它根据路径将图像和片段共享到多边形

private fun createBitmap() {
    var bitmap = BitmapFactory.decodeResource(resources, R.drawable.gr)
    val mutableBitmap: Bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true)
    val bitmap2 = Bitmap.createBitmap(400, 400, Bitmap.Config.ARGB_8888)
    val polyCanvas = Canvas(bitmap2)
    val canvas = Canvas(mutableBitmap)
   
    var paint = Paint()
    paint.strokeWidth = 9f
   
    val path = Path()
    path.moveTo(150f, 0f)
    path.lineTo(230f, 120f)
    path.lineTo(290f, 160f)
    path.lineTo(150f, 170f)
    path.lineTo(70f, 200f)
    path.lineTo(150f, 0f)
    polyCanvas.drawPath(path, paint)
    paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN);
    polyCanvas.drawBitmap(mutableBitmap, 0f, 0f, paint)
    imageView.setImageBitmap(bitmap2)
  }