Android - 从多点裁剪图像 [英] Android - Crop an image from multipoints

问题描述

我需要裁剪一个位图，但不是有一个 矩形 裁剪图像(我成功地做到了)，我需要它是 任何形式 定义坐标.

I need to crop a Bitmap, but instead of having a rectangular cropped image (which I managed successfully to do), I need it to be any form defined by coordinates.

我正在关注此线程的答案:从 Bitmap 中剪下一个多点多边形并将其置于透明度上，并尝试实现它，但不幸的是它没有剪裁图像.

I'm following the answer from this thread: Cutting a multipoint ploygon out of Bitmap and placing it on transparency , and trying to implement it, but unfortunatly it does not clip the image.

我按照描述进行了操作，但似乎某处存在错误.图像以矩形方式绘制.我错过了什么吗?

I did as in the description, but it seems there's a bug somewhere. The image is drawn in rectangular way. Am I missing something?

Bitmap originalBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.test_image);
// Image cropped
Bitmap croppedBitmap=Bitmap.createBitmap(originalBitmap, 10, 10, 200, 200);
Canvas canvas=new Canvas(croppedBitmap);

// Create a path
Path path=new Path();
path.setFillType(FillType.INVERSE_EVEN_ODD);
path.moveTo(0, 0);
path.moveTo(0, 100);
path.moveTo(100, 0);
path.moveTo(0, 0);

// Paint with Xfermode
Paint paint=new Paint();
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

// Draw the path
canvas.drawPath(path, paint);

imageView.setImageBitmap(croppedBitmap);

推荐答案

我非常接近解决方案.这里是:

I was very close to the solution. Here it is:

compositeImageView = (ImageView) findViewById(R.id.imageView);

Bitmap bitmap1=BitmapFactory.decodeResource(getResources(), R.drawable.batman_ad);
Bitmap bitmap2=BitmapFactory.decodeResource(getResources(), R.drawable.logo);

Bitmap resultingImage=Bitmap.createBitmap(320, 480, bitmap1.getConfig());

Canvas canvas = new Canvas(resultingImage);

Paint paint = new Paint();
paint.setAntiAlias(true);
Path path=new Path();
path.lineTo(150, 0);
path.lineTo(230, 120);
path.lineTo(70, 120);
path.lineTo(150, 0);

canvas.drawPath(path, paint);

paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap2, 0, 0, paint);

compositeImageView.setImageBitmap(resultingImage);

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