在位图上画圆
我写了一个应用程序来捕获图片并将其保存在 SD 卡上。然后我可以将该图像加载到图像视图中以显示它。我想在显示位图之前先在位图上画一个圆圈。下面的代码显示位图但没有圆圈，您知道为什么圆圈不存在吗？
谢谢。
BitmapFactory.Options bfo = new BitmapFactory.Options();
bfo.inSampleSize = 5;
Bitmap bm = BitmapFactory.decodeByteArray(imageArray, 0, imageArray.length, bfo);
Log.e(TAG, bm.toString());
//imageview.setImageBitmap(bm);
Bitmap bmOverlay = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig());
canvas = new Canvas(bmOverlay);
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawBitmap(bm, new Matrix(), null);
canvas.drawCircle(750, 14, 11, paint);
imageview.setImageBitmap(bmOverlay);
i've written an app that captures a picture and saves it on the sdcard. i then can load that image into an imageview to display it. i'd like to draw a circle on the bitmap before i display it. the code below displays the bitmap but no circle, any ideas why the circle is not there?
thanks.
BitmapFactory.Options bfo = new BitmapFactory.Options();
bfo.inSampleSize = 5;
Bitmap bm = BitmapFactory.decodeByteArray(imageArray, 0, imageArray.length, bfo);
Log.e(TAG, bm.toString());
//imageview.setImageBitmap(bm);
Bitmap bmOverlay = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig());
canvas = new Canvas(bmOverlay);
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawBitmap(bm, new Matrix(), null);
canvas.drawCircle(750, 14, 11, paint);
imageview.setImageBitmap(bmOverlay);
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您可以检查
bm.getWidth。如果您使用的样本大小为 5，那么您的图像将比原始图像小 5 倍，导致您的圆圈从图像右侧消失。您可以尝试：
只是作为健全性检查。
You might check
bm.getWidth. If you are using a sample size of 5 then your image will be 5 times smaller than the original, causing your circle to disappear off the right side of the image.You could try:
just as a sanity check.