android-如何边框canvas

Question

我正在制作一个圆 canvas，我想给它添加一个边框。

final int color = 0xffa19774;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawCircle(sbmp.getWidth() / 2+0.7f, sbmp.getHeight() / 2+0.7f,
        sbmp.getWidth() / 2+0.1f, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(sbmp, rect, rect, paint);

如何在 canvas 周围添加边框？

Answer 1

您可以使用 Paint.STYLE.STROKE 绘制边框。您需要对 drawCircle() 进行两次单独的调用：

paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.parseColor("#BAB399")); // set fill color
canvas.drawCircle(sbmp.getWidth() / 2+0.7f, sbmp.getHeight() / 2+0.7f,
    sbmp.getWidth() / 2+0.1f, paint);

paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(10); // set stroke width
paint.setColor(Color.parseColor("#ffffff")); // set stroke color
canvas.drawCircle(sbmp.getWidth() / 2+0.7f, sbmp.getHeight() / 2+0.7f,
    sbmp.getWidth() / 2+0.1f, paint);

Answer 2

要围绕一个圆画边框，您只需在 canvas 上画两个圆。两个圆的尺寸相同，但下面的圆应该有笔划。

此外，要绘制图像边框，下面的圆应该比上面的圆的半径大。

   public static Bitmap getRoundedCroppedBitmap(Bitmap bitmap, int radius) {
        Bitmap finalBitmap;
        if (bitmap.getWidth() != radius || bitmap.getHeight() != radius)
            finalBitmap = Bitmap.createScaledBitmap(bitmap, radius, radius,
                    false);
        else
            finalBitmap = bitmap;
        Bitmap output = Bitmap.createBitmap(finalBitmap.getWidth(),
                finalBitmap.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, finalBitmap.getWidth(),
                finalBitmap.getHeight());

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.parseColor("#BAB399"));
        canvas.drawCircle(finalBitmap.getWidth() / 2 + 0.7f, finalBitmap.getHeight() / 2 + 0.7f, finalBitmap.getWidth() / 2 + 0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(finalBitmap, rect, rect, paint);

        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(20); // set stroke width
        paint.setColor(Color.parseColor("#00ff00")); // set stroke color
        canvas.drawCircle(finalBitmap.getWidth() / 2 + 0.7f, finalBitmap.getHeight() / 2 + 0.7f, finalBitmap.getWidth() / 2 + 0.1f, paint);


        return output;
    }

上面的示例returns 带边框的位图圆形图像。

这是绘制笔画的代码

  paint.setStyle(Paint.Style.STROKE);
  paint.setStrokeWidth(20); // set stroke width
  paint.setColor(Color.parseColor("#00ff00")); // set stroke color
  canvas.drawCircle(finalBitmap.getWidth() / 2 + 0.7f, finalBitmap.getHeight() / 2 + 0.7f, finalBitmap.getWidth() / 2 + 0.1f, paint);

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