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我希望能夠將矩形圖像中心裁剪爲圓形。我已經設法做到了，但我確信有更有效的方法來做到這一點？這裏是我的代碼：Android位圖：居中裁剪+創建位圖的圓形
中心作物：
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
// Compute the scaling factors to fit the new height and width, respectively.
// To cover the final image, the final scaling will be the bigger
// of these two.
int newWidth = 300;
int newHeight = 300;
float xScale = (float) newWidth/sourceWidth;
float yScale = (float) newHeight/sourceHeight;
float scale = Math.max(xScale, yScale);
// Now get the size of the source bitmap when scaled
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
// Let's find out the upper left coordinates if the scaled bitmap
// should be centered in the new size give by the parameters
float left = (newWidth - scaledWidth)/2;
float top = (newHeight - scaledHeight)/2;
// The target rectangle for the new, scaled version of the source bitmap will now
// be
RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
// Finally, we create a new bitmap of the specified size and draw our new,
// scaled bitmap onto it.
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawBitmap(source, null, targetRect, null);
一次，我已經創造了這個新的中心裁剪位圖，我現在希望把它圓。我將上面的位圖傳遞給此方法：
public Bitmap getRoundedBitmap(Bitmap bitmap) {
final Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(output);
final int color = Color.RED;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawOval(rectF, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
bitmap.recycle();
return output;
}
是否可以將這些方法組合在一起？我對位圖操作相當陌生。謝謝！
創建另一個位圖，然後在getRoundedBitmap（）方法中操作似乎是不必要的。