我想将加载的图像更改为具有圆角。
您知道任何提示,教程和最佳做法吗?
最佳答案
对于更受控的方法,请绘制一个圆角矩形,并使用油漆的波特Xfer Xfer模式将其蒙版到您的图像上。
首先设置Xfer绘画和圆角位图:
Bitmap myCoolBitmap = ... ; // <-- Your bitmap you want rounded
int w = myCoolBitmap.getWidth(), h = myCoolBitmap.getHeight();
// We have to make sure our rounded corners have an alpha channel in most cases
Bitmap rounder = Bitmap.createBitmap(w,h,Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(rounder);
// We're going to apply this paint eventually using a porter-duff xfer mode.
// This will allow us to only overwrite certain pixels. RED is arbitrary. This
// could be any color that was fully opaque (alpha = 255)
Paint xferPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
xferPaint.setColor(Color.RED);
// We're just reusing xferPaint to paint a normal looking rounded box, the 20.f
// is the amount we're rounding by.
canvas.drawRoundRect(new RectF(0,0,w,h), 20.0f, 20.0f, xferPaint);
// Now we apply the 'magic sauce' to the paint
xferPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
现在,将此位图应用到图像的顶部:
Bitmap result = Bitmap.createBitmap(myCoolBitmap.getWidth(), myCoolBitmap.getHeight() ,Bitmap.Config.ARGB_8888);
Canvas resultCanvas = new Canvas(result)
resultCanvas.drawBitmap(myCoolBitmap, 0, 0, null);
resultCanvas.drawBitmap(rounder, 0, 0, xferPaint);
现在,具有圆角的位图驻留在结果中。