我正在尝试将画布绘制操作剪切为弧形楔形。但是,在将剪切路径设置为画布后,我没有得到预期的结果。
为了说明,这是我正在做的事情:
path.reset();
//Move to point #1
path.moveTo(rect.centerX(), rect.centerY());
//Per the documentation, this will draw a connecting line from the current
//position to the starting position of the arc (at 0 degrees), add the arc
//and my current position now lies at #2.
path.arcTo(rect, 0, -30);
//This should then close the path, finishing back at the center point (#3)
path.close();
这是有效的,当我简单地绘制这条路径(canvas.drawPath(path, paint)
)时,它会绘制如上所示的楔形。但是,当我将此路径设置为画布的剪切路径并绘制到其中时:
//I've tried it with and without the Region.Op parameter
canvas.clipPath(path, Region.Op.REPLACE);
canvas.drawColor(Color.BLUE);
我得到以下结果(仅留下楔形以显示参考):
所以它似乎会剪切到Path
的边界矩形,而不是Path
本身。任何想法在这里发生了什么?
编辑就像更新一样,我发现了一种更有效的方法,可以实现硬件加速。首先,将整个图像(您要裁剪)绘制到屏幕外位图中。使用此BitmapShader
制作Bitmap
,将该着色器设置为Paint
,然后使用该Paint
对象绘制楔形路径:
drawMyBitmap(bitmap);
Shader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setShader(shader);
@Override
public void onDraw(Canvas canvas) {
canvas.drawArc(rect, //The rectangle bounding the circle
startAngle, //The angle (CW from 3 o'clock) to start
sweepAngle, //The angle (CW from 3 o'clock) of the arc
true, //Boolean of whether to draw a filled arc (wedge)
paint //The paint with the shader attached
);
}
答案 0 :(得分:12)
您使用的是HC还是以上或其他使用硬件加速?
如果是这样,则不支持clipPath并且有问题。
developer.android.com/guide/topics/graphics/hardware-accel.html
答案 1 :(得分:3)
OP的问题是关于使用剪辑区域的问题,@Simon回答了这个问题。但请记住,有一种更简单的绘制填充弧的方法:
创建Paint
:
mPaint = new Paint();
mPaint.setColor(Color.BLUE);
mPaint.setStyle(Style.FILL);
mPaint.setAntiAlias(true);
绘图时,只需绘制路径:
canvas.drawPath(path, mPaint);