java - 安卓填充局部圆弧

Question

如何使用 paint 和 canvas 方法填充如下所示的两条弧线之间的绿色部分？

这是我画两条弧线的方法，我也可以弄清楚如何用线连接它们，但我不知道如何填充内部区域。

    // set to stroke black
    paint.setColor(Color.BLACK);
    paint.setStyle(Paint.Style.STROKE);
    paint.setStrokeWidth((float) STROKE_WIDTH);

    // outside arc
    RectF arc_oval_outside = new RectF((float) (getX()), (float) (getY()),
            (float) (getX() + getWidth()), (float) (getY() + getHeight()));
    canvas.drawArc(arc_oval_outside, (float) (0.0), (45.0) (ARC_SWEEP), false, paint);

    // inside arc
    RectF arc_oval_inside = new RectF((float) (getX() + ARC_WIDTH), (float) (getY() + ARC_WIDTH),
            (float) (getX() + getWidth() - ARC_WIDTH), (float) (getY() + getHeight() - ARC_WIDTH));
    canvas.drawArc(arc_oval_inside, (float) (0.0), (float) (ARC_SWEEP), false, paint);

Answer 1

下面是绘制带边框的实心圆弧的简单方法:

Point center = new Point(canvas.getWidth()/2, canvas.getHeight()/2);
int inner_radius = 100;
int outer_radius = 150;
int arc_sweep = 90;
int arc_ofset = 30;

RectF outer_rect = new RectF(center.x-outer_radius, center.y-outer_radius, center.x+outer_radius, center.y+outer_radius);
RectF inner_rect = new RectF(center.x-inner_radius, center.y-inner_radius, center.x+inner_radius, center.y+inner_radius);

Path path = new Path();
path.arcTo(outer_rect, arc_ofset, arc_sweep);
path.arcTo(inner_rect, arc_ofset + arc_sweep, -arc_sweep);
path.close();

Paint fill = new Paint();
fill.setColor(Color.GREEN);
canvas.drawPath(path, fill);

Paint border = new Paint();
border.setStyle(Paint.Style.STROKE);
border.setStrokeWidth(2);
canvas.drawPath(path, border);

(Path 和 Paint 分配显然不是最优的)