前言
上一篇，我們說了繪製基本的幾何圖形，這一篇我們說說繪製路徑（Path）
這裡主要用到的方法是 canvas.drawPath(path, paint);
- 1.直線
主要用到的方法
moveTo(float x, float y) 起始點
lineTo(float x, float y)當前點直線的結束點，也是下條直線的起始點
close()閉合
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(10);
paint.setStyle(Paint.Style.FILL);
Path path = new Path();
path.moveTo(20, 20); //設定起始點
path.lineTo(300, 100);//第1條直線
path.lineTo(300, 300);//第2條直線
path.close();//閉合
canvas.drawPath(path, paint);
複製程式碼
- 2.矩形
addRect(RectF rect, Direction dir)
addRect(float left, float top, float right, float bottom, Direction dir)
RectF和float left, float top, float right, float bottom是一樣的，Direction有2種方式，CW和CCW，其中CW表示順時針，CCW表示逆時針
Path ccw = new Path();
RectF rect1 = new RectF(50, 50, 300, 300);
ccw.addRect(rect1, Path.Direction.CCW);//逆時針
Path cw = new Path();
RectF rect2 = new RectF(350, 50, 600, 300);
cw.addRect(rect2, Path.Direction.CW);//順時針
canvas.drawPath(ccw, paint);
canvas.drawPath(cw, paint);
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- 3.圓角矩形
addRoundRect(RectF rect, float rx, float ry, Direction dir)
addRoundRect(float left, float top, float right, float bottom, float rx, float ry, Direction dir)
addRoundRect(RectF rect, float[] radii, Direction dir)
addRoundRect(float left, float top, float right, float bottom, float[] radii,Direction dir)
其中，radii只能傳入8個數值，多於8個不會有效果，rx表示x方向的半徑，ry表示y方向的半徑
Path ccw = new Path();
RectF rect1 = new RectF(50, 50, 500, 500);
float[] radii = {5, 20, 50, 100, 150, 200, 250, 300};
ccw.addRoundRect(rect1, radii, Path.Direction.CCW);
Path cw = new Path();
RectF rect2 = new RectF(550, 50, 1000, 500);
cw.addRoundRect(rect2, 10, 100, Path.Direction.CCW);
canvas.drawPath(ccw, paint);
paint.setColor(Color.BLUE);
canvas.drawPath(cw, paint);
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- 4.圓形
addCircle(float x, float y, float radius, Direction dir)
Path cw = new Path();
cw.addCircle(200, 200, 100, Path.Direction.CW);
canvas.drawPath(cw, paint);
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- 5.橢圓
addOval(RectF oval, Direction dir)
addOval(float left, float top, float right, float bottom, Direction dir)
Path cw = new Path();
RectF rect1 = new RectF(50, 50, 500, 300);
cw.addOval(rect1, Path.Direction.CW);
canvas.drawPath(cw, paint);
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- 6.弧形
addArc(RectF oval, float startAngle, float sweepAngle)
addArc(float left, float top, float right, float bottom, float startAngle, float sweepAngle)
startAngle 開始的角度，X軸正方向為0度
sweepAngel 持續的度數
Path cw = new Path();
RectF rect1 = new RectF(50, 50, 500, 300);
cw.addArc(rect1, 0, 180);
canvas.drawPath(cw, paint);
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- 7.帶軌跡的文字
drawTextOnPath(String text, Path path, float hOffset,float vOffset, Paint paint)
drawTextOnPath(char[] text, int index, int count, Path path, float hOffset, float vOffset, Paint paint)
index 表示開始位置
count 表示結束位置，可以對文字進行擷取
hOffset 表示繪製位置離開始位置的偏移量
vOffset 表示繪製位置離開路徑的偏移量
String text = "ABCDEFGHIJKLMNOPQRSTYVWXYZ";
paint.setTextSize(72);
Path ccw = new Path();
RectF rect1 = new RectF(50, 50, 500, 500);
ccw.addRect(rect1, Path.Direction.CCW);//逆時針
Path cw = new Path();
RectF rect2 = new RectF(650, 50, 1100, 500);
cw.addRect(rect2, Path.Direction.CW);//順時針
canvas.drawPath(ccw, paint);
canvas.drawPath(cw, paint);
canvas.drawTextOnPath(text, ccw, 0, 0, paint);
canvas.drawTextOnPath(text, cw, 0, 0, paint);
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CCW和CW的區別了
修改hOffset和vOffset
String text = "ABCDEFGHIJKLMNOPQRSTYVWXYZ";
paint.setTextSize(72);
Path ccw = new Path();
RectF rect1 = new RectF(50, 50, 500, 500);
ccw.addRect(rect1, Path.Direction.CCW);//逆時針
Path cw = new Path();
RectF rect2 = new RectF(650, 50, 1100, 500);
cw.addRect(rect2, Path.Direction.CW);//順時針
canvas.drawPath(ccw, paint);
canvas.drawPath(cw, paint);
canvas.drawTextOnPath(text, ccw, 100, 0, paint);
canvas.drawTextOnPath(text, cw, 0, 100, paint);
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可以看到，hOffset 表示繪製位置離開始位置的偏移量，vOffset 表示繪製位置離開路徑的偏移量，vOffset 越大，離圓心越近。