Evan的app 學習筆記: Android Canvas 繪製幾何圖形

Canvas的意思就是畫布
Paint 代表了Canvas上的畫筆
以下範列記錄幾種Canvas繪製幾何圖向的方法

canvas.drawArc （扇形）
canvas.drawCircle（圓）
canvas.drawOval（橢圓）
canvas.drawPoint（點）
canvas.drawRect（矩形）
canvas.drawRoundRect（圓角矩形）
canvas.drawLine（線）
cnavas.drawPath（路徑）

DrawCircle

	private void drawCircle(){
	Paint p = new Paint();
	p.setStrokeWidth(3);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);
	canvas.drawCircle(240, 240, 150, p);
	}

view raw CanvasSample_drawCircle.java hosted with ❤ by GitHub

DrawArc

	private void drawArc(){
	Paint p = new Paint();
	p.setStrokeWidth(2);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);

	RectF oval1=new RectF(100, 100,400,400);
	canvas.drawArc(oval1, 30, 300, true, p);
	}

view raw CanvasSample_drawArc.java hosted with ❤ by GitHub

DrawOval

	private void drawOval()
	{
	Paint p = new Paint();
	p.setStrokeWidth(10);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);

	RectF oval=new RectF();
	oval.left=100;
	oval.top=100;
	oval.right=400;
	oval.bottom=300;
	canvas.drawOval(oval, p);
	}

view raw CanvasSample_DrawOval.java hosted with ❤ by GitHub

DrawLine

	private void drawLine(){
	Paint p = new Paint();
	p.setStrokeWidth(10);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);
	canvas.drawLine(60, 40, 200, 400, p);
	}

view raw CanvasSample_drawLine.java hosted with ❤ by GitHub

DrawPath

	private void drawPath(){
	Paint p = new Paint();
	p.setStrokeWidth(5);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);

	Path path =new Path();
	path.moveTo(200, 200);
	path.lineTo(400, 200);
	path.lineTo(400, 400);
	path.close();
	canvas.drawPath(path, p);
	}

view raw CanvasSample_drawPath.java hosted with ❤ by GitHub

DrawPoints

	private void drawPoints()
	{
	Paint p = new Paint();
	p.setStrokeWidth(20);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);

	canvas.drawPoint(60, 390, p);
	canvas.drawPoints(new float[]{60,300,100,300,200,300}, p);
	}

view raw CanvasSample_drawPoints.java hosted with ❤ by GitHub

DrawRect

	private void drawRect()
	{
	Paint p = new Paint();
	p.setStrokeWidth(2);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.STROKE);

	Canvas canvas = new Canvas(bitmap);

	RectF rect = new RectF(100,100,400,400);
	canvas.drawRect(rect, p);
	}

view raw CanvasSample_drawRect.java hosted with ❤ by GitHub

DrawRoundRect

	private void drawRoundRect()
	{
	Paint p = new Paint();
	p.setStrokeWidth(2);
	p.setColor(Color.RED);
	p.setStyle(Paint.Style.FILL);
	p.setAntiAlias(true);

	Canvas canvas = new Canvas(bitmap);

	RectF rect = new RectF(100, 50, 300, 500);
	canvas.drawRoundRect(rect, 20, 20, p);
	}