Flutter 画笔(Paint)、绘制直线(drawLine)

@override

bool shouldRepaint(CustomPainter oldDelegate) => true;

}

class MyPainter extends CustomPainter {

@override

void paint(Canvas canvas, Size size) {

//画背景

var paint = Paint()

…isAntiAlias = false

…strokeWidth=30.0

…color = Colors.red;

canvas.drawLine(Offset(50.0, 50.0), Offset(100.0,70.0), paint…strokeCap);

}

//在实际场景中正确利用此回调可以避免重绘开销，本示例我们简单的返回true

@override

bool shouldRepaint(CustomPainter oldDelegate) => true;

}

isAntiAlias=true（消除锯齿）

    

class MyPainter extends CustomPainter {

@override

void paint(Canvas canvas, Size size) {

//画背景

var paint = Paint()

…isAntiAlias = true

…strokeWidth=30.0

…color = Colors.red;

canvas.drawLine(Offset(50.0, 50.0), Offset(100.0,60.0), paint…strokeCap);

}

//在实际场景中正确利用此回调可以避免重绘开销，本示例我们简单的返回true

@override

bool shouldRepaint(CustomPainter oldDelegate) => true;

}

class MyPainter extends CustomPainter {

@override

void paint(Canvas canvas, Size size) {

//画背景

var paint = Paint()

…isAntiAlias = true

…strokeWidth=30.0

…color = Colors.red;

canvas.drawLine(Offset(50.0, 50.0), Offset(100.0,70.0), paint…strokeCap);

}

//在实际场景中正确利用此回调可以避免重绘开销，本示例我们简单的返回true

@override

bool shouldRepaint(CustomPainter oldDelegate) => true;

}

strokeWidth（画笔宽度）

class MyPainter extends CustomPainter {

@override

void paint(Canvas canvas, Size size) {

//画背景

var paint = Paint()

…isAntiAlias = true

…color = Colors.red;

canvas.drawLine(Offset(50.0, 46.0), Offset(200.0,46.0), paint…strokeCap…strokeWidth=4.0);

canvas.drawLine(Offset(50.0, 60.0), Offset(200.0,60.0), paint…strokeCap…strokeWidth=8.0);

canvas.drawLine(Offset(50.0, 80.0), Offset(200.0,80.0), paint…strokeCap…strokeWidth=16.0);

canvas.drawLine(Offset(50.0, 110.0), Offset(200.0,110.0), paint…strokeCap…strokeWidth=20.0);

}

//在实际场景中正确利用此回调可以避免重绘开销，本示例我们简单的返回true

@override

bool shouldRepaint(CustomPainter oldDelegate) => true;

}

strokeCap（buff、round、square）