我知道如何使用 CGPath
s 绘制线条和形状。但是我不知道如何为电路图绘制这个符号
我应该写什么代码来获得那个半圆形状?
这是我目前所拥有的:
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 5.0);
CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);
CGContextMoveToPoint(context, 60, 80);
CGContextAddLineToPoint(context, 120, 80);
CGContextMoveToPoint(context, 120, 80);
CGContextAddArc(120,80,M_PI,M_PI/2);
CGContextMoveToPoint(context, 200, 80);
CGContextAddLineToPoint(context, 300, 80);
CGContextStrokePath(context);
}
最佳答案
您可以创建一个 UIBezierPath
,例如像这样的东西:
UIBezierPath *path = [UIBezierPath bezierPath];
CGPoint point = CGPointMake(0, 50);
CGFloat radius = 15.0;
CGFloat lineLength = 25.0;
[path moveToPoint:point];
point.x += lineLength;
[path addLineToPoint:point];
point.x += radius;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2 clockwise:YES];
point.x += radius * 2;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2 clockwise:YES];
point.x += radius * 2;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2 clockwise:YES];
point.x += radius * 2;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2 clockwise:YES];
point.x += lineLength + radius;
[path addLineToPoint:point];
您可以让您的 View Controller 只创建一个 CAShapeLayer
并将其添加到您的 View 的 layer
。
CAShapeLayer *layer = [CAShapeLayer layer];
layer.path = [path CGPath];
layer.lineWidth = 2.0;
layer.fillColor = [[UIColor clearColor] CGColor];
layer.strokeColor = [[UIColor blackColor] CGColor];
[self.view.layer addSublayer:layer];
如果您想在UIView
子类的drawRect
中执行此操作,您可以stroke
此路径:
- (void)drawRect:(CGRect)rect
{
UIBezierPath *path = [UIBezierPath bezierPath];
CGPoint point = CGPointMake(0, 50);
CGFloat radius = 20.0;
CGFloat lineLength = 45.0;
[path moveToPoint:point];
point.x += lineLength;
[path addLineToPoint:point];
point.x += radius;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2.0 clockwise:YES];
point.x += radius * 2.0;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2.0 clockwise:YES];
point.x += radius * 2.0;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2.0 clockwise:YES];
point.x += radius * 2.0;
[path addArcWithCenter:point radius:radius startAngle:M_PI endAngle:M_PI * 2.0 clockwise:YES];
point.x += lineLength + radius;
[path addLineToPoint:point];
path.lineWidth = 2.0;
[[UIColor blackColor] setStroke];
[[UIColor clearColor] setFill];
[path stroke];
}
或者,正如您修改后的问题所暗示的那样,如果您更习惯使用 CoreGraphics,您也可以这样做:
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGPoint point = CGPointMake(0, 50);
CGFloat radius = 20.0;
CGFloat lineLength = 45.0;
CGContextMoveToPoint(context, point.x, point.y);
point.x += lineLength;
CGContextAddLineToPoint(context, point.x, point.y);
point.x += radius;
CGContextAddArc(context, point.x, point.y, radius, M_PI, M_PI * 2.0, NO);
point.x += radius * 2.0;
CGContextAddArc(context, point.x, point.y, radius, M_PI, M_PI * 2.0, NO);
point.x += radius * 2.0;
CGContextAddArc(context, point.x, point.y, radius, M_PI, M_PI * 2.0, NO);
point.x += radius * 2.0;
CGContextAddArc(context, point.x, point.y, radius, M_PI, M_PI * 2.0, NO);
point.x += lineLength + radius;
CGContextAddLineToPoint(context, point.x, point.y);
CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);
CGContextSetLineWidth(context, 2.0);
CGContextDrawPath(context, kCGPathStroke);
}
关于ios - 使用 CoreGraphics 绘制半圆,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20035548/