如何在IOS中使用核心图形绘制一组45度平行线跨越形状的填充?示例代码?
(我特别关注在MKMapKit中使用MKPolygon,但目前只是尝试查看是否可以在UIView中使用drawRect?因此用交叉斜线填充UIView的背景)
如何在IOS中使用核心图形绘制一组45度平行线跨越形状的填充?示例代码?
(我特别关注在MKMapKit中使用MKPolygon,但目前只是尝试查看是否可以在UIView中使用drawRect?因此用交叉斜线填充UIView的背景)
对于Swift 3,使用来自@user3230875的方法
final class CrossHatchView: UIView {
// MARK: - LifeCycle
override func draw(_ rect: CGRect) {
// create rect path with bounds that equal to the
// size of a view, in addition it adds rounded corners, this will
// be used later as a canvas for dash drawing
let path:UIBezierPath = UIBezierPath(roundedRect: bounds, cornerRadius: 5)
// specify the new area where the our drawing will be visible
// check [link][1] for more
path.addClip()
// grab the size of drawing area
let pathBounds = path.bounds
// cleanUp rounded rect, that is drawn above
// just remove roundedRect in the words
path.removeAllPoints()
// get start and end point of the line
let p1 = CGPoint(x:pathBounds.maxX, y:0)
let p2 = CGPoint(x:0, y:pathBounds.maxX)
// draw line
path.move(to: p1)
path.addLine(to: p2)
// set line width equal to double width of view
// because we later will draw this line using dash pattern
path.lineWidth = bounds.width * 2
// set dash pattern with some interval
let dashes:[CGFloat] = [0.5, 7.0]
path.setLineDash(dashes, count: 2, phase: 0.0)
// set color for line
UIColor.lightGray.withAlphaComponent(0.5).set()
// actually draw a line using specific
// color and dash pattern
path.stroke()
}
}
结果:
嘿,试试这个示例代码,我在一个300x300的UIView上尝试过。
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 1.5);
CGContextSetStrokeColorWithColor(context, [UIColor grayColor].CGColor);
int backward=0;
for (int i=0;i<15; i++)
{
CGContextMoveToPoint(context, backward, 0);
CGContextAddLineToPoint(context, 300, 300-backward);
backward=backward+20;
}
int backwardNegitive=0;
for (int i=0;i<15; i++)
{
CGContextMoveToPoint(context, 0,backwardNegitive);
CGContextAddLineToPoint(context, 300-backwardNegitive,300);
backwardNegitive=backwardNegitive+20;
}
int forward=0;
for (int i=0;i<15; i++)
{
CGContextMoveToPoint(context, 300-forward, 0);
CGContextAddLineToPoint(context, 0, 300-forward);
forward=forward+20;
}
int forwardNegative=0;
for (int i=0;i<15; i++)
{
CGContextMoveToPoint(context, 0,300+forwardNegative);
CGContextAddLineToPoint(context,300+forwardNegative,0);
forwardNegative=forwardNegative+20;
}
CGContextStrokePath(context);
}
以下是我在苹果开发者论坛上谈论的内容:
#import "CrossHatchView.h"
@implementation CrossHatchView
static CGFloat sides = 5.0;
- (void)drawRect:(CGRect)rect
{
CGRect bounds = self.bounds;
UIBezierPath *path = [UIBezierPath bezierPath];
CGFloat xCentre = CGRectGetMidX(bounds);
CGFloat yCentre = CGRectGetMidY(bounds);
CGFloat radius = 0.0;
if (CGRectGetWidth(bounds) > CGRectGetHeight(bounds)) {
radius = CGRectGetHeight(bounds) / 2.0;
} else {
radius = CGRectGetWidth(bounds) / 2.0;
}
CGFloat angleIncrement = 2.0 * M_PI / sides;
CGFloat initialAngle = ( M_PI + (2.0 * M_PI / sides) ) / 2.0;
for (NSUInteger i = 0; i < sides; i++) {
CGFloat angle = initialAngle + i * angleIncrement;
CGFloat x = xCentre + radius * cos(angle);
CGFloat y = yCentre + radius * sin(angle);
CGPoint point = CGPointMake(x, y);
if (i == 0) {
[path moveToPoint:point];
} else {
[path addLineToPoint:point];
}
}
[path closePath];
[[UIColor cyanColor] set];
[path addClip];
CGRect pathBounds = [path bounds];
[path removeAllPoints];
CGPoint p1 = pathBounds.origin;
CGPoint p2 = CGPointMake(CGRectGetMaxX(pathBounds), CGRectGetMaxY(pathBounds));
[path moveToPoint:p1];
[path addLineToPoint:p2];
path.lineWidth = 400.0;
CGFloat dashes[] = { 2.0, 2.0 };
[path setLineDash:dashes count:2 phase:0.0];
[[UIColor blackColor] set];
[path stroke];
}
@end