带颜色渐变的UIBezierPath [英] UIBezierPath with color gradient
本文介绍了带颜色渐变的UIBezierPath的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个关于UIBezierPath的问题。
I've got an question about UIBezierPath.
例如我有这条道路:
现在我想要一个颜色渐变从白色到红色。从左到右。
Now I want to have a color gradient from white to red. From left to right.
这是我的代码:
UIBezierPath *bezierPath;
bezierPath = [UIBezierPath bezierPathWithArcCenter:_center radius:_radius startAngle:((4 * angle)) endAngle:(((20) * angle)) clockwise:YES];
[bezierPath addLineToPoint:_center];
[bezierPath closePath];
UIColor *color = [UIColor colorWithHue:0/sectors saturation:1. brightness:1. alpha:1];
[color setFill];
[color setStroke];
[bezierPath fill];
[bezierPath stroke];
任何人都可以帮助我吗?
Can anyone help me?
编辑1:
我有这个色轮:
UIBezierPath *bezierPath;
for ( int i = 0; i < 360; i++) {
bezierPath = [UIBezierPath bezierPathWithArcCenter:_center radius:_radius startAngle:((i * angle)) endAngle:(((i + 1) * angle)) clockwise:YES];
[bezierPath addLineToPoint:_center];
[bezierPath closePath];
UIColor *color = [UIColor colorWithHue:i/sectors saturation:1. brightness:1. alpha:1];
[color setFill];
[color setStroke];
[bezierPath fill];
[bezierPath stroke];
}
但我希望如此:(使用白色渐变色)
but I want this: (With the white Gradient)
推荐答案
你可以给它试一试:)
- (void)drawRect:(CGRect)rect
{
CGFloat arcStep = (M_PI *2) / 360; // M_PI*2 is equivalent of full cirle
BOOL clocklwise = NO;
CGFloat x = CGRectGetWidth(rect) / 2; // circle's center
CGFloat y = CGRectGetHeight(rect) / 2; // circle's center
CGFloat radius = MIN(x, y) / 2;
CGContextRef ctx = UIGraphicsGetCurrentContext();
// draw colorful circle
CGContextSetLineWidth(ctx, radius*2);
for (CGFloat i = 0; i < 360; i+=1)
{
UIColor* c = [UIColor colorWithHue:i/360 saturation:1. brightness:1. alpha:1];
CGContextSetStrokeColorWithColor(ctx, c.CGColor);
CGFloat startAngle = i * arcStep;
CGFloat endAngle = startAngle + arcStep + 0.02;
CGContextAddArc(ctx, x, y, radius, startAngle, endAngle, clocklwise);
CGContextStrokePath(ctx);
}
// drawing circles then, you might want few of them - smaller radius and less alpha with each step
UIColor* c = [[UIColor whiteColor] colorWithAlphaComponent: 0.03];
for (CGFloat fillRadius = radius/2; fillRadius > 0; fillRadius -= 1.f)
{
CGContextSetLineWidth(ctx, fillRadius*2);
CGContextSetStrokeColorWithColor(ctx, c.CGColor);
CGContextAddArc(ctx, x, y, fillRadius, 0, M_PI * 2, clocklwise);
CGContextStrokePath(ctx);
}
}
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