如何使用UIBezierPath创建UIImage [英] How to create a UIImage with UIBezierPath

问题描述

我写了一些代码，用 UIBezierPath 创建一个 UIImage ，但它没有用。
有人可以帮我找出我的代码有什么问题。

I wrote some code to create a UIImage with UIBezierPath but it didn't work. Can someone help me find out what's wrong with my code.

-(UIImage*) drawTriangle{
CGRect rect = CGRectMake(0.0, 0.0, 30.0, 30.0);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
UIGraphicsPushContext(context);
UIBezierPath *bezier = [UIBezierPath bezierPathWithRect:rect];
[bezier moveToPoint:CGPointMake(25, 5)];
[bezier addLineToPoint:CGPointMake(5, 15)];
[bezier addLineToPoint:CGPointMake(25, 25)];
[bezier setLineWidth:3.0];
[bezier setLineJoinStyle:kCGLineJoinBevel];
[bezier stroke];
CGContextAddPath(context, bezier.CGPath);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsPopContext();
UIGraphicsEndImageContext();
return image;
}

推荐答案

将此类别尝试为UIBezierPath

try this category to UIBezierPath

@interface UIBezierPath (Image)

/** Returns an image of the path drawn using a stroke */
-(UIImage*) strokeImageWithColor:(UIColor*)color;

@end

@implementation UIBezierPath (Image)

-(UIImage*) strokeImageWithColor:(UIColor*)color {
    // adjust bounds to account for extra space needed for lineWidth
    CGFloat width = self.bounds.size.width + self.lineWidth * 2;
    CGFloat height = self.bounds.size.height + self.lineWidth * 2;
    CGRect bounds = CGRectMake(self.bounds.origin.x, self.bounds.origin.y, width, height);

    // create a view to draw the path in
    UIView *view = [[UIView alloc] initWithFrame:bounds];

    // begin graphics context for drawing
    UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, [[UIScreen mainScreen] scale]);

    // configure the view to render in the graphics context
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    // get reference to the graphics context
    CGContextRef context = UIGraphicsGetCurrentContext();

    // translate matrix so that path will be centered in bounds
    CGContextTranslateCTM(context, -(bounds.origin.x - self.lineWidth), -(bounds.origin.y - self.lineWidth));

    // set color
    [color set];

    // draw the stroke
    [self stroke];

    // get an image of the graphics context
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

    // end the context
    UIGraphicsEndImageContext();

    return viewImage;
}

@end

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