ios - 如何使用 UIBezierPath 创建 UIImage

Question

我写了一些代码来创建一个带有 UIBezierPath 的 UIImage 但它没有用。

有人可以帮我找出我的代码有什么问题吗？

-(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;
}

Answer 1

试试这个类到 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