iOS，在 UIImage 上绘制带笔划的文本

Question

我目前正在将文本绘制到 UIImage 上，该 UIImage 出现在 iOS map 的 AnnotationView 中 - 出现在某些长/纬度坐标处的自定义图标。效果很好。但是，我想用白色笔划(您可以称之为轮廓)绘制此文本。

//Draw text and add to a UIImage iOS 5/6

+ (UIImage*)drawText:(NSString*)string inImage:(UIImage*)image atPoint:(CGPoint)point {

    UIFont *font = [UIFont boldSystemFontOfSize:12];
    UIGraphicsBeginImageContext(image.size);
    [image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];

    CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
    [[UIColor whiteColor] set];
    [string drawInRect:CGRectIntegral(rect) withFont:font];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;

}

Answer 1

NSAttributedString 绝对是最佳选择，特别是如果你想让它在 iOS7 中工作。对于您的示例，您可以将两个文本 block 替换为以下内容:

// draw stroke
NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:font forKey:NSFontAttributeName];
[attributes setObject:[NSNumber numberWithFloat:4] forKey:NSStrokeWidthAttributeName];
[attributes setObject:[UIColor whiteColor] forKey:NSStrokeColorAttributeName];
[self.text drawInRect:rect withAttributes:attributes];

// draw fill
[attributes removeObjectForKey:NSStrokeWidthAttributeName];
[attributes removeObjectForKey:NSStrokeColorAttributeName];
[attributes setObject:[UIColor blackColor] forKey:NSForegroundColorAttributeName];
[self.text drawInRect:rect withAttributes:attributes];