如何在 Objective-C (iOS) 中的图像上写文本？

在图像内绘制文本并返回结果图像:

+(UIImage*) drawText:(NSString*) text 
             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];
    [text drawInRect:CGRectIntegral(rect) withFont:font]; 
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

用法:

// note: replace "ImageUtils" with the class where you pasted the method above
UIImage *img = [ImageUtils drawText:@"Some text"
                            inImage:img 
                            atPoint:CGPointMake(0, 0)];

将图像中文本的原点从0,0更改为您喜欢的任意点.

要在文本后面绘制一个纯色矩形，请在第[[UIColor whiteColor] set];行之前添加以下内容:

[[UIColor brownColor] set];
CGContextFillRect(UIGraphicsGetCurrentContext(), 
                  CGRectMake(0, (image.size.height-[text sizeWithFont:font].height), 
                                  image.size.width, image.size.height));

我使用文本大小来计算纯色矩形的原点，但是您可以用任何数字替换它.