发表于(2016-04-30 23:40:20)

http://blog.sina.com.cn/s/blog_70854cfb0101d2dr.html
转载自这里，最近有做类似图片、视频的进阶，所以查阅了下博客，谢谢博主的分享啦

1.加文字

-(UIImage )addText:(UIImage )img text:(NSString )text1
{
//get image width and height
int w = img.size.width;
int h = img.size.height;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
//create a graphic context with CGBitmapContextCreate
CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 w, colorSpace, kCGImageAlphaPremultipliedFirst);
CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);
CGContextSetRGBFillColor(context, 0.0, 1.0, 1.0, 1);
char text = (char )[text1 cStringUsingEncoding:NSASCIIStringEncoding];
CGContextSelectFont(context, “Georgia”, 30, kCGEncodingMacRoman);
CGContextSetTextDrawingMode(context, kCGTextFill);
CGContextSetRGBFillColor(context, 255, 0, 0, 1);
CGContextShowTextAtPoint(context, w/2-strlen(text)*5, h/2, text, strlen(text));
//Create image ref from the context
CGImageRef imageMasked = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
return [UIImage imageWithCGImage:imageMasked];
}

2.加图片
-(UIImage )addImageLogo:(UIImage )img text:(UIImage )logo
{
//get image width and height
int w = img.size.width;
int h = img.size.height;
int logoWidth = logo.size.width;
int logoHeight = logo.size.height;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
//create a graphic context with CGBitmapContextCreate
CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 w, colorSpace, kCGImageAlphaPremultipliedFirst);
CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);
CGContextDrawImage(context, CGRectMake(w-logoWidth, 0, logoWidth, logoHeight), [logo CGImage]);
CGImageRef imageMasked = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
return [UIImage imageWithCGImage:imageMasked];
// CGContextDrawImage(contextRef, CGRectMake(100, 50, 200, 80), [smallImg CGImage]);
}

3.加半透明的水印

• (UIImage )addImage:(UIImage )useImage addImage1:(UIImage )addImage1
  {
  UIGraphicsBeginImageContext(useImage.size);
  [useImage drawInRect:CGRectMake(0, 0, useImage.size.width, useImage.size.height)];
  [addImage1 drawInRect:CGRectMake(0, useImage.size.height-addImage1.size.height, addImage1.size.width, addImage1.size.height)];
  UIImage resultingImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return resultingImage;
  }