IOS 给图片添加水印 打印文字

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;
}