ios 加水印

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;   

}