添加水印

1.加文字

- (UIImage *)imageWithLogoText:(UIImage *)img text:( NSString *)text1
{
    /注：此为后来更改，用于显示中文。zyq,2013-5-8
    CGSize size = CGSizeMake(200, img.size.height);           //设置上下文（画布）大小
    UIGraphicsBeginImageContext(size);                       //创建一个基于位图的上下文(context)，并将其设置为当前上下文
    CGContextRef contextRef = UIGraphicsGetCurrentContext(); //获取当前上下文
    CGContextTranslateCTM(contextRef, 0, img.size.height);   //画布的高度
    CGContextScaleCTM(contextRef, 1.0, -1.0);                 //画布翻转
    CGContextDrawImage(contextRef, CGRectMake(0, 0, img.size.width, img.size.height), [img CGImage]);   //在上下文种画当前图片

    [[UIColor redColor] set];                                 //上下文种的文字属性
    CGContextTranslateCTM(contextRef, 0, img.size.height);
    CGContextScaleCTM(contextRef, 1.0, -1.0);
    UIFont *font = [UIFont boldSystemFontOfSize:16];
    [text1 drawInRect:CGRectMake(0, 0, 200, 80) withFont:font];       //此处设置文字显示的位置
    UIImage *targetimg =UIGraphicsGetImageFromCurrentImageContext();   //从当前上下文种获取图片
    UIGraphicsEndImageContext();                             //移除栈顶的基于当前位图的图形上下文。
    return targetimg;


    //注：此为原来，不能显示中文。无用。
    //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: NSUnicodeStringEncoding ];
    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.新的添加文字水印的方法一

#pragma mark -也是文字水印
- (UIImage *) imageWithStringWaterMark:( NSString *)markString inRect:(CGRect)rect color:(UIColor *)color font:(UIFont *)font
{
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)
    {
        UIGraphicsBeginImageContextWithOptions([ self size], NO , 0.0); // 0.0 for scale means "scale for device's main screen".
    }
#else
    if ([[[UIDevice currentDevice] systemVersion] floatValue] < 4.0)
    {
        UIGraphicsBeginImageContext([ self size]);
    }
#endif

    //原图
    [ self drawInRect:CGRectMake(0, 0, self .size.width, self .size.height)];

    //文字颜色
    [color set];

    //水印文字
    [markString drawInRect:rect withFont:font];

    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newPic;
}

3.还是添加文字水印方法二

#pragma mark -还是文字水印
- (UIImage *) imageWithStringWaterMark:( NSString *)markString atPoint:(CGPoint)point color:(UIColor *)color font:(UIFont *)font
{
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)
    {
        UIGraphicsBeginImageContextWithOptions([ self size], NO , 0.0); // 0.0 for scale means "scale for device's main screen".
    }
#else
    if ([[[UIDevice currentDevice] systemVersion] floatValue] < 4.0)
    {
        UIGraphicsBeginImageContext([ self size]);
    }
#endif

    //原图
    [ self drawInRect:CGRectMake(0, 0, self .size.width, self .size.height)];

    //文字颜色
    [color set];

    //水印文字
    [markString drawAtPoint:point withFont:font];

    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newPic;
}

4.加图片

#pragma mark - 加图片水印
-(UIImage *)imageWithLogoImage:(UIImage *)img logo:(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]);
}

5.新的添加图片水印的方法

#pragma mark -还是图片水印
- (UIImage *) imageWithWaterMask:(UIImage*)mask inRect:(CGRect)rect
{
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)
    {
        UIGraphicsBeginImageContextWithOptions([ self size], NO , 0.0); // 0.0 for scale means "scale for device's main screen".
    }
#else
    if ([[[UIDevice currentDevice] systemVersion] floatValue] < 4.0)
    {
        UIGraphicsBeginImageContext([ self size]);
    }
#endif

    //原图
    [ self drawInRect:CGRectMake(0, 0, self .size.width, self .size.height)];
    //水印图
    [mask drawInRect:rect];

    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newPic;
}

6 .加半透明的水印

//加半透明的水印
-(UIImage *)imageWithTransImage:(UIImage *)useImage addtransparentImage:(UIImage *)transparentimg
{
    UIGraphicsBeginImageContext(useImage.size);
    [useImage drawInRect:CGRectMake(0, 0, useImage.size.width, useImage.size.height)];
    [transparentimg drawInRect:CGRectMake(0, useImage.size.height-transparentimg.size.height, transparentimg.size.width, transparentimg.size.height) blendMode:kCGBlendModeOverlay alpha:0.4f];

    UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return resultingImage;
}

转载于:https://www.cnblogs.com/piaojin/p/5853361.html