使用掩蔽从图像裁剪字母 [英] Crop letter from image using Masking

问题描述

我需要的是：

1）从库或相机中选择图片

1) Choose image from library or camera

2）写和文字

3）用图像裁剪文字！

3) Text is cropped with image!

下面的图片可以澄清更多我究竟需要什么。

Below image can clarify more on what exactly I need.

我知道屏蔽和裁剪图像，即使我在 emoji me app 。我只需要知道如何根据动态文本裁剪图像。

I know masking and cropping of image even I did masking with frame in emoji me app . Just I need to know how the image should be cropped according to dynamic text.

请提出您的建议。

...
UIImage *image = [UIImage imageNamed:@"dogs.png"];
UIImage *mask = [UIImage imageNamed:@"mask.png"];

// result of the masking method
UIImage *maskedImage = [self maskImage:image withMask:mask];

...

- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {

    CGImageRef maskRef = maskImage.CGImage; 

    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
        CGImageGetHeight(maskRef),
        CGImageGetBitsPerComponent(maskRef),
        CGImageGetBitsPerPixel(maskRef),
        CGImageGetBytesPerRow(maskRef),
        CGImageGetDataProvider(maskRef), NULL, false);

    CGImageRef maskedImageRef = CGImageCreateWithMask([image CGImage], mask);
    UIImage *maskedImage = [UIImage imageWithCGImage:maskedImageRef];

    CGImageRelease(mask);
    CGImageRelease(maskedImageRef);

    // returns new image with mask applied
    return maskedImage;
}

推荐答案

1）写包含以下代码的文字图片

UIImage *textedImage = [self imageFromText:@"Text to show"];



-(UIImage *)imageFromText:(NSString *)text
{
   //set width for string to wrap.

    CGSize maximumSize;
    maximumSize = CGSizeMake(320, 300); 

    //set your text image font here
    UIFont *font = [UIFont boldSystemFontOfSize:50];

    CGSize strSize1 = [text sizeWithFont:font constrainedToSize:maximumSize lineBreakMode:UILineBreakModeWordWrap];
    CGSize strSize =CGSizeMake(320, strSize1.height);

    if (UIGraphicsBeginImageContextWithOptions != NULL)
        UIGraphicsBeginImageContextWithOptions(strSize,NO,0.0);
    else
        UIGraphicsBeginImageContext(strSize);

    //set your new text iamge frame here
    CGRect newframe = CGRectMake(0, 0, 320, 400);

    UIColor *color = [UIColor redColor];
     [color set];

    [text  drawInRect:newframe
                 withFont:font
            lineBreakMode:UILineBreakModeCharacterWrap
                alignment:UITextAlignmentCenter];

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


    return textImg;
}

2）获取纹理图像后应用所需图像进行图像制作

UIImage *maskedImage = [self maskImage:finalImage withMask: textedImage];


- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    //UIImage *maskImage = [UIImage imageNamed:@"mask.png"];
    CGImageRef maskImageRef = [maskImage CGImage];

    // create a bitmap graphics context the size of the image
    CGContextRef mainViewContentContext = CGBitmapContextCreate (NULL, maskImage.size.width, maskImage.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);


    if (mainViewContentContext==NULL)
        return NULL;

    CGFloat ratio = 0;

    ratio = maskImage.size.width/ image.size.width;

    if(ratio * image.size.height < maskImage.size.height) {
        ratio = maskImage.size.height/ image.size.height;
    }

    CGRect rect1  = {{0, 0}, {maskImage.size.width, maskImage.size.height}};
    CGRect rect2  = {{-((image.size.width*ratio)-maskImage.size.width)/2 , -((image.size.height*ratio)-maskImage.size.height)/2}, {image.size.width*ratio, image.size.height*ratio}};


    CGContextClipToMask(mainViewContentContext, rect1, maskImageRef);
    CGContextDrawImage(mainViewContentContext, rect2, image.CGImage);


    // Create CGImageRef of the main view bitmap content, and then
    // release that bitmap context
    CGImageRef newImage = CGBitmapContextCreateImage(mainViewContentContext);
    CGContextRelease(mainViewContentContext);

    UIImage *theImage = [UIImage imageWithCGImage:newImage];

    CGImageRelease(newImage);

    // return the image
    return theImage;
}

这篇关于使用掩蔽从图像裁剪字母的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！