本文将带你了解IOS开发入门iOS图片拼接，图片文字合成总结，希望本文对大家学IOS有所帮助。

iOS图片拼接，图片文字合成总结

一、注意事项：项目报错，图片模糊，内存问题，离屏渲染

二、以下是合成的步骤：

1、先读取两张图片把创建出CGImageRef

2、创建上下文画布

3、把图片依次画在画布指定位置上

4、从上下文中获得合并后的图片

5、关闭上下文

6、释放内存

7、两张图片合成：

(void)composeImg {

    UIImage *img = [UIImage   imageNamed:@"0.png"];

    CGImageRef imgRef = img.CGImage;

    CGFloat w = CGImageGetWidth(imgRef);

    CGFloat h = CGImageGetHeight(imgRef);

    //以1.png的图大小为底图

    UIImage *img1 = [UIImage   imageNamed:@"1.png"];

    CGImageRef imgRef1 =   img1.CGImage;

    CGFloat w1 =   CGImageGetWidth(imgRef1);

    CGFloat h1 =   CGImageGetHeight(imgRef1);

    //以1.png的图大小为画布创建上下文

    UIGraphicsBeginImageContext(CGSizeMake(w1,   h1));

    [img1 drawInRect:CGRectMake(0, 0, w1,   h1)];//先把1.png   画到上下文中

    [img   drawInRect:CGRectMake(100,   100, w,   h)];//再把小图放在上下文中

    UIImage *resultImg =   UIGraphicsGetImageFromCurrentImageContext();//从当前上下文中获得最终图片

    UIGraphicsEndImageContext();//关闭上下文

    NSString *path =   [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask,   YES) lastObject];

    NSString *filePath = [path   stringByAppendingPathComponent:@"01.png"];

    [UIImagePNGRepresentation(resultImg)   writeToFile:filePath atomically:YES];//保存图片到沙盒

    CGImageRelease(imgRef);

    CGImageRelease(imgRef1);

}

图片与文字合成：

(UIImage   *)CSImage:(UIImage *)img AddText:(NSString   *)text

{

    UIImageView *view = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0,   img.size.width, img.size.height)];

    view.image = img;

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0,0,0,0)];

    [label setNumberOfLines:0];

    label.lineBreakMode =   UILineBreakModeWordWrap;

    NSString *s =   text;

    UIFont *font = [UIFont   fontWithName:@"Arial" size:12];

    CGSize size =   CGSizeMake(320,2000);

    CGSize labelsize = [s sizeWithFont:font   constrainedToSize:size   lineBreakMode:UILineBreakModeWordWrap];

    label.frame =   CGRectMake(0,0,   labelsize.width, labelsize.height);

    [view   addSubview:label];

    return [self convertViewToImage:view];

}

-(UIImage*)convertViewToImage:(UIView*)v

{

    CGSize s =   v.bounds.size;

    UIGraphicsBeginImageContextWithOptions(s, NO,   [UIScreen mainScreen].scale);

    CGContextRef context =   UIGraphicsGetCurrentContext();

    [v.layer   renderInContext:context];

    UIImage *image =   UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    v.layer.contents = nil;  

    return image;

}

图片模糊问题，解决方法：1本身图片有问题，2图片压缩的太狠了，3使用WithOptions函数

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