iOS图片拼接，图片文字合成总结

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