IOS 图片水印位置因分辨率不同问题

  前两天公司让在所有上传的图片上加上 水印，并且是，地址和时间 与公司logo 都在图片的不同位置。
    一开始用iPhone6做调试，拍摄的照片加上的水印都能实现，后来突然想到，如果是不同的图片。那么获取的画布的尺寸就不同。如下：

UIGraphicsBeginImageContext(image.size);
 [image drawInRect:CGRectMake(0, 0, W, H)];

  然后用iPhoneX测试后果然，水印不知道画到哪里去了。
  然后就想怎么适配所有机型的水印呢，然后想着，照片这玩意在手机上
  显示不就跟相框差不多吗。不管图片多大，相框就那么大。那么灵感就来了.
  为什么不试一试拿图片的宽度除以当前屏幕的宽度 来拿到一个参数呢，高类      
  似。 这么一想，就赶紧试一试
  具体代码如下：

+ (CGRect)getCgrect:(CGFloat)x y:(CGFloat)y w:(CGFloat)w h:(CGFloat)h wC:(CGFloat)wC hC:(CGFloat)hC{
    CGFloat screenW = [UIScreen mainScreen].bounds.size.width;
    CGFloat screenH = [UIScreen mainScreen].bounds.size.height;
    
    return CGRectMake(x * screenW/375.0 * wC, y*screenH/667.0 * hC, w * wC, h * wC);
}

// 画水印
+(UIImage *)waterMarkImage:(UIImage *)image time:(NSString *)time date:(NSString *)date week:(NSString *)week
                      icon:(UIImage *)icon customerImage:(UIImage *)customerImage positionImage:(UIImage *)positionImage Name:(NSString *)name position:(NSString *)position{
    
    CGFloat screenW = [UIScreen mainScreen].bounds.size.width;
    CGFloat screenH = [UIScreen mainScreen].bounds.size.height;
    
    //画布
    CGFloat W = image.size.width;
    CGFloat H = image.size.height;
    //修正参数
    CGFloat correctH = 0;
    if(W >= H){
        correctH = 15;
    }else{
        correctH = 0;
    }
    
    CGFloat Font = 13;
    
    CGFloat wC = W/screenW;
    CGFloat hC = H/screenH;
    
    UIGraphicsBeginImageContext(image.size);
    [image drawInRect:CGRectMake(0, 0, W, H)];
   
    Font = Font * wC;
//显示时间
    NSString *timeStr = time;
    NSDictionary *timeAttr = @{
                               NSFontAttributeName: [UIFont boldSystemFontOfSize:2 * Font],
                               NSForegroundColorAttributeName : [UIColor whiteColor]
                               };
    [timeStr drawInRect:[UIImage getCgrect:280 y:26 w:90 h:28 wC:wC hC:hC] withAttributes:timeAttr];
    //日期
    NSString *dateStr = date;
    NSDictionary *dateAttr = @{
                               NSFontAttributeName: [UIFont boldSystemFontOfSize:Font],
                               NSForegroundColorAttributeName : [UIColor whiteColor]
                               };
    [dateStr drawInRect:[UIImage getCgrect:230 y:75 + 2*correctH w:110 h:20 wC:wC hC:hC] withAttributes:dateAttr];
    //星期
    NSString *weekStr = week;
//    weekStr = @"星期二";
    NSDictionary *weekAttr = @{
                               NSFontAttributeName: [UIFont boldSystemFontOfSize:Font],
                               NSForegroundColorAttributeName : [UIColor whiteColor]
                               };
    [weekStr drawInRect:[UIImage getCgrect:312 y:75 + 2*correctH w:60 h:20 wC:wC hC:hC] withAttributes:weekAttr];
    //企业logo
    UIImage *comLogo = icon;
    [comLogo drawInRect:[UIImage getCgrect:300 y:113 + 3 * correctH w:40 h:40 wC:wC hC:hC]];
    
    //客户图片
    UIImage *uesrIcon = customerImage;
    [uesrIcon drawInRect:[UIImage getCgrect:18 y:589.5 - 3*correctH w:11 h:16 wC:wC hC:hC]];
    
    //客户姓名
    NSString *userName = name;
    NSDictionary *nameAttr = @{
                               NSFontAttributeName: [UIFont boldSystemFontOfSize:Font],
                               NSForegroundColorAttributeName : [UIColor whiteColor]
                               };
    [userName drawInRect:[UIImage getCgrect:40 y:589.5 - 3*correctH w:200 h:40 wC:wC hC:hC] withAttributes:nameAttr];
    
    //定位图片
    UIImage *positionIcon = positionImage;
    [positionIcon drawInRect:CGRectMake(18*screenW/375.0 * wC , 615*screenH/667.0 * hC , 12 * wC, 16 * hC)];
    [positionIcon drawInRect:[UIImage getCgrect:18 y:615 w:12 h:16 wC:wC hC:hC]];
    
    //定位信息
    NSString *postionStr = position;
    NSDictionary *positionAttr = @{
                               NSFontAttributeName: [UIFont boldSystemFontOfSize:Font],
                               NSForegroundColorAttributeName : [UIColor whiteColor]
                               };
    [postionStr drawInRect:[UIImage getCgrect:40 y:615 w:200 h:40 wC:wC hC:hC] withAttributes:positionAttr];
    
    UIImage *imageEnd = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return imageEnd;
}

最终实现效果如下：最终效果不错，不过我是以iPhone6的屏幕尺寸来的，
如果屏幕尺寸有变化，可以在图一中修改参数。

3ACEE38C-05B3-475C-A41C-665945AB638E.png