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in Technique[技术] by (71.8m points)

ios - Print a UIView, but NOT by rendering as a bitmap image

Say you have a simple UIView with only text (ie, UILabel) and maybe some black lines.

enter image description here

Here's exactly how you can print that UIView...

render it as a UIImage, and print that...

- (IBAction)printB:(id)sender
    {
    // we want to print a normal view ... some UILabels, maybe a black line

    // in this technique, depressingly we CREATE AN IMAGE of the view...

    // step 1. make a UIImage, of the whole view.

    UIGraphicsBeginImageContextWithOptions(self.printMe.bounds.size, NO, 0.0);

    // [self.printMe.layer renderInContext:UIGraphicsGetCurrentContext()];
    // UIImage *asAnImage = UIGraphicsGetImageFromCurrentImageContext();
    // .... or, more futuristically.....
    [self.printMe drawViewHierarchyInRect:self.printMe.bounds
        afterScreenUpdates:NO];
    UIImage *snapshotImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    // step 2. choose grayscale, etc

    UIPrintInfo *info = [UIPrintInfo printInfo];
    info.orientation = UIPrintInfoOrientationPortrait;
    info.outputType = UIPrintInfoOutputGrayscale;

    // step 3, print that UIImage

    UIPrintInteractionController *pic =
       [UIPrintInteractionController sharedPrintController];
    pic.delegate = self;
    //pic.printingItem = asAnImage;
    pic.printingItem = snapshotImage;
    pic.printInfo = info;

    UIPrintInteractionCompletionHandler completionHandler =
    ^(UIPrintInteractionController *pic, BOOL completed, NSError *error)
        {
        if (error)
            NSLog(@"failed... %@ %ld", error.domain, (long)error.code);
        if (completed)
            NSLog(@"completed yes");
        else
            NSLog(@"completed no");
        };     

    [pic presentAnimated:YES completionHandler:completionHandler];
    }

But this gives you crap results. It's a ridiculous way to print typography. It should be being sent as postscript, or something.

on iPad screen...

enter image description here

when printed ..

enter image description here

Note that, of course, if you use a retina ipad it's a bit better, but that's not the point. it's ridiculous to print text information, black lines, as an image.

Now, you'd think you could print a UIView something like this ...

pic.printFormatter = [someUIView viewPrintFormatter];

but I can't get that to work no matter what I try.

Does anyone have anything on this? Thanks!

PS - note that in iOS, we've recently changed from using renderInContext to using the snapshot call. It makes absolutely no difference to the issue here, cheers.

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by (71.8m points)

As Apple Doc states, viewPrintFormatter attribute of UIView is defined in a UIView category but it's available only for instances of type: UITextView, MKMapView and UIWebView.

So you can either:


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