Print paper size and content inset

问题

I'm using following code to print HTML content containing text and images.

if (![UIPrintInteractionController isPrintingAvailable]) {
    UIAlertView *alertView = [[[UIAlertView alloc] 
        initWithTitle:NSLocalizedString(@"Printer Availability Error Title", @"")
        message:NSLocalizedString(@"Printer Availability Error Message", @"")
        delegate:nil
        cancelButtonTitle:NSLocalizedString(@"OK", @"OK")
        otherButtonTitles:nil] autorelease];
    [alertView show];
    return;
}

UIPrintInteractionController *pic = 
    [UIPrintInteractionController sharedPrintController];

if(!pic) {
    NSLog(@"Couldn't get shared UIPrintInteractionController!");
    return;
}

pic.delegate = self;

UIPrintInfo *printInfo = [UIPrintInfo printInfo];
printInfo.outputType = UIPrintInfoOutputGeneral;
printInfo.jobName = @"Sample";
pic.printInfo = printInfo;

NSString *htmlString = [self prepareHTMLText];
UIMarkupTextPrintFormatter *htmlFormatter = 
    [[UIMarkupTextPrintFormatter alloc] initWithMarkupText:htmlString];
htmlFormatter.startPage = 0;
// 1-inch margins on all sides
htmlFormatter.contentInsets = UIEdgeInsetsMake(72.0, 72.0, 72.0, 72.0); 
// printed content should be 6-inches wide within those margins
htmlFormatter.maximumContentWidth = 6 * 72.0;   
pic.printFormatter = htmlFormatter;
[htmlFormatter release];

pic.showsPageRange = YES;

void (^completionHandler)(UIPrintInteractionController *, BOOL, NSError *) =
^(UIPrintInteractionController *printController, BOOL completed, NSError *error) {

    if (!completed && error) {
        NSLog(@"Printing could not complete because of error: %@", error);
    }
};

if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
    [pic presentFromBarButtonItem:self.myPrintBarButton 
        animated:YES 
        completionHandler:completionHandler];

} else {
    [pic presentAnimated:YES completionHandler:completionHandler];
}

See attached for results (the scaled down version may not be very clear, but, hopefully, you get the picture).

Here are my questions:

1. How is the print paper size determined by AirPrint? What if I want to specifically format and print data for A4 paper?

2. The result of using the above code and printing using different simulated printers (Printer Simulator) is that, in all cases, I get a 1 inch margin on the top of first page, but not on consecutive pages. Why?

3. The result of using the above code and printing using different simulated printers (Printer Simulator) is that, in some cases, the font style is lost. As a result, the content is shifted down. Why?

回答1:

1. To specifically select A4 paper size, I implemented the printInteractionController:choosePaper: method of the <UIPrintInteractionControllerDelegate> protocol, and returned an A4 paper size if supported by the printer (test with [UIPrintPaper bestPaperForPageSize:withPapersFromArray:]. Note that portrait/landscape orientation is not set here, but by the UIPrintInfo property orientation.

2. The property htmlFormatter.contentInsets only sets the inset for the content as a whole, before it's been split across pages by the page renderer. I was able to set a 1cm per-page margin by adding blank headers and footers via a UIPrintPageRenderer, and then adding a 1cm margin to the left and right of the HTML print formatter:

   UIPrintPageRenderer *renderer = [[UIPrintPageRenderer alloc] init];
   renderer.headerHeight = 30.0f;
   renderer.footerHeight = 30.0f;
   pic.printPageRenderer = renderer;
   [renderer release];
   
   UIMarkupTextPrintFormatter *htmlFormatter = [[UIMarkupTextPrintFormatter alloc] initWithMarkupText: htmlString];
   htmlFormatter.startPage = 0;
   htmlFormatter.contentInsets = UIEdgeInsetsMake(0.0f, 30.0f, 0.0f, 30.0f);
   [renderer addPrintFormatter: htmlFormatter startingAtPageAtIndex: 0];
   [htmlFormatter release];
   

3. Can't help with this one sorry.

来源：https://stackoverflow.com/questions/5817840/print-paper-size-and-content-inset