Convert html file to PDF Document in iOS using Cocoa-Touch

问题

I want to convert local html file on iPhone to PDF document. I have used the following code I found online to generate PDF file from Picture, I tried to replace the image with the html file but it failed. I would very much appreciate your help. Thanks in advance,

// Our method to create a PDF file natively on the iPhone
// This method takes two parameters, a CGRect for size and
// a const char, which will be the name of our pdf file
void CreatePDFFile (CGRect pageRect, const char *filename) {

    // This code block sets up our PDF Context so that we can draw to it
    CGContextRef pdfContext;
    CFStringRef path;
    CFURLRef url;
    CFMutableDictionaryRef myDictionary = NULL;
    // Create a CFString from the filename we provide to this method when we call it
    path = CFStringCreateWithCString (NULL, filename,
                                      kCFStringEncodingUTF8);
    // Create a CFURL using the CFString we just defined
    url = CFURLCreateWithFileSystemPath (NULL, path,
                                         kCFURLPOSIXPathStyle, 0);
    CFRelease (path);
    // This dictionary contains extra options mostly for 'signing' the PDF
    myDictionary = CFDictionaryCreateMutable(NULL, 0,
                                             &kCFTypeDictionaryKeyCallBacks,
                                             &kCFTypeDictionaryValueCallBacks);
    CFDictionarySetValue(myDictionary, kCGPDFContextTitle, CFSTR("My PDF File"));
    CFDictionarySetValue(myDictionary, kCGPDFContextCreator, CFSTR("My Name"));
    // Create our PDF Context with the CFURL, the CGRect we provide, and the above defined dictionary
    pdfContext = CGPDFContextCreateWithURL (url, &pageRect, myDictionary);
    // Cleanup our mess
    CFRelease(myDictionary);
    CFRelease(url);
    // Done creating our PDF Context, now it's time to draw to it

    // Starts our first page
    CGContextBeginPage (pdfContext, &pageRect);

    // Draws a black rectangle around the page inset by 50 on all sides
    CGContextStrokeRect(pdfContext, CGRectMake(50, 50, pageRect.size.width - 100, pageRect.size.height - 100));

    // This code block will create an image that we then draw to the page
    const char *picture = "Picture";
    CGImageRef image;
    CGDataProviderRef provider;
    CFStringRef picturePath;
    CFURLRef pictureURL;

    picturePath = CFStringCreateWithCString (NULL, picture,
                                      kCFStringEncodingUTF8);
    pictureURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), picturePath, CFSTR("png"), NULL);
    CFRelease(picturePath);
    provider = CGDataProviderCreateWithURL (pictureURL);
    CFRelease (pictureURL);
    image = CGImageCreateWithPNGDataProvider (provider, NULL, true, kCGRenderingIntentDefault);
    CGDataProviderRelease (provider);
    CGContextDrawImage (pdfContext, CGRectMake(200, 200, 207, 385),image);
    CGImageRelease (image);


    // End image code

    // Adding some text on top of the image we just added
    CGContextSelectFont (pdfContext, "Helvetica", 16, kCGEncodingMacRoman);
    CGContextSetTextDrawingMode (pdfContext, kCGTextFill);
    CGContextSetRGBFillColor (pdfContext, 0, 0, 0, 1);
    const char *text = "Hello World!";
    CGContextShowTextAtPoint (pdfContext, 260, 390, text, strlen(text));
    // End text

    // We are done drawing to this page, let's end it
    // We could add as many pages as we wanted using CGContextBeginPage/CGContextEndPage
    CGContextEndPage (pdfContext);

    // We are done with our context now, so we release it
    CGContextRelease (pdfContext);
}

- (IBAction)createPDF:(id)sender {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *saveDirectory = [paths objectAtIndex:0];
    NSString *saveFileName = @"myPDF.pdf";
    NSString *newFilePath = [saveDirectory stringByAppendingPathComponent:saveFileName];
    const char *filename = [newFilePath UTF8String];
    CreatePDFFile(CGRectMake(0, 0, 612, 792),filename);
}

回答1:

To convert html to pdf, you need to:

• Create a Webview and load the HTML.
• Take Webview Capture.
• Convert it into PDF file.

The second step (webview capture) have to be done once your webview content is loaded For this capture you can find sample as in How Do I Take a Screen Shot of a UIView? Then you use this context to convert into PDF file.

For the webview you don't need to show it, just create it without adding the view on screen.

Edit: Other detail, for webview height you can calculate the webview content height and change your webview frame

- (void)webViewDidFinishLoad:(UIWebView *)theWebView {
    NSUInteger contentHeight = [[theWebView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"document.body.scrollHeight;"]] intValue];
    NSUInteger contentWidth = [[theWebView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"document.body.scrollWidth;"]] intValue];
    [theWebView setFrame:CGRectMake(0, 0, contentWidth, contentHeight)];
}

回答2:

I created a class based on every good advice I found around. I've been digging a lot and I hope my class will offer some good start for anyone trying to create multi-page PDF directly out of some HTML source.

You'll find the whole code here with some basic sample code : https://github.com/iclems/iOS-htmltopdf

I had just the same issue as you and my requirements were: - full PDF (real text, no bitmap) - smart multi-pages (compared to cutting a full height webview every X pixels...)

Thus, the solution I use is pretty nice as it resorts to the same tools iOS uses to split pages for print.

Let me explain, I setup a UIPrintPageRenderer based on the web view print formatter (first tip) :

UIPrintPageRenderer *render = [[UIPrintPageRenderer alloc] init];

[render addPrintFormatter:webView.viewPrintFormatter startingAtPageAtIndex:0];

CGRect printableRect = CGRectMake(self.pageMargins.left,
                              self.pageMargins.top,
                              self.pageSize.width - self.pageMargins.left - self.pageMargins.right,
                              self.pageSize.height - self.pageMargins.top - self.pageMargins.bottom);

CGRect paperRect = CGRectMake(0, 0, self.pageSize.width, self.pageSize.height);

[render setValue:[NSValue valueWithCGRect:paperRect] forKey:@"paperRect"];
[render setValue:[NSValue valueWithCGRect:printableRect] forKey:@"printableRect"];

NSData *pdfData = [render printToPDF];

[pdfData writeToFile: self.PDFpath  atomically: YES];

In the meantime, I have created a category on UIPrintPageRenderer to support:

-(NSData*) printToPDF
{
    [self doNotRasterizeSubviews:self.view];

    NSMutableData *pdfData = [NSMutableData data];

    UIGraphicsBeginPDFContextToData( pdfData, CGRectZero, nil );

    [self prepareForDrawingPages: NSMakeRange(0, self.numberOfPages)];

    CGRect bounds = UIGraphicsGetPDFContextBounds();

    for ( int i = 0 ; i < self.numberOfPages ; i++ )
    {
        UIGraphicsBeginPDFPage();

        [self drawPageAtIndex: i inRect: bounds];
    }

    UIGraphicsEndPDFContext();

    return pdfData;
}

来源：https://stackoverflow.com/questions/6316192/convert-html-file-to-pdf-document-in-ios-using-cocoa-touch