How to Debug HTML in Chrome to Create Pixel Perfect PDFs
As the developers of IronPDF, we understand that PDF documents made by IronPDF not only need to look perfect, but also need to look exactly how our customers expect them to. To achieve pixel-perfect PDFs, you will need to develop excellent HTML templates or collaborate with a web developer to create them for you. IronPDF offers options to render your PDFs pixel-perfect to your HTML, ensuring they appear identical to how they display in Chrome due to our Chrome Renderer.
What is IronPDF's Chrome Renderer?
It makes IronPDF unique from other .NET PDF Libraries
IronPDF is distinct in the market as it utilizes the Google Chromium Renderer, meaning the HTML you see in Chrome browsers will look exactly the same as what you see in our PDFs. In this guide we will walk you through some settings you will need to apply in Chrome and in IronPDF to achieve this.
To be clear, many claimed "HTML to PDF" technologies implemented by competitors do not comply to W3C standards, or even support HTML5, CSS3 or JavaScript and use underlying renderers such as wkhtmltopdf.
IronPDF compared with Competitors
To see a full list of comparisons with other products, see our blog.
Features | IronPDF's Chrome Renderer | Aspose vs IronPDF | iText vs IronPDF
IronPDF's Optimized Chrome Renderer is better than Chrome
Two examples of IronPDF surpassing Chrome itself. Buttons and Text that would otherwise be split onto two pages with Chrome remain in-tact with IronPDF.
Example of Buttons and Text being cut off in Chrome:
Another Example of Text being cut off in Chrome:
Why use HTML to PDF?
Developers love HTML to PDF because it delivers predictable results that match existing web branding. Design is implemented using well documented standardized HTML, CSS and JavaScript technologies.
- The layout and design of the output matches the website exactly.
- Web Developers can focus on designing with absolute precision.
- .NET developers can focus on application logic rather than layout. Back-end developers can delegate layout and design tasks to web designers.
1. Decide to use CSS Media Type Print or Screen
IronPDF's renderer has two media rendering options: Print (default) and Screen. For a visual side-by-side comparison please see the end of this section. Under the "Comparison of Screen and Print Example" section.
CssMediaType.Printis the default rendering option that optimizes your HTML for general use with a printer. This means that some background images, icons, and other ink-heavy elements on the page may render differently or be omitted. This option is good for documents without background images and is the default print-preview.CssMediaType.Screenis the rendering option that will allow your PDFs to look exactly how they appear within Chrome on your screen. You will need to set up some options within your Chrome browser to enable the print-preview to look exactly how IronPDF will render for HTML debugging purposes.
:path=/static-assets/pdf/content-code-examples/how-to/pixel-perfect-html-to-pdf-1.cs// Pixel Perfect HTML Formatting Settings
IronPdf.ChromePdfRenderer renderer = new IronPdf.ChromePdfRenderer();
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Print; // or Screen' Pixel Perfect HTML Formatting Settings
Dim renderer As New IronPdf.ChromePdfRenderer()
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Print ' or ScreenRepeating Table Headers
If you have HTML containing a table that will span more than one page, you would probably like the Table Headers to repeat on each PDF page.
- In this case, you can only use the
PrintCssMediaType. - Using
Screeninstructs Chrome to only print the headers once.
Comparison of Screen and Print Example
Many images and icons will not load in Print mode which will load in Screen mode:
2. Set up Chrome
IronPDF proudly utilizes a Chrome Rendering Engine. Follow these steps for IronPDF to render your HTML exactly as you see it within Chrome. These are the few steps that need to be done beforehand within Chrome to achieve this.
To render pixel-perfect PDFs that include all images, icons, and backgrounds typically omitted in print format, make sure to use the Screen CSS Media option.
2a. Open DevTools and set Enable Emulate CSS media to Screen/Print in Chrome
- To do this, within Chrome open DevTools.
- Press Command+Shift+P (Mac) or Control+Shift+P (Windows, Linux, ChromeOS) to open the Command Menu. Start typing rendering, select Show Rendering, and press Enter. DevTools displays the Rendering tab at the bottom of your DevTools window. (more help)
- Navigate down and find the drop-down for
Emulate CSS mediaand choose the optionScreenorPrint. If you are on a webpage, you may need to reload (Ctrl+R) for settings to take effect.
Screen
2b. Open the Print Preview Window (Ctrl+P on Windows)
You may need to change the paper size and enable 'printing background images' in the Chrome Print dialog in order to get an accurate display.
2c. Set the correct Print Preview settings
- Please choose the Paper Size you are using in your IronPDF project, such as
A4, orLetter. - Under the
Marginsdrop-down selectCustomand set all four sides to (1") one inch margin. - Enable the
Background Graphicscheckbox. - Ensure you set your
LayouttoLandscapeif you intend to output a landscape document.
And that is all. You can now debug your HTML and use the print preview to see exactly how IronPDF will render your layout.
3. Set up IronPDF
3a. Set the CSS Media Type in IronPDF
In order to match the webpage design with 100% precision, we must choose the same CSS Media Type that we set in Chrome in our code.
Recall that PdfCssMediaType.Screen includes backgrounds, and larger images that may be omitted in the PdfCssMediaType.Print format which is the default and designed for printers to save ink.
:path=/static-assets/pdf/content-code-examples/how-to/pixel-perfect-html-to-pdf-2.cs// Example using PdfCssMediaType.Screen
IronPdf.ChromePdfRenderer renderer = new IronPdf.ChromePdfRenderer();
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Screen; // or Print
renderer.RenderingOptions.PrintHtmlBackgrounds = true;' Example using PdfCssMediaType.Screen
Dim renderer As New IronPdf.ChromePdfRenderer()
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Screen ' or Print
renderer.RenderingOptions.PrintHtmlBackgrounds = True3b. Setting Render Delay and Render Timeout appropriately
IronPDF's default rendering timeout is 60 seconds. If the rendering process takes longer than this, a timeout exception will be thrown. To override the default settings, you will need to adjust the RenderingOptions.Timeout option. The render delay value on the other hand is the time IronPDF should wait before starting to render. This wait time is crucial for assets such as images, fonts, and JavaScript code to execute properly.
Keep in mind that having no timeout set or having a render delay longer than your set timeout will produce a "Unable to Render PDF" Exception. So if you are encountering this error you may need to increase these values.
:path=/static-assets/pdf/content-code-examples/how-to/pixel-perfect-html-to-pdf-3.cs// Example of setting Timeout and RenderDelay options
renderer.RenderingOptions.Timeout = 90; // seconds (default is 60)
renderer.RenderingOptions.WaitFor.RenderDelay(30000); // millisecondsIRON VB CONVERTER ERROR developers@ironsoftware.com- WaitFor and JavaScript (Code Example)
- WaitFor (API Reference)
