How to use C# Virtual Viewport and Zoom in IronPDF

What Are the Paper Fit Modes in IronPDF?

Access the PaperFit field in RenderingOptions to use preset methods for specific rendering types and modes. These modes provide different approaches for rendering HTML content onto PDF pages, similar to techniques used when creating custom paper sizes. Let's examine each PaperFit mode by rendering the Wikipedia main page for comparison.

PaperFit modes handle various content layouts, from standard web pages to specialized documents like receipts or reports. Each mode optimizes for specific use cases, ensuring PDFs maintain the intended design and readability regardless of the source content's original format.

How Do I Use Chrome Default Rendering?

This mode lays out PDF pages as they appear in Google Chrome's print preview. It configures rendering options to match the appearance of a web page when printed from Chrome. The responsive CSS viewport interprets the specified paper size based on its width. Use the UseChromeDefaultRendering method to configure this.

Chrome default rendering maintains consistency with browser print expectations. It works well for standard web pages and documents where you want to preserve the natural content flow as it appears in typical browser print operations. For advanced scenarios involving JavaScript rendering, this mode ensures proper execution and display of dynamic content.

:path=/static-assets/pdf/content-code-examples/how-to/viewport-zoom-default-chrome.cs

using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

// Chrome default rendering
renderer.RenderingOptions.PaperFit.UseChromeDefaultRendering();

// Render web URL to PDF
PdfDocument pdf = renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Main_Page");

pdf.SaveAs("chromeDefault.pdf");

How Do I Use Responsive CSS Rendering?

In responsive CSS mode, specify a viewport width by passing a value to the UseResponsiveCssRendering method. The default ViewPortWidth is 1280 pixels. The viewport unit is pixel-based, representing a virtual browser viewport for responsive CSS designs. This mode handles modern frameworks and works with Bootstrap and Flex CSS layouts.

Responsive CSS defines HTML rendering based on the ViewPortWidth parameter, scaling content to fit the specified paper size width. This approach suits modern web applications using responsive design principles, ensuring PDFs maintain the intended layout regardless of original viewport size. When working with custom margins, this mode provides precise control over content adaptation to different page dimensions.

:path=/static-assets/pdf/content-code-examples/how-to/viewport-zoom-responsive-css.cs

using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

// Responsive CSS rendering
renderer.RenderingOptions.PaperFit.UseResponsiveCssRendering(1280);

// Render web URL to PDF
PdfDocument pdf = renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Main_Page");

pdf.SaveAs("responsiveCss.pdf");

How Do I Use Scaled Rendering?

The UseScaledRendering method mimics Chrome Print Preview behavior for a specified paper size while providing an adjustable zoom level. This method scales content according to the input zoom percentage.

Scaled rendering offers precise control over content appearance in PDFs. Unlike fixed viewport approaches, this method allows dynamic content size adjustment, making it ideal for documents requiring readability at different scales or when preparing PDFs for various display contexts. This technique complements page orientation and rotation settings for optimal document presentation.

:path=/static-assets/pdf/content-code-examples/how-to/viewport-zoom-scaled.cs

using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

// Scaled rendering
renderer.RenderingOptions.PaperFit.UseScaledRendering(180);

// Render web URL to PDF
PdfDocument pdf = renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Main_Page");

pdf.SaveAs("scaled.pdf");

How Do I Use Fit to Page Rendering?

Fit to page rendering scales content to fit the specified paper size. It measures the minimum HTML content width after rendering and scales it to fit one sheet of paper width where possible. The configurable minimum pixel width ensures correct display and responsiveness to CSS3 layout rules.

This mode handles content that might span multiple pages horizontally. It works well for wide tables, charts, or dashboards that must fit within a single page width. Automatic scaling ensures all content remains visible without horizontal scrolling, making it ideal for generating PDF reports where readability matters.

:path=/static-assets/pdf/content-code-examples/how-to/viewport-zoom-fit-to-page.cs

using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

// Fit to page rendering
renderer.RenderingOptions.PaperFit.UseFitToPageRendering();

// Render web URL to PDF
PdfDocument pdf = renderer.RenderUrlAsPdf("https://en.wikipedia.org/wiki/Main_Page");

pdf.SaveAs("fitToPage.pdf");

How Do I Use Continuous Feed Rendering?

Continuous feed rendering creates a single-page PDF that fits all content onto one page, suitable for documents like consumer bills or receipts. The default PDF page width is 80.0 millimeters with 5-millimeter margins. Let's render the 'receipt.html' file to PDF.

Customize page width and margin using the width and margin parameters for flexibility. This mode creates concise, single-page documents. It generates receipts, invoices, or any document requiring continuous flow without page breaks. Combined with HTML to PDF page break control, you can create sophisticated document layouts for specific requirements.

:path=/static-assets/pdf/content-code-examples/how-to/viewport-zoom-continuous-feed.cs

using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

int width = 90;
int margin = 0;

// Continuous feed rendering
renderer.RenderingOptions.PaperFit.UseContinuousFeedRendering(width, margin);

// Render web URL to PDF
PdfDocument pdf = renderer.RenderHtmlFileAsPdf("receipt.html");

pdf.SaveAs("continuousFeed.pdf");

Ready to see what else you can do? Check out our tutorial page here: Convert PDFs