Screenshots

A deep dive into image capture options: formats, viewport, zoom, delay, and more. nokap gives you fine-grained control over how pages are rendered and captured, from choosing between PNG, JPEG, and WebP output to configuring viewport dimensions and device scale factor. This page covers every screenshot-related parameter so you can produce exactly the output you need.

Image Formats

nokap supports three image formats, determined by the output file extension:

Extension Format Notes
.png PNG Default. Lossless, supports transparency
.jpg / .jpeg JPEG Lossy compression, smaller files
.webp WebP Modern format, excellent compression 
import nokap

nokap.webshot("https://example.com", "page.png")   # PNG
nokap.webshot("https://example.com", "page.jpg")   # JPEG
nokap.webshot("https://example.com", "page.webp")  # WebP

Viewport Size

Control the browser viewport dimensions with vwidth and vheight:

# Mobile viewport
nokap.webshot("https://example.com", "mobile.png", vwidth=375, vheight=812)

# Desktop widescreen
nokap.webshot("https://example.com", "wide.png", vwidth=1920, vheight=1080)

The defaults are 992×744 pixels, matching common screenshot tool conventions.

Zoom / Scale Factor

The zoom parameter scales the output resolution without changing the viewport layout:

# Standard resolution
nokap.webshot("https://example.com", "1x.png", zoom=1)

# Retina (2×)
nokap.webshot("https://example.com", "2x.png", zoom=2)

# Triple resolution
nokap.webshot("https://example.com", "3x.png", zoom=3)

A zoom=2 produces an image that is 2× the viewport dimensions in pixels. This is ideal for HiDPI displays.

Note

The zoom parameter applies only to raster image output (PNG, JPEG, WebP). It is ignored for PDF output since PDFs are vector format and always render at full resolution. See PDF Generation for details on vector PDF output.

In general, zoom=2 is a good default for images destined for documentation or presentations, balancing file size with crisp rendering on modern screens.

Delay

The delay parameter adds a wait (in seconds) after the page load event fires, before capturing. This is useful for pages with animations or lazy-loaded content:

# Wait 1 second for animations to complete
nokap.webshot("https://example.com", "animated.png", delay=1.0)

# No delay (capture immediately after load)
nokap.webshot("https://example.com", "instant.png", delay=0)

The default delay is 0.2 seconds.

Custom User-Agent

Override the browser’s User-Agent string:

nokap.webshot(
    "https://example.com",
    "bot.png",
    useragent="MyBot/1.0"
)

From HTML Strings

The from_html() function writes an HTML string to a temp file and screenshots it:

html = "<h1 style='color: navy;'>Generated Report</h1>"
nokap.from_html(html, "report.png")

All webshot() options are available as keyword arguments:

nokap.from_html(
    html,
    "report.png",
    zoom=2,
    vwidth=800,
    delay=0.5,
)

Next Steps

You now have a solid foundation for capturing raster screenshots with nokap, from choosing formats and viewport sizes to controlling resolution with zoom and timing with delay. These options cover the majority of screenshot workflows, but nokap offers much more.

With formats, dimensions, and timing under your belt, the next step is learning to target specific elements on a page rather than capturing the entire viewport.