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Chapter 3

Embedding Content

Helios Open Reader includes shortcodes for embedding rich content responsively, with automatic dark/light theme detection where supported.

iFrame – [iframe]

TXT
[iframe url="https://example.com/embed"]

Embeds any URL in a responsive 16:9 container. Optionally set a different ratio:

TXT
[iframe url="https://example.com" ratio="4:3"]

Google Slides – [googleslides]

TXT
[googleslides url="https://docs.google.com/presentation/d/..."]

Embeds a Google Slides presentation responsively. Paste the "Publish to the web" embed URL. Supports ratio="4:3".

PDF Viewer – [pdf]

TXT
[pdf url="https://example.com/document.pdf"]

Displays a PDF via Google Docs viewer. Default ratio is 16:9. For letter or A4 documents:

TXT
[pdf url="https://example.com/document.pdf" ratio="portrait"]

H5P Interactive Content – [h5p]

Embed via full URL:

TXT
[h5p url="https://h5p.org/h5p/embed/123"]

Or via Content ID (requires H5P Content Embed Source URL to be set in plugin settings):

TXT
[h5p id="123"]

Embedly Cards – [embedly]

TXT
[embedly url="https://example.com/article"]

Renders an Embedly card with dark mode support. Useful for embedding links to articles, videos, and other web content with rich previews.

Tip

All embed shortcodes are responsive by default. The 16:9 ratio works well for video content and slides; use ratio="portrait" for PDF documents and ratio="4:3" for older slide formats.