Render Images

Render a Cover Image of a Document into an <img> Tag

1
GET /documents/:document_id/cover

Rendering a cover image of a document into an <img> tag requires the query parameter jwt, which must encode the document_id.

It also requires either width or height (but not both) to be included in the query parameters; each has to have a value in the interval (0; 10000]. The other dimension will be calculated based on the aspect ratio of the document.

The request can optionally include the page_index query parameter to specify which page should be rendered. If the page_index parameter does not exist, it defaults to 0, meaning the first page will be rendered. The page_index parameter has to be an integer between 0 and page_count - 1.

If the request includes the Accept: image/webp header, a cover image in the WebP format will be returned; otherwise it will be a PNG. When you use the <img> method described below, the browser will automatically include the appropriate Accept header if it supports WebP images.

This endpoint can be used to provide thumbnail images for your document list. You can use it in a regular <img> tag. The following example will load the cover of a document with the ID abc and a width of 400px. We set the width of the <img> tag to 200px so that the image will be sharp on high-DPI screens.

In case this endpoint is called on a password-protected PDF, you can either add the password claim to the JSON Web Token (JWT) or include the password query parameter. If no password is present or an incorrect password is supplied, a placeholder lock image is returned with content-type set to image/svg+xml. You can use the disable_fallback_image query parameter:

Copy
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
<img
  src="https://example.com/documents/abc/cover?width=400&jwt=<jwt>"
  width="200"
/>

<img
  src="https://example.com/documents/abc/cover?width=400&page_index=1&jwt=<jwt>"
  width="200"
/>

<img
  src="https://example.com/documents/abc/cover?width=400&page_index=1&jwt=<jwt>"
  width="200"
/>

<img
  src="https://example.com/documents/abc/cover?width=400&page_index=1&jwt=<jwt>&password=<password>"
  width="200"
/>

<img
  src="https://example.com/documents/abc/cover?width=400&page_index=1&jwt=<jwt>&disable_fallback_image=true"
  width="200"
/>