Browser-based Stereo Viewer

Zerene Systems provides a stereo viewer that runs entirely in your browser.

This means that it works not only on desktop computers (Windows, macOS, and Linux), but also on cell phones and tablets.

It accepts as input stereo pairs that are formatted as single files in side-by-side layout.

It then provides displays in several formats:

• Side-by-side (two images)
• LRL (three images side-by-side, typically left/right/left)
• Over/Under (two side-by-side pairs, one as left/right and the other as right/left)
• Red-cyan anaglyph
• Single image (for larger non-stereo display of one eye's view)

The viewer provides pan/zoom, controlled by either mouse (drag/wheel) or touch (drag/pinch).

A button is provided for swapping left/right with a single click.

Fullscreen display is provided on most devices. (Apple does not permit this on iPhone.)

The viewer is hosted at https://zerenesystems.com/webapps/sv1.html. Images to be viewed can be hosted on any server.

Optional arguments for the viewer can be provided as follows, following a question mark (?) and separated by ampersands (&) as in the example below:

• src=URL to specify the URL of the stereo pair to be loaded.
• load to force loading if src is specified.
• trim=# to omit an existing border around the images, for example trim=10 to get omit a 10 pixel border.
• layoutindex=# to preselect some layout other than side-by-side, for example layoutindex=5 for anaglyph.
• swapsides{=yes|no} to swap sides before initial display.
• pagetitle=String+of+text to specify a title for the browser tab.

The URL of the image to be displayed can be entered in a text field once the viewer is loaded, or often better, you can provide the image URL as part of a link that launches the viewer and automatically loads the image, for example:

• https://zerenesystems.com/webapps/sv1.html?src=https://zerenesystems.com/webapps/Lichen20110209.jpg&load
  (The lichen shown in this sample is only about 3 mm wide. See https://www.photomacrography.net/forum/viewtopic.php?p=77462#p77462 for more information.)

Notes:

• Image panels are sized to fill the viewport of the browser, but there's a row of controls that initially pushes the bottom of the image panels off the screen. To see the whole image, you'll need to scroll up so the controls are hidden.
• The image to be displayed must be a URL that begins with “http:” or “https:”. Due to browser security limitations, the viewer is not allowed to access local files directly using the “file:” notation. However, if you do want to display local files on a desktop computer, it is pretty straightforward to run your own local HTTP server using Python's http.server module, as described at https://realpython.com/python-http-server/ .