README.md
1# CI screenshot diff viewer
2
3This directory contains the source of screenshots diff viewer used on Perfetto
4CI. The way it works as follows:
5
6When a screenshot test is failing, the testing code will write a line of the
7form
8
9```
10failed-screenshot.png;failed-screenshot-diff.png
11```
12
13To a file called `report.txt`. Diff viewer is just a static page that uses Fetch
14API to download this file, parse it, and display images in a list of rows.
15
16The page assumes `report.txt` to be present in the same directory, same goes for
17screenshot files. To simplify deployment, the viewer is developed without a
18framework and constructs DOM using `document.createElement` API.
19
