Gerber Viewer for GitHub

Preview PCB design files inline while browsing GitHub. No more downloading Gerber archives, unzipping them, and opening a separate tool just to see what a board looks like. Gerber Viewer for GitHub adds an interactive preview panel above the regular file view whenever you open a Gerber, Excellon drill, ZIP archive, or KiCad file in a public or private repository. It works in five places, plus pull requests: * On a single-file blob page (e.g. /blob/main/board.gtl), it renders the layer immediately, then fetches sibling files in the same folder to build a realistic Top and Bottom composite view with copper, soldermask, silkscreen, and drill holes. * On a folder page (e.g. /tree/main/gerbers/), it detects layer-set folders automatically and shows the same composite view without needing to open an individual file first. * On a ZIP archive committed to a repo, it downloads and extracts the archive entirely in your browser, finds the Gerber files inside, and builds the same multi-layer preview. * On a GitHub Gist that contains Gerber files, it does the same as the blob and folder cases, using the Gist API to fetch file content inline. * On a pull request's "Files changed" tab, it finds the Gerber, drill, and KiCad files the pull request touches and renders a before/after preview for each one, so you can see what a board change looks like without checking out the branch. Added files show the new board, removed files show the old one, and modified files show both side by side. For KiCad .kicad_pcb board files and .kicad_sch schematic files, the extension embeds the KiCanvas viewer directly in the page, giving you full layer toggles, zoom, and pan over the native KiCad format. ---------------------------------------- What's in the toolbar ---------------------------------------- Layer / Top / In1 / In2 / ... / Bottom tabs to switch between views. Inner copper tabs appear automatically for multi-layer boards. Zoom controls with zoom-to-cursor, step buttons, and Fit. Plain scrolling passes through to the page so you can scroll past the board normally. To zoom, pinch on a trackpad, or hold Cmd (Ctrl on Windows and Linux) while scrolling. Click-and-drag panning. Two rotation buttons for 90 degree steps. Measurement tool. Click a start point, then an end point, to measure the distance in mm or mil. The measurement locks when you finish, so it does not auto-start a new line. Click again to measure something else, or Shift-click to extend the current measurement into a multi-segment chain with a running total. Backspace undoes the last point, Escape exits. Layers menu for hiding silkscreen, soldermask, solderpaste, copper, substrate, or board outline independently. Useful for design reviews where you want to inspect routing without silkscreen clutter. The hidden state persists across Top / Bottom switches. Color menu for rendering the board in green, red, blue, black, white, yellow, or purple soldermask, so the preview can match the board you actually ordered. Dark colors automatically pair with white silkscreen and light colors with black silkscreen so the legend stays readable. A default color can be set in the settings page. Outline toggle for boards whose .gko / Edge_Cuts file has disconnected segments, fab markings, or fiducials mixed into the boundary geometry. Flips between using the outline file and computing the boundary from the union of features. Invert (dark mode) for the rendered board. Download SVG of the current view at the current zoom. Hide / Show to collapse the panel without losing state. ---------------------------------------- Bill of materials extraction ---------------------------------------- When a folder, ZIP archive, or Gist contains a bom.csv, bom.tsv, bom.xlsx, or bom.xls file alongside the Gerber files, the extension parses it and shows the rows in a sortable table below the board preview. CSV parsing is built in; Excel parsing uses a bundled copy of SheetJS that loads lazily on the first BOM encountered. Multi-sheet Excel workbooks get a sheet picker, with the sheet named "BOM" or "Bill of Materials" selected by default. Numeric and date cells are coerced to their display values so a date column reads as "2024-03-15" rather than as Excel's serial number 45366. A Copy as TSV button copies the current view to your clipboard in a spreadsheet-friendly format. ---------------------------------------- Keyboard shortcuts ---------------------------------------- Z fits the view, R rotates clockwise (Shift+R counter-clockwise), M toggles the measurement tool, U toggles between mm and mil, L / T / B switch to Layer / Top / Bottom views, O toggles the outline file, I inverts the theme, H hides the panel, and ? opens a help overlay listing every shortcut along with a note on how the measurement tool works. ---------------------------------------- Gerber X2 and X3 attribute support ---------------------------------------- When a Gerber file declares its role via %TF.FileFunction*%, %TF.GenerationSoftware*%, or related X2/X3 attributes, the preview header shows that information directly. So instead of guessing "is this top copper or bottom?" from a cryptic .gtl filename, you see "Top copper (L1) - KiCad 7.0.5" in the toolbar. ---------------------------------------- Settings page ---------------------------------------- Open via the Extensions menu (puzzle-piece icon) -> three-dot menu -> Options. Toggle the default measurement unit (mm or mil), default theme (light or dark), default outline mode, default board color, default panel collapsed state, and an optional cap on GitHub API calls per page. Settings persist across browser sessions. The Settings page also has a Copy Diagnostics button that writes a JSON blob to your clipboard with the extension version, your browser's user-agent, and the most recent 50 events (activations, file loads, errors). Useful for bug reports. The blob is purely local; nothing i…