Zooming
ZeroCount uses zoom-to-cursor:
- Scroll wheel up — zoom in, centred on the cursor.
- Scroll wheel down — zoom out, centred on the cursor.
The cursor position is the anchor — wherever your mouse is on the drawing stays under the mouse as you zoom. This means you don't need to pan after zooming to find what you were looking at — just position the cursor over your target before scrolling.
Zoom has no fixed minimum or maximum but very high zoom levels can get jittery on large drawings.
Panning
Default control scheme: hold ⌥ and drag the canvas. The cursor changes to a hand while panning.
If you've turned on Legacy Controls in user preferences, panning uses CTRL / CMD instead. See User preferences.
When panning doesn't work
ZeroCount disables panning automatically when your cursor is over a marker. The reasoning: hovering a marker should make it interactive, not slip out from under you.
If you find you can't pan from where you are, move the cursor a few pixels off the marker — panning kicks back in immediately.
Rotation
Rotation is handled at the file level rather than as a canvas gesture. Three places to rotate:
- The file card's dotted menu in the project view.
- The service's Actions menu to rotate every file in the service.
- The drawing editor's Actions menu to rotate while a drawing is open.
Each click rotates by 90° clockwise or counter-clockwise. See Rotating files.
There's no free-rotation tool — the canvas can only display the drawing in one of four orientations.
Hover behaviour
Hovering a marker:
- Disables canvas panning so the marker is interactive.
- Highlights the marker (slight outline change, depending on appearance settings).
- Reveals any per-marker context-menu affordances (right-click in this state opens the marker's menu).
Hovering a marker that has overlapping siblings at the same position triggers the overlap context menu on right-click — see overlap context menu.
Selection — quick reference
Already covered in detail in Selecting and moving markers. Short form:
- Single click — select the marker under the cursor.
- CTRL + drag — marquee multi-select.
- CTRL + click — add to / remove from selection.
- ESC — deselect everything.
Working with the file-switcher
The breadcrumb at the top of the editor shows your location. The filename segment has a chevron next to it — click to open a file-selection sheet that lets you switch between ticked files without going back to the project view.
If you have unsaved changes when switching files (or following any breadcrumb), the Leaving Takeoff dialog appears with Cancel / Leave buttons. Click Cancel to stay, Leave to continue.
Performance tips for large drawings
Very dense drawings (A0 with hundreds of detected symbols) can get slow. Strategies that help:
- Collapse marker types you're not using. Use the sidebar toolbar's Filter marker types to hide Annotation or Linear groups while you work on Detection.
- Hide groups not in focus. Use Visibility → Hide on groups you're not currently reviewing. They still count in the export; they just don't render.
- Toggle Remove Background off when you're not actively running detection — it adds processing overhead.
- Reduce the Detection Border Width in user preferences. Thinner outlines render faster.