The magic button

The magic button is the round button in the bottom-right corner of the map. It holds the tool the crosshair uses: when you click with the crosshair, the point is added, inserted, moved or deleted, a circle or rectangle is drawn, or a shape's details open, depending on the tool on the button. The button always shows the icon of the tool in use, or add_comment while you are adding comments. It also holds the switches for snapping and for the help box.

The magic button is there only when you can edit the project. People who open a project to view it do not see it.

Use a tool#

1. Press the magic button. Its menu opens.
2. Under Tools, press the tool you want. The button now shows that tool's icon.
3. Hold Shift to show the crosshair, move it to the right spot and click. You can also right-click the map to turn the crosshair on, and right-click again to turn it off.

The tool stays selected until you choose another one. Every tool works through the crosshair: see the crosshair and pins for how to aim it. On a touch screen, turn on Always show crosshair (for touch screens) in the settings to keep a crosshair on the map that you drag and tap.

The tools#

Add#

The tool you use most, and the one selected when you open a project. What it adds depends on the  Crosshair mode chosen in the top toolbar:

• Polygon or Polyline: each click adds a corner to the shape you are drawing. The first click starts a new one. See drawing polygons and polylines.
• Spot: each click opens the Create spot window to name a spot at that place. See points and spots.

Insert#

1. Click a point of the shape. It turns grey.
2. Click one of its neighbours, the point on either side of it. It turns grey too.
3. Click where the new point goes. It is added between the two.

If the two points are shared with a neighbouring polygon along the same edge, the new point is added to that polygon too, so the shared edge stays shared. Press Esc to let go of the points you picked.

Move#

1. Click the point or spot you want to move. It turns grey.
2. Click where it should go, or press Esc to let go of it.

What moves depends on the shape:

• A point of a shape you are still drawing (unlocked) moves on its own.
• A point of a locked shape moves the whole shape, using that point as the handle. The outline follows the crosshair so you can see where it will land.
• A point that sits exactly on a point of another polygon (a shared corner) moves together with it, in every polygon that shares it.

If there is no point near the crosshair, the app says Cannot move point.

Delete#

Click near a point to delete it. When it is the last point of a shape, the app asks before deleting the whole shape. Spots are deleted after you confirm. To bring back something deleted by mistake, press undo Undo in the bottom toolbar, or Ctrl+Z.

Circle and rectangle#

• radio_button_uncheckedCircle: click the centre, move the crosshair to set the radius (the circle follows it), and click again.
• crop_16_9Rectangle: click two corners to set one side, move the crosshair to set the width, and click a third time.

The lock Lock polygon window then opens to name the shape. Circles and rectangles keep their shape afterwards: if you unlock one to edit it, the magic button switches back to the circle or rectangle tool.

Switching between these tools and addAdd while a shape is in progress finishes that shape first: the lock Lock polygon window opens. If you cancel it, an unfinished circle or rectangle is removed.

Info#

Click near a shape's label, a point or a spot to open its details panel. This is useful when a point is hard to click directly, for example where several shapes meet.

Comment#

Press add_commentComment to start adding comments. The button and the crosshair show add_comment, and a click on the map opens a box to write a comment there instead of placing a point. To go back to drawing, press the tile again, pick any other tool, or press Esc. See comments.

Other tools the button shows#

Some tasks start somewhere else and borrow the magic button while they run: splitting, joining and subtracting polygons (from a polygon's panel, see editing shapes) and placing an image overlay. The button then shows that task's icon. Splitting and placing an image also show a red clear button next to it: press it, or Esc, to cancel and go back to addAdd.

Snapping#

With Snap mode on, the crosshair jumps to a nearby point or line so that new shapes line up exactly with the ones already on the map: a new polygon can share a corner or an edge with its neighbour, and a moved point can land exactly on another shape's corner.

• It snaps to corners, to any point along an outline (including a circle's), and to spots, when the crosshair is within a few pixels of them.
• A small marker shows where the crosshair has snapped. Its colour says what the next click will do: green to add or insert, blue to put down a point you are moving, red to delete, and grey while you are choosing a point (for forwardMove, shareInsert and infoInfo).
• removeDelete, forwardMove, shareInsert and infoInfo always pick the nearest point, even with snapping off.

Snapping is on until you turn it off. To turn it off, open the magic button and switch off Snap mode; a crossed-out magnet then sits on the button as a reminder. To get past a snap for a moment without turning it off, hold Shift+S: snapping pauses until you let go.

The help box#

Turn on Help box in the magic button's menu to show a short step-by-step hint above the button for the tool in use. The hint changes when you change tools, and gives the touch-screen steps when the always-on crosshair is on. Click the hint to hide it.