When you hover over a shape that isn't selected, the connection points (or anchor points) are shown as small crosses.
You can use the connection points on a shape to connect a fixed connector. When you move the shape around, the connector stays attached to exactly that connection point, it doesn't float around the perimeter of the shape.
Connection points are also used when you enable the snap to point shape property - instead of a connector floating smoothly around the perimeter when you move it or the shape, it will snap to the defined connection points.
Edit the shape style to customise connection points
To customise the connection points on a shape, you can define your own custom shape style and specify exactly where the connection points should be located around the shape perimeter. The custom coordinates you specify in the shape style override the default connection points. In this way, you can add or delete connection points, or change their positions.
Add new points in x,y pairs, with values between 0 and 1, which correspond to positions on the shape's outline, relative to the outer four 'corners' of the shape. Top left is [0,0], top right is [1,0], bottom left is [0,1], bottom right is [1,1].
For example, you can redefine a cloud shape to have just two connection points (on the left), instead of the default connection points (on the right).
- Select the shape, then click Edit Style in the Style tab of the format panel. Alternatively, press Ctrl+E (on Windows) or Cmd+E on macOS.
- Enter the new connection points in the form of an array of x,y coordinates to the shape style definition. For example, to add only two points, one to the left and one to the right: points=[[0,0.5],[1,0.5]];
- Click Apply.
In the example below, the snap to point shape property has been enabled to show how the connector moves to another custom connection point as you move the shape around.
Clear custom connection points
If you no longer want a shape to have custom connection points, you can delete the points array from the shape style to reset the connection points of a shape back to their defaults.
Ignore custom connection points
You can force a floating or fixed connection at any location by using a keyboard shortcut, even if the shape has custom connection points or the snap to pointshape property enabled.
- Hold down Shift as you drop the connector on a shape to connect it to the shape's outline.
- Hold down Alt as you drop the connector on a shape to add a fixed connection inside the shape.
Build your own custom shapes
You can create your own custom shapes in addition to simply modifying an existing shape's connection points by specifying the custom shape's foreground and background geometry, connection points, shape styles and label text.
Note: An optional third coordinate in the points array may function as a toggle (outline/perimeter), or an offset to move the connection point around inside the shape or between its outline and its perimeter, but this works only on some shapes. This third coordinate is therefore only used for development purposes.