Let’s start with wires. As before, you can drag on each end of a wire, and it will stretch along with your mouse.
You can drag out a bendpoint simply by mousing down somewhere on the middle of the wire and dragging. Or you can add a new bendpoint by double-clicking somewhere in the middle of the wire, or right-clicking to bring up the context menu, and selecting the appropriate option. To delete a bendpoint you can double-click it, or right-click to bring up the context menu.
Adding a curve to a wire is like dragging out a new bendpoint, except that you hold the control key down. How the curve bends depends upon where on the curve you drag it. To be specific, these are Bézier curves, which means that the curves are influenced by four points: the two endpoints, and two “control points”. As you drag on a curve, Fritzing will display the control points to give you a better sense of what’s happening. The image below is an example.
There is one control point at the end of the grey line and another control point at the end of the white line. Since you can only affect one control point at a time, the white line shows which one is active–in this case the point controlling the lower bend. The next image is the same curve, but now after mousing up from the lower bend and mousing down again and dragging the upper bend.
By the way, if you prefer curvy wires to straight ones, you can set that as the default in Preferences. So in that case, the normal drag behavior would produce curves, and to make a bendpoint, you would hold down the control key