Points

Points are a useful tool.   They have two main purposes: to enable simple measurements to be made, and to make it easier to use the Resize/Rotate/Move function.  

To set a point on a Frame: make the Frame visible, let the mouse pointer rest on the location where you want the point to be set and press a number 1, 2, 3 or 4, the numbers correspond to the 4 possible Points.   In what follows P1 refers to the Point set by pressing 1 etc.

There is a menu item Clear Points which removes all set points.

Measurements

As soon as you set a Point, a dialog box pops up.   It shows you the coordinates of the point and the result of various calculations based on the Points that have been set so far.   The lengths shown are in Pixels and are only valid if your Pixels are square, which they are in most cases.   This dialog can be recalled at any time by pressing 0 (zero).

You can jump to the Frame on which a point lies by pressing Control+1 etc.

P1P2, and P3P4 are lines joining the corresponding pairs of Points.   If all 4 points are set, the ratio of the lengths of the two lines is shown.   This is the magnification factor required to make them both the same length.   The angle between these two lines is also shown.   This is the rotation needed to make one line line up with the other.

Making Frames Register

In this process P1 and P2 are set on the reference Frame, i.e. the Frame that will not be altered.   P3 and P4 are set on the Frame to alter.

Notice the button Set and Use Parameters.   Pressing this sets parameters in the Resize/RotateMove dialog, which is immediately displayed for your inspection, and if you wish you can initiate the suggested alteration.

If only P1 and P3 are set, only the displacement parameters are set.   This allows one frame to be moved relative to the other.

If all 4 points are appropriately set, the frame containing P3 and P4 is adjusted to make P3 coincide with P1 and P4 coincide with P2.

Here is how to make two frames register that will not with the Automatic functions.

1. Decide on two features that are wide apart and that can be seen in both Frames
2. On the reference Frame point at the first point and press 1 followed by Return
3. Again on the reference Frame point at the 2nd feature and press 2 followed by Return
4. Now switch to the frame to move and repeat steps 2 and 3 only setting P3 and P4.   Instead of pressing Return when P4 is set click on Set and Use Parameters.
5. If you are satisfied with the suggested settings, click OK or press Return.

It is advisable to at least Save All Frames on the Undo menu.   Then if you spoil a Frame, you can reload it by pressing Backspace.   Don't be tempted to repeatedly alter a Frame until it is correct.   Instead, reload the original by pressing Backspace, alter the parameters or the position of the Points slightly, and repeat the operation.   That way you won't be accumulating errors.