Like links, interpolations go in one direction, so the toolbar has two interpolation tools: one for the X direction and one for the Y direction:
The respective tool will be available only if the Show X Direction or Show Y Direction options are selected in the Display Options dialog found on the Display menu. Selecting an interpolation tool changes the pointer into a pair of arrowheads from opposite directions to a control point. The pointer is horizontal or vertical, depending on the X or Y direction of the tool:
You begin an interpolation by connecting the two control points that Visual TrueType refers to position the interpolated point(s). These are the “parent” points, connected by a black line with short lines at each end. Then you drag the black line to the “child” point, which you want to stay in the same position relative to the parent points. When you release the mouse button, the black line splits into two white lines, one from each parent, ending in arrowheads at the interpolated child point.
If you have not previously rounded the parent points, Visual TrueType may round them for you. If you want a different rounding method, you can display a pop-up menu of rounding options. For details, see “Rounding Control Points”
Tip When you’re not working with interpolations, you can hide them to make more room on the screen for other visual hinting. In the Display Options dialog, you can set the Interpolates option to show or hide Interpolation commands.
To create Interpolations via the keyboard, you must type the appropriate VTT Talk commands into the VTT Talk window (Ctrl + 5).
To select the X-interpolation tool
1. In the Visual TrueType Options submenu of the Display menu, ensure that the Show X Direction option is enabled.
2. Select the YInter tool by clicking its icon in the toolbar or by pressing the F7 key.
To select the Y-interpolation tool
1. In the Visual TrueType Options submenu of the Display menu, ensure that the Show Y Direction option is enabled.
2. Select the YInter tool by clicking its icon in the toolbar or by pressing the F3 key.
To interpolate a point
1. Select the XInter or YInter tool by clicking the appropriate icon, or by pressing the F5 or F1 key, respectively.
2. If necessary, zoom in for a better view (for details, see “Resizing the View”).
3. Click on the first “parent” point and drag to the second to connect the two “parent” points.
4. Position the pointer on the grey connector line.
5. Drag the line to the “child” point.
6. Repeat step 5 for any additional “child” points you wish to interpolate.
To display or hide all interpolations
1. In the Visual TrueType Options submenu of the Display menu, select the Interpolates option.
To delete an interpolation
1. Select the XInter or YInter tool by clicking the appropriate icon, or by pressing the F5 or F1 key, respectively.
2. Drag the arrowhead off each “child” point, one at a time. When you delete the last “child” point, the entire interpolation command will be deleted.