Points control curve and line segments that define the shape of letters. Depending on the type of curve they control, points can be of different types and names. In PostScript curves, the points that lie on segments are called Nodes, whereas off-curve points are called Handles, TrueType Control Points or Bézier Control Points (BCPs). While on-curve points continue to be called Nodes in TrueType curves, off-curve points are called TrueType Control Points (TT Control Points, or TTCPs).
Types of nodes»
|Smooth node (or Curve node) represented by a green, round node symbol indicates a smooth connection between two curve segments.|
|Tangent node represented by a violet, triangular node symbol indicates a smooth connection between a curve segment and a straight segment.|
|Sharp node (or Corner node) represented by a red, square node symbol indicates a sharp connection between any segment types.|
Corner nodes can exist between two segments of any type, whether straight or curved. If you do not intend to have an actual corner, you should convert a corner node between two curve segments into a curve node; and a corner node between a curve segment and a straight segment into a tangent node. There is no special node type for a smooth connection between two straight segments – it is always a sharp connection. If two straight segments are collinear, you almost always ought to be delete the node connecting them to turn the two segments into a single segment.
Types of connections»
There are two types of connections:
At a sharp connection, the two connected segments (curve and curve or straight segment and curve) are absolutely free in their angle relative to each other at the connecting node.
At a smooth connection, the direction of the straight segment and the control vector of a curve or the control vectors of two sequential curves are kept collinear (lie on the same straight line), i.e. the angle between the two segments at the node is fixed at 180 degrees.
To change the connection type between two segments, double click the node between them, or follow the alternate steps outlined here.
Handles or control points are off-curve points.
When dragging a curve to alter the curve segment, use the Shift key to maintain pre-existing angles of control handles on the curve. (This was a preference setting in FontLab Studio 5: All BCPs are fixed).
Under Preferences > Glyph Window there is a middle Node Style option. When this option is selected, any node whose handles are aligned perfectly vertically or horizontally (or corner node whose adjacent line is almost vertical/horizontal) will be a darker solid color. Any node that does not meet such a test will be lighter and outlined. This helps identify points that are not quite where you intended, or are not quite proper extrema.
Visual appearance of nodes»
As described above, smooth nodes are displayed as a green circle , tangent nodes by a violet triangle , and sharp nodes by a red square . Further, the starting point of a contour is displayed as blue node with an arrow . Visual appearance of nodes, including their size, style and color, along with whether and how to display their coordinates can be changed in Preferences:
To display nodes in the same way as they are in Fontographer, change their color to black and white.