Logic behind node controls
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Hello,
Could someone explain me the logic behind node controls in VectorStyler?
There are two sets of options when node tool is active for controlling how nodes of a path behave. First thing that confused me is the "cusp" option. I was sure it was not working because I expected it to convert point to "sharp" point. With no controls for controlling curves on either side of that point. But that is not the case and I'm not sure what it does. Then I saw there is another set of options. One of them was a "line" option which converts curve to a line. This sort of makes point sharp, but only on one side. Then there is "quadratic" option which does not look particularly useful.
What is wrong with node controls in most other tools where users can only control node type and it dictates how curves behave on either side of a point? Why VectorStyler chose to have two sets of options instead of only having "sharp", "symmetrical", "asymmetrical" and perhaps "broken" options for nodes?
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@grix An explanation of how nodes work in VS:
There are two concepts to define first:
- the node is a point location.
- the segment goes between two nodes.
The type of a node can be cusp, smooth or symmetric. This affects how the curve changes when the node is edited. Changing the node type from smooth (or symmetric) to cusp will not have a visible effect, since the two control points (on the two sides of the node) are not changed. The node type is only visible when the control points are moved.
In cusp nodes the two control points around the node can be moved independently of each other.
In smooth nodes, the distance of the two control points from the node is idependent, but the direction along the same line (creating a smooth curvature).
In symmetric nodes, both the distance and the direction are constrained. (Most apps don't implement symmetric nodes, except CorelDraw).The type of a segment can be line, quadratic and cubic. Typically we have lines and cubic curves. VS includes quadratic also, these are the curve types used in TTF font glyphs, and also required for SVG. The difference between quadratic and cubic is the number of control points (and degree of freedom) on the curve. Most apps don't have the quadratic mode.
The change that you were looking for (removing the control points) can be found in the Path panel, with the first two icons in the third row. These change the node type to cusp, and move the incoming / outgoing control point over to the node location.
