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| -rw-r--r-- | ppmdraw.html | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/ppmdraw.html b/ppmdraw.html index 2ddfe1dd..14317386 100644 --- a/ppmdraw.html +++ b/ppmdraw.html @@ -190,9 +190,16 @@ The command moves the current position to the terminal point after drawing. <dt>spline3 <dd>This draws a spline in the current color between 2 points, using a third -as a control point in some arcane way. The 6 arguments are the starting point -column, starting point row, control point column, control point row, ending -point column, and ending point row. +as a control point. It approximates a cubic spline segment. + +<p>The shape of the curve is such that it passes through the specified +endpoints, and lines tangent to the curve at those endpoints intersect at the +control point. Controlling the tangents allows you to connect this curve to +other curves generated the same way without having corners at the connection +points. + +<p>The 6 arguments are the starting point column, starting point row, control +point column, control point row, ending point column, and ending point row. <p>This command does not affect the current position. |