Bitmap/Bézier curves/Cubic: Difference between revisions

=={{header|Factor}}==

The points should probably be in a sequence...

<lang factor>! this gives a function

:: (cubic-bezier) ( P0 P1 P2 P3 -- bezier )

[ :> x

1 x - 3 ^ P0 n*v

1 x - sq 3 * x * P1 n*v

1 x - 3 * x sq * P2 n*v

x 3 ^ P3 n*v

v+ v+ v+ ] ; inline

! gives an interval of x from 0 to 1 to map the bezier function

: t-interval ( x -- interval )

[ iota ] keep 1 - [ / ] curry map ;

! turns a list of points into the list of lines between them

: points-to-lines ( seq -- seq )

dup rest [ 2array ] 2map ;

: draw-lines ( {R,G,B} points image -- )

[ [ first2 ] dip draw-line ] curry with each ;

:: bezier-lines ( {R,G,B} P0 P1 P2 P3 image -- )

! 100 is an arbitrary value.. could be given as a parameter..

100 t-interval P0 P1 P2 P3 (cubic-bezier) map

points-to-lines

{R,G,B} swap image draw-lines ;</lang>