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Fiddling with precision.

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This commit is contained in:
Brad Nelson
2022-03-08 14:34:19 -08:00
parent 632cb47afe
commit 85824c8b04
1 changed files with 19 additions and 5 deletions
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24
examples/bezier_test.fs
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@ -65,12 +65,15 @@ scanlines max-scanlines cells erase
;
: draw-spans max-scanlines 0 do i draw-row loop ;
: 0.<< 16 lshift ;
: 0.>> 16 rshift ;
: 2span { a b -- n } a b max a b min - ;
: 3span { a b c -- n } a b max c max a b min c min - ;
: bezier 0 0 0 0 0 0 { x1 y1 x2 y2 x3 y3 x1.5 x2.5 y1.5 y2.5 xn yn }
y1 y2 y3 3span 2 < if
y1 y3 2span if
x1 x3 + 2/ y1 y2 min y3 min add-edge
x1 x3 + 2/ 0.>> y1 y2 min y3 min add-edge
then
else
x1 x2 + 2/ to x1.5 x2 x3 + 2/ to x2.5
@ -81,12 +84,23 @@ scanlines max-scanlines cells erase
xn yn x2.5 y2.5 x3 y3 recurse
then
;
: line ( x1 y1 x2 y2 ) 2dup bezier ;
: line 0 0 { x1 y1 x2 y2 dx dy }
y1 y2 > if
y1 y2 to y1 to y2
x1 x2 to x1 to x2
then
y2 y1 - to dy
x2 x1 - to dx
dy 0 ?do
x1 dx i dy */ + 0.>> y1 i + add-edge
loop
;
\ : line ( x1 y1 x2 y2 ) 2dup bezier ;
0 value pen-x 0 value pen-y
: move-to { x y } x to pen-x y to pen-y ;
: line-to { x y } pen-x pen-y x y line x y move-to ;
: bezier-to { x' y' x y } pen-x pen-y x' y' x y bezier x y move-to ;
: move-to { x y } x 0.<< to pen-x y to pen-y ;
: line-to { x y } pen-x pen-y x 0.<< y line x y move-to ;
: bezier-to { x' y' x y } pen-x pen-y x' 0.<< y' x 0.<< y bezier x y move-to ;
-1 -1 window