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Xiaolin Wu's line algorithm: Difference between revisions
Added solution for Action!
(Added solution for Action!) |
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* See [[Bresenham's line algorithm]] for ''aliased'' lines.
<br><br>
=={{header|Action!}}==
{{libheader|Action! Tool Kit}}
{{libheader|Action! Real Math}}
<lang Action!>INCLUDE "H6:REALMATH.ACT"
REAL one
PROC PutBigPixel(INT x,y,col)
IF x>=0 AND x<=79 AND y>=0 AND y<=47 THEN
y==LSH 2
IF col<0 THEN col=0
ELSEIF col>15 THEN col=15 FI
Color=col
Plot(x,y)
DrawTo(x,y+3)
FI
RETURN
INT FUNC Abs(INT x)
IF x<0 THEN RETURN (-x) FI
RETURN (x)
PROC Swap(INT POINTER a,b)
INT tmp
tmp=a^ a^=b^ b^=tmp
RETURN
PROC Line(INT x1,y1,x2,y2,col)
INT x,y,dx,dy,c
INT POINTER px,py
REAL rx,ry,grad,rcol,tmp1,tmp2
dx=Abs(x2-x1)
dy=Abs(y2-y1)
IF dy>dx THEN
Swap(@x1,@y1)
Swap(@x2,@y2)
px=@y py=@x
ELSE
px=@x py=@y
FI
IF x1>x2 THEN
Swap(@x1,@x2)
Swap(@y1,@y2)
FI
x=x2-x1
IF x=0 THEN x=1 FI
IntToRealForNeg(x,rx)
IntToRealForNeg(y2-y1,ry)
RealDiv(ry,rx,grad)
IntToRealForNeg(y1,ry)
IntToReal(col,rcol)
FOR x=x1 TO x2
DO
Frac(ry,tmp1)
IF IsNegative(tmp1) THEN
RealAdd(one,tmp1,tmp2)
RealAssign(tmp2,tmp1)
FI
RealMult(rcol,tmp1,tmp2)
c=Round(tmp2)
y=Floor(ry)
PutBigPixel(px^,py^,col-c)
y==+1
PutBigPixel(px^,py^,c)
RealAdd(ry,grad,tmp1)
RealAssign(tmp1,ry)
OD
RETURN
PROC Main()
BYTE CH=$02FC ;Internal hardware value for last key pressed
REAL tmp,c
BYTE i,x1,y1,x2,y2
MathInit()
IntToReal(1,one)
Graphics(9)
FOR i=0 TO 11
DO
Line(0,i*4,38,1+i*5,15)
Line(40+i*4,0,41+i*6,47,15)
OD
DO UNTIL CH#$FF OD
CH=$FF
RETURN</lang>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Xiaolin_Wu's_line_algorithm.png Screenshot from Atari 8-bit computer]
=={{header|ARM Assembly}}==
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