Bitmap/Bresenham's line algorithm: Difference between revisions

=={{header|Action!}}==

Part of the task is available in [http://www.rosettacode.org/wiki/Category:Action!_Bitmap_tools#RGBLINE.ACT RGBLINE.ACT].

{{libheader|Action! Bitmap tools}}

<lang Action!>INCLUDE "H6:RGBLINE.ACT" ;from task Bresenham's line algorithm

RGB black,yellow,violet,blue

PROC DrawImage(RgbImage POINTER img BYTE x,y)

RGB POINTER ptr

BYTE i,j

ptr=img.data

FOR j=0 TO img.h-1

DO

FOR i=0 TO img.w-1

DO

IF RgbEqual(ptr,yellow) THEN

Color=1

ELSEIF RgbEqual(ptr,violet) THEN

Color=2

ELSEIF RgbEqual(ptr,blue) THEN

Color=3

ELSE

Color=0

FI

Plot(x+i,y+j)

ptr==+RGBSIZE

OD

OD

RETURN

PROC Main()

RgbImage img

BYTE CH=$02FC,width=[81],height=[51],st=[5]

BYTE ARRAY ptr(12393)

BYTE c,i,n

INT x,y,nx,ny

RGB POINTER col

Graphics(7+16)

SetColor(0,13,12) ;yellow

SetColor(1,4,8) ;violet

SetColor(2,8,6) ;blue

SetColor(4,0,0) ;black

RgbBlack(black)

RgbYellow(yellow)

RgbViolet(violet)

RgbBlue(blue)

InitRgbImage(img,width,height,ptr)

FillRgbImage(img,black)

nx=width/st ny=height/st

FOR n=0 TO 2*nx+2*ny-1

DO

IF n MOD 3=0 THEN col=yellow

ELSEIF n MOD 3=1 THEN col=violet

ELSE col=blue FI

IF n<nx THEN

x=n*st y=0

ELSEIF n<nx+ny THEN

x=width-1 y=(n-nx)*st

ELSEIF n<2*nx+ny THEN

x=width-1-(n-nx-ny)*st y=height-1

ELSE

x=0 y=height-1-(n-2*nx-ny)*st

FI

RgbLine(img,width/2,height/2,x,y,col)

OD

DrawImage(img,(160-width)/2,(96-height)/2)

DO UNTIL CH#$FF OD

CH=$FF

RETURN</lang>

{{out}}

[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Bresenham's_line_algorithm.png Screenshot from Atari 8-bit computer]