M_pixel__writegif Module

writegif(3f) - [M_pixel__writegif] Codes pixel-map with palette into GIF
               format. Optional transparent color
(LICENSE:PD)

character(len=*), intent(in)         :: FileName
integer, intent(in), dimension(:,:)  :: Pixel
integer, intent(in), dimension(:,0:) :: ColorMap
integer, intent(in), optional        :: Transparent

Write GIF file from pixel array and color map.

FileName       file to create or replace
Pixel          Pixel values 0 to ncol
ColorMap       Color map (RGB 0:255 for colours 0:ncol)
Transparent    Optional

program demo_writegif
use M_pixel__writegif, only : writegif
integer  :: Pixel(100,100)
integer  :: Transparent = 0
integer  :: ColorMap (3,0:7)
colormap(:,0)=[255,255,255]
colormap(:,1)=[255,  0,  0]
colormap(:,2)=[  0,255,  0]
colormap(:,3)=[  0,  0,255]
colormap(:,4)=[255,255,  0]
colormap(:,5)=[255,  0,255]
colormap(:,6)=[  0,255,255]
colormap(:,7)=[  0,  0,  0]

! put some colored boxes into pixmap
pixel(:,:)=0
pixel(1:80,1:80)=1
pixel(11:20,11:20)=2
pixel(21:40,21:40)=3

! write gif with a transparent background
call writegif('boxes_t.gif',pixel,ColorMap,Transparent)

! change background color and write standard gif file
where (pixel.eq.0) pixel=4
call writegif('boxes.gif',pixel,ColorMap)

end program demo_writegif

o Version 1.01, 1999 August: Written by Jos Bergervoet
o Version 2, 2008 Jan 28: Modified by Clive Page to use stream I/O,
  array as colourmap.
o Version 3, 2017 July 6: Modified by John Urban to make it easier
  to use with M_PIXEL(3f) module.

Public Domain.