🚀 go-pugleaf

Miklos,

I have solved the problem (including the A-channel, this is not in
the example but simple).
The only remaining problem is:

I cannot define a File "Imi" which is in memory instead of disk.

The program executes:
Read BMP-24 "src". Decode header. Read raw RGB data.
Swap BGR . Write to file "Imi". Read "Imi" and show.
Everything OK. even for huge images.

Best regards --Gernot

The original text was nicely formatted, appears here garbled.

%!PS-Adobe-3.0 EPSF-3.0
%%BoundingBox: 0 0 1000 1000
%%Creator: Gernot Hoffmann
%%Title: BmpImage01
%%CreationDate: March 07,2003
%%DocumentNeededResources: font Helvetica
%%EndComments

% Read, store and show a named BMP-24 RGB image

/mm {2.834646 mul} def

/ReadHead
{/buf 54 string def
 /bmp true def
% Read 54 header bytes 0..53
  Src buf readstring pop
% Code (BM)
 /cd1 buf 0 1 getinterval def
 /cd2 buf 1 1 getinterval def
  cd1 (B) ne { /bmp false def } if
  cd2 (M) ne { /bmp false def } if
% File Size (Bytes)
 /fsz buf 2 get def
 /fsz buf 3 get 256 mul fsz add def
 /fsz buf 4 get 256 mul 256 mul fsz add def
 /fsz buf 5 get 256 mul 256 mul 256 mul fsz add def
% Image Start (54)
 /ims buf 10 get def
 /ims ims buf 11 get 256 mul add def
 /ims ims buf 12 get 256 mul 256 mul add def
 /ims ims buf 13 get 256 mul 256 mul 256 mul add def
% Info Size (40)
 /ifs buf 14 get def
 /ifs ifs buf 15 get 256 mul add def
 /ifs ifs buf 16 get 256 mul 256 mul add def
 /ifs ifs buf 17 get 256 mul 256 mul 256 mul add def
% x-Pixel
 /xpx buf 18 get def
 /xpx xpx buf 19 get 256 mul add def
 /xpx xpx buf 20 get 256 mul 256 mul add def
 /xpx xpx buf 21 get 256 mul 256 mul 256 mul add def
% y-Pixel
 /ypx buf 22 get def
 /ypx ypx buf 23 get 256 mul add def
 /ypx ypx buf 24 get 256 mul 256 mul add def
 /ypx ypx buf 25 get 256 mul 256 mul 256 mul add def
% pages (1,0)
 /pg1 buf 26 get def
 /pg2 buf 27 get def
  pg1 1 ne { /bmp false def } if
  pg2 0 ne { /bmp false def } if
% BitperPixel (24,0 )
 /bp1 buf 28 get def
 /bp2 buf 29 get def
  bp1 24 ne { /bmp false def } if
% Uncompressed (0,0)
 /cp1 buf 30 get def
 /cp2 buf 31 get def
  cp1 0 ne { /bmp false def } if
  cp2 0 ne { /bmp false def } if
% Bytes per Pixel
 /byt bp1 8 idiv def
} def

/ShowHead
{/b10 10 string def
 /fh 14 def
 /Helvetica findfont fh scalefont setfont
 /x1 10 mm def
 /x2 60 mm def
 /y 200 mm def
 /dy fh 1.2 mul def
  x1 y moveto (BM code) show x2 y moveto cd1 show cd2 show /y y dy sub def
  x1 y moveto (Size/Byte) show x2 y moveto fsz b10 cvs show /y y dy sub def
  x1 y moveto (Image Start) show x2 y moveto ims b10 cvs show /y y dy sub def
  x1 y moveto (Info Size) show x2 y moveto ifs b10 cvs show /y y dy sub def
  x1 y moveto (x-Pixels) show x2 y moveto xpx b10 cvs show /y y dy sub def
  x1 y moveto (y-Pixels) show x2 y moveto ypx b10 cvs show /y y dy sub def
  x1 y moveto (Page) show x2 y moveto pg1 b10 cvs show ( ) show pg2 b10 cvs show /y y dy sub def
  x1 y moveto (Bit per Pix) show x2 y moveto bp1 b10 cvs show ( ) show bp2 b10 cvs show /y y dy sub def
  x1 y moveto (Compression) show x2 y moveto cp1 b10 cvs show ( ) show cp2 b10 cvs show /y y dy sub def
} def

/ReadImag
{% Read Src,swap RGB->BGR,write Imi
 /row xpx byt mul string def
 /bufA 3 string def
 /bufB 3 string def
 1 1 ypx
 { pop
  /k 0 def
   Src row readstring pop
   1 1 xpx
   { pop
    /bufA row k 3 getinterval def
     bufB 0 bufA 2 get put
     bufB 1 bufA 1 get put
     bufB 2 bufA 0 get put
     row k bufB putinterval
    /k k 3 add def
   } for
   Imi row writestring
 } for
} def

/ShowImag
{ /DeviceRGB setcolorspace
<< /ImageType 1
   /Width xpx
   /Height ypx
   /BitsPerComponent 8
   /ImageMatrix [ xpx 0 0 ypx 0 0 ]
   /Decode [ 0 1 0 1 0 1]
   /DataSource Imi
">>" actually without ""
image
} def

/Src (J:\\WEmma\\WEmma300.bmp) (r) file def
/Imi (Imi) (w+) file def

ReadHead
ShowHead
ReadImag

10 mm 20 mm translate
xpx ypx scale

ShowImag

showpage