Mercurial > hg > octave-image
changeset 1:7f7a565d2e8b
Write .bmp files
author | pkienzle |
---|---|
date | Fri, 07 Dec 2001 16:21:05 +0000 |
parents | 587e29845b1d |
children | 03a4b2a9101b |
files | bmpwrite.m |
diffstat | 1 files changed, 42 insertions(+), 0 deletions(-) [+] |
line wrap: on
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new file mode 100644 --- /dev/null +++ b/bmpwrite.m @@ -0,0 +1,42 @@ +## bmpwrite(X,map,file) +## Write the bitmap X into file (8-bit uncompressed format). +## The values in X are indices into the given RGB colour map. + +## This code is in the public domain. +## Based information from Jörn Daub's web page: +## http://www.daubnet.com/formats/BMP.html + +function bmpwrite(x,map,file) + header = 14+40+4*rows(map); + filesize = header+prod(size(x)); + arch = "ieee-le"; + file = fopen(file, "wb"); + fwrite(file,toascii("BM"),"uchar",0,arch); # file tag + fwrite(file,filesize,"long",0,arch); # length of file + fwrite(file,0,"long",0,arch); # reserved + fwrite(file,header,"long",0,arch); # offset of raster data in file + + fwrite(file,40,"long",0,arch); # header size + fwrite(file,columns(x),"long",0,arch); # image width + fwrite(file,rows(x),"long",0,arch); # image height + fwrite(file,1,"short",0,arch); # number of planes + fwrite(file,8,"short",0,arch); # pixels per plane + fwrite(file,0,"long",0,arch); # compression (none) + fwrite(file,0,"long",0,arch); # compressed size of image + resolution = 72/2.54*100; # 72 dpi / 2.54 cm/in * 100 cm/m + fwrite(file,resolution,"long",0,arch); # horizontal resolution + fwrite(file,resolution,"long",0,arch); # vertical resolution + fwrite(file,rows(map),"long",0,arch); # number of colours used + fwrite(file,0,"long",0,arch); # number of "important" colors + + ## colormap BGR0BGR0BGR0BGR0... + map=[round(map*255), zeros(rows(map),1)]; + map=map(:,[3,2,1,4]); + fwrite(file,map',"uchar",0,arch); + + ## raster image, each line on a 32-bit boundary, padded with zeros + ## lines written bottom to top. + fwrite(file,postpad(flipud(x)',ceil(columns(x)/4)*4),"uchar",0,arch); + fclose(file); +endfunction +