in reply to Re: BMP file manipulation
in thread BMP file manipulation
Thank you for your very helpful example. I am trying to adapt it my own needs and I am struggling with parts 4 and 5 in your example.
I am working with images that are 1024 high x 1280 wide using 8 bit grey scale to represent each color. So for instance I have used the following to get the color table:
<c>
my @rgbQuad = wq (
rgbBlue
rgbGreen
rgbRed
rgbReserved
);
my @rgb_dat = unpack "LLLL", $data;
my %rgbQuadList;
@rgbQuadList{@rgbQuad} = @rgb_dat;
print "$_\t$rgbQuad{$_}\n" for @rgbQuad;
<\c>
to retrieve the rgb color table data. This returns one line of data for the Blue, Green, Red and Reserved colors. What I am not understanding is how to get every instance of this color table by reiterating through $data. I have also tried assigning < BMP > to an array but that does not seem to behave like the standard file handles I am more typically used to.
Secondly I don't understand how to extract the data lines for the image. So my offset is 1078 bits. According to your calculation, and using an 8 bit pixel assignment, I need to capture 10242 bytes per line for my bit maps. How do I set this for unpack?
Thank you for taking the time to answer my questions.
MadraghRua
yet another biologist hacking perl....
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