Yes, the graph is a web based tool. I'm interested in extracting the data from the graph but wondering what module to use for this type of project. | [reply] |
Thats a very tough problem to solve. Just brainstorming about how to solve it reliably, I think the hardest part would be to get the axis tick mark values. How would you know, or get a program to detect what the graph's axis gradations are? Just for the sake of argument, if they were constant, and you could hard-code those into the program, you might be able to use one of the graphics modules, like Imager or ImageMagick, to do a pixel-by-pixel deconstruction of the image. Since most graphs have a constant background color, and a single graph color, you probably could analyze that data for peaks and lows. I'm not suggesting the following code is a solution, but it shows how to do a pixel-by-pixel deconstruction.
#!/usr/bin/perl
use strict;
use warnings;
use Imager;
# assumes a rgba image ( with alpha )
# otherwise use rgb instead of rgba
my $image_source = shift @ARGV;
my $image = Imager->new;
$image->read( file => $image_source )
or die "Cannot load $image: ", $image->errstr;
my $width = $image->getwidth();
my $height = $image->getheight();
print "Image dimensions: height = $height, width = $width\n";
# only grab some pixels on line 10
# for the whole image iterate over $width and $height
my $x = 10;
foreach my $y ( 10 .. 15 ) {
my $color = $image->getpixel( x => $x, y => $y );
my ( $r, $g, $b, $a ) = $color->rgba();
print " shade = $r, $g, $b\n";
}
| [reply]
[d/l] |