Reassembling a fragmented image - image

Question

I have an image that has been broken in to parts, 64 rows by 64 columns. Each image is 256x256px. The images are all PNG. They are named "Image--.png" for example "Image-3-57". The rows and columns numbering start from 0 rather than 1.
How can I assemble this back in to one image? Ideally using BASH and tools (I'm a sysadmin) though PHP would be acceptable as well.

Answer 1

Well, it is not very complicated, if you want to use PHP. What you need is just a few image gunctions - imagecreate and imagecopy. If your PNG is semi transparent, you will also need imagefilledrectangle to create a transparent background.
In code below, I rely on fact, that all chunks are same size - so the pixel size must be able to be divided by the number of chunks.
<?php
$width = 256*64; //height of the big image, pixels
$height = 256*64;
$chunks_X = 64; //Number of chunks
$chunks_Y = 64; //Same for Y
$chuk_size_X = $width/$chunks_X; //Compute size of one chunk, will be needed in copying
$chuk_size_Y = $height/$chunks_Y;
$big = imagecreate($width, $height); //Create the big one
for($y=0; $y<$chunks_Y; $y++) {
for($x=0; $x<chunks_X; $x++) {
$chunk = imagecreatefrompng("Image-$x-$y.png");
imagecopy($big, $chunk,
$x*$chuk_size_X, //position where to place little image
$y*$chuk_size_Y,
0, //where to copy from on little image
0,
$chuk_size_X, //size of the copyed area - whole little image here
$chuk_size_Y,
);
imagedestroy($chunk); //Don't forget to clear memory
}
}
?>
This is just a draft. I'm not sure about all theese xs and ys as well as ather details. It is late and I'm tired.