Virtual gridding/resizing of image collage in PHP

Question

I'm looking for a finshed solution or possibly some math/algorithms for creating a big image collage out of smaller product pictures? I know how to do it in a square fashion, from same sized pictures with gd/imagemagick but I'd like to have some variation built in.

For example, some of the pictures might be slightly taller, and if all are the same size and square - i might want 1 of them take up more space, just to mix up the design. keeping it interesting.

the more i think about this the harder it seems to do with a formula. having predefined "templates" for all the possible scenarios isn't going to work since the amount of pictures could vary from just 1 (no work needed) to 10+.

i'm not looking for any rotation or special effects, just the images in a grid with maybe some spacing inbetween and no overlapping.

any ideas how to accomplish this, and is there really nothing ready to go out there?

Answer 1

Implement transparency

First on the __construct method, replace :

    $white = imagecolorallocate($this->image, 255, 255, 255);
    imagefill($this->image, 0, 0, $white);

By :

    $transparent = imagecolorallocate($this->image, 255, 0, 255);
    imagefill($this->image, 0, 0, $transparent);
    imagecolortransparent($this->image, $transparent);

Then, on the resizePreservingAspectRatio method, add just after :

    $targetImg = imagecreatetruecolor($targetWidth, $targetHeight);

The following lines :

    $targetTransparent = imagecolorallocate($targetImg, 255, 0, 255);
    imagefill($targetImg, 0, 0, $targetTransparent);
    imagecolortransparent($targetImg, $targetTransparent);

And here we go.