Pizza slice shape using GD Image?

Question

I need to "transform" a normal rectangle image into a "pizze slice". So this:

Must be stretched into this:

This way I lose the actual wording, so it's not 100% correct. I need it to not just mask those parts, but also "stretch" the slice so it will fit into the new triangle shape, so none of the text is lost.

My photoshopping skills are so limited, I can't even do a proper preview in photoshop that shows how it must be cut.

How would I do this using GD Image?

Answer 1

This should get the job done - the script is commented, so you should have no trouble understanding it.

<?php
$img = imagecreatetruecolor(600, 130);
$text = "Text that can be\nwrapped to next line";

//draw red background
imagefilledrectangle($img, 0, 0, imagesx($img), imagesy($img), 0xa00000);

//draw green text
putenv('GDFONTPATH=/usr/share/fonts/TTF');
imagettftext($img, 40, 0, 20, 50, 0x00a000, 'arial.ttf', $text);

//stretch whole thing vertically
$img = imagescale($img, imagesx($img), imagesy($img) * 2);

//compute pizza transformation
$y_arr = [];
for ($x = 0; $x < imagesx($img); $x++)
{
    //compute simple "triangle" shape
    $linear_y = $x * imagesy($img) / 2 / imagesx($img);
    //get some variations with cos()
    $cos_y = cos($x * 2 * M_PI / imagesx($img));
    $cos_y *= cos($x * 2 * M_PI / imagesx($img) / 2);
    $cos_y = (1 - $cos_y) * imagesy($img) / 4;
    //finally combine these two
    $y = ($cos_y + $linear_y * 2) / 3;
    //and push the coordinate onto stack
    $y_arr []= $y;
}

//create target image
$dstimg = imagecreatetruecolor(imagesx($img), imagesy($img));

//scale each column according to pizza transformation
foreach ($y_arr as $x => $y)
    imagecopyresized($dstimg, $img, $x, $y, $x, 0, 1, max(1, imagesy($img) - 2 * $y), 1, imagesy($img) - 1);

//write the image to PNG file
imagepng($dstimg, 'test.png');

Result: