THESE CODES ARE PROVIDED FOR AN EXAMPLE OF HOW TO USE IMAGEMAGICK WITH PHP. CARE SHOULD BE TAKEN WHEN ACCEPTING USER INPUT.
I TAKE NO RESPONSABILTY FOR ANY PROBLEMS THAT MAY OCCURE WHEN USING ANY OF THIS CODE.
IT IS UP TO YOU TO SECURE THE CODE AND VALIDATE USER INPUT.
// Create a new image with everything transparent apart from the selected colour.
// This image must be saved as a png due to the transparency.
$cmd = " $input20 -matte ".
" ( +clone -fuzz 20% -transparent rgb(38,134,71) ) ".
" -compose DstOut -composite ";
exec("convert $cmd output_hat.png");
// Another temporary image is made from the original but completely grey.
$cmd = " $input20 -colorspace Gray ";
exec("convert $cmd grey_background.png");
// The two images are combined and flattened into one image.
$cmd = " grey_background.png -page +0+0 output_hat.png -flatten ";
exec("convert $cmd green.jpg");
// The tempory images are deleted.
unlink ('output_hat.png');
unlink ('grey_background.png');
Do not forget to change this line ( +clone -fuzz 20% -transparent rgb(38,134,71) ) to this on Linux \( +clone -fuzz 20% -transparent rgb\(38,134,71\) \)