如何在PHP中识别CMYK图像

Question

Can anyone tell me how to identify an image if it is in CMYK or RGB using PHP ?

Answer 1

Take a good look at getimagesize.

Example:

<?php
$size = getimagesize($filename);
$fp = fopen($filename, "rb");
if ($size && $fp) {
    header("Content-type: {$size['mime']}");
    fpassthru($fp);
    exit;
} else {
    // error
}
?>

It returns an array with 7 elements.

Index 0 and 1 contains respectively the width and the height of the image.

Index 2 is one of the IMAGETYPE_XXX constants indicating the type of the image.

Index 3 is a text string with the correct height="yyy" width="xxx" string that can be used directly in an IMG tag.

mime is the correspondant MIME type of the image. This information can be used to deliver images with the correct HTTP Content-type header: channels will be 3 for RGB pictures and 4 for CMYK pictures.

bits is the number of bits for each color.

For some image types, the presence of channels and bits values can be a bit confusing. As an example, GIF always uses 3 channels per pixel, but the number of bits per pixel cannot be calculated for an animated GIF with a global color table.

On failure, FALSE is returned.