Problem with composite and invalid icc

[JohnnyTWA]

Hello,

I'm running the code below and getting an error (albeit only with this image...so far)

libvips error: composite: images do not have same numbers of bands

require_once("vendor/autoload.php");

use Jcupitt\Vips\Exception;
use Jcupitt\Vips\Image as VipsImage;
use Jcupitt\Vips\BlendMode;

$overlay_file = 'avatar.png';

$overlay = VipsImage::newFromFile($overlay_file);

$file = 'problem-image.jpg';

$image = VipsImage::newFromFile($file);

$x = 50;
$y = 50;

if (!$overlay->hasAlpha()) {
    $overlay = $overlay->bandjoin(255);
}

$watermark_alpha = $overlay[$overlay->bands - 1];
$overlay = $overlay->extract_band(0, ['n' => $watermark->bands - 1]);
$watermark_alpha = $watermark_alpha->multiply((50 / 100));
$overlay = $overlay->bandjoin($watermark_alpha);

$image = $image->composite($overlay, [BlendMode::OVER], ['x' => $x, 'y' => $y]);

$output = 'output.jpg';

$image->writeToFile($output, ['Q' => 70, 'strip' => true, 'optimize_coding' => true, 'background' => 255]);

From doing some investigation Photoshop tells me the problem image has an invalid ICC profile, and removing it before processing the image does mean the code completes successfully.

Is there a way of detecting whether the profile is compatible with the image, icc_import succeeds (The number of bands changes from 3 to 5).

Thanks in advance.

[jcupitt]

Hi @JohnnyTWA,

I had a quick look -- your image has three bands, even though it's black and white. I guess someone saved as RGB at some point in the past. The profile on the image is still monochrome.

When icc_import runs it sees a three-band image plus a mono profile and decides you probably have a mono image with two alpha channels (ie. GAA). That gets turned into LAB, so LABAA, so five bands.

Maybe we could tune the rules it uses a little -- GAA has to be pretty unusual, so RGB might be a better guess. Let's leave this issue open as an enhancement.