Issue with loading animated gif file from buffer

[yellow1912]

For some reason, when loading gif from string my loader is VipsForeignLoadNsgifBuffer instead of VipsForeignLoadGifBuffer. The n option is not applied correctly.

The following addition fixes the issue (for now):

protected function getLoadOptions($loader, $loadOptions = [])
    {
        $options = [];
        switch ($loader) {
            case 'VipsForeignLoadJpegFile':
            case 'VipsForeignLoadJpegBuffer':
                $options['autorotate'] = true;
                break;
            case 'VipsForeignLoadHeifFile':
            case 'VipsForeignLoadHeifBuffer':
                $options['autorotate'] = true;
                $options['n'] = -1; // not sure this should be enabled by default, to discuss
                break;
            case 'VipsForeignLoadGifFile':
            case 'VipsForeignLoadGifBuffer':
            case 'VipsForeignLoadNsgifBuffer':
                $options['n'] = -1; // not sure this should be enabled by default, to discuss
                break;
        }
        $options = array_merge($loadOptions, $options);
        // FIXME: remove not allowed options

        if (isset($options['shrink'])) {
            switch ($loader) {
                case 'VipsForeignLoadJpegFile':
                case 'VipsForeignLoadJpegBuffer':
                case 'VipsForeignLoadWebpFile':
                case 'VipsForeignLoadWebpBuffer':
                    break;
                default:
                    unset($options['shrink']);
               }
        }
        return $options;
    }

My current vips config is:

enable debug: no
enable deprecated library components: yes
enable modules: no
use fftw3 for FFT: no
accelerate loops with orc: yes
ICC profile support with lcms: yes (lcms2)
zlib: yes
text rendering with pangocairo: no
font file support with fontconfig:
RAD load/save: yes
Analyze7 load/save: yes
PPM load/save: yes
GIF load: yes
GIF save with cgif: yes
EXIF metadata support with libexif: yes
JPEG load/save with libjpeg: yes (pkg-config)
JXL load/save with libjxl: no (dynamic module: no)
JPEG2000 load/save with libopenjp2: no
PNG load with libspng: no
PNG load/save with libpng: yes (pkg-config libpng >= 1.2.9)
quantisation to 8 bit: yes
TIFF load/save with libtiff: no
image pyramid save: yes
HEIC/AVIF load/save with libheif: no (dynamic module: no)
WebP load/save with libwebp: yes
PDF load with PDFium: no
PDF load with poppler-glib: no (dynamic module: no)
SVG load with librsvg-2.0: yes
EXR load with OpenEXR: no
OpenSlide load: no (dynamic module: no)
Matlab load with matio: no
NIfTI load/save with niftiio: no
FITS load/save with cfitsio: no
Magick package: none (dynamic module: no)
Magick API version: none
load with libMagickCore: no
save with libMagickCore: no

Should I send a PR for this fix?

[chregu]

A PR would be fine. I actually never used libnsgif, that may be the issue why I didn't catch it. Somehow strange that there are two different loaders for that, but anyway, easy fix and no potential harm.

[andi-wr]

Somehow strange that there are two different loaders for that, but anyway, easy fix and no potential harm.

See here: https://stackoverflow.com/questions/75772029/vips-warning-error-in-tile-0-x-1104-gif-crashing-website-ruby-on-rails#comment133680071_75777349

libvips used to use giflib for loading GIFs, but switched to the (much better) nsgif loader in 8.11