Stdlib: ext/gd — imagecreate / imagepng baseline (ext/gd/gd.c parity)

[PurHur]

Category

stdlib

Problem

ext/gd image creation API (imagecreate, imagecreatetruecolor, imagepng, imagejpeg, …) is absent. function_exists('imagecreate') → false. Blocks thumbnail pipelines and anything using GD resources; related but not replaced by getimagesize() (#3271).

php-src reference

• php/php-src ext/gd/gd.c — PHP_FUNCTION(imagecreate), truecolor, output functions
• php/php-src ext/gd/php_gd.h — gdImagePtr resource zval

Repro (failure today)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r "var_export(function_exists(\"imagecreate\"));"'
# bool(false)

<?php
$im = imagecreatetruecolor(10, 10);
$white = imagecolorallocate($im, 255, 255, 255);
imagefill($im, 0, 0, $white);
ob_start();
imagepng($im);
$png = ob_get_clean();
imagedestroy($im);
echo strlen($png) > 8 ? 'ok' : 'fail';

Scope (this repo)

Layer	Files	Notes
VM	new ext/gd/ module, lib/VM/Resource.php GD handle	Link -lgd in AOT when needed
Docker	Docker/dev/ubuntu-22.04/Dockerfile	libgd-dev if missing
Tests	test/compliance/cases/stdlib/gd_imagecreate.phpt	PNG magic bytes
Phase 1	imagecreatetruecolor, imagecolorallocate, imagefill, imagepng, imagedestroy	Expand in follow-ups

Done when

• Repro prints ok on VM in Docker image
• GD resource type distinct from stream resources
• ./script/ci-fast.sh --filter gd_imagecreate green
• Capability matrix row for core GD functions

Links

• Stdlib: getimagesize() / getimagesizefromstring() — image metadata (ext/standard/image.c parity) #3271 getimagesize — metadata only
• Stdlib: ext/exif — exif_read_data / exif_imagetype (ext/exif parity) #3400 exif — metadata from JPEG