feat(picture): add initial picture library

.gitignore

@@ -1,2 +1,8 @@
 .cache/
 .vscode/launch.json
+
+# Important: must exclude all the files/folders under subprojects/ and not just
+# subprojects/ itself, otherwise the exclusion rule for wrap files does not
+# work.
+subprojects/*
+!subprojects/*.wrap

meson.build

@@ -1,8 +1,11 @@
 project('saltytools', 'c', version: '0.1.0')
 
+libpng_dep = dependency('libpng', fallback: ['libpng', 'libpng_dep'])
+
 inc = include_directories('.')
 
 subdir('573file')
+subdir('picture')
 subdir('util')
 
 subdir('ifsdump')

picture/meson.build

@@ -0,0 +1,12 @@
+picture_lib = static_library(
+  'picture',
+  dependencies: [libpng_dep],
+  include_directories: [inc],
+  c_pch: '../precompiled.h',
+  sources: [
+    'picture-png.c',
+    'picture-png.h',
+    'picture.c',
+    'picture.h',
+  ]
+)

picture/picture-png.c

@@ -0,0 +1,34 @@
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include <png.h>
+
+#include "picture/picture-png.h"
+#include "picture/picture.h"
+
+#include "util/log.h"
+
+int picture_write_png(const struct picture *pic, const char *path) {
+  png_image png;
+  int r;
+
+  assert(pic != NULL);
+  assert(path != NULL);
+
+  memset(&png, 0, sizeof(png));
+  png.version = PNG_IMAGE_VERSION;
+  png.width = pic->dim.width;
+  png.height = pic->dim.height;
+  png.format = PNG_FORMAT_BGRA;
+
+  r = png_image_write_to_file(&png, path, 0, pic->pixels, 0, NULL);
+
+  if (r != 1 || (png.warning_or_error & 2)) {
+    log_write("libpng error writing to \"%s\": %s", path, png.message);
+
+    return -EIO;
+  }
+
+  return 0;
+}

picture/picture-png.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "picture/picture.h"
+
+int picture_write_png(const struct picture *pic, const char *path);

picture/picture.c

@@ -0,0 +1,34 @@
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "picture/picture.h"
+
+int picture_alloc(struct picture **out, const struct dim *dim) {
+  struct picture *pic;
+  size_t nbytes;
+
+  assert(out != NULL);
+  assert(dim != NULL);
+
+  *out = NULL;
+  nbytes = sizeof(*pic) + dim->width * dim->height * sizeof(uint32_t);
+
+  if (nbytes > UINT_MAX) {
+    return -EOVERFLOW;
+  }
+
+  pic = malloc(nbytes);
+
+  if (pic == NULL) {
+    return -ENOMEM;
+  }
+
+  memcpy(&pic->dim, dim, sizeof(*dim));
+
+  *out = pic;
+
+  return 0;
+}

picture/picture.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <stdint.h>
+
+typedef uint32_t pixel_t;
+
+struct dim {
+  unsigned int width;
+  unsigned int height;
+};
+
+struct point {
+  unsigned int x;
+  unsigned int y;
+};
+
+struct rect {
+  struct point p1;
+  struct point p2;
+};
+
+struct picture {
+  struct dim dim;
+  pixel_t pixels[];
+};
+
+int picture_alloc(struct picture **out, const struct dim *dim);

precompiled.h

@@ -1,5 +1,6 @@
 #include <assert.h>  // IWYU pragma: keep
 #include <errno.h>   // IWYU pragma: keep
+#include <limits.h>  // IWYU pragma: keep
 #include <stdarg.h>  // IWYU pragma: keep
 #include <stdbool.h> // IWYU pragma: keep
 #include <stddef.h>  // IWYU pragma: keep

subprojects/libpng.wrap

@@ -0,0 +1,13 @@
+[wrap-file]
+directory = libpng-1.6.40
+source_url = https://github.com/glennrp/libpng/archive/v1.6.40.tar.gz
+source_filename = libpng-1.6.40.tar.gz
+source_hash = 62d25af25e636454b005c93cae51ddcd5383c40fa14aa3dae8f6576feb5692c2
+patch_filename = libpng_1.6.40-1_patch.zip
+patch_url = https://wrapdb.mesonbuild.com/v2/libpng_1.6.40-1/get_patch
+patch_hash = bad558070e0a82faa5c0ae553bcd12d49021fc4b628f232a8e58c3fbd281aae1
+source_fallback_url = https://github.com/mesonbuild/wrapdb/releases/download/libpng_1.6.40-1/libpng-1.6.40.tar.gz
+wrapdb_version = 1.6.40-1
+
+[provide]
+libpng = libpng_dep