Unix now uses XDG paths to find icons, making it easier to provide im…

.gitignore

@@ -1,3 +1,4 @@
 docs/Gemfile.lock
 docs/_site
 docs/.jekyll-cache
+build/

src/image.c

@@ -11,6 +11,7 @@
 #include "util.h"
 #include "debug.h"
 #include <ini.h>
+#include <string.h>
 #define NANOSVG_IMPLEMENTATION
 #include <nanosvg.h>
 #define NANOSVGRAST_IMPLEMENTATION
@@ -106,6 +107,55 @@ int load_next_slideshow_background_async(void *data)
     return 0;
 }
 
+#ifdef __unix__
+SDL_Surface *load_surface_from_xdg(const char *path){
+    // TODO: allow the user to specify a specific theme in the config.ini
+    // then prefer that to `hicolor`.
+    // Spec for this is here: https://specifications.freedesktop.org/icon-theme/latest/#icon_lookup
+    SDL_Surface *surface = NULL;
+    const char* xdg_dirs = getenv("XDG_DATA_DIRS");
+    const char* sizes[] = {
+        "scalable",
+        "512x512",
+        "256x256",
+        "128x128",
+        "64x64",
+        "32x32"
+    };
+
+    for(int i = 0; i < sizeof(sizes) / sizeof(void*); i++){
+        char icon_path[128] = {};
+        snprintf(icon_path, 127, "/icons/hicolor/%s/apps/", sizes[i]);
+
+        if(xdg_dirs != NULL){
+            ssize_t last_delim = -1;
+            ssize_t dirs_len = strlen(xdg_dirs);
+            while(surface == NULL && last_delim < dirs_len){
+                char xdg_path[4096] = {0};
+                ssize_t start_ind = last_delim;
+                if(start_ind < 0)
+                    start_ind = 0;
+
+                ssize_t end = strcspn(&xdg_dirs[start_ind], ":");
+                memcpy(&xdg_path, &xdg_dirs[start_ind], end);
+                memcpy(&xdg_path[end], icon_path, strlen(icon_path));
+                memcpy(&xdg_path[end + strlen(icon_path)], path, strlen(path));
+                surface = IMG_Load(xdg_path);
+                if (surface != NULL)
+                    return surface;
+
+                last_delim += end + 1;
+            }
+        }
+    }
+
+    log_error(
+        "Could not load %s from XDG_DATA_DIRS",
+        path
+    );
+}
+#endif
+
 // A function to load a texture from a file
 SDL_Texture *load_texture_from_file(const char *path)
 {
@@ -119,8 +169,13 @@ SDL_Texture *load_texture_from_file(const char *path)
                 path, 
                 IMG_GetError()
             );
+#ifdef __unix__
+            // we failed to find the image normally, lets try xdg on unix
+            surface = load_surface_from_xdg(path);
+#endif
         }
-        else
+
+        if(surface != NULL)
             texture = load_texture(surface);
     }
     return texture;

src/image.h

@@ -28,6 +28,9 @@ void render_scroll_indicators(Scroll *scroll, int height, Geometry *geo);
 SDL_Surface *load_next_slideshow_background(Slideshow *slideshow, bool transition);
 int load_next_slideshow_background_async(void *data);
 SDL_Texture *load_texture(SDL_Surface *surface);
+#ifdef __unix__
+SDL_Surface *load_surface_from_xdg(const char *path);
+#endif
 SDL_Texture *load_texture_from_file(const char *path);
 SDL_Texture *rasterize_svg(char *buffer, int w, int h, SDL_Rect *rect);
 SDL_Texture *rasterize_svg_from_file(const char *path, int w, int h, SDL_Rect *rect);