Show the app icon on the macOS Dock via AppKit.

Co-authored-by: Cursor <cursoragent@cursor.com>

CMakeLists.txt

@@ -60,6 +60,10 @@ else()
     target_link_libraries(maturita PRIVATE PkgConfig::GTK4 m)
     target_compile_options(maturita PRIVATE
         -Wall -Wextra -Wno-deprecated-declarations)
+    if(APPLE)
+        target_link_libraries(maturita PRIVATE
+            "-framework AppKit" "-framework Foundation")
+    endif()
 endif()
 
 # The GTK stylesheet and window icon are loaded at runtime from the working

Makefile

@@ -23,6 +23,10 @@ TARGET = maturita.exe
 LIBS += -mwindows
 else
 TARGET = maturita
+# macOS Dock icon is set via AppKit (see macos_dock.c).
+ifeq ($(shell uname -s 2>/dev/null),Darwin)
+LIBS += -framework AppKit -framework Foundation
+endif
 endif
 
 SRC = $(wildcard *.c)

macos_dock.c

@@ -0,0 +1,55 @@
+#include "maturita.h"
+
+#ifdef __APPLE__
+#include <objc/message.h>
+#include <objc/runtime.h>
+
+/* Set the macOS Dock tile icon. GTK's window icon-name is ignored on
+ * Quartz, so we talk to AppKit directly via the Objective-C runtime. */
+void macos_set_dock_icon(const char *path) {
+    Class nsstring;
+    Class nsimage;
+    Class nsapp;
+    id path_str;
+    id image;
+    id app;
+
+    if (!path || !path[0])
+        return;
+
+    nsstring = objc_getClass("NSString");
+    nsimage = objc_getClass("NSImage");
+    nsapp = objc_getClass("NSApplication");
+    if (!nsstring || !nsimage || !nsapp)
+        return;
+
+    path_str = ((id (*)(Class, SEL, const char *))objc_msgSend)(
+        nsstring, sel_registerName("stringWithUTF8String:"), path);
+    if (!path_str)
+        return;
+
+    /* NSImage has -initWithContentsOfFile:, not +imageWithContentsOfFile:. */
+    image = ((id (*)(id, SEL, id))objc_msgSend)(
+        ((id (*)(Class, SEL))objc_msgSend)(
+            nsimage, sel_registerName("alloc")),
+        sel_registerName("initWithContentsOfFile:"),
+        path_str);
+    if (!image)
+        return;
+
+    app = ((id (*)(Class, SEL))objc_msgSend)(
+        nsapp, sel_registerName("sharedApplication"));
+    if (!app) {
+        ((void (*)(id, SEL))objc_msgSend)(image, sel_registerName("release"));
+        return;
+    }
+
+    ((void (*)(id, SEL, id))objc_msgSend)(
+        app, sel_registerName("setApplicationIconImage:"), image);
+    ((void (*)(id, SEL))objc_msgSend)(image, sel_registerName("release"));
+}
+#else
+void macos_set_dock_icon(const char *path) {
+    (void)path;
+}
+#endif

main.c

@@ -185,26 +185,51 @@ static gboolean ui_scale_tick(GtkWidget *w, GdkFrameClock *clock,
     return G_SOURCE_CONTINUE;
 }
 
+static const char *find_app_icon_file(void) {
+    static const char *paths[] = {
+        ICON_FILE,
+        ICON_THEME_DIR "/hicolor/512x512/apps/" ICON_NAME ".png",
+        ICON_FILE_ALT,
+        NULL,
+    };
+    int i;
+
+    for (i = 0; paths[i]; i++) {
+        if (g_file_test(paths[i], G_FILE_TEST_IS_REGULAR))
+            return paths[i];
+    }
+    return NULL;
+}
+
 /* GTK4 has no gtk_window_set_icon_from_file(); register a local hicolor
- * theme dir and set the window icon by name instead. */
+ * theme dir and set the window icon by name instead. On macOS the Dock
+ * tile ignores that, so also push the PNG through AppKit. */
 static void setup_window_icon(GtkWindow *window) {
     GtkIconTheme *theme;
     static const char *dirs[] = { ICON_THEME_DIR, ICON_THEME_DIR_ALT, NULL };
+    const char *icon_file;
+    int i;
 
     theme = gtk_icon_theme_get_for_display(gdk_display_get_default());
-    for (int i = 0; dirs[i]; i++) {
+    for (i = 0; dirs[i]; i++) {
         if (g_file_test(dirs[i], G_FILE_TEST_IS_DIR))
             gtk_icon_theme_add_search_path(theme, dirs[i]);
     }
 
-    if (!gtk_icon_theme_has_icon(theme, ICON_NAME)) {
+    if (gtk_icon_theme_has_icon(theme, ICON_NAME)) {
+        gtk_window_set_default_icon_name(ICON_NAME);
+        gtk_window_set_icon_name(window, ICON_NAME);
+    } else {
         g_warning("App icon '%s' not found (tried %s/ and %s/)",
                   ICON_NAME, ICON_THEME_DIR, ICON_THEME_DIR_ALT);
-        return;
     }
 
-    gtk_window_set_default_icon_name(ICON_NAME);
-    gtk_window_set_icon_name(window, ICON_NAME);
+    icon_file = find_app_icon_file();
+    if (icon_file)
+        macos_set_dock_icon(icon_file);
+    else
+        g_warning("Dock icon PNG not found (tried %s and %s)",
+                  ICON_FILE, ICON_FILE_ALT);
 }
 
 void activate(GtkApplication *app, gpointer user_data) {

maturita.h

@@ -16,8 +16,10 @@
 #define CZ_SUBJ        3    /* index of "Český jazyk a literatura"    */
 #define CSS_FILE      "style.css"
 #define ICON_NAME     "maturita"
+#define ICON_FILE     "assets/app-icon.png"
 #define ICON_THEME_DIR "assets/icons"   /* cwd when run from source tree */
 #define ICON_THEME_DIR_ALT "icons"      /* next to the binary after install */
+#define ICON_FILE_ALT "icons/hicolor/512x512/apps/maturita.png"
 #define PROGRESS_DIR  "progress"
 #define PROGRESS_U1   "progress/unit1.conf"
 #define PROGRESS_U2   "progress/unit2.conf"
@@ -1192,6 +1194,7 @@ GtkWidget *build_net_unit24_exercise_page(void);
 GtkWidget *build_net_unit25_exercise_page(void);
 GtkWidget *build_net_unit26_exercise_page(void);
 GtkWidget *build_net_unit27_exercise_page(void);
+void macos_set_dock_icon(const char *path);
 void activate(GtkApplication *app, gpointer user_data);
 int main(int argc, char **argv);