Wire app icon into the GTK window and build.

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

.gitignore

@@ -16,6 +16,9 @@ progress/
 dist/
 build/
 
+# Generated from assets/app-icon.png (Makefile / CMake POST_BUILD)
+assets/icons/
+
 # Object files
 *.o
 *.ko

CMakeLists.txt

@@ -62,9 +62,19 @@ else()
         -Wall -Wextra -Wno-deprecated-declarations)
 endif()
 
-# The GTK stylesheet is loaded at runtime from the working directory, so keep
-# a copy next to the built binary as well.
+# The GTK stylesheet and window icon are loaded at runtime from the working
+# directory (or next to the binary), so keep copies beside the built binary.
 add_custom_command(TARGET maturita POST_BUILD
     COMMAND ${CMAKE_COMMAND} -E copy_if_different
             ${CMAKE_CURRENT_SOURCE_DIR}/style.css
-            $<TARGET_FILE_DIR:maturita>/style.css)
+            $<TARGET_FILE_DIR:maturita>/style.css
+    COMMAND ${CMAKE_COMMAND} -E make_directory
+            $<TARGET_FILE_DIR:maturita>/icons/hicolor/512x512/apps
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            ${CMAKE_CURRENT_SOURCE_DIR}/assets/app-icon.png
+            $<TARGET_FILE_DIR:maturita>/icons/hicolor/512x512/apps/maturita.png
+    COMMAND ${CMAKE_COMMAND} -E make_directory
+            ${CMAKE_CURRENT_SOURCE_DIR}/assets/icons/hicolor/512x512/apps
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            ${CMAKE_CURRENT_SOURCE_DIR}/assets/app-icon.png
+            ${CMAKE_CURRENT_SOURCE_DIR}/assets/icons/hicolor/512x512/apps/maturita.png)

Makefile

@@ -28,9 +28,16 @@ endif
 SRC = $(wildcard *.c)
 OBJ = $(SRC:.c=.o)
 
+ICON_SRC = assets/app-icon.png
+ICON_DST = assets/icons/hicolor/512x512/apps/maturita.png
+
 all: $(TARGET)
 
-$(TARGET): $(SRC)
+$(ICON_DST): $(ICON_SRC)
+	mkdir -p $(dir $@)
+	cp "$(ICON_SRC)" "$@"
+
+$(TARGET): $(SRC) $(ICON_DST)
 	$(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(LIBS)
 
 clean:
@@ -48,6 +55,8 @@ bundle: $(TARGET)
 	@mkdir -p dist
 	@cp $(TARGET) dist/
 	@cp style.css dist/
+	@mkdir -p dist/icons/hicolor/512x512/apps
+	@cp "$(ICON_DST)" dist/icons/hicolor/512x512/apps/
 	@ldd $(TARGET) | grep -Ei '/(ucrt64|mingw64)/bin/' | awk '{print $$3}' \
 		| xargs -r -I{} cp -f {} dist/
 	@echo "Bundled into dist/ - run dist/$(TARGET)"

main.c

@@ -185,6 +185,28 @@ static gboolean ui_scale_tick(GtkWidget *w, GdkFrameClock *clock,
     return G_SOURCE_CONTINUE;
 }
 
+/* GTK4 has no gtk_window_set_icon_from_file(); register a local hicolor
+ * theme dir and set the window icon by name instead. */
+static void setup_window_icon(GtkWindow *window) {
+    GtkIconTheme *theme;
+    static const char *dirs[] = { ICON_THEME_DIR, ICON_THEME_DIR_ALT, NULL };
+
+    theme = gtk_icon_theme_get_for_display(gdk_display_get_default());
+    for (int 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)) {
+        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);
+}
+
 void activate(GtkApplication *app, gpointer user_data) {
     GtkWindow *window;
     GtkWidget *headerbar;
@@ -208,6 +230,7 @@ void activate(GtkApplication *app, gpointer user_data) {
     main_window = window;
     gtk_window_set_title(window, "maturita.c");
     gtk_window_set_default_size(window, 760, 560);
+    setup_window_icon(window);
 
     headerbar = gtk_header_bar_new();
     gtk_widget_add_css_class(headerbar, "titlebar");

maturita.h

@@ -15,6 +15,9 @@
 #define HW_SUBJ        2    /* index of "Technické vybavení"          */
 #define CZ_SUBJ        3    /* index of "Český jazyk a literatura"    */
 #define CSS_FILE      "style.css"
+#define ICON_NAME     "maturita"
+#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 PROGRESS_DIR  "progress"
 #define PROGRESS_U1   "progress/unit1.conf"
 #define PROGRESS_U2   "progress/unit2.conf"