Add options for relative positioning of window on screen

data/lightdm-mini-greeter.conf

@@ -52,6 +52,9 @@ border-width = 2px
 # The pixels of empty space around the password input.
 # Do not include a trailing `px`.
 layout-space = 15
+# Relative position of password window on screen (give value between 0.0 and 1.0)
+window-position-x = 0.5
+window-position-y = 0.5
 # The color of the text in the password input.
 password-color = "#F8F8F0"
 # The background color of the password input.

src/config.c

@@ -11,6 +11,7 @@
 
 static GdkRGBA *parse_greeter_color_key(GKeyFile *keyfile, const char *key_name);
 static guint parse_greeter_hotkey_keyval(GKeyFile *keyfile, const char *key_name);
+static gdouble get_relative_position(GKeyFile *keyfile, const char *axis);
 
 /* Initialize the configuration, sourcing the greeter's configuration file */
 Config *initialize_config(void)
@@ -96,6 +97,8 @@ Config *initialize_config(void)
         config->layout_spacing = (guint) layout_spacing;
     }
 
+    config->position_x = get_relative_position(keyfile, "x");
+    config->position_y = get_relative_position(keyfile, "y");
 
     g_key_file_free(keyfile);
 
@@ -157,3 +160,21 @@ static guint parse_greeter_hotkey_keyval(GKeyFile *keyfile, const char *key_name
 
     return gdk_unicode_to_keyval((guint) key[0]);
 }
+
+/* Get relative window position double value, return 0.5 if missing or unable to parse */
+static gdouble get_relative_position(GKeyFile *keyfile, const char *axis) {
+    g_autoptr(GError) error = NULL;
+    char key[80];
+    gdouble pos = g_key_file_get_double(
+                    keyfile,
+                    "greeter-theme",
+                    strcat(strcpy(key, "window-position-"), axis),
+                    &error);
+
+    if (error != NULL || pos < 0.0 || pos > 1.0) {
+        g_message("Error while parsing window-position-%s", axis);
+        pos = 0.5;
+    }
+
+    return pos;
+}

src/config.h

@@ -28,6 +28,8 @@ typedef struct Config_ {
     GdkRGBA  *border_color;
     gchar    *border_width;
     guint     layout_spacing;
+    gdouble   position_x;
+    gdouble   position_y;
     // Password Input
     GdkRGBA  *password_color;
     GdkRGBA  *password_background_color;

src/ui.c

@@ -124,7 +124,7 @@ static void setup_main_window(Config *config, UI *ui)
     gtk_container_set_border_width(GTK_CONTAINER(main_window), config->layout_spacing);
     gtk_widget_set_name(GTK_WIDGET(main_window), "main");
 
-    g_signal_connect(main_window, "show", G_CALLBACK(place_main_window), NULL);
+    g_signal_connect(main_window, "show", G_CALLBACK(place_main_window), config);
     g_signal_connect(main_window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
 
     ui->main_window = main_window;
@@ -144,15 +144,20 @@ static void place_main_window(GtkWidget *main_window, gpointer user_data)
     GdkMonitor *primary_monitor = gdk_display_get_primary_monitor(display);
     GdkRectangle primary_monitor_geometry;
     gdk_monitor_get_geometry(primary_monitor, &primary_monitor_geometry);
+    Config *config = (Config *) user_data;
 
     // Get the Geometry of the Window
     gint window_width, window_height;
     gtk_window_get_size(GTK_WINDOW(main_window), &window_width, &window_height);
 
-    gtk_window_move(
-        GTK_WINDOW(main_window),
-        primary_monitor_geometry.x + primary_monitor_geometry.width / 2 - window_width / 2,
-        primary_monitor_geometry.y + primary_monitor_geometry.height / 2 - window_height / 2);
+    gint offset_x = primary_monitor_geometry.x
+                     + (gint) (primary_monitor_geometry.width * config->position_x)
+                     - window_width / 2;
+    gint offset_y = primary_monitor_geometry.y
+                     + (gint) (primary_monitor_geometry.height * config->position_y)
+                     - window_height / 2;
+
+    gtk_window_move(GTK_WINDOW(main_window), offset_x, offset_y);
 }