Show Pen Buttons in penpal

src/drivers/Wayland/Fl_Wayland_Pen_Events.cxx

@@ -552,8 +552,8 @@ static void tool_cb_button(void *data, struct zwp_tablet_tool_v2 *,
   // Map physical button codes to State bits.
   State bit = (State)0;
   switch (button) {
-    case BTN_STYLUS:  bit = State::BUTTON0; break;
-    case BTN_STYLUS2: bit = State::BUTTON1; break;
+    case BTN_STYLUS:  bit = State::BUTTON1; break; // upper barell button
+    case BTN_STYLUS2: bit = State::BUTTON0; break; // lower barrel button, closer to the pen tip
     case BTN_STYLUS3: bit = State::BUTTON2; break;
     default: break;
   }

src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx

@@ -50,6 +50,7 @@
 #include <errno.h>
 #include <string.h> // for strerror()
 #include <map>
+
 extern "C" {
   bool libdecor_get_cursor_settings(char **theme, int *size);
   bool fl_is_surface_from_GTK_titlebar (struct wl_surface *surface, struct libdecor_frame *frame,

test/penpal.cxx

@@ -1,7 +1,7 @@
 //
 // Penpal pen/stylus/tablet test program for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2025 by Bill Spitzak and others.
+// Copyright 2025-2026 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -63,6 +63,7 @@ public:
   }
   int cv_handle(int event);
   void cv_draw();
+  void cv_draw_buttons();
   void cv_paint();
   void cv_pen_paint();
 };
@@ -83,6 +84,8 @@ int CanvasInterface::cv_handle(int event)
       /* fall through */
     case Fl::Pen::HOVER:
       // Pen move over the surface without touching it.
+      if (Fl::event_state(FL_CTRL) || Fl::Pen::event_state(Fl::Pen::State::BUTTON1))
+        return popup_app_menu();
       overlay_ = PEN_HOVER;
       ov_x_ = Fl::event_x();
       ov_y_ = Fl::event_y();
@@ -90,8 +93,6 @@ int CanvasInterface::cv_handle(int event)
       return 1;
     case Fl::Pen::TOUCH:
       // Pen tip or eraser just touched the surface.
-      if (Fl::event_state(FL_CTRL) || Fl::Pen::event_state(Fl::Pen::State::BUTTON0))
-        return popup_app_menu();
       /* fall through */
     case Fl::Pen::DRAW:
       // Pen is dragged over the surface, or hovers with a button pressed.
@@ -177,6 +178,7 @@ void CanvasInterface::cv_draw()
     case NONE: break;
     case PEN_HOVER:
       fl_color(FL_RED);
+      cv_draw_buttons();
       /* fall through */
     case HOVER:
       fl_xyline(ov_x_-10, ov_y_, ov_x_+10);
@@ -194,6 +196,7 @@ void CanvasInterface::cv_draw()
         fl_line(ov_x_-r, ov_y_-r, ov_x_+r, ov_y_+r);
         fl_line(ov_x_-r, ov_y_+r, ov_x_+r, ov_y_-r);
       }
+      cv_draw_buttons();
       /* fall through */
     case DRAW:
       // Draw a circle at the mouse or pan position
@@ -202,6 +205,20 @@ void CanvasInterface::cv_draw()
   }
 }
 
+void CanvasInterface::cv_draw_buttons()
+{
+  // Button indicators
+  fl_rect(ov_x_-16, ov_y_-20, 32, 10);
+  if (Fl::Pen::event_state(Fl::Pen::State::BUTTON0))
+    fl_rectf(ov_x_-16, ov_y_-20, 8, 10);
+  if (Fl::Pen::event_state(Fl::Pen::State::BUTTON1))
+    fl_rectf(ov_x_-8, ov_y_-20, 8, 10);
+  if (Fl::Pen::event_state(Fl::Pen::State::BUTTON2))
+    fl_rectf(ov_x_-0, ov_y_-20, 8, 10);
+  if (Fl::Pen::event_state(Fl::Pen::State::BUTTON3))
+    fl_rectf(ov_x_+8, ov_y_-20, 8, 10);
+}
+
 //
 // Paint a circle with mouse events.
 //