From 594379f584d1130b08ea0816722bdf44aa252c2d Mon Sep 17 00:00:00 2001
From: Hemidark <support@hemidark.net>
Date: Thu, 12 May 2022 02:11:07 -0700
Subject: [PATCH] gesturestylus: honor `GtkGestureSingle:button` property

Use the `GtkGestureSingle:button` property to determine which
buttons count for stylus contact. Press/release events for
other buttons will not be consumed by the gesture.

With the property's default value of 0, any button press
will count as contact, which is approximately the historical
behavior, to ensure some measure of backwards compatibility.

Most users will want to set the property to 1, so that only
button 1 registers as contact.
---
 gtk/gtkgesturestylus.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/gtk/gtkgesturestylus.c b/gtk/gtkgesturestylus.c
index eba6848759..e6356014ce 100644
--- a/gtk/gtkgesturestylus.c
+++ b/gtk/gtkgesturestylus.c
@@ -47,6 +47,25 @@ enum {
 
 static guint signals[N_SIGNALS] = { 0, };
 
+enum {
+  ALL_BUTTONS,
+  BUTTON_1,
+  BUTTON_2,
+  BUTTON_3,
+  BUTTON_4,
+  BUTTON_5,
+  N_BUTTON_MASKS,
+};
+
+static const guint button_masks[N_BUTTON_MASKS] = {
+  GDK_BUTTON1_MASK | GDK_BUTTON2_MASK | GDK_BUTTON3_MASK | GDK_BUTTON4_MASK | GDK_BUTTON5_MASK,
+  GDK_BUTTON1_MASK,
+  GDK_BUTTON2_MASK,
+  GDK_BUTTON3_MASK,
+  GDK_BUTTON4_MASK,
+  GDK_BUTTON5_MASK
+};
+
 static gboolean
 gtk_gesture_stylus_handle_event (GtkEventController *controller,
                                  GdkEvent           *event,
@@ -55,24 +74,33 @@ gtk_gesture_stylus_handle_event (GtkEventController *controller,
 {
   GdkModifierType modifiers;
   guint n_signal;
+  guint button;
+  guint button_mask;
 
   GTK_EVENT_CONTROLLER_CLASS (gtk_gesture_stylus_parent_class)->handle_event (controller, event, x, y);
 
+  button = gtk_gesture_single_get_button (GTK_GESTURE_SINGLE (controller));
+
   if (!gdk_event_get_device_tool (event))
     return FALSE;
 
   switch ((guint) gdk_event_get_event_type (event))
     {
     case GDK_BUTTON_PRESS:
+      if (button != ALL_BUTTONS && gdk_button_event_get_button (event) != button)
+        return FALSE;
       n_signal = DOWN;
       break;
     case GDK_BUTTON_RELEASE:
+      if (button != ALL_BUTTONS && gdk_button_event_get_button (event) != button)
+        return FALSE;
       n_signal = UP;
       break;
     case GDK_MOTION_NOTIFY:
       modifiers = gdk_event_get_modifier_state (event);
+      button_mask = (button >= 0 && button < N_BUTTON_MASKS) ? button_masks[button] : 0;
 
-      if (modifiers & GDK_BUTTON1_MASK)
+      if (modifiers & button_mask)
         n_signal = MOTION;
       else
         n_signal = PROXIMITY;
-- 
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