From c5491474de1696962853f0dc321463e4f3eff261 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Tue, 18 Aug 2026 15:57:46 -0400
Subject: [PATCH] pen: If a pen leaves proximity, force all its pressed buttons
to released.
Some platforms do this for us, but just in case there is a badly-behaved one,
this will help keep application state correct.
Reference Issue #16125.
---
src/events/SDL_pen.c | 107 ++++++++++++++++++++++++++-----------------
1 file changed, 64 insertions(+), 43 deletions(-)
diff --git a/src/events/SDL_pen.c b/src/events/SDL_pen.c
index 849f12be5354f..7202559ffb1c7 100644
--- a/src/events/SDL_pen.c
+++ b/src/events/SDL_pen.c
@@ -562,6 +562,35 @@ void SDL_SendPenMotion(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *wind
}
}
+static void SendPenButtonEvents(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *window, Uint8 button, bool down, SDL_PenInputFlags input_state, float x, float y)
+{
+ const SDL_EventType evtype = down ? SDL_EVENT_PEN_BUTTON_DOWN : SDL_EVENT_PEN_BUTTON_UP;
+ if (SDL_EventEnabled(evtype)) {
+ SDL_Event event;
+ SDL_zero(event);
+ event.pbutton.type = evtype;
+ event.pbutton.timestamp = timestamp;
+ event.pbutton.windowID = window ? window->id : 0;
+ event.pbutton.which = instance_id;
+ event.pbutton.pen_state = input_state;
+ event.pbutton.x = x;
+ event.pbutton.y = y;
+ event.pbutton.button = button;
+ event.pbutton.down = down;
+ SDL_PushEvent(&event);
+
+ if (window && (!pen_touching || (pen_touching == instance_id))) {
+ SDL_Mouse *mouse = SDL_GetMouse();
+ if (mouse && mouse->pen_mouse_events) {
+ static const Uint8 mouse_buttons[] = { SDL_BUTTON_LEFT, SDL_BUTTON_RIGHT, SDL_BUTTON_MIDDLE, SDL_BUTTON_X1, SDL_BUTTON_X2 };
+ if (button < SDL_arraysize(mouse_buttons)) {
+ SDL_SendMouseButton(timestamp, window, SDL_PEN_MOUSEID, mouse_buttons[button], down);
+ }
+ }
+ }
+ }
+}
+
void SDL_SendPenButton(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *window, Uint8 button, bool down)
{
bool send_event = false;
@@ -583,7 +612,7 @@ void SDL_SendPenButton(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *wind
EnsurePenProximity(timestamp, pen, window);
input_state = pen->input_state;
- const Uint32 flag = (Uint32) (1u << button);
+ const SDL_PenInputFlags flag = (SDL_PenInputFlags) (1u << button);
const bool current = ((input_state & flag) != 0);
x = pen->x;
y = pen->y;
@@ -599,37 +628,7 @@ void SDL_SendPenButton(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *wind
SDL_UnlockRWLock(pen_device_rwlock);
if (send_event) {
- const SDL_EventType evtype = down ? SDL_EVENT_PEN_BUTTON_DOWN : SDL_EVENT_PEN_BUTTON_UP;
- if (SDL_EventEnabled(evtype)) {
- SDL_Event event;
- SDL_zero(event);
- event.pbutton.type = evtype;
- event.pbutton.timestamp = timestamp;
- event.pbutton.windowID = window ? window->id : 0;
- event.pbutton.which = instance_id;
- event.pbutton.pen_state = input_state;
- event.pbutton.x = x;
- event.pbutton.y = y;
- event.pbutton.button = button;
- event.pbutton.down = down;
- SDL_PushEvent(&event);
-
- if (window && (!pen_touching || (pen_touching == instance_id))) {
- SDL_Mouse *mouse = SDL_GetMouse();
- if (mouse && mouse->pen_mouse_events) {
- static const Uint8 mouse_buttons[] = {
- SDL_BUTTON_LEFT,
- SDL_BUTTON_RIGHT,
- SDL_BUTTON_MIDDLE,
- SDL_BUTTON_X1,
- SDL_BUTTON_X2
- };
- if (button < SDL_arraysize(mouse_buttons)) {
- SDL_SendMouseButton(timestamp, window, SDL_PEN_MOUSEID, mouse_buttons[button], down);
- }
- }
- }
- }
+ SendPenButtonEvents(timestamp, instance_id, window, button, down, input_state, x, y);
}
}
@@ -637,6 +636,9 @@ void SDL_SendPenProximity(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *w
{
bool send_event = false;
SDL_PenInputFlags input_state = 0;
+ SDL_PenInputFlags orig_input_state = 0;
+ float x = 0.0f;
+ float y = 0.0f;
// note that this locks for _reading_ because the lock protects the
// pen_devices array from being reallocated from under us, not the data in it;
@@ -646,16 +648,22 @@ void SDL_SendPenProximity(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *w
SDL_Pen *pen = FindPenByInstanceId(instance_id);
if (pen) {
if (in || immediate) {
- input_state = pen->input_state;
+ orig_input_state = input_state = pen->input_state;
const bool in_proximity = ((input_state & SDL_PEN_INPUT_IN_PROXIMITY) != 0);
if (in_proximity != in) {
if (in) {
input_state |= SDL_PEN_INPUT_IN_PROXIMITY;
} else {
input_state &= ~SDL_PEN_INPUT_IN_PROXIMITY;
+ // drop all still-pressed buttons, too.
+ for (int button = 1; button <= 5; button++) {
+ input_state &= ~(1u << button);
+ }
}
send_event = true;
pen->input_state = input_state; // we could do an SDL_SetAtomicInt here if we run into trouble...
+ x = pen->x;
+ y = pen->y;
}
pen->pending_proximity_out = false;
} else {
@@ -666,16 +674,29 @@ void SDL_SendPenProximity(Uint64 timestamp, SDL_PenID instance_id, SDL_Window *w
}
SDL_UnlockRWLock(pen_device_rwlock);
- const Uint32 event_type = in ? SDL_EVENT_PEN_PROXIMITY_IN : SDL_EVENT_PEN_PROXIMITY_OUT;
- if (send_event && SDL_EventEnabled(event_type)) {
- SDL_Event event;
- SDL_zero(event);
- event.pproximity.type = event_type;
- event.pproximity.timestamp = timestamp;
- event.pproximity.windowID = window ? window->id : 0;
- event.pproximity.which = instance_id;
- event.pproximity.pen_state = input_state;
- SDL_PushEvent(&event);
+ if (send_event) {
+ // report any currently-pressed buttons as released if we're leaving proximity.
+ if (!in) {
+ for (int button = 1; button <= 5; button++) {
+ const SDL_PenInputFlags flag = (SDL_PenInputFlags) (1u << button);
+ if (orig_input_state & flag) { // orig_input_state continues to report we're in proximity.
+ orig_input_state &= ~flag; // drop the button we're reporting on.
+ SendPenButtonEvents(timestamp, instance_id, window, button, false, orig_input_state, x, y);
+ }
+ }
+ }
+
+ const Uint32 event_type = in ? SDL_EVENT_PEN_PROXIMITY_IN : SDL_EVENT_PEN_PROXIMITY_OUT;
+ if (SDL_EventEnabled(event_type)) {
+ SDL_Event event;
+ SDL_zero(event);
+ event.pproximity.type = event_type;
+ event.pproximity.timestamp = timestamp;
+ event.pproximity.windowID = window ? window->id : 0;
+ event.pproximity.which = instance_id;
+ event.pproximity.pen_state = input_state;
+ SDL_PushEvent(&event);
+ }
}
}