--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDL3/SDL_pen.h	Mon Jan 05 02:15:46 2026 -0500
@@ -0,0 +1,198 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/**
+ * # CategoryPen
+ *
+ * SDL pen event handling.
+ *
+ * SDL provides an API for pressure-sensitive pen (stylus and/or eraser)
+ * handling, e.g., for input and drawing tablets or suitably equipped mobile /
+ * tablet devices.
+ *
+ * To get started with pens, simply handle pen events:
+ *
+ * - SDL_EVENT_PEN_PROXIMITY_IN, SDL_EVENT_PEN_PROXIMITY_OUT
+ *   (SDL_PenProximityEvent)
+ * - SDL_EVENT_PEN_DOWN, SDL_EVENT_PEN_UP (SDL_PenTouchEvent)
+ * - SDL_EVENT_PEN_MOTION (SDL_PenMotionEvent)
+ * - SDL_EVENT_PEN_BUTTON_DOWN, SDL_EVENT_PEN_BUTTON_UP (SDL_PenButtonEvent)
+ * - SDL_EVENT_PEN_AXIS (SDL_PenAxisEvent)
+ *
+ * Pens may provide more than simple touch input; they might have other axes,
+ * such as pressure, tilt, rotation, etc.
+ *
+ * When a pen starts providing input, SDL will assign it a unique SDL_PenID,
+ * which will remain for the life of the process, as long as the pen stays
+ * connected. A pen leaving proximity (being taken far enough away from the
+ * digitizer tablet that it no longer reponds) and then coming back should
+ * fire proximity events, but the SDL_PenID should remain consistent.
+ * Unplugging the digitizer and reconnecting may cause future input to have a
+ * new SDL_PenID, as SDL may not know that this is the same hardware.
+ *
+ * Please note that various platforms vary wildly in how (and how well) they
+ * support pen input. If your pen supports some piece of functionality but SDL
+ * doesn't seem to, it might actually be the operating system's fault. For
+ * example, some platforms can manage multiple devices at the same time, but
+ * others will make any connected pens look like a single logical device, much
+ * how all USB mice connected to a computer will move the same system cursor.
+ * cursor. Other platforms might not support pen buttons, or the distance
+ * axis, etc. Very few platforms can even report _what_ functionality the pen
+ * supports in the first place, so best practices is to either build UI to let
+ * the user configure their pens, or be prepared to handle new functionality
+ * for a pen the first time an event is reported.
+ */
+
+#ifndef SDL_pen_h_
+#define SDL_pen_h_
+
+#include <SDL3/SDL_stdinc.h>
+#include <SDL3/SDL_mouse.h>
+#include <SDL3/SDL_touch.h>
+
+#include <SDL3/SDL_begin_code.h>
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * SDL pen instance IDs.
+ *
+ * Zero is used to signify an invalid/null device.
+ *
+ * These show up in pen events when SDL sees input from them. They remain
+ * consistent as long as SDL can recognize a tool to be the same pen; but if a
+ * pen's digitizer table is physically detached from the computer, it might
+ * get a new ID when reconnected, as SDL won't know it's the same device.
+ *
+ * These IDs are only stable within a single run of a program; the next time a
+ * program is run, the pen's ID will likely be different, even if the hardware
+ * hasn't been disconnected, etc.
+ *
+ * \since This datatype is available since SDL 3.2.0.
+ */
+typedef Uint32 SDL_PenID;
+
+/**
+ * The SDL_MouseID for mouse events simulated with pen input.
+ *
+ * \since This macro is available since SDL 3.2.0.
+ */
+#define SDL_PEN_MOUSEID ((SDL_MouseID)-2)
+
+/**
+ * The SDL_TouchID for touch events simulated with pen input.
+ *
+ * \since This macro is available since SDL 3.2.0.
+ */
+#define SDL_PEN_TOUCHID ((SDL_TouchID)-2)
+
+/**
+ * Pen input flags, as reported by various pen events' `pen_state` field.
+ *
+ * \since This datatype is available since SDL 3.2.0.
+ */
+typedef Uint32 SDL_PenInputFlags;
+
+#define SDL_PEN_INPUT_DOWN         (1u << 0)  /**< pen is pressed down */
+#define SDL_PEN_INPUT_BUTTON_1     (1u << 1)  /**< button 1 is pressed */
+#define SDL_PEN_INPUT_BUTTON_2     (1u << 2)  /**< button 2 is pressed */
+#define SDL_PEN_INPUT_BUTTON_3     (1u << 3)  /**< button 3 is pressed */
+#define SDL_PEN_INPUT_BUTTON_4     (1u << 4)  /**< button 4 is pressed */
+#define SDL_PEN_INPUT_BUTTON_5     (1u << 5)  /**< button 5 is pressed */
+#define SDL_PEN_INPUT_ERASER_TIP   (1u << 30) /**< eraser tip is used */
+#define SDL_PEN_INPUT_IN_PROXIMITY (1u << 31) /**< pen is in proximity (since SDL 3.4.0) */
+
+/**
+ * Pen axis indices.
+ *
+ * These are the valid values for the `axis` field in SDL_PenAxisEvent. All
+ * axes are either normalised to 0..1 or report a (positive or negative) angle
+ * in degrees, with 0.0 representing the centre. Not all pens/backends support
+ * all axes: unsupported axes are always zero.
+ *
+ * To convert angles for tilt and rotation into vector representation, use
+ * SDL_sinf on the XTILT, YTILT, or ROTATION component, for example:
+ *
+ * `SDL_sinf(xtilt * SDL_PI_F / 180.0)`.
+ *
+ * \since This enum is available since SDL 3.2.0.
+ */
+typedef enum SDL_PenAxis
+{
+    SDL_PEN_AXIS_PRESSURE,  /**< Pen pressure.  Unidirectional: 0 to 1.0 */
+    SDL_PEN_AXIS_XTILT,     /**< Pen horizontal tilt angle.  Bidirectional: -90.0 to 90.0 (left-to-right). */
+    SDL_PEN_AXIS_YTILT,     /**< Pen vertical tilt angle.  Bidirectional: -90.0 to 90.0 (top-to-down). */
+    SDL_PEN_AXIS_DISTANCE,  /**< Pen distance to drawing surface.  Unidirectional: 0.0 to 1.0 */
+    SDL_PEN_AXIS_ROTATION,  /**< Pen barrel rotation.  Bidirectional: -180 to 179.9 (clockwise, 0 is facing up, -180.0 is facing down). */
+    SDL_PEN_AXIS_SLIDER,    /**< Pen finger wheel or slider (e.g., Airbrush Pen).  Unidirectional: 0 to 1.0 */
+    SDL_PEN_AXIS_TANGENTIAL_PRESSURE,    /**< Pressure from squeezing the pen ("barrel pressure"). */
+    SDL_PEN_AXIS_COUNT       /**< Total known pen axis types in this version of SDL. This number may grow in future releases! */
+} SDL_PenAxis;
+
+/**
+ * An enum that describes the type of a pen device.
+ *
+ * A "direct" device is a pen that touches a graphic display (like an Apple
+ * Pencil on an iPad's screen). "Indirect" devices touch an external tablet
+ * surface that is connected to the machine but is not a display (like a
+ * lower-end Wacom tablet connected over USB).
+ *
+ * Apps may use this information to decide if they should draw a cursor; if
+ * the pen is touching the screen directly, a cursor doesn't make sense and
+ * can be in the way, but becomes necessary for indirect devices to know where
+ * on the display they are interacting.
+ *
+ * \since This enum is available since SDL 3.4.0.
+ */
+typedef enum SDL_PenDeviceType
+{
+    SDL_PEN_DEVICE_TYPE_INVALID = -1, /**< Not a valid pen device. */
+    SDL_PEN_DEVICE_TYPE_UNKNOWN,      /**< Don't know specifics of this pen. */
+    SDL_PEN_DEVICE_TYPE_DIRECT,       /**< Pen touches display. */
+    SDL_PEN_DEVICE_TYPE_INDIRECT      /**< Pen touches something that isn't the display. */
+} SDL_PenDeviceType;
+
+/**
+ * Get the device type of the given pen.
+ *
+ * Many platforms do not supply this information, so an app must always be
+ * prepared to get an SDL_PEN_DEVICE_TYPE_UNKNOWN result.
+ *
+ * \param instance_id the pen instance ID.
+ * \returns the device type of the given pen, or SDL_PEN_DEVICE_TYPE_INVALID
+ *          on failure; call SDL_GetError() for more information.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.4.0.
+ */
+extern SDL_DECLSPEC SDL_PenDeviceType SDLCALL SDL_GetPenDeviceType(SDL_PenID instance_id);
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include <SDL3/SDL_close_code.h>
+
+#endif /* SDL_pen_h_ */
+