1 files changed, 214 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/src/video/uikit/SDL_uikitpen.m b/contrib/SDL-3.2.8/src/video/uikit/SDL_uikitpen.m
new file mode 100644
index 0000000..5209681
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+++ b/contrib/SDL-3.2.8/src/video/uikit/SDL_uikitpen.m
@@ -0,0 +1,214 @@
+/*
+  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.
+*/
+#include "SDL_internal.h"
+
+#ifdef SDL_VIDEO_DRIVER_UIKIT
+
+#include "SDL_uikitevents.h"
+#include "SDL_uikitpen.h"
+#include "SDL_uikitwindow.h"
+
+#include "../../events/SDL_pen_c.h"
+
+// Fix build errors when using an older SDK by defining these selectors
+#if !defined(SDL_PLATFORM_TVOS)
+
+@interface UITouch (SDL)
+#if !(__IPHONE_OS_VERSION_MAX_ALLOWED >= 170500)
+@property (nonatomic, readonly) CGFloat rollAngle;
+#endif
+@end
+
+@interface UIHoverGestureRecognizer (SDL)
+#if !(__IPHONE_OS_VERSION_MAX_ALLOWED >= 160100)
+@property (nonatomic, readonly) CGFloat zOffset;
+#endif
+#if !(__IPHONE_OS_VERSION_MAX_ALLOWED >= 160400)
+- (CGFloat) azimuthAngleInView:(UIView *) view;
+
+@property (nonatomic, readonly) CGFloat altitudeAngle;
+#endif
+#if !(__IPHONE_OS_VERSION_MAX_ALLOWED >= 170500)
+@property (nonatomic, readonly) CGFloat rollAngle;
+#endif
+@end
+
+#endif // !SDL_PLATFORM_TVOS
+
+static SDL_PenID apple_pencil_id = 0;
+
+bool UIKit_InitPen(SDL_VideoDevice *_this)
+{
+    return true;
+}
+
+// we only have one Apple Pencil at a time, and it must be paired to the iOS device.
+// We only know about its existence when it first sends an event, so add an single SDL pen
+// device here if we haven't already.
+static SDL_PenID UIKit_AddPenIfNecesary()
+{
+    if (!apple_pencil_id) {
+        SDL_PenInfo info;
+        SDL_zero(info);
+        info.capabilities = SDL_PEN_CAPABILITY_PRESSURE | SDL_PEN_CAPABILITY_XTILT | SDL_PEN_CAPABILITY_YTILT;
+        info.max_tilt = 90.0f;
+        info.num_buttons = 0;
+        info.subtype = SDL_PEN_TYPE_PENCIL;
+
+        if (@available(iOS 17.5, *)) {  // need rollAngle method.
+            info.capabilities |= SDL_PEN_CAPABILITY_ROTATION;
+        }
+
+        if (@available(ios 16.1, *)) {  // need zOffset method.
+            info.capabilities |= SDL_PEN_CAPABILITY_DISTANCE;
+        }
+
+        // Apple Pencil and iOS can report when the pencil is being "squeezed" but it's a boolean thing,
+        // so we can't use it for tangential pressure.
+
+        // There's only ever one Apple Pencil at most, so we just pass a non-zero value for the handle.
+        apple_pencil_id = SDL_AddPenDevice(0, "Apple Pencil", &info, (void *) (size_t) 0x1);
+    }
+
+    return apple_pencil_id;
+}
+
+static void UIKit_HandlePenAxes(SDL_Window *window, NSTimeInterval nstimestamp, float zOffset, const CGPoint *point, float force,
+                                float maximumPossibleForce, float azimuthAngleInView, float altitudeAngle, float rollAngle)
+{
+    const SDL_PenID penId = UIKit_AddPenIfNecesary();
+    if (penId) {
+        const Uint64 timestamp = UIKit_GetEventTimestamp(nstimestamp);
+        const float radians_to_degrees = 180.0f / SDL_PI_F;
+
+        // Normalize force to 0.0f ... 1.0f range.
+        const float pressure = force / maximumPossibleForce;
+
+        // azimuthAngleInView is in radians, with 0 being the pen's back end pointing due east on the screen when the
+        // tip is touching the screen, and negative when heading north from there, positive to the south.
+        // So convert to degrees, 0 being due east, etc.
+        const float azimuth_angle = azimuthAngleInView * radians_to_degrees;
+
+        // altitudeAngle is in radians, with 0 being the pen laying flat on (parallel to) the device
+        //  screen and PI/2 being it pointing straight up from (perpendicular to) the device screen.
+        // So convert to degrees, 0 being flat and 90 being straight up.
+        const float altitude_angle = altitudeAngle * radians_to_degrees;
+
+        // the azimuth_angle goes from -180 to 180 (with abs(angle) moving from 180 to 0, left to right), but SDL wants
+        // it from -90 (back facing west) to 90 (back facing east).
+        const float xtilt = (180.0f - SDL_fabsf(azimuth_angle)) - 90.0f;
+
+        // the altitude_angle goes from 0 to 90 regardless of which direction the pen is lifting off the device, but SDL wants
+        // it from -90 (flat facing north) to 90 (flat facing south).
+        const float ytilt = (azimuth_angle < 0.0f) ? -(90.0f - altitude_angle) : (90.0f - altitude_angle);
+
+        // rotation is in radians, and only available on a later iOS.
+        const float rotation = rollAngle * radians_to_degrees;  // !!! FIXME: this might need adjustment, I don't have a pencil that supports it.
+
+        SDL_SendPenMotion(timestamp, penId, window, point->x, point->y);
+        SDL_SendPenAxis(timestamp, penId, window, SDL_PEN_AXIS_PRESSURE, pressure);
+        SDL_SendPenAxis(timestamp, penId, window, SDL_PEN_AXIS_XTILT, xtilt);
+        SDL_SendPenAxis(timestamp, penId, window, SDL_PEN_AXIS_YTILT, ytilt);
+        SDL_SendPenAxis(timestamp, penId, window, SDL_PEN_AXIS_ROTATION, rotation);
+        SDL_SendPenAxis(timestamp, penId, window, SDL_PEN_AXIS_DISTANCE, zOffset);
+    }
+}
+
+#if !defined(SDL_PLATFORM_TVOS)
+extern void UIKit_HandlePenHover(SDL_uikitview *view, UIHoverGestureRecognizer *recognizer)
+{
+    float zOffset = 0.0f;
+    if (@available(iOS 16.1, *)) {
+        zOffset = (float) [recognizer zOffset];
+    }
+
+    float azimuthAngleInView = 0.0f;
+    if (@available(iOS 16.4, *)) {
+        azimuthAngleInView = (float) [recognizer azimuthAngleInView:view];
+    }
+
+    float altitudeAngle = 0.0f;
+    if (@available(iOS 16.4, *)) {
+        altitudeAngle = (float) [recognizer altitudeAngle];
+    }
+
+    float rollAngle = 0.0f;
+    if (@available(iOS 17.5, *)) {
+        rollAngle = (float) [recognizer rollAngle];
+    }
+
+    SDL_Window *window = [view getSDLWindow];
+    const CGPoint point = [recognizer locationInView:view];
+
+    // force is zero here; if you're here, you're not touching.
+    // !!! FIXME: no timestamp on these...?
+    UIKit_HandlePenAxes(window, 0, zOffset, &point, 0.0f, 1.0f, azimuthAngleInView, altitudeAngle, rollAngle);
+}
+#endif
+
+static void UIKit_HandlePenAxesFromUITouch(SDL_uikitview *view, UITouch *pencil)
+{
+    float rollAngle = 0.0f;
+#if !defined(SDL_PLATFORM_TVOS)
+    if (@available(iOS 17.5, *)) {
+        rollAngle = (float) [pencil rollAngle];
+    }
+#endif
+
+    SDL_Window *window = [view getSDLWindow];
+    const CGPoint point = [pencil locationInView:view];
+
+    // zOffset is zero here; if you're here, you're touching.
+    UIKit_HandlePenAxes(window, [pencil timestamp], 0.0f, &point, [pencil force], [pencil maximumPossibleForce], [pencil azimuthAngleInView:view], [pencil altitudeAngle], rollAngle);
+}
+
+void UIKit_HandlePenMotion(SDL_uikitview *view, UITouch *pencil)
+{
+    UIKit_HandlePenAxesFromUITouch(view, pencil);
+}
+
+void UIKit_HandlePenPress(SDL_uikitview *view, UITouch *pencil)
+{
+    const SDL_PenID penId = UIKit_AddPenIfNecesary();
+    if (penId) {
+        UIKit_HandlePenAxesFromUITouch(view, pencil);
+        SDL_SendPenTouch(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], false, true);
+    }
+}
+
+void UIKit_HandlePenRelease(SDL_uikitview *view, UITouch *pencil)
+{
+    const SDL_PenID penId = UIKit_AddPenIfNecesary();
+    if (penId) {
+        SDL_SendPenTouch(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], false, false);
+        UIKit_HandlePenAxesFromUITouch(view, pencil);
+    }
+}
+
+void UIKit_QuitPen(SDL_VideoDevice *_this)
+{
+    if (apple_pencil_id) {
+        SDL_RemovePenDevice(0, apple_pencil_id);
+        apple_pencil_id = 0;
+    }
+}
+
+#endif // SDL_VIDEO_DRIVER_UIKIT