From 0ad3a1893790115e926d38a7add534d3712342b1 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 28 Dec 2024 14:57:14 -0500
Subject: [PATCH] uikit: reworked Apple Pencil code.
This manages axes correctly across events, sorts out the math to convert from
Apple's data to what SDL expects, and a few other tweaks and corrections.
---
src/video/uikit/SDL_uikitpen.h | 8 +-
src/video/uikit/SDL_uikitpen.m | 164 +++++++++++++++++++++++++-------
src/video/uikit/SDL_uikitview.m | 8 +-
3 files changed, 137 insertions(+), 43 deletions(-)
diff --git a/src/video/uikit/SDL_uikitpen.h b/src/video/uikit/SDL_uikitpen.h
index c63df2c2857b6..ffcfd0f57eab1 100644
--- a/src/video/uikit/SDL_uikitpen.h
+++ b/src/video/uikit/SDL_uikitpen.h
@@ -26,12 +26,14 @@
#include "SDL_uikitwindow.h"
extern bool UIKit_InitPen(SDL_VideoDevice *_this);
-extern void UIKit_HandlePenEnter();
-extern void UIKit_HandlePenLeave();
-extern void UIKit_HandlePenHover(SDL_uikitview *view, CGPoint point);
extern void UIKit_HandlePenMotion(SDL_uikitview *view, UITouch *pencil);
extern void UIKit_HandlePenPress(SDL_uikitview *view, UITouch *pencil);
extern void UIKit_HandlePenRelease(SDL_uikitview *view, UITouch *pencil);
+
+#if !defined(SDL_PLATFORM_TVOS) && defined(__IPHONE_13_0)
+extern void UIKit_HandlePenHover(SDL_uikitview *view, UIHoverGestureRecognizer *recognizer) API_AVAILABLE(ios(13.0));
+#endif
+
extern void UIKit_QuitPen(SDL_VideoDevice *_this);
#endif // SDL_uikitpen_h_
diff --git a/src/video/uikit/SDL_uikitpen.m b/src/video/uikit/SDL_uikitpen.m
index bfa62ebc00679..6a26e46cc80e4 100644
--- a/src/video/uikit/SDL_uikitpen.m
+++ b/src/video/uikit/SDL_uikitpen.m
@@ -28,66 +28,162 @@
#include "../../events/SDL_pen_c.h"
-SDL_PenID penId;
-
-typedef struct UIKit_PenHandle
-{
- SDL_PenID pen;
-} UIKit_PenHandle;
+static SDL_PenID apple_pencil_id = 0;
bool UIKit_InitPen(SDL_VideoDevice *_this)
{
return true;
}
-void UIKit_HandlePenEnter()
+// 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()
{
- SDL_PenInfo penInfo;
- SDL_zero(penInfo);
- penInfo.capabilities = SDL_PEN_CAPABILITY_PRESSURE | SDL_PEN_CAPABILITY_ROTATION | SDL_PEN_CAPABILITY_XTILT | SDL_PEN_CAPABILITY_YTILT | SDL_PEN_CAPABILITY_TANGENTIAL_PRESSURE;
- penInfo.max_tilt = 90.0f;
- penInfo.num_buttons = 0;
- penInfo.subtype = SDL_PEN_TYPE_PENCIL;
-
- // probably make this better
- penId = SDL_AddPenDevice(0, [@"Apple Pencil" UTF8String], &penInfo, calloc(1, sizeof(UIKit_PenHandle)));
+ 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;
}
-void UIKit_HandlePenHover(SDL_uikitview *view, CGPoint point)
+static void UIKit_HandlePenAxes(SDL_Window *window, NSTimeInterval nstimestamp, float zOffset, const CGPoint *point, float force,
+ float maximumPossibleForce, float azimuthAngleInView, float altitudeAngle, float rollAngle)
{
- SDL_SendPenMotion(0, penId, [view getSDLWindow], point.x, point.y);
+ 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);
+ }
}
-void UIKit_HandlePenMotion(SDL_uikitview *view, UITouch *pencil)
+#if !defined(SDL_PLATFORM_TVOS) && defined(__IPHONE_13_0)
+extern void UIKit_HandlePenHover(SDL_uikitview *view, UIHoverGestureRecognizer *recognizer)
{
- CGPoint point = [pencil locationInView:view];
- SDL_SendPenMotion(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], point.x, point.y);
- SDL_SendPenAxis(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], SDL_PEN_AXIS_PRESSURE, [pencil force] / [pencil maximumPossibleForce]);
- NSLog(@"ALTITUDE: %f", [pencil altitudeAngle]);
- NSLog(@"AZIMUTH VECTOR: %@", [NSValue valueWithCGVector: [pencil azimuthUnitVectorInView:view]]);
- NSLog(@"AZIMUTH ANGLE: %f", [pencil azimuthAngleInView:view]);
- // hold it
- // SDL_SendPenAxis(0, penId, [view getSDLWindow], SDL_PEN_AXIS_XTILT, [pencil altitudeAngle] / M_PI);
+ 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
-void UIKit_HandlePenPress(SDL_uikitview *view, UITouch *pencil)
+static void UIKit_HandlePenAxesFromUITouch(SDL_uikitview *view, UITouch *pencil)
{
- SDL_SendPenTouch(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], false, true);
+ 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_HandlePenRelease(SDL_uikitview *view, UITouch *pencil)
+void UIKit_HandlePenMotion(SDL_uikitview *view, UITouch *pencil)
{
- SDL_SendPenTouch(UIKit_GetEventTimestamp([pencil timestamp]), penId, [view getSDLWindow], false, false);
+ UIKit_HandlePenAxesFromUITouch(view, pencil);
}
-void UIKit_HandlePenLeave()
+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)
{
- SDL_RemovePenDevice(0, penId);
- penId = 0;
+ 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
diff --git a/src/video/uikit/SDL_uikitview.m b/src/video/uikit/SDL_uikitview.m
index b5629517ea711..82d66adef2346 100644
--- a/src/video/uikit/SDL_uikitview.m
+++ b/src/video/uikit/SDL_uikitview.m
@@ -261,17 +261,13 @@ - (void)pencilHovering:(UIHoverGestureRecognizer *)recognizer API_AVAILABLE(ios(
{
switch (recognizer.state) {
case UIGestureRecognizerStateBegan:
- UIKit_HandlePenEnter();
- UIKit_HandlePenHover(self, [recognizer locationInView:self]);
- break;
-
case UIGestureRecognizerStateChanged:
- UIKit_HandlePenHover(self, [recognizer locationInView:self]);
+ UIKit_HandlePenHover(self, recognizer);
break;
case UIGestureRecognizerStateEnded:
case UIGestureRecognizerStateCancelled:
- UIKit_HandlePenLeave();
+ // we track touches elsewhere, so if a hover "ends" we'll deal with that there.
break;
default: