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x11: Implement precision/pixel scrolling

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Manual rebase of #5382 with some changes for SDL3 (thanks @wooosh).
This commit is contained in:
Frank Praznik
2025-08-02 17:31:41 -04:00
parent 23e08f7807
commit 483b8d4d98
6 changed files with 247 additions and 37 deletions
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11
cmake/sdlchecks.cmake
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@@ -416,6 +416,17 @@ macro(CheckX11)
endif()
set(SDL_VIDEO_DRIVER_X11_XINPUT2 1)
# Check for scroll info
check_c_source_compiles("
#include <X11/Xlib.h>
#include <X11/Xproto.h>
#include <X11/extensions/XInput2.h>
XIScrollClassInfo *s;
int main(int argc, char **argv) {}" HAVE_XINPUT2_SCROLLINFO)
if(HAVE_XINPUT2_SCROLLINFO)
set(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO 1)
endif()
# Check for multitouch
check_c_source_compiles_static("
#include <X11/Xlib.h>

1
include/build_config/SDL_build_config.h.cmake
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@@ -429,6 +429,7 @@
#cmakedefine SDL_VIDEO_DRIVER_X11_XFIXES 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XRANDR 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XSCRNSAVER 1
#cmakedefine SDL_VIDEO_DRIVER_X11_XSHAPE 1

1
src/video/x11/SDL_x11video.c
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@@ -468,6 +468,7 @@ void X11_VideoQuit(SDL_VideoDevice *_this)
}
#endif
X11_QuitXinput2(_this);
X11_QuitModes(_this);
X11_QuitKeyboard(_this);
X11_QuitMouse(_this);

2
src/video/x11/SDL_x11window.c
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@@ -475,7 +475,7 @@ static void SetupWindowInput(SDL_VideoDevice *_this, SDL_Window *window)
}
#endif
X11_Xinput2SelectTouch(_this, window);
X11_Xinput2Select(_this, window);
{
unsigned int x11_keyboard_events = KeyPressMask | KeyReleaseMask;

265
src/video/x11/SDL_x11xinput2.c
View File

@@ -45,6 +45,28 @@ static bool xinput2_multitouch_supported;
* this extension */
static int xinput2_opcode;
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
typedef struct
{
int number;
int scroll_type;
double prev_value;
double increment;
bool prev_value_valid;
} SDL_XInput2ScrollInfo;
typedef struct
{
int device_id;
int scroll_info_count;
SDL_XInput2ScrollInfo *scroll_info;
} SDL_XInput2ScrollableDevice;
static SDL_XInput2ScrollableDevice *scrollable_devices;
static int scrollable_device_count;
static bool xinput2_scrolling_supported;
#endif
static void parse_valuators(const double *input_values, const unsigned char *mask, int mask_len,
double *output_values, int output_values_len)
{
@@ -95,6 +117,62 @@ static SDL_Window *xinput2_get_sdlwindow(SDL_VideoData *videodata, Window window
return windowdata ? windowdata->window : NULL;
}
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
static void xinput2_reset_scrollable_valuators(SDL_VideoData *videodata)
{
for (int i = 0; i < scrollable_device_count; ++i) {
for (int j = 0; j < scrollable_devices[i].scroll_info_count; ++j) {
scrollable_devices[i].scroll_info[j].prev_value_valid = false;
}
}
}
static void xinput2_parse_scrollable_valuators(const XIDeviceEvent *xev)
{
for (int i = 0; i < scrollable_device_count; ++i) {
const SDL_XInput2ScrollableDevice *sd = &scrollable_devices[i];
if (xev->sourceid == sd->device_id) {
int values_i = 0;
for (int j = 0; j < xev->valuators.mask_len * 8; ++j) {
if (!XIMaskIsSet(xev->valuators.mask, j)) {
continue;
}
for (int k = 0; k < sd->scroll_info_count; ++k) {
SDL_XInput2ScrollInfo *info = &sd->scroll_info[k];
if (info->number == j) {
const double current_val = xev->valuators.values[values_i];
const double delta = (info->prev_value - current_val) / info->increment;
/* Ignore very large jumps that can happen as a result of overflowing
* the maximum range, as the driver will reset the position to zero
* at "something that's close to 2^32".
*
* The first scroll event is meaningless by itself and must be discarded,
* as it is only useful for establishing a baseline for future deltas.
* This is a known deficiency of the XInput2 scroll protocol, and,
* unfortunately, there is nothing we can do about it.
*
* http://who-t.blogspot.com/2012/06/xi-21-protocol-design-issues.html
*/
if (info->prev_value_valid && SDL_fabs(delta) < (double)SDL_MAX_SINT32 * 0.95) {
const double x = info->scroll_type == XIScrollTypeHorizontal ? delta : 0;
const double y = info->scroll_type == XIScrollTypeVertical ? delta : 0;
SDL_Mouse *mouse = SDL_GetMouse();
SDL_SendMouseWheel(xev->time, mouse->focus, (SDL_MouseID)xev->sourceid, (float)x, (float)y, SDL_MOUSEWHEEL_NORMAL);
}
info->prev_value = current_val;
info->prev_value_valid = true;
}
}
++values_i;
}
}
}
}
#endif // SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
static void xinput2_normalize_touch_coordinates(SDL_Window *window, double in_x, double in_y, float *out_x, float *out_y)
{
@@ -119,6 +197,24 @@ static void xinput2_normalize_touch_coordinates(SDL_Window *window, double in_x,
#endif // SDL_VIDEO_DRIVER_X11_XINPUT2
static bool X11_Xinput2IsMultitouchSupported(void)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
return xinput2_initialized && xinput2_multitouch_supported;
#else
return false;
#endif
}
static bool X11_Xinput2IsScrollingSupported(void)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
return xinput2_initialized && xinput2_scrolling_supported;
#else
return false;
#endif
}
bool X11_InitXinput2(SDL_VideoDevice *_this)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
@@ -126,7 +222,7 @@ bool X11_InitXinput2(SDL_VideoDevice *_this)
int version = 0;
XIEventMask eventmask;
unsigned char mask[4] = { 0, 0, 0, 0 };
unsigned char mask[5] = { 0, 0, 0, 0, 0 };
int event, err;
/* XInput2 is required for relative mouse mode, so you probably want to leave this enabled */
@@ -156,6 +252,10 @@ bool X11_InitXinput2(SDL_VideoDevice *_this)
xinput2_initialized = true;
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO // Smooth scrolling needs XInput 2.1
xinput2_scrolling_supported = xinput2_version_atleast(version, 2, 1);
#endif
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH // Multitouch needs XInput 2.2
xinput2_multitouch_supported = xinput2_version_atleast(version, 2, 2);
#endif
@@ -171,6 +271,12 @@ bool X11_InitXinput2(SDL_VideoDevice *_this)
XISetMask(mask, XI_RawButtonPress);
XISetMask(mask, XI_RawButtonRelease);
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
if (X11_Xinput2IsScrollingSupported()) {
XISetMask(mask, XI_Motion);
}
#endif
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
// Enable raw touch events if supported
if (X11_Xinput2IsMultitouchSupported()) {
@@ -199,6 +305,18 @@ bool X11_InitXinput2(SDL_VideoDevice *_this)
#endif
}
void X11_QuitXinput2(SDL_VideoDevice *_this)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
for (int i = 0; i < scrollable_device_count; ++i) {
SDL_free(scrollable_devices[i].scroll_info);
}
SDL_free(scrollable_devices);
scrollable_devices = NULL;
scrollable_device_count = 0;
#endif
}
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
// xi2 device went away? take it out of the list.
static void xinput2_remove_device_info(SDL_VideoData *videodata, const int device_id)
@@ -409,6 +527,11 @@ void X11_HandleXinput2Event(SDL_VideoDevice *_this, XGenericEventCookie *cookie)
X11_PenHandle *pen = X11_FindPenByDeviceID(xev->sourceid);
const int button = xev->detail;
const bool down = (cookie->evtype == XI_ButtonPress);
#if defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO) || defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH)
bool pointer_emulated = (xev->flags & XIPointerEmulated) != 0;
#else
bool pointer_emulated = false;
#endif
if (pen) {
if (xev->deviceid != xev->sourceid) {
@@ -429,8 +552,12 @@ void X11_HandleXinput2Event(SDL_VideoDevice *_this, XGenericEventCookie *cookie)
/* Discard wheel events from "Master" devices to avoid duplicates,
* as coarse wheel events are stateless and can't be deduplicated.
*
* If the pointer emulation flag is set on a wheel event, it is being
* emulated from a scroll valuator, which will be handled natively.
*/
if (xev->deviceid != xev->sourceid && X11_IsWheelEvent(button, &x_ticks, &y_ticks)) {
if ((pointer_emulated || xev->deviceid != xev->sourceid) &&
X11_IsWheelEvent(button, &x_ticks, &y_ticks)) {
break;
}
@@ -443,13 +570,19 @@ void X11_HandleXinput2Event(SDL_VideoDevice *_this, XGenericEventCookie *cookie)
}
} break;
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
case XI_Enter:
xinput2_reset_scrollable_valuators(videodata);
break;
#endif
/* Register to receive XI_Motion (which deactivates MotionNotify), so that we can distinguish
real mouse motions from synthetic ones, for multitouch and pen support. */
case XI_Motion:
{
const XIDeviceEvent *xev = (const XIDeviceEvent *)cookie->data;
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
bool pointer_emulated = ((xev->flags & XIPointerEmulated) != 0);
#if defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO) || defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH)
bool pointer_emulated = (xev->flags & XIPointerEmulated) != 0;
#else
bool pointer_emulated = false;
#endif
@@ -475,14 +608,22 @@ void X11_HandleXinput2Event(SDL_VideoDevice *_this, XGenericEventCookie *cookie)
SDL_SendPenAxis(0, pen->pen, window, (SDL_PenAxis) i, axes[i]);
}
}
} else if (!pointer_emulated && xev->deviceid == videodata->xinput_master_pointer_device) {
// Use the master device for non-relative motion, as the slave devices can seemingly lag behind.
SDL_Mouse *mouse = SDL_GetMouse();
if (!mouse->relative_mode) {
SDL_Window *window = xinput2_get_sdlwindow(videodata, xev->event);
if (window) {
X11_ProcessHitTest(_this, window->internal, (float)xev->event_x, (float)xev->event_y, false);
SDL_SendMouseMotion(0, window, SDL_GLOBAL_MOUSE_ID, false, (float)xev->event_x, (float)xev->event_y);
} else if (!pointer_emulated) {
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
if (xev->deviceid == xev->sourceid) {
xinput2_parse_scrollable_valuators(xev);
}
#endif
if (xev->deviceid == videodata->xinput_master_pointer_device) {
// Use the master device for non-relative motion, as the slave devices can seemingly lag behind.
SDL_Mouse *mouse = SDL_GetMouse();
if (!mouse->relative_mode) {
SDL_Window *window = xinput2_get_sdlwindow(videodata, xev->event);
if (window) {
X11_ProcessHitTest(_this, window->internal, (float)xev->event_x, (float)xev->event_y, false);
SDL_SendMouseMotion(0, window, SDL_GLOBAL_MOUSE_ID, false, (float)xev->event_x, (float)xev->event_y);
}
}
}
}
@@ -524,29 +665,36 @@ void X11_InitXinput2Multitouch(SDL_VideoDevice *_this)
{
}
void X11_Xinput2SelectTouch(SDL_VideoDevice *_this, SDL_Window *window)
void X11_Xinput2Select(SDL_VideoDevice *_this, SDL_Window *window)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
SDL_VideoData *data = NULL;
#if defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO) || defined(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH)
SDL_VideoData *data = _this->internal;
SDL_WindowData *window_data = window->internal;
XIEventMask eventmask;
unsigned char mask[4] = { 0, 0, 0, 0 };
SDL_WindowData *window_data = NULL;
unsigned char mask[5] = { 0, 0, 0, 0, 0 };
if (!X11_Xinput2IsMultitouchSupported()) {
if (!X11_Xinput2IsScrollingSupported() && !X11_Xinput2IsMultitouchSupported()) {
return;
}
data = _this->internal;
window_data = window->internal;
eventmask.deviceid = XIAllMasterDevices;
eventmask.mask_len = sizeof(mask);
eventmask.mask = mask;
XISetMask(mask, XI_TouchBegin);
XISetMask(mask, XI_TouchUpdate);
XISetMask(mask, XI_TouchEnd);
XISetMask(mask, XI_Motion);
if (X11_Xinput2IsScrollingSupported()) {
/* Track enter events that inform us that we need to update
* the previous scroll coordinates since we cannot track
* them outside our window.
*/
XISetMask(mask, XI_Enter);
}
if (X11_Xinput2IsMultitouchSupported()) {
XISetMask(mask, XI_TouchBegin);
XISetMask(mask, XI_TouchUpdate);
XISetMask(mask, XI_TouchEnd);
XISetMask(mask, XI_Motion);
}
X11_XISelectEvents(data->display, window_data->xwindow, &eventmask, 1);
#endif
@@ -610,15 +758,6 @@ bool X11_Xinput2SelectMouseAndKeyboard(SDL_VideoDevice *_this, SDL_Window *windo
return false;
}
bool X11_Xinput2IsMultitouchSupported(void)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
return xinput2_initialized && xinput2_multitouch_supported;
#else
return true;
#endif
}
void X11_Xinput2GrabTouch(SDL_VideoDevice *_this, SDL_Window *window)
{
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
@@ -748,6 +887,16 @@ void X11_Xinput2UpdateDevices(SDL_VideoDevice *_this, bool initial_check)
old_mice = SDL_GetMice(&old_mouse_count);
old_touch_devices = SDL_GetTouchDevices(&old_touch_count);
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
// Scroll devices don't get add/remove events, so just rebuild the list.
for (int i = 0; i < scrollable_device_count; ++i) {
SDL_free(scrollable_devices[i].scroll_info);
}
SDL_free(scrollable_devices);
scrollable_devices = NULL;
scrollable_device_count = 0;
#endif
for (int i = 0; i < ndevices; i++) {
XIDeviceInfo *dev = &info[i];
@@ -778,6 +927,54 @@ void X11_Xinput2UpdateDevices(SDL_VideoDevice *_this, bool initial_check)
break;
}
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO
SDL_XInput2ScrollableDevice *sd = NULL;
int allocated_scroll_info_count = 0;
for (int j = 0; j < dev->num_classes; j++) {
const XIAnyClassInfo *class = dev->classes[j];
const XIScrollClassInfo *s = (XIScrollClassInfo *)class;
if (class->type != XIScrollClass) {
continue;
}
// Allocate a new scrollable device.
if (!sd) {
scrollable_devices = SDL_realloc(scrollable_devices, (scrollable_device_count + 1) * sizeof(SDL_XInput2ScrollableDevice));
if (!scrollable_devices) {
// No memory; so just skip this.
break;
}
sd = &scrollable_devices[scrollable_device_count];
++scrollable_device_count;
SDL_zerop(sd);
sd->device_id = dev->deviceid;
}
// Allocate new scroll info entries two at a time, as they typically come in a horizontal/vertical pair.
if (sd->scroll_info_count == allocated_scroll_info_count) {
sd->scroll_info = SDL_realloc(sd->scroll_info, (allocated_scroll_info_count + 2) * sizeof(SDL_XInput2ScrollInfo));
if (!sd->scroll_info) {
// No memory; just skip this.
break;
}
allocated_scroll_info_count += 2;
}
SDL_XInput2ScrollInfo *scroll_info = &sd->scroll_info[sd->scroll_info_count];
++sd->scroll_info_count;
SDL_zerop(scroll_info);
scroll_info->number = s->number;
scroll_info->scroll_type = s->scroll_type;
scroll_info->increment = s->increment;
}
#endif
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
for (int j = 0; j < dev->num_classes; j++) {
Uint64 touchID;

4
src/video/x11/SDL_x11xinput2.h
View File

@@ -31,11 +31,11 @@ typedef struct XGenericEventCookie XGenericEventCookie;
#endif
extern bool X11_InitXinput2(SDL_VideoDevice *_this);
extern void X11_QuitXinput2(SDL_VideoDevice *_this);
extern void X11_InitXinput2Multitouch(SDL_VideoDevice *_this);
extern void X11_HandleXinput2Event(SDL_VideoDevice *_this, XGenericEventCookie *cookie);
extern bool X11_Xinput2IsInitialized(void);
extern bool X11_Xinput2IsMultitouchSupported(void);
extern void X11_Xinput2SelectTouch(SDL_VideoDevice *_this, SDL_Window *window);
extern void X11_Xinput2Select(SDL_VideoDevice *_this, SDL_Window *window);
extern void X11_Xinput2GrabTouch(SDL_VideoDevice *_this, SDL_Window *window);
extern void X11_Xinput2UngrabTouch(SDL_VideoDevice *_this, SDL_Window *window);
extern bool X11_Xinput2SelectMouseAndKeyboard(SDL_VideoDevice *_this, SDL_Window *window);