Add Touch events for win32. (#377)

* Add Touch events for win32.

* Add entry to CHANGELOG.md

CHANGELOG.md

@@ -4,6 +4,7 @@
 - Dead keys now work properly on X11, no longer resulting in a panic.
 - On X11, input method creation first tries to use the value from the user's `XMODIFIERS` environment variable, so application developers should no longer need to manually call `XSetLocaleModifiers`. If that fails, fallbacks are tried, which should prevent input method initialization from ever outright failing.
 - Fixed thread safety issues with input methods on X11.
+- Add support for `Touch` for win32 backend.
 
 # Version 0.11.3 (2018-03-28)
 

src/platform/windows/events_loop.rs

@@ -26,7 +26,7 @@ use std::sync::Mutex;
 use std::sync::Condvar;
 use std::thread;
 
-use winapi::shared::minwindef::{LOWORD, HIWORD, DWORD, WPARAM, LPARAM, UINT, LRESULT, MAX_PATH};
+use winapi::shared::minwindef::{LOWORD, HIWORD, DWORD, WPARAM, LPARAM, INT, UINT, LRESULT, MAX_PATH};
 use winapi::shared::windef::{HWND, POINT};
 use winapi::shared::windowsx;
 use winapi::um::{winuser, shellapi, processthreadsapi};
@@ -44,6 +44,8 @@ use KeyboardInput;
 use WindowAttributes;
 use WindowEvent;
 use WindowId as SuperWindowId;
+use events::{Touch, TouchPhase};
+
 
 /// Contains information about states and the window that the callback is going to use.
 #[derive(Clone)]
@@ -730,6 +732,40 @@ pub unsafe extern "system" fn callback(window: HWND, msg: UINT,
             }
         },
 
+        winuser::WM_TOUCH => {
+            let pcount = LOWORD( wparam as DWORD ) as usize;
+            let mut inputs = Vec::with_capacity( pcount );
+            inputs.set_len( pcount );
+            let htouch = lparam as winuser::HTOUCHINPUT;
+            if winuser::GetTouchInputInfo( htouch, pcount as UINT,
+                                           inputs.as_mut_ptr(),
+                                           mem::size_of::<winuser::TOUCHINPUT>() as INT ) > 0 {
+                for input in &inputs {
+                    send_event( Event::WindowEvent {
+                        window_id: SuperWindowId(WindowId(window)),
+                        event: WindowEvent::Touch(Touch {
+                            phase:
+                            if input.dwFlags & winuser::TOUCHEVENTF_DOWN != 0 {
+                                TouchPhase::Started
+                            } else if input.dwFlags & winuser::TOUCHEVENTF_UP != 0 {
+                                TouchPhase::Ended
+                            } else if input.dwFlags & winuser::TOUCHEVENTF_MOVE != 0 {
+                                TouchPhase::Moved
+                            } else {
+                                continue;
+                            },
+                            location: ((input.x as f64) / 100f64,
+                                       (input.y as f64) / 100f64),
+                            id: input.dwID as u64,
+                            device_id: DEVICE_ID,
+                        })
+                    });
+                }
+            }
+            winuser::CloseTouchInputHandle( htouch );
+            0
+        }
+
         winuser::WM_SETFOCUS => {
             use events::WindowEvent::{Focused, CursorMoved};
             send_event(Event::WindowEvent {

src/platform/windows/window.rs

@@ -473,6 +473,15 @@ unsafe fn init(window: WindowAttributes, pl_attribs: PlatformSpecificWindowBuild
         winuser::RegisterRawInputDevices(&rid, 1, mem::size_of::<winuser::RAWINPUTDEVICE>() as u32);
     }
 
+    // Register for touch events if applicable
+    {
+        let digitizer = winuser::GetSystemMetrics( winuser::SM_DIGITIZER ) as u32;
+        if digitizer & winuser::NID_READY != 0 {
+            winuser::RegisterTouchWindow( real_window.0, winuser::TWF_WANTPALM );
+        }
+    }
+    
+
     // Creating a mutex to track the current window state
     let window_state = Arc::new(Mutex::new(events_loop::WindowState {
         cursor: winuser::IDC_ARROW, // use arrow by default