TouchInputHandler.cpp

#include "stdafx.h"
#include <Windows.h>
#include "Windows/TouchInputHandler.h"

#include <algorithm>

#include "Common/System/Display.h"
#include "Common/System/NativeApp.h"

#include "Common/CommonWindows.h"
#include "Common/CommonFuncs.h"
#include "Common/Input/InputState.h"
#include "Common/Log.h"
#include "Common/SysError.h"
#include "Windows/MainWindow.h"

TouchInputHandler::TouchInputHandler() {
	HMODULE user32 = GetModuleHandle(TEXT("User32.dll"));
	if (!user32)
		return;
	touchInfo = (getTouchInputProc)GetProcAddress(user32, "GetTouchInputInfo");
	closeTouch = (closeTouchInputProc)GetProcAddress(user32, "CloseTouchInputHandle");
	registerTouch = (registerTouchProc)GetProcAddress(user32, "RegisterTouchWindow");
}

int TouchInputHandler::ToTouchID(int windowsID, bool allowAllocate) {
	// Find the id for the touch.  Avoid 0 (mouse.)
	for (int localId = 1; localId < (int)ARRAY_SIZE(touchIds); ++localId) {
		if (touchIds[localId] == windowsID) {
			return localId;
		}
	}

	// Allocate a new one, perhaps?
	if (allowAllocate) {
		for (int localId = 1; localId < (int)ARRAY_SIZE(touchIds); ++localId) {
			if (touchIds[localId] == 0) {
				touchIds[localId] = windowsID;
				return localId;
			}
		}

		// None were free.
		// TODO: Better to just ignore this touch instead?
		touchUp(0, 0, 0);
		return 0;
	}

	return -1;
}

bool TouchInputHandler::GetTouchPoint(HWND hWnd, const TOUCHINPUT &input, float &x, float &y) {
	POINT point;
	point.x = (LONG)(TOUCH_COORD_TO_PIXEL(input.x));
	point.y = (LONG)(TOUCH_COORD_TO_PIXEL(input.y));
	if (ScreenToClient(hWnd, &point)) {
		x = point.x * g_display.dpi_scale_x;
		y = point.y * g_display.dpi_scale_y;
		return true;
	}

	return false;
}

void TouchInputHandler::handleTouchEvent(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	if (hasTouch()) {
		UINT inputCount = LOWORD(wParam);
		HTOUCHINPUT touchInputData = (HTOUCHINPUT)lParam;
		TOUCHINPUT *inputs = new TOUCHINPUT[inputCount];
		if (touchInfo(touchInputData, inputCount, inputs, sizeof(TOUCHINPUT))) {
			for (UINT i = 0; i < inputCount; i++) {
				float x, y;
				if (!GetTouchPoint(hWnd, inputs[i], x, y))
					continue;

				if (inputs[i].dwFlags & TOUCHEVENTF_DOWN) {
					touchDown(ToTouchID(inputs[i].dwID), x, y);
				}
				if (inputs[i].dwFlags & TOUCHEVENTF_MOVE) {
					touchMove(ToTouchID(inputs[i].dwID), x, y);
				}
				if (inputs[i].dwFlags & TOUCHEVENTF_UP) {
					int id = ToTouchID(inputs[i].dwID, false);
					if (id >= 0) {
						touchUp(id, x, y);
						touchIds[id] = 0;
					}
				}
			}
			closeTouch(touchInputData);
		} else {
			WARN_LOG(Log::System, "Failed to read input data: %s", GetLastErrorMsg().c_str());
		}
		delete [] inputs;
	}
}

// from http://msdn.microsoft.com/en-us/library/ms812373.aspx
// disable the press and hold gesture for the given window
void TouchInputHandler::disablePressAndHold(HWND hWnd) {
	// The atom identifier and Tablet PC atom
	LPCTSTR tabletAtom = _T("MicrosoftTabletPenServiceProperty");
	ATOM atomID = GlobalAddAtom(tabletAtom);
	
	// If getting the ID failed, return false
	if (atomID != 0) {
		// Try to disable press and hold gesture by setting the window property.
		SetProp(hWnd, tabletAtom, (HANDLE)1);
	}

	GlobalDeleteAtom(atomID);
}

void TouchInputHandler::touchUp(int id, float x, float y){
	TouchInput touchevent;
	touchevent.id = id;
	touchevent.x = x;
	touchevent.y = y;
	touchevent.flags = TOUCH_UP;
	NativeTouch(touchevent);
}

void TouchInputHandler::touchDown(int id, float x, float y){
	TouchInput touchevent;
	touchevent.id = id;
	touchevent.x = x;
	touchevent.y = y;
	touchevent.flags = TOUCH_DOWN;
	NativeTouch(touchevent);
}

void TouchInputHandler::touchMove(int id, float x, float y){
	TouchInput touchevent;
	touchevent.id = id;
	touchevent.x = x;
	touchevent.y = y;
	touchevent.flags = TOUCH_MOVE;
	NativeTouch(touchevent);
}

void TouchInputHandler::registerTouchWindow(HWND wnd)
{
	if (hasTouch())
	{
		registerTouch(wnd, TWF_WANTPALM);
		disablePressAndHold(wnd);
	}
}

bool TouchInputHandler::hasTouch(){
	return (
		touchInfo		!= nullptr &&
		closeTouch		!= nullptr &&
		registerTouch	!= nullptr
		);
}