Simple HID "driver" for the AIPTEK HyperPen model T-6000U using libHID

main.cpp

/*
 * Simple HID "driver" for the AIPTEK HyperPen model T-6000U using libHID
 * http://bfoz.github.io/libhid/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013 Roy Shilkrot
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include <iostream>
#include <iomanip>
using namespace std;

#include <unistd.h>

#include <ApplicationServices/ApplicationServices.h>

#include <hid.h>

HID::device_type* device;

void printElement(HID::element_type& el) {
	cout << "element " << el.name() <<
			" report: " << el.reportID() <<
			" typeName: " << el.typeName() <<
			" usage: " << el.usage() <<
			" \n";

	if(el.children().size() > 0) {
		HID::elements_type& els = el.children();
		for (int i = 0; i < els.size(); ++i) {
			printElement(*(els[i]));
		}
	}
}

/**
 * Connect to the AIPTEK tablet, using product and vendor IDs from Apple's USB Prober
 */
bool connectLIBHID() {
	HID::filter::And filters;
	filters.push_back(new HID::filter::vendorID(0x08CA));
	filters.push_back(new HID::filter::productID(0x0021));

	HID::device_list devices = HID::find(&filters);
	if (devices.size()) {
		device = devices.front();
		cout <<"found device: "<<device->manufacturer()<<"\n";

		for (int i = 0; i < device->elements().size(); ++i) {
			printElement(*(device->elements()[i]));
		}

		cout <<"open\n";
		if(!device->open(HID::ReadMode)) {
			cerr << "cannot open\n"; return false;
		} else {
			cout << "opened.\n";
			return true;
		}
	}
	return false;
}

void disconnectLIBHID() {
	cout << "disconnect\n";
    // We're finished with the device, so close it
    device->close();
}

/**
 * Emulate mouse movement and button clicks
 * https://developer.apple.com/library/mac/documentation/Carbon/Reference/QuartzEventServicesRef/Reference/reference.html#//apple_ref/doc/uid/TP40003550-CH202-BBCFCJGH
 *
 */
void mouse(int x, int y, uint32_t mouseButton, bool down) {
    CGPoint newloc;
    newloc.x = x;
    newloc.y = y;

    uint32_t mouseType_down = -1, mouseType_up = -1;
    if(mouseButton == kCGMouseButtonLeft) {
    	mouseType_down = kCGEventLeftMouseDown;
    	mouseType_up = kCGEventLeftMouseUp;
    } else {
    	mouseType_down = kCGEventOtherMouseDown;
    	mouseType_up = kCGEventOtherMouseUp;
    }

	CGEventType eventType = down ? mouseType_down : mouseType_up;
	CGEventRef eventRef = CGEventCreateMouseEvent(NULL, eventType, newloc, mouseButton);
    CGEventSetType(eventRef, eventType);
    CGEventPost(kCGSessionEventTap, eventRef);
    CFRelease(eventRef);
}

/*
 * Change mouse on-screen location
 */
int to(int x, int y, CGEventType eventType)
{
    CGPoint newloc;
    CGEventRef eventRef;
    newloc.x = x;
    newloc.y = y;

    eventRef = CGEventCreateMouseEvent(NULL, eventType, newloc, kCGMouseButtonLeft);
    CGEventSetType(eventRef, eventType);
    CGEventPost(kCGSessionEventTap, eventRef);
    CFRelease(eventRef);

    return 0;
}

int last_buf2 = -1;

/**
 * Poll the device for information, which should be flowing steadily
 * Parse the buffer for location and button commands
 *
 * unremark the cout-ings to see some debug info on the console.
 */
void pollLIBHID(void*) {
//	cout << "poll: ";tm
	HID::buffer_type buffer;

    device->read(buffer);

//	for (int i = 0; i < buffer.size(); ++i) cout << std::setw(5) << (int)buffer[i];
//	cout << "\n";

    //buffer[3] and buffer[4] (both uint_8) make a uint16_t with X axis location information,
    //same goes for 5 and 6 for the Y axis
	int x = ((int)buffer[3] + (int)buffer[4] * 255);
	int y = ((int)buffer[5] + (int)buffer[6] * 255);
//	cout << "to " << x << " x " << y << "\n";

	//buffer[2] states: (learned that simply from looking at the data)
	// 0 - pen up (goes away from tablet)
	// 192 - pen hovering near tablet
	// 193 - pen touching tablet (dragging)
	// 194 - pen hovering + low pen button pressed
	// 196 - either: pen hover + high button pressed, or pen dragging + low button pressed

	if(buffer[2] == 193 && (last_buf2 == 192 || last_buf2 == 0)) 		//was hovering (or off the tablet) now touching
		mouse(x,y,kCGMouseButtonLeft,true); 							//left button down
	else if((buffer[2] == 192 || buffer[2] == 0) && last_buf2 == 193) 	//now touching, was hovering
		mouse(x,y,kCGMouseButtonLeft,false); 							//left button up
	else																//else: mouse drag or just move
		to(x,y,(buffer[2] == 193)?kCGEventLeftMouseDragged:kCGEventMouseMoved);

	last_buf2 = buffer[2];

	//TODO: where is the pressure level information? I donno. it must be in another HID report or usage... or - it doesn't exist

	//TODO: there's a memory leak, I think. It gets slussigh after working a while
}

/**
 * Simple.
 */
int main(int argc, char** argv) {
	if(!connectLIBHID()) return 0;

	while(true) {
		pollLIBHID(NULL);

		usleep(1 * 1000);
	}

	disconnectLIBHID();

	return 0;
}