From af84249d3450f851a297ed1abae21ad032a9dbb4 Mon Sep 17 00:00:00 2001
From: - <->
Date: Sun, 4 Oct 2020 10:44:54 -0700
Subject: [PATCH] Got tablet to report button events.

---
 hanvon-libusb.c | 61 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 23 deletions(-)

diff --git a/hanvon-libusb.c b/hanvon-libusb.c
index 8bab1b2..71e62b6 100644
--- a/hanvon-libusb.c
+++ b/hanvon-libusb.c
@@ -124,31 +124,44 @@ void callback(struct libusb_transfer *transfer) {
 void callback_gp0504 (struct libusb_transfer *tx) { // for callback
     unsigned char *data = tx -> buffer;
     unsigned short temp;
+    int err   = 0;
     struct libevdev_uinput *ud = tx -> user_data;
     switch(data[0]) {
         case 0x01:
             break;
         case 0x02:
-            if((data[1] & 0xf0) != 0) {
-                //absolute x
-                temp = data[2];
-                temp <<= 8;
-                temp += data[3];
-                libevdev_uinput_write_event(ud, EV_ABS, ABS_X, temp);                  
-                //absolute y
-                temp = data[4];
-                temp <<= 8;
-                temp += data[5];
-                libevdev_uinput_write_event(ud, EV_ABS, ABS_Y, temp);
-            }
-            break;
-        default: 
+            // pen touches surface
+            err += libevdev_uinput_write_event(ud, EV_KEY, BTN_LEFT, data[6] > 68);
+            // data[1]:
+            // 0x10 = lift,         0x90 = close,           0x91 = press
+            // 0x12 = btn (lift),   0x92 = btn (close),     0x93 = btn (press)
+            err += libevdev_uinput_write_event(ud, EV_KEY, BTN_RIGHT, data[1] & 0x02);
+//             if((data[1] & 0xf0) != 0) {
+//                 //absolute x
+//                 temp = data[2];
+//                 temp <<= 8;
+//                 temp += data[3];
+//                 err += libevdev_uinput_write_event(ud, EV_ABS, ABS_X, temp);                  
+//                 //absolute y
+//                 temp = data[4];
+//                 temp <<= 8;
+//                 temp += data[5];
+//                 err += libevdev_uinput_write_event(ud, EV_ABS, ABS_Y, temp);
+//             }
+
+        default:
             display_packets(data);
             break;
+
     }
+    err += libevdev_uinput_write_event(ud, EV_SYN, SYN_REPORT, 0);
+    if (err != 0) {
+        printf("error : gp0504, %i\n", err);
+    }
+    return;
 }
 
-// determine which callback devices to use and how to initialize libevdev
+// https://www.freedesktop.org/software/libevdev/doc/latest/group__kernel.html
 int init_ctrl(struct libusb_device * const d, struct libevdev **evdev, struct libevdev_uinput **uidev) {
     printf("init_ctrl: %x\n", uidev);
     int is_ok = 0;
@@ -158,19 +171,21 @@ int init_ctrl(struct libusb_device * const d, struct libevdev **evdev, struct li
     struct libusb_device_descriptor desc;
     libusb_get_device_descriptor(d, &desc);
     (*evdev) = libevdev_new();
+    libevdev_enable_event_type((*evdev), EV_SYN);
+    libevdev_enable_event_code((*evdev), EV_SYN, SYN_REPORT, NULL);
+    // every tablet has these features
+    libevdev_enable_event_type((*evdev), EV_KEY); // enable pen button
+    libevdev_enable_event_type((*evdev), EV_ABS); // enable absolute position
+    libevdev_enable_event_code((*evdev), EV_KEY, BTN_LEFT, NULL);  // pen tap 
+    libevdev_enable_event_code((*evdev), EV_KEY, BTN_RIGHT, NULL); // pen button
     switch(desc.idProduct) {
-        default: // every tablet has these features - allow fall through
-            libevdev_enable_event_type((*evdev), EV_ABS); // enable absolute position
-            libevdev_enable_event_type((*evdev), EV_KEY); // enable pen button
-            libevdev_enable_event_code((*evdev), EV_KEY, BTN_LEFT, NULL);  // pen tap 
-            libevdev_enable_event_code((*evdev), EV_KEY, BTN_RIGHT, NULL); // pen button
+        case PRODUCT_ID_GP0504:
+            libevdev_set_name((*evdev), "Hanvon Graphicpal GP0504");
+            break;
         case PRODUCT_ID_GP0906:
             break;
         case PRODUCT_ID_APPIV0906:
             break;
-        case PRODUCT_ID_GP0504:
-            libevdev_set_name((*evdev), "Hanvon Graphicpal GP0504");
-            break;
     }
     int err = libevdev_uinput_create_from_device((*evdev), LIBEVDEV_UINPUT_OPEN_MANAGED, uidev);
     printf("Initializing controls status: %x, \n", uidev);