1 files changed, 101 insertions, 0 deletions
diff --git a/users/muppetjones/features/etchamouse.c b/users/muppetjones/features/etchamouse.c
new file mode 100644
index 0000000000..e1d4c38e81
--- /dev/null
+++ b/users/muppetjones/features/etchamouse.c
@@ -0,0 +1,101 @@
+/* Copyright 2020 Stephen J. Bush
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include QMK_KEYBOARD_H
+#include "etchamouse.h"
+#include "pointing_device.h"
+
+#if defined(POINTING_DEVICE_ENABLE) && defined(ENCODER_ENABLE)
+
+/** Track movement separately in both directions. This will allow us to
+ *  smooth out the movement along diagonals
+ */
+typedef struct {
+    bool     clockwise : 1;
+    uint8_t  count : 7;
+    uint16_t timer : 16;
+    uint16_t elapsed : 16;
+} key_tracker_t;
+
+static key_tracker_t tracker_x = {false, 0, 0, 0};
+static key_tracker_t tracker_y = {false, 0, 0, 0};
+
+/**
+ * @brief Calculate the mouse move units for the given tracker.
+ *
+ * By using a key tracker rederence, we can minimize the amount of space
+ * required on the stack. As we will have the tracker object, we will also
+ * take the clockwise direction into account, which completely internalizes
+ * the movement unit logic within this single function.
+ *
+ * @param tracker: Pointer to a key tracker object.
+ * @return A integer from -127 to 127
+ */
+static int8_t move_unit(key_tracker_t *tracker) {
+    if (0 == tracker->count) return 0;
+
+    const uint16_t modifier = TAPPING_TERM_MOUSE_ENCODER < tracker->elapsed ? 1 : (TAPPING_TERM_MOUSE_ENCODER - tracker->elapsed) >> 1;
+    uint16_t       speed    = MOUSEKEY_INITIAL_SPEED + MOUSEKEY_MOVE_DELTA * modifier * (tracker->count >> 1);
+
+    /* convert speed to USB mouse speed 1 to 127 */
+    speed = (uint8_t)(speed / (1000.0f / MOUSEKEY_INTERVAL));
+    speed = speed < 1 ? 1 : speed;
+
+    return (tracker->clockwise ? 1 : -1) * (speed > MOUSEKEY_MOVE_MAX ? MOUSEKEY_MOVE_MAX : speed);
+}
+
+/**
+ * @brief Update key press tracker
+ *
+ * Update the time elapsed since the last keypress.
+ * If the key has not been pressed since the tapping term, then reset the count to zero.
+ * If the key was pressed, update the timer and increment the count.
+ * Number of keypresses will degrade based on tapping term and zero out based
+ * on the persistenc term.
+ *
+ * @param tracker: The object to update
+ * @param pressed: A boolean indicating whether or not the key was pressed
+ * @return None.
+ */
+static void update_tracker(key_tracker_t *tracker, bool pressed, bool clockwise) {
+    tracker->elapsed = timer_elapsed(tracker->timer);
+    if (pressed) {
+        tracker->timer = timer_read();
+        tracker->count += 1;
+        tracker->clockwise = clockwise;
+    } else if (TAPPING_TERM_PERSISTENCE < tracker->elapsed) {
+        tracker->count = 0;
+    } else if (TAPPING_TERM_MOUSE_ENCODER < tracker->elapsed) {
+        tracker->count >>= 1;
+    }
+}
+
+bool encoder_update_mouse(uint8_t index, bool clockwise) {
+    report_mouse_t curr_report = pointing_device_get_report();
+
+    update_tracker(&tracker_x, 0 == index, clockwise);
+    update_tracker(&tracker_y, 1 == index, clockwise);
+
+    curr_report.x += move_unit(&tracker_x);
+    curr_report.y += move_unit(&tracker_y);
+
+    pointing_device_set_report(curr_report);
+    pointing_device_send();
+
+    return true;
+}
+
+#endif