Touch support

1 files changed, 512 insertions, 325 deletions

diff --git a/source/saw/main.c b/source/saw/main.c
index 865b0ab..bdbb5ad 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -1,3 +1,9 @@
+//  ================================================================
+//
+//      Headers
+//
+//  ================================================================
+
 #include "../kit/math.h"
 #include "../kit/time.h"
 #include "../kit/string_ref.h"
@@ -24,14 +30,31 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+//  Fonts data
 #include "fonts.inl.h"
 
+//  ================================================================
+//
+//      Definitions
+//
+//  ================================================================
+
+//  Program version
+//
+
 #define VERSION_MAJOR 0
 #define VERSION_MINOR 0
 #define VERSION_BABY 2
 #define VERSION_DEV 1
 
+//  Constants
+//
+
 enum {
+  //  TODO
+  //  Use 28224000 for time rate, divisible by common sample rates
+  //  like 192000, 44100 etc.
+
   CHANNEL_COUNT = 2,
   SAMPLE_RATE   = 44100,
 
@@ -42,8 +65,8 @@ enum {
   UNISON_COUNT = 100,
   SHEET_SIZE   = 200,
 
-  ROLL_DEFAULT_RATE     = 8,
-  ROLL_DEFAULT_OFFSET_Y = 710,
+  ROLL_DEFAULT_RATE        = 8,
+  ROLL_DEFAULT_UI_OFFSET_Y = 710,
 
   INSTRUMENT_SINE = 0,
   INSTRUMENT_SAW_UP,
@@ -65,8 +88,16 @@ enum {
   TRACK_INPUT_ATTACK,
   TRACK_INPUT_DECAY,
   TRACK_INPUT_RELEASE,
+
+  EDIT_MODE_HAND = 0,
+  EDIT_MODE_ERASE,
+  EDIT_MODE_PAN,
+  EDIT_MODE_CLONE,
 };
 
+//  Data types
+//
+
 typedef struct {
   b8  enabled;
   i64 time;
@@ -93,8 +124,8 @@ typedef struct {
   i64             time;
   i64             duration;
   i64             loop_duration;
-  i64             offset_x;
-  i64             offset_y;
+  i64             ui_offset_x;
+  i64             ui_offset_y;
 
   //  dynamic properties
   //
@@ -102,8 +133,8 @@ typedef struct {
   b8  grid_input;
   i32 grid_note;
   i32 grid_time;
-  b8  offset_x_input;
-  b8  offset_y_input;
+  b8  ui_offset_x_input;
+  b8  ui_offset_y_input;
   b8  loop_input;
 } saw_roll_t;
 
@@ -138,34 +169,46 @@ typedef struct {
   b8  grid_input;
   i32 grid_roll;
   i32 grid_cell;
-  b8  offset_input;
-  i64 offset_x;
-  i64 offset_y;
+  b8  ui_offset_input;
+  i64 ui_offset_x;
+  i64 ui_offset_y;
   b8  duplicate_input;
 } saw_compose_t;
 
 static struct NVGcontext *saw_nvg;
-static ma_device          saw_ma;
+static ma_device          saw_audio_device;
 
-static char         saw_project_file_buf[4096];
-static str_t        saw_project_file;
-static i32          saw_font_text  = -1;
-static i32          saw_font_icons = -1;
-static mt64_state_t saw_mt64;
+//  Input events
+//
 
-static i32 saw_mouse_x       = 0;
-static i32 saw_mouse_y       = 0;
-static b8  saw_lbutton_click = 0;
-static b8  saw_lbutton_down  = 0;
-static b8  saw_rbutton_click = 0;
-static b8  saw_rbutton_down  = 0;
-static b8  saw_mbutton_click = 0;
-static b8  saw_mbutton_down  = 0;
+static i64 saw_mouse_x          = 0;
+static i64 saw_mouse_y          = 0;
+static i64 saw_mouse_dx         = 0;
+static i64 saw_mouse_dy         = 0;
+static b8  saw_lbutton_click    = 0;
+static b8  saw_lbutton_down     = 0;
+static b8  saw_rbutton_click    = 0;
+static b8  saw_rbutton_down     = 0;
+static b8  saw_mbutton_click    = 0;
+static b8  saw_mbutton_down     = 0;
+static b8  saw_shift_on         = 0;
+static b8  saw_ctrl_on          = 0;
+static b8  saw_key_pressed[512] = { 0 };
+
+//  Global state
+//
 
 static b8  saw_playback_on    = 0;
 static i64 saw_playback_frame = 0;
 static i64 saw_current_track  = 0;
 static i64 saw_current_roll   = 0;
+static i64 saw_edit_mode      = EDIT_MODE_HAND;
+
+static char         saw_project_file_buf[4096];
+static str_t        saw_project_file;
+static i32          saw_font_text  = -1;
+static i32          saw_font_icons = -1;
+static mt64_state_t saw_mt64; // RNG
 
 static saw_voice_t saw_voices[VOICE_COUNT] = { 0 };
 static saw_roll_t  saw_rolls[ROLL_COUNT];
@@ -176,15 +219,15 @@ static saw_compose_t saw_compose = {
   .grid_input      = 0,
   .grid_roll       = 0,
   .grid_cell       = 0,
-  .offset_input    = 0,
-  .offset_x        = 0,
-  .offset_y        = 0,
+  .ui_offset_input = 0,
+  .ui_offset_x     = 0,
+  .ui_offset_y     = 0,
   .duplicate_input = 0,
 };
 
 //  ================================================================
 //
-//      Audio
+//      Sound
 //
 //  ================================================================
 
@@ -316,9 +359,8 @@ static f64 saw_oscillator(i32 type, f64 frequency, f64 phase,
 
 static void saw_audio(ma_device *device, void *void_out_,
                       void const *void_in_, ma_uint32 frame_count) {
-  //  FIXME
+  //  TODO
   //  Render to audio buffer separately.
-  //
 
   saw_playback(frame_count);
 
@@ -378,10 +420,21 @@ static void saw_audio(ma_device *device, void *void_out_,
 //
 //  ================================================================
 
+static void saw_reset_ui_offset(void) {
+  if (saw_current_roll != -1) {
+    saw_rolls[saw_current_roll].ui_offset_x = 0;
+    saw_rolls[saw_current_roll].ui_offset_y =
+        ROLL_DEFAULT_UI_OFFSET_Y;
+  }
+
+  saw_compose.ui_offset_x = 0;
+  saw_compose.ui_offset_y = 0;
+}
+
 static void saw_ui_header(i64 x0, u64 y0, u64 width, i64 height) {
   i64 frame_height = sapp_height();
 
-  i64 border = 12;
+  i64 border = 14;
 
   nvgFontSize(saw_nvg, height - border * 2);
   nvgFontFaceId(saw_nvg, saw_font_icons);
@@ -398,46 +451,81 @@ static void saw_ui_header(i64 x0, u64 y0, u64 width, i64 height) {
   char panning[]       = "\uf047";
   char clone[]         = "\uf24d";
 
-  u8 color[] = { 220, 220, 220, 255 };
-
-#define ICON_(i_)                                                    \
-  do {                                                               \
-    b8 has_cursor = saw_mouse_x >= x && saw_mouse_x < x + height &&  \
-                    saw_mouse_y >= frame_height - y0 - height &&     \
-                    saw_mouse_y < frame_height - y0;                 \
-    if (has_cursor)                                                  \
-      nvgFillColor(saw_nvg, nvgRGBA(255, 255, 220, 255));            \
-    nvgText(saw_nvg, x, h, (i_), (i_) + (sizeof(i_) - 1));           \
-    if (has_cursor)                                                  \
-      nvgFillColor(saw_nvg,                                          \
-                   nvgRGBA(color[0], color[1], color[2], color[3])); \
-    x += height;                                                     \
+  u8 color_active[]   = { 220, 220, 220, 255 };
+  u8 color_hover[]    = { 255, 255, 220, 255 };
+  u8 color_selected[] = { 255, 255, 255, 255 };
+
+  b8 has_cursor = 0;
+
+#define ICON_(i_, selected_)                                       \
+  do {                                                             \
+    has_cursor = saw_mouse_x >= x && saw_mouse_x < x + height &&   \
+                 saw_mouse_y >= frame_height - y0 - height &&      \
+                 saw_mouse_y < frame_height - y0;                  \
+    if (has_cursor)                                                \
+      nvgFillColor(saw_nvg,                                        \
+                   nvgRGBA(color_hover[0], color_hover[1],         \
+                           color_hover[2], color_hover[3]));       \
+    else if (selected_)                                            \
+      nvgFillColor(saw_nvg,                                        \
+                   nvgRGBA(color_selected[0], color_selected[1],   \
+                           color_selected[2], color_selected[3])); \
+    else                                                           \
+      nvgFillColor(saw_nvg,                                        \
+                   nvgRGBA(color_active[0], color_active[1],       \
+                           color_active[2], color_active[3]));     \
+    nvgText(saw_nvg, x, h, (i_), (i_) + (sizeof(i_) - 1));         \
+    x += height;                                                   \
   } while (0)
 
-  nvgFillColor(saw_nvg,
-               nvgRGBA(color[0], color[1], color[2], color[3]));
+  //  Global actions
+  //
 
-  ICON_(backward_fast);
+  ICON_(backward_fast, 0);
+  if (has_cursor && saw_lbutton_click)
+    saw_playback_frame = 0;
 
   if (saw_playback_on)
-    ICON_(stop);
+    ICON_(stop, 0);
   else
-    ICON_(play);
+    ICON_(play, 0);
+  if (has_cursor && saw_lbutton_click)
+    saw_playback_on = !saw_playback_on;
+
+  ICON_(anchor, 0);
+  if (has_cursor && saw_lbutton_click)
+    saw_reset_ui_offset();
+
+  //  Editing mode
+  //
 
-  ICON_(anchor);
-  ICON_(hand_pointer);
+  x += height / 2;
 
-  color[0] = 220;
-  color[1] = 220;
-  color[2] = 220;
-  color[3] = 160;
+  color_active[0] = 220;
+  color_active[1] = 180;
+  color_active[2] = 80;
+  color_active[3] = 160;
 
-  nvgFillColor(saw_nvg,
-               nvgRGBA(color[0], color[1], color[2], color[3]));
+  color_selected[0] = 220;
+  color_selected[1] = 180;
+  color_selected[2] = 80;
+  color_selected[3] = 255;
 
-  ICON_(eraser);
-  ICON_(panning);
-  ICON_(clone);
+  ICON_(hand_pointer, saw_edit_mode == EDIT_MODE_HAND);
+  if (has_cursor && saw_lbutton_click)
+    saw_edit_mode = EDIT_MODE_HAND;
+
+  ICON_(eraser, saw_edit_mode == EDIT_MODE_ERASE);
+  if (has_cursor && saw_lbutton_click)
+    saw_edit_mode = EDIT_MODE_ERASE;
+
+  ICON_(panning, saw_edit_mode == EDIT_MODE_PAN);
+  if (has_cursor && saw_lbutton_click)
+    saw_edit_mode = EDIT_MODE_PAN;
+
+  ICON_(clone, saw_edit_mode == EDIT_MODE_CLONE);
+  if (has_cursor && saw_lbutton_click)
+    saw_edit_mode = EDIT_MODE_CLONE;
 
 #undef ICON_
 }
@@ -475,11 +563,11 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
 
     i64 top    = frame_height - y0 - height + track_height;
     i64 bottom = frame_height - y0;
-    i64 dx     = x0 + saw_compose.offset_x;
+    i64 dx     = x0 + saw_compose.ui_offset_x;
     i64 l      = dx + (roll->time * grid_scale) / SAMPLE_RATE;
     i64 r      = l + (roll->duration * grid_scale) / SAMPLE_RATE;
     i64 u      = frame_height - y0 - height + track_height +
-            saw_compose.offset_y + roll->track * track_height;
+            saw_compose.ui_offset_y + roll->track * track_height;
     i64 d = u + track_height;
     i64 s = grid_scale / grid_rate;
 
@@ -521,15 +609,16 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
     nvgFill(saw_nvg);
 
     if (has_cursor) {
-      if (saw_rbutton_down) {
+      if (saw_rbutton_down ||
+          (saw_edit_mode == EDIT_MODE_ERASE && saw_lbutton_down)) {
         if (saw_current_roll == saw_compose.rolls[i])
           saw_current_roll = -1;
         saw_compose.rolls[i] = -1;
         roll->enabled        = 0;
       } else {
-        if (saw_lbutton_click) {
+        if (saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_click) {
           if (saw_current_roll == saw_compose.rolls[i]) {
-            i64 cell = ((saw_mouse_x - saw_compose.offset_x) *
+            i64 cell = ((saw_mouse_x - saw_compose.ui_offset_x) *
                         grid_rate) /
                        grid_scale;
             i64 c0 = (roll->time * grid_rate) / SAMPLE_RATE;
@@ -558,24 +647,26 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
   //  Placing new sheet
   //
 
-  if (!hover_any && saw_lbutton_down &&
-      saw_mouse_x >= x0 + saw_compose.offset_x &&
+  if (!hover_any && saw_edit_mode == EDIT_MODE_HAND &&
+      saw_lbutton_down &&
+      saw_mouse_x >= x0 + saw_compose.ui_offset_x &&
       saw_mouse_x < x0 + width) {
     if (!saw_compose.grid_input &&
         saw_mouse_y >= frame_height - y0 - height &&
         saw_mouse_y < frame_height - y0 - height + track_height)
-      saw_playback_frame = ((saw_mouse_x - saw_compose.offset_x) *
+      saw_playback_frame = ((saw_mouse_x - saw_compose.ui_offset_x) *
                             SAMPLE_RATE) /
                            grid_scale;
-    else if (saw_lbutton_click &&
+    else if (saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_click &&
              saw_mouse_y >=
                  frame_height - y0 - height + track_height &&
              saw_mouse_y < frame_height - y0) {
-      i64 track = (saw_mouse_y - saw_compose.offset_y - frame_height +
-                   y0 + height) /
+      i64 track = (saw_mouse_y - saw_compose.ui_offset_y -
+                   frame_height + y0 + height) /
                       track_height -
                   1;
-      i64 cell = ((saw_mouse_x - saw_compose.offset_x) * grid_rate) /
+      i64 cell = ((saw_mouse_x - saw_compose.ui_offset_x) *
+                  grid_rate) /
                  grid_scale;
       i64 frame = (cell * SAMPLE_RATE) / grid_rate;
 
@@ -587,10 +678,10 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
           break;
         }
 
-      i64 x = x0 + saw_compose.offset_x +
+      i64 x = x0 + saw_compose.ui_offset_x +
               (frame * grid_scale) / SAMPLE_RATE;
       i64 y = frame_height - y0 - height + track_height +
-              saw_compose.offset_y + track * track_height;
+              saw_compose.ui_offset_y + track * track_height;
 
       if (track < 0 || track >= TRACK_COUNT || x < x0 ||
           x >= x0 + width || y < frame_height - y0 - height ||
@@ -616,16 +707,16 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
           .time             = frame,
           .duration = (ROLL_DEFAULT_RATE * SAMPLE_RATE) / grid_rate,
           .loop_duration = 0,
-          .offset_x      = 0,
-          .offset_y      = ROLL_DEFAULT_OFFSET_Y,
-
-          .last_index     = -1,
-          .grid_input     = 0,
-          .grid_note      = 0,
-          .grid_time      = 0,
-          .offset_x_input = 0,
-          .offset_y_input = 0,
-          .loop_input     = 0,
+          .ui_offset_x   = 0,
+          .ui_offset_y   = ROLL_DEFAULT_UI_OFFSET_Y,
+
+          .last_index        = -1,
+          .grid_input        = 0,
+          .grid_note         = 0,
+          .grid_time         = 0,
+          .ui_offset_x_input = 0,
+          .ui_offset_y_input = 0,
+          .loop_input        = 0,
         };
 
         saw_current_roll  = n;
@@ -644,11 +735,12 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
       if (saw_current_roll == -1)
         break;
 
-      i64 track = (saw_mouse_y - saw_compose.offset_y - frame_height +
-                   y0 + height) /
+      i64 track = (saw_mouse_y - saw_compose.ui_offset_y -
+                   frame_height + y0 + height) /
                       track_height -
                   1;
-      i64 cell = ((saw_mouse_x - saw_compose.offset_x) * grid_rate) /
+      i64 cell = ((saw_mouse_x - saw_compose.ui_offset_x) *
+                  grid_rate) /
                  grid_scale;
 
       if (cell < 0 || track < 0 || track >= TRACK_COUNT)
@@ -700,22 +792,25 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
   //  Panning input
   //
 
-  if (saw_mbutton_click) {
+  if (saw_mbutton_click ||
+      (saw_edit_mode == EDIT_MODE_PAN && saw_lbutton_click)) {
     if (saw_mouse_x >= x0 &&
         saw_mouse_y >= frame_height - y0 - height + track_height &&
         saw_mouse_x < x0 + width && saw_mouse_y < frame_height - y0)
-      saw_compose.offset_input = 1;
+      saw_compose.ui_offset_input = 1;
   }
 
-  if (!saw_mbutton_down)
-    saw_compose.offset_input = 0;
+  if (!(saw_mbutton_down ||
+        (saw_edit_mode == EDIT_MODE_PAN && saw_lbutton_down)))
+    saw_compose.ui_offset_input = 0;
 
   //  Track stretching input
   //
 
   if (saw_compose.grid_input) {
-    if (saw_lbutton_down) {
-      i64 cell = ((saw_mouse_x - saw_compose.offset_x) * grid_rate) /
+    if (saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_down) {
+      i64 cell = ((saw_mouse_x - saw_compose.ui_offset_x) *
+                  grid_rate) /
                  grid_scale;
       saw_roll_t *p = saw_rolls + saw_compose.grid_roll;
 
@@ -768,7 +863,7 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
   //  Playback indicator
   //
 
-  i64 x = x0 + saw_compose.offset_x - border * 2 +
+  i64 x = x0 + saw_compose.ui_offset_x - border * 2 +
           (saw_playback_frame * grid_scale + SAMPLE_RATE / 2) /
               SAMPLE_RATE;
   i64 w = border * 4;
@@ -784,17 +879,17 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
   //
 
   if (!hover_any && !saw_compose.grid_input &&
-      saw_mouse_x >= x0 + saw_compose.offset_x) {
-    i64 track = (saw_mouse_y - saw_compose.offset_y - frame_height +
-                 y0 + height) /
+      saw_mouse_x >= x0 + saw_compose.ui_offset_x) {
+    i64 track = (saw_mouse_y - saw_compose.ui_offset_y -
+                 frame_height + y0 + height) /
                     track_height -
                 1;
-    i64 cell = ((saw_mouse_x - saw_compose.offset_x) * grid_rate) /
+    i64 cell = ((saw_mouse_x - saw_compose.ui_offset_x) * grid_rate) /
                grid_scale;
-    i64 x = x0 + saw_compose.offset_x +
+    i64 x = x0 + saw_compose.ui_offset_x +
             (cell * grid_scale) / grid_rate;
     i64 y = frame_height - y0 - height + track_height +
-            saw_compose.offset_y + track * track_height;
+            saw_compose.ui_offset_y + track * track_height;
     i64 w = grid_scale / grid_rate;
 
     if (track >= 0 && track < TRACK_COUNT && x >= x0 &&
@@ -812,11 +907,11 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
   //  Cursor indicator
   //
 
-  if (saw_mouse_x >= x0 + saw_compose.offset_x &&
+  if (saw_mouse_x >= x0 + saw_compose.ui_offset_x &&
       saw_mouse_x < x0 + width &&
       saw_mouse_y >= frame_height - y0 - height &&
       saw_mouse_y < frame_height - y0) {
-    i64 dx = x0 + saw_compose.offset_x;
+    i64 dx = x0 + saw_compose.ui_offset_x;
     i64 s  = grid_scale / grid_rate;
     i64 x  = dx + ((saw_mouse_x - dx + s / 2) / s) * s;
     i64 w  = border * 4;
@@ -854,9 +949,9 @@ static void saw_ui_track(saw_track_t *track, i64 x0, i64 y0,
 
   for (i64 input_index = TRACK_INPUT_INSTRUMENT;
        input_index <= TRACK_INPUT_RELEASE; ++input_index) {
-    //  FIXME
+    //  TODO
     //  Implement Unison and Spread.
-    //
+
     if (input_index == TRACK_INPUT_UNISON ||
         input_index == TRACK_INPUT_SPREAD)
       continue;
@@ -956,11 +1051,11 @@ static void saw_ui_track(saw_track_t *track, i64 x0, i64 y0,
           title.values, title.values + title.size);
   next_y = header_offset + text_height;
 
-  char buf_instr[][100] = { "Sine",      "Saw up",      "Saw down",
-                            "Square up", "Square down", "Kick" };
+  char buf_instr[][100] = { "Sine",   "Saw up",   "Saw down",
+                            "Sqr up", "Sqr down", "Kick" };
   nvgText(saw_nvg, x0 + border * 2,
-          frame_height - y0 - height + next_y - border * 2,
-          "Instrument", 0);
+          frame_height - y0 - height + next_y - border * 2, "Instr.",
+          0);
   if (track->instrument >= 0 && track->instrument < INSTRUMENT_COUNT)
     nvgText(saw_nvg, x0 + column_width + border * 2,
             frame_height - y0 - height + next_y - border * 2,
@@ -1099,25 +1194,45 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
     char repeat[] = "\uf363";
 
-    nvgFontSize(saw_nvg, header_height - 4);
+    i64 border = 5;
+    nvgFontSize(saw_nvg, header_height - border * 2);
     nvgFontFaceId(saw_nvg, saw_font_icons);
-    nvgFillColor(saw_nvg, nvgRGBA(180, 80, 40, 200));
-    nvgText(saw_nvg, x - header_height * 2 + 2, y + header_height - 2,
-            repeat, repeat + (sizeof repeat - 1));
-
-    i64 w0 = (roll->loop_duration * roll->rate * sheet_scale +
+    if (roll->loop_duration == 0)
+      nvgFillColor(saw_nvg, nvgRGBA(80, 80, 80, 160));
+    else
+      nvgFillColor(saw_nvg, nvgRGBA(180, 80, 40, 200));
+    nvgText(saw_nvg, x - header_height * 2 + border,
+            y + header_height - border, repeat,
+            repeat + (sizeof repeat - 1));
+
+    i64 rw = (roll->loop_duration * roll->rate * sheet_scale +
               SAMPLE_RATE / 2) /
              SAMPLE_RATE;
+    i64 rx = roll->ui_offset_x;
 
-    nvgBeginPath(saw_nvg);
-    nvgRect(saw_nvg, x, y, w0, h);
-    nvgRect(saw_nvg, x, y + h * 4, w0, h);
-    nvgFillColor(saw_nvg, nvgRGBA(180, 80, 40, 160));
-    nvgFill(saw_nvg);
+    if (rx < 0) {
+      rw += rx;
+      rx = 0;
+    }
+
+    if (rw > w - rx)
+      rw = w - rx;
+
+    if (rw > 0) {
+      nvgBeginPath(saw_nvg);
+      nvgRect(saw_nvg, x + rx, y, rw, h);
+      nvgRect(saw_nvg, x + rx, y + h * 4, rw, h);
+      nvgFillColor(saw_nvg, nvgRGBA(180, 80, 40, 160));
+      nvgFill(saw_nvg);
+    }
 
     nvgBeginPath(saw_nvg);
-    nvgRect(saw_nvg, x + w0, y, w - w0, h);
-    nvgRect(saw_nvg, x + w0, y + h * 4, w - w0, h);
+    if (rx > 0) {
+      nvgRect(saw_nvg, x, y, rx, h);
+      nvgRect(saw_nvg, x, y + h * 4, rx, h);
+    }
+    nvgRect(saw_nvg, x + rx + rw, y, w - rx - rw, h);
+    nvgRect(saw_nvg, x + rx + rw, y + h * 4, w - rx - rw, h);
     nvgFillColor(saw_nvg, nvgRGBA(80, 80, 80, 160));
     nvgFill(saw_nvg);
 
@@ -1128,7 +1243,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
     if (roll->loop_input && saw_lbutton_down) {
       i64 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset -
-               roll->offset_x + sheet_scale / 2) /
+               roll->ui_offset_x + sheet_scale / 2) /
               sheet_scale;
 
       if (t <= 0)
@@ -1150,7 +1265,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   for (i64 pitch = 0; pitch < PITCH_COUNT; pitch++) {
     i64 x = x0 + border;
     i64 y = frame_height - y0 - (pitch + 1) * pianokey_height +
-            border + roll->offset_y;
+            border + roll->ui_offset_y;
     i64 w = pianokey_width - border * 2;
     i64 h = pianokey_height - border * 2;
 
@@ -1178,12 +1293,14 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       hover_any = 1;
 
       if (!roll->pitch_turned_off[pitch] &&
-          (saw_lbutton_click ||
-           (saw_lbutton_down && roll->last_index != pitch)))
+          ((saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_click) ||
+           (saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_down &&
+            roll->last_index != pitch)))
         saw_play_voice(saw_tracks + roll->track, roll, pitch,
                        SAMPLE_RATE / roll->rate);
 
-      if (saw_rbutton_click)
+      if (saw_rbutton_click ||
+          (saw_edit_mode == EDIT_MODE_ERASE && saw_lbutton_click))
         roll->pitch_turned_off[pitch] =
             !roll->pitch_turned_off[pitch];
 
@@ -1197,20 +1314,23 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   //  Panning input
   //
 
-  if (saw_mbutton_click) {
+  if (saw_mbutton_click || (saw_edit_mode == EDIT_MODE_PAN &&
+                            saw_lbutton_click && !roll->loop_input)) {
     if (saw_mouse_x >= x0 + pianokey_width + sheet_offset &&
         saw_mouse_y >= frame_height - y0 - height + text_height &&
         saw_mouse_x < x0 + width && saw_mouse_y < frame_height - y0)
-      roll->offset_x_input = 1;
+      roll->ui_offset_x_input = 1;
     if (saw_mouse_x >= x0 &&
         saw_mouse_y >= frame_height - y0 - height + text_height &&
         saw_mouse_x < x0 + width && saw_mouse_y < frame_height - y0)
-      roll->offset_y_input = 1;
+      roll->ui_offset_y_input = 1;
   }
 
-  if (!saw_mbutton_down) {
-    roll->offset_x_input = 0;
-    roll->offset_y_input = 0;
+  if (!(saw_mbutton_down ||
+        (saw_edit_mode == EDIT_MODE_PAN && saw_lbutton_down &&
+         !roll->loop_input))) {
+    roll->ui_offset_x_input = 0;
+    roll->ui_offset_y_input = 0;
   }
 
   //  Draw music sheet
@@ -1218,7 +1338,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
   for (i64 pitch = 0; pitch < PITCH_COUNT; pitch++) {
     i64 y = frame_height - y0 - (pitch + 1) * pianokey_height +
-            roll->offset_y;
+            roll->ui_offset_y;
 
     if (y > frame_height - y0 - pianokey_height)
       continue;
@@ -1230,7 +1350,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
     for (i64 t = 0; t < (roll->duration * roll->rate) / SAMPLE_RATE;
          t++) {
       i64 x = x0 + pianokey_width + sheet_offset + t * sheet_scale +
-              roll->offset_x;
+              roll->ui_offset_x;
 
       if (x >= x0 + width - sheet_scale - border)
         break;
@@ -1284,7 +1404,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       //
 
       if (!roll->grid_input && !turned_off && has_cursor &&
-          saw_lbutton_click)
+          saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_click)
         for (i64 n = 0; n < SHEET_SIZE; n++)
           if (!roll->notes[n].enabled) {
             roll->notes[n] = (saw_roll_note_t) {
@@ -1312,14 +1432,14 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       continue;
 
     i64 y = frame_height - y0 - (note->pitch + 1) * pianokey_height +
-            roll->offset_y;
+            roll->ui_offset_y;
 
     if (y + pianokey_height > frame_height - y0)
       continue;
     if (y < frame_height - y0 - height + text_height + header_height)
       continue;
 
-    i64 x = x0 + pianokey_width + sheet_offset + roll->offset_x +
+    i64 x = x0 + pianokey_width + sheet_offset + roll->ui_offset_x +
             (note->time * roll->rate * sheet_scale +
              SAMPLE_RATE / 2) /
                 SAMPLE_RATE;
@@ -1377,7 +1497,9 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
     //  Note input
     //
 
-    if (has_cursor && saw_rbutton_down)
+    if (has_cursor &&
+        (saw_rbutton_down ||
+         (saw_edit_mode == EDIT_MODE_ERASE && saw_lbutton_down)))
       note->enabled = 0;
   }
 
@@ -1385,9 +1507,9 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   //
 
   if (roll->grid_input) {
-    if (saw_lbutton_down) {
+    if (saw_edit_mode == EDIT_MODE_HAND && saw_lbutton_down) {
       i64 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset -
-               roll->offset_x) /
+               roll->ui_offset_x) /
               sheet_scale;
 
       saw_roll_note_t *p = roll->notes + roll->grid_note;
@@ -1442,7 +1564,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       frame -= ((frame - roll->time) / roll->loop_duration) *
                roll->loop_duration;
 
-    i64 x = x0 + pianokey_width + sheet_offset + roll->offset_x -
+    i64 x = x0 + pianokey_width + sheet_offset + roll->ui_offset_x -
             border * 2 +
             ((frame - roll->time) * roll->rate * sheet_scale +
              SAMPLE_RATE / 2) /
@@ -1465,7 +1587,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       saw_mouse_x < x0 + width &&
       saw_mouse_y >= frame_height - y0 - height &&
       saw_mouse_y < frame_height - y0) {
-    i64 dx = x0 + pianokey_width + sheet_offset + roll->offset_x;
+    i64 dx = x0 + pianokey_width + sheet_offset + roll->ui_offset_x;
     i64 x  = dx +
             ((saw_mouse_x - dx + sheet_scale / 2) / sheet_scale) *
                 sheet_scale;
@@ -1516,12 +1638,13 @@ static void saw_init(void) {
   config.dataCallback      = saw_audio;
   config.pUserData         = NULL;
 
-  if (ma_device_init(NULL, &config, &saw_ma) != MA_SUCCESS) {
+  if (ma_device_init(NULL, &config, &saw_audio_device) !=
+      MA_SUCCESS) {
     printf("ma_device_init failed.\n");
     return;
   }
 
-  ma_device_start(&saw_ma);
+  ma_device_start(&saw_audio_device);
 
   //  Load fonts
   //
@@ -1554,15 +1677,15 @@ static void saw_init(void) {
       .time             = 0,
       .duration         = (48 * SAMPLE_RATE) / ROLL_DEFAULT_RATE,
       .loop_duration    = 0,
-      .offset_x         = 0,
-      .offset_y         = ROLL_DEFAULT_OFFSET_Y,
-
-      .grid_input     = 0,
-      .grid_note      = 0,
-      .grid_time      = 0,
-      .offset_x_input = 0,
-      .offset_y_input = 0,
-      .loop_input     = 0,
+      .ui_offset_x      = 0,
+      .ui_offset_y      = ROLL_DEFAULT_UI_OFFSET_Y,
+
+      .grid_input        = 0,
+      .grid_note         = 0,
+      .grid_time         = 0,
+      .ui_offset_x_input = 0,
+      .ui_offset_y_input = 0,
+      .loop_input        = 0,
     };
   }
 
@@ -1692,7 +1815,8 @@ static void saw_init(void) {
       SCAN_(" time %lld", 1, &roll->time);
       SCAN_(" duration %lld", 1, &roll->duration);
       SCAN_(" loop_duration %lld", 1, &roll->loop_duration);
-      SCAN_(" offset %lld %lld", 2, &roll->offset_x, &roll->offset_y);
+      SCAN_(" ui_offset %lld %lld", 2, &roll->ui_offset_x,
+            &roll->ui_offset_y);
     }
 
     i32 total_tracks;
@@ -1734,8 +1858,8 @@ static void saw_init(void) {
 }
 
 static void saw_frame(void) {
-  //  FIXME
-  //  - Adjust sleep depending on how much compute we need
+  //  TODO
+  //  Adjust sleep depending on how much compute we need
 
   //  Sleep to prevent high CPU load
   thrd_sleep(&(struct timespec) { .tv_nsec = 10000000 }, NULL);
@@ -1744,7 +1868,7 @@ static void saw_frame(void) {
   i64 frame_height = sapp_height();
 
   glViewport(0, 0, frame_width, frame_height);
-  glClearColor(.15f, .12f, .10f, 1.f);
+  glClearColor(.11f, .09f, .08f, 1.f);
 #ifdef SOKOL_GLCORE33
   glClearDepth(1.);
 #else
@@ -1753,10 +1877,148 @@ static void saw_frame(void) {
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT |
           GL_STENCIL_BUFFER_BIT);
 
-  nvgBeginFrame(saw_nvg, frame_width, frame_height, sapp_dpi_scale());
+  //  Process input
+  //
+  {
+    if (saw_key_pressed[SAPP_KEYCODE_SPACE])
+      saw_playback_on = !saw_playback_on;
+    if (saw_key_pressed[SAPP_KEYCODE_ENTER])
+      saw_playback_frame = 0;
+    if (saw_key_pressed[SAPP_KEYCODE_ESCAPE])
+      saw_reset_ui_offset();
+    if (saw_key_pressed[SAPP_KEYCODE_D] ||
+        (saw_edit_mode == EDIT_MODE_CLONE && saw_lbutton_click))
+      saw_compose.duplicate_input = 1;
+
+    //  Panning control
+    //
+    for (i64 i = 0; i < ROLL_COUNT; i++) {
+      if (saw_rolls[i].ui_offset_x_input)
+        saw_rolls[i].ui_offset_x += saw_mouse_dx;
+      if (saw_rolls[i].ui_offset_y_input)
+        saw_rolls[i].ui_offset_y += saw_mouse_dy;
+    }
+    if (saw_compose.ui_offset_input) {
+      saw_compose.ui_offset_x += saw_mouse_dx;
+      saw_compose.ui_offset_y += saw_mouse_dy;
+    }
+
+    if (saw_current_track != -1 &&
+        saw_tracks[saw_current_track].value_input !=
+            TRACK_INPUT_NONE) {
+      //  Value input
+      //
+
+      saw_track_t *track = saw_tracks + saw_current_track;
+
+      track->value_buffer -= saw_shift_on  ? saw_mouse_dy * 300
+                             : saw_ctrl_on ? saw_mouse_dy
+                                           : saw_mouse_dy * 20;
+
+      //  TODO
+      //  Unify value input logic.
+
+      //  Change input value buffer for selected value.
+      //
+      switch (track->value_input) {
+        case TRACK_INPUT_INSTRUMENT:
+          track->instrument = (i64) (track->value_buffer * .002 +
+                                     0.5);
+          if (track->instrument < 0)
+            track->instrument = 0;
+          if (track->instrument >= INSTRUMENT_COUNT)
+            track->instrument = INSTRUMENT_COUNT - 1;
+          break;
+
+        case TRACK_INPUT_WARP:
+          track->warp = track->value_buffer * .0001;
+          if (track->warp < -1.)
+            track->warp = -1.;
+          if (track->warp > 1.)
+            track->warp = 1.;
+          break;
+
+        case TRACK_INPUT_PHASE:
+          track->value_buffer = (f64) ((i64) track->value_buffer %
+                                       10000);
+          while (track->value_buffer < 0)
+            track->value_buffer += 10000;
+          track->phase = track->value_buffer * .0001;
+          break;
+
+        case TRACK_INPUT_UNISON:
+          track->unison = (i64) (track->value_buffer * .01 + 0.5);
+          if (track->unison < 1)
+            track->unison = 1;
+          if (track->unison > UNISON_COUNT)
+            track->unison = UNISON_COUNT;
+          break;
+
+        case TRACK_INPUT_SPREAD:
+          track->spread = track->value_buffer * .0001;
+          if (track->spread < 0.)
+            track->spread = 0.;
+          if (track->spread > 1.)
+            track->spread = 1.;
+          break;
+
+        case TRACK_INPUT_STEREO_WIDTH:
+          track->stereo_width = track->value_buffer * .0001;
+          if (track->stereo_width < 0.)
+            track->stereo_width = 0.;
+          if (track->stereo_width > 2.)
+            track->stereo_width = 2.;
+          break;
+
+        case TRACK_INPUT_VOLUME:
+          track->volume = track->value_buffer * .0001;
+          if (track->volume < 0.)
+            track->volume = 0.;
+          if (track->volume > 2.)
+            track->volume = 2.;
+          break;
+
+        case TRACK_INPUT_SUSTAIN:
+          track->envelope.sustain = track->value_buffer * .0001;
+          if (track->envelope.sustain < 0.)
+            track->envelope.sustain = 0.;
+          if (track->envelope.sustain > 1.)
+            track->envelope.sustain = 1.;
+          break;
+
+        case TRACK_INPUT_ATTACK:
+          track->envelope.attack = track->value_buffer * .00001;
+          if (track->envelope.attack < 0.)
+            track->envelope.attack = 0.;
+          if (track->envelope.attack > 60.)
+            track->envelope.attack = 60.;
+          break;
+
+        case TRACK_INPUT_DECAY:
+          track->envelope.decay = track->value_buffer * .00001;
+          if (track->envelope.decay < 0.)
+            track->envelope.decay = 0.;
+          if (track->envelope.decay > 60.)
+            track->envelope.decay = 60.;
+          break;
+
+        case TRACK_INPUT_RELEASE:
+          track->envelope.release = track->value_buffer * .00001;
+          if (track->envelope.release < 0.)
+            track->envelope.release = 0.;
+          if (track->envelope.release > 60.)
+            track->envelope.release = 60.;
+          break;
+
+        default:;
+      }
+    }
+  }
 
   //  Render UI
   //
+
+  nvgBeginFrame(saw_nvg, frame_width, frame_height, sapp_dpi_scale());
   {
     //  Adjust UI layout
     //
@@ -1820,19 +2082,27 @@ static void saw_frame(void) {
       );
     }
   }
-
   nvgEndFrame(saw_nvg);
 
   //  Cleanup input state.
   //
+  {
+    saw_mouse_dx = 0;
+    saw_mouse_dy = 0;
+
+    saw_lbutton_click = 0;
+    saw_rbutton_click = 0;
+    saw_mbutton_click = 0;
+
+    saw_shift_on = 0;
+    saw_ctrl_on  = 0;
 
-  saw_lbutton_click = 0;
-  saw_rbutton_click = 0;
-  saw_mbutton_click = 0;
+    memset(saw_key_pressed, 0, sizeof saw_key_pressed);
+  }
 }
 
 static void saw_cleanup(void) {
-  ma_device_uninit(&saw_ma);
+  ma_device_uninit(&saw_audio_device);
 
 #ifdef SOKOL_GLCORE33
   nvgDeleteGL3(saw_nvg);
@@ -1899,8 +2169,8 @@ static void saw_cleanup(void) {
     fprintf(f, "time              %lld\n", roll->time);
     fprintf(f, "duration          %lld\n", roll->duration);
     fprintf(f, "loop_duration     %lld\n", roll->loop_duration);
-    fprintf(f, "offset            %lld %lld\n\n", roll->offset_x,
-            roll->offset_y);
+    fprintf(f, "ui_offset            %lld %lld\n\n",
+            roll->ui_offset_x, roll->ui_offset_y);
   }
 
   //  Save tracks
@@ -1937,144 +2207,23 @@ static void saw_cleanup(void) {
 }
 
 static void saw_event(sapp_event const *event) {
-  //  FIXME
-  //  Do input processing in frame update procedure.
-  //
-
   switch (event->type) {
     case SAPP_EVENTTYPE_MOUSE_MOVE:
-      saw_mouse_x = event->mouse_x;
-      saw_mouse_y = event->mouse_y;
-
-      for (i64 i = 0; i < ROLL_COUNT; i++) {
-        //  Panning control
-        //
-        if (saw_rolls[i].offset_x_input)
-          saw_rolls[i].offset_x += event->mouse_dx;
-        if (saw_rolls[i].offset_y_input)
-          saw_rolls[i].offset_y += event->mouse_dy;
-      }
-
-      if (saw_compose.offset_input) {
-        //  Panning control
-        //
-        saw_compose.offset_x += event->mouse_dx;
-        saw_compose.offset_y += event->mouse_dy;
-      }
-
-      if (saw_current_track != -1) {
-        //  Value control
-        //
-
-        saw_track_t *track = saw_tracks + saw_current_track;
-
-        track->value_buffer -= (event->modifiers &
-                                SAPP_MODIFIER_SHIFT)
-                                   ? event->mouse_dy * 300
-                               : (event->modifiers &
-                                  SAPP_MODIFIER_CTRL)
-                                   ? event->mouse_dy
-                                   : event->mouse_dy * 20;
-
-        //  Change input value buffer for selected value.
-        //
-        switch (track->value_input) {
-          case TRACK_INPUT_INSTRUMENT:
-            track->instrument = (i64) (track->value_buffer * .002 +
-                                       0.5);
-            if (track->instrument < 0)
-              track->instrument = 0;
-            if (track->instrument >= INSTRUMENT_COUNT)
-              track->instrument = INSTRUMENT_COUNT - 1;
-            break;
-
-          case TRACK_INPUT_WARP:
-            track->warp = track->value_buffer * .0001;
-            if (track->warp < -1.)
-              track->warp = -1.;
-            if (track->warp > 1.)
-              track->warp = 1.;
-            break;
-
-          case TRACK_INPUT_PHASE:
-            track->value_buffer = (f64) ((i64) track->value_buffer %
-                                         10000);
-            while (track->value_buffer < 0)
-              track->value_buffer += 10000;
-            track->phase = track->value_buffer * .0001;
-            break;
-
-          case TRACK_INPUT_UNISON:
-            track->unison = (i64) (track->value_buffer * .01 + 0.5);
-            if (track->unison < 1)
-              track->unison = 1;
-            if (track->unison > UNISON_COUNT)
-              track->unison = UNISON_COUNT;
-            break;
-
-          case TRACK_INPUT_SPREAD:
-            track->spread = track->value_buffer * .0001;
-            if (track->spread < 0.)
-              track->spread = 0.;
-            if (track->spread > 1.)
-              track->spread = 1.;
-            break;
-
-          case TRACK_INPUT_STEREO_WIDTH:
-            track->stereo_width = track->value_buffer * .0001;
-            if (track->stereo_width < 0.)
-              track->stereo_width = 0.;
-            if (track->stereo_width > 2.)
-              track->stereo_width = 2.;
-            break;
+      saw_shift_on = (event->modifiers & SAPP_MODIFIER_SHIFT) != 0;
+      saw_ctrl_on  = (event->modifiers & SAPP_MODIFIER_CTRL) != 0;
 
-          case TRACK_INPUT_VOLUME:
-            track->volume = track->value_buffer * .0001;
-            if (track->volume < 0.)
-              track->volume = 0.;
-            if (track->volume > 2.)
-              track->volume = 2.;
-            break;
-
-          case TRACK_INPUT_SUSTAIN:
-            track->envelope.sustain = track->value_buffer * .0001;
-            if (track->envelope.sustain < 0.)
-              track->envelope.sustain = 0.;
-            if (track->envelope.sustain > 1.)
-              track->envelope.sustain = 1.;
-            break;
-
-          case TRACK_INPUT_ATTACK:
-            track->envelope.attack = track->value_buffer * .00001;
-            if (track->envelope.attack < 0.)
-              track->envelope.attack = 0.;
-            if (track->envelope.attack > 60.)
-              track->envelope.attack = 60.;
-            break;
-
-          case TRACK_INPUT_DECAY:
-            track->envelope.decay = track->value_buffer * .00001;
-            if (track->envelope.decay < 0.)
-              track->envelope.decay = 0.;
-            if (track->envelope.decay > 60.)
-              track->envelope.decay = 60.;
-            break;
+      saw_mouse_dx += (i64) floor(event->mouse_dx + .5);
+      saw_mouse_dy += (i64) floor(event->mouse_dy + .5);
 
-          case TRACK_INPUT_RELEASE:
-            track->envelope.release = track->value_buffer * .00001;
-            if (track->envelope.release < 0.)
-              track->envelope.release = 0.;
-            if (track->envelope.release > 60.)
-              track->envelope.release = 60.;
-            break;
-
-          default:;
-        }
-      }
+      saw_mouse_x = (i64) floor(event->mouse_x + .5);
+      saw_mouse_y = (i64) floor(event->mouse_y + .5);
 
       break;
 
     case SAPP_EVENTTYPE_MOUSE_DOWN:
+      saw_shift_on = (event->modifiers & SAPP_MODIFIER_SHIFT) != 0;
+      saw_ctrl_on  = (event->modifiers & SAPP_MODIFIER_CTRL) != 0;
+
       switch (event->mouse_button) {
         case SAPP_MOUSEBUTTON_LEFT:
           saw_lbutton_down  = 1;
@@ -2090,59 +2239,81 @@ static void saw_event(sapp_event const *event) {
           break;
         default:;
       }
+
       break;
 
     case SAPP_EVENTTYPE_MOUSE_UP:
+      saw_shift_on = (event->modifiers & SAPP_MODIFIER_SHIFT) != 0;
+      saw_ctrl_on  = (event->modifiers & SAPP_MODIFIER_CTRL) != 0;
+
       switch (event->mouse_button) {
         case SAPP_MOUSEBUTTON_LEFT: saw_lbutton_down = 0; break;
         case SAPP_MOUSEBUTTON_RIGHT: saw_rbutton_down = 0; break;
         case SAPP_MOUSEBUTTON_MIDDLE: saw_mbutton_down = 0; break;
         default:;
       }
+
       break;
 
     case SAPP_EVENTTYPE_MOUSE_LEAVE:
+      saw_shift_on = (event->modifiers & SAPP_MODIFIER_SHIFT) != 0;
+      saw_ctrl_on  = (event->modifiers & SAPP_MODIFIER_CTRL) != 0;
+
       saw_lbutton_down = 0;
       saw_rbutton_down = 0;
       saw_mbutton_down = 0;
+
       break;
 
     case SAPP_EVENTTYPE_KEY_DOWN:
-      if (!event->key_repeat) {
-        switch (event->key_code) {
-          case SAPP_KEYCODE_SPACE:
-            //  Playback control
-            saw_playback_on = !saw_playback_on;
-            break;
-
-          case SAPP_KEYCODE_ENTER:
-            //  Reset playback time
-            saw_playback_frame = 0;
-            break;
+      saw_shift_on = (event->modifiers & SAPP_MODIFIER_SHIFT) != 0;
+      saw_ctrl_on  = (event->modifiers & SAPP_MODIFIER_CTRL) != 0;
 
-          case SAPP_KEYCODE_ESCAPE:
-            //  Reset panning
-            //
+      if (!event->key_repeat && event->key_code >= 0 &&
+          event->key_code <
+              sizeof saw_key_pressed / sizeof *saw_key_pressed)
+        saw_key_pressed[event->key_code] = 1;
 
-            if (saw_current_roll != -1) {
-              saw_rolls[saw_current_roll].offset_x = 0;
-              saw_rolls[saw_current_roll].offset_y =
-                  ROLL_DEFAULT_OFFSET_Y;
-            }
+      break;
 
-            saw_compose.offset_x = 0;
-            saw_compose.offset_y = 0;
+      //  Touch events.
+      //  We treat touch as left mouse button and cursor.
+      //
 
-            break;
+    case SAPP_EVENTTYPE_TOUCHES_BEGAN:
+      if (event->num_touches >= 1) {
+        saw_mouse_x       = (i64) floor(event->touches[0].pos_x + .5);
+        saw_mouse_y       = (i64) floor(event->touches[0].pos_y + .5);
+        saw_lbutton_down  = 1;
+        saw_lbutton_click = 1;
+      }
+      break;
 
-          case SAPP_KEYCODE_D:
-            //  Duplicate selected track
-            saw_compose.duplicate_input = 1;
-            break;
+    case SAPP_EVENTTYPE_TOUCHES_MOVED:
+      if (event->num_touches >= 1) {
+        i64 x = (i64) floor(event->touches[0].pos_x + .5);
+        i64 y = (i64) floor(event->touches[0].pos_y + .5);
+        saw_mouse_dx += x - saw_mouse_x;
+        saw_mouse_dy += y - saw_mouse_y;
+        saw_mouse_x = x;
+        saw_mouse_y = y;
+      }
+      break;
 
-          default:;
-        }
+    case SAPP_EVENTTYPE_TOUCHES_ENDED:
+      if (event->num_touches >= 1) {
+        i64 x = (i64) floor(event->touches[0].pos_x + .5);
+        i64 y = (i64) floor(event->touches[0].pos_y + .5);
+        saw_mouse_dx += x - saw_mouse_x;
+        saw_mouse_dy += y - saw_mouse_y;
+        saw_mouse_x = x;
+        saw_mouse_y = y;
       }
+      saw_lbutton_down = 0;
+      break;
+
+    case SAPP_EVENTTYPE_TOUCHES_CANCELLED:
+      saw_lbutton_down = 0;
       break;
 
     default:;
@@ -2165,11 +2336,24 @@ static void log_(char const *tag, u32 log_level, u32 log_item_id,
 
 sapp_desc sokol_main(i32 argc, char **argv) {
   b8 print_version = 0;
+  b8 print_help    = 0;
 
   for (i32 i = 0; i < argc; i++)
     if (strcmp(argv[i], "--version") == 0)
       print_version = 1;
-    else if (i > 0 && saw_project_file.size == 0)
+    else if (strcmp(argv[i], "--help") == 0)
+      print_help = 1;
+    else if (argv[i][0] == '-' && argv[i][1] != '-' &&
+             argv[i][1] != '\0') {
+      for (i32 k = 1; argv[i][k] != '\0'; k++)
+        if (argv[i][k] == 'V')
+          print_version = 1;
+        else if (argv[i][k] == 'H')
+          print_help = 1;
+        else
+          printf("Unknown command line argument: \"-%c\"\n",
+                 argv[i][k]);
+    } else if (i > 0 && saw_project_file.size == 0)
       saw_project_file = kit_str(strlen(argv[i]), argv[i]);
     else if (i > 0)
       printf("Unknown command line argument: \"%s\"\n", argv[i]);
@@ -2185,9 +2369,12 @@ sapp_desc sokol_main(i32 argc, char **argv) {
            " - Music sequencer standalone application.\n",
            VERSION_MAJOR, VERSION_MINOR, VERSION_BABY);
 
+  if (print_help)
+    printf("Usage:\n%s [PROJECT_FILE]\n", argv[0]);
+
   fflush(stdout);
 
-  if (print_version)
+  if (print_version || print_help)
     exit(0);
 
   return (sapp_desc) {