From 35db4371e920641167f5b85d46bb7fb491ee91b5 Mon Sep 17 00:00:00 2001
From: Jenny Diomidova <diomidova@mit.edu>
Date: Sat, 13 Dec 2025 19:35:47 +0100
Subject: [PATCH] improve RotateTo logic

---
 src/c/digit_layer.cpp | 31 +++++++++++++++++++------------
 src/c/digit_layer.hpp | 11 +----------
 src/c/main.cpp        |  2 +-
 3 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/src/c/digit_layer.cpp b/src/c/digit_layer.cpp
index 126b89f..0b1ddd4 100644
--- a/src/c/digit_layer.cpp
+++ b/src/c/digit_layer.cpp
@@ -5,6 +5,10 @@
 using namespace Pebble;
 
 namespace {
+  static constexpr int16_t extraDigits = 6;
+  static constexpr int16_t digitHeight = 56;
+  static constexpr int16_t digitCount = 10;
+
   void draw_digit(const Pebble::GContext& ctx, const Pebble::GRect& bounds, const uint16_t digit) {
     Pebble::GBitmapBase& bitmap = bitmaps::GetDigitBitmap(digit);
     auto rect = bitmap.GetBounds();
@@ -15,13 +19,13 @@ namespace {
 
 void DigitLayerInner::OnUpdate(const Pebble::GContext& ctx) {
   auto bounds = this->GetBounds();
-  // LOG("Digit layer update. %d digits", this->digitCount);
+  // LOG("Digit layer update. %d digits", digitCount);
 
   ctx.SetCompositingMode(GCompOpSet);
-  for (int i = 0; i <= this->digitCount + 2 * this->extraDigits; i++) {
-    Pebble::GRect rect(0, i * this->digitHeight, bounds.size.w, this->digitHeight);
-    uint16_t digit = ((i - this->extraDigits) % this->digitCount + this->digitCount) % this->digitCount % 10;
-    // LOG("Digit %d -> %d", i - this->extraDigits, digit);
+  for (int i = 0; i <= digitCount + 2 * extraDigits; i++) {
+    Pebble::GRect rect(0, i * digitHeight, bounds.size.w, digitHeight);
+    uint16_t digit = ((i - extraDigits) % digitCount + digitCount) % digitCount;
+    // LOG("Digit %d -> %d", i - extraDigits, digit);
     draw_digit(ctx, rect, digit);
   }
 }
@@ -35,7 +39,7 @@ DigitLayer::DigitLayer() : Pebble::SimpleLayer(Pebble::GRect()) {
 void DigitLayer::UpdateLayout() {
   auto bounds = this->GetBounds();
   this->scrollLayer.SetFrame(bounds);
-  bounds.size.h = (this->innerLayer.digitCount + 2 * this->innerLayer.extraDigits) * this->innerLayer.digitHeight;
+  bounds.size.h = (digitCount + 2 * extraDigits) * digitHeight;
   this->innerLayer.SetFrame(bounds);
   this->scrollLayer.SetContentSize(bounds.size);
 }
@@ -43,18 +47,21 @@ void DigitLayer::UpdateLayout() {
 
 int16_t DigitLayer::ComputeOffset(uint16_t digit) {
   auto bounds = this->GetBounds();
-  return bounds.size.h / 2 - this->innerLayer.digitHeight / 2
-      - (digit + this->innerLayer.extraDigits) * this->innerLayer.digitHeight;
+  return bounds.size.h / 2 - digitHeight / 2 - (digit + extraDigits) * digitHeight;
 }
 
 void DigitLayer::RotateTo(uint16_t digit, bool animate) {
-  // LOG("Digit %d, out of %d", digit, innerLayer.digitCount);
-  digit %= innerLayer.digitCount;
+  // LOG("Digit %d, out of %d", digit, digitCount);
+  digit %= digitCount;
   auto currentOffset = this->scrollLayer.GetContentOffset();
-  if (digit == 0 && currentOffset.y <= ComputeOffset(this->innerLayer.digitCount / 2)) {
-    currentOffset.y += this->innerLayer.digitCount * this->innerLayer.digitHeight;
+  if (digit > this->currentDigit + digitCount / 2) {
+    currentOffset.y -= digitCount * digitHeight;
+    this->scrollLayer.SetContentOffset(currentOffset, false);
+  } else if (digit < this->currentDigit - digitCount / 2) {
+    currentOffset.y += digitCount * digitHeight;
     this->scrollLayer.SetContentOffset(currentOffset, false);
   }
 
   this->scrollLayer.SetContentOffset(this->ComputeOffset(digit), animate);
+  this->currentDigit = digit;
 }
\ No newline at end of file
diff --git a/src/c/digit_layer.hpp b/src/c/digit_layer.hpp
index 82c68bd..7e66cae 100644
--- a/src/c/digit_layer.hpp
+++ b/src/c/digit_layer.hpp
@@ -3,10 +3,6 @@
 #include <pebble-cpp/pebble.hpp>
 
 class DigitLayerInner : public Pebble::CustomLayer {
-  static constexpr int16_t extraDigits = 2;
-  static constexpr int16_t digitHeight = 56;
-  int16_t digitCount = 10;
-
   DigitLayerInner() : Pebble::CustomLayer(Pebble::GRect()) {}
 
   static void DrawDigit(const Pebble::GContext& ctx, const Pebble::GRect& bounds, const uint16_t digit);
@@ -20,15 +16,10 @@ protected:
 class DigitLayer : public Pebble::SimpleLayer {
   DigitLayerInner innerLayer;
   Pebble::ScrollLayer scrollLayer;
+  int16_t currentDigit = 0;
 public:
   DigitLayer();
 
-  void SetDigitCount(uint16_t cnt = 10) {
-    if (this->innerLayer.digitCount != cnt) {
-      this->innerLayer.digitCount = cnt;
-      this->UpdateLayout();
-    }
-  }
   void UpdateLayout();
   void RotateTo(uint16_t digit, bool animate=true);
 private:
diff --git a/src/c/main.cpp b/src/c/main.cpp
index 89e8045..48f7cad 100644
--- a/src/c/main.cpp
+++ b/src/c/main.cpp
@@ -8,7 +8,7 @@
 using namespace Pebble;
 
 // For debugging
-const bool USE_SECONDS_INSTEAD_OF_MINUTES = false;
+constexpr bool USE_SECONDS_INSTEAD_OF_MINUTES = false;
 
 class MainWindow : public AppWindow, public TickTimer {
   DigitLayer digitLayers[4];