Update README.md with checkout instructions

Fixes https://github.com/daveallie/crosspoint-reader/issues/1

README.md

@@ -31,7 +31,9 @@ This project is **not affiliated with Xteink**; it's built as a community projec
 - [x] EPUB parsing and rendering
 - [x] Saved reading position
 - [ ] File explorer with file picker
-  - Currently CrossPoint will just open the first EPUB it finds at the root of the SD card
+  - [x] Basic EPUB picker from root directory
+  - [x] Support nested folders
+  - [ ] EPUB picker with cover art
 - [ ] Image support within EPUB
 - [ ] Configurable font, layout, and display options
 - [ ] WiFi connectivity
@@ -46,6 +48,17 @@ This project is **not affiliated with Xteink**; it's built as a community projec
 * USB-C cable for flashing the ESP32-C3
 * Xteink X4
 
+### Checking out the code
+
+CrossPoint uses PlatformIO for building and flashing the firmware. To get started, clone the repository:
+
+```
+git clone --recursive https://github.com/daveallie/crosspoint-reader
+
+# Or, if you've already cloned without --recursive:
+git submodule update --init --recursive
+```
+
 ### Flashing your device
 
 #### Command line

lib/EpdFont/EpdFontFamily.cpp

@@ -0,0 +1,37 @@
+#include "EpdFontFamily.h"
+
+const EpdFont* EpdFontFamily::getFont(const EpdFontStyle style) const {
+  if (style == BOLD && bold) {
+    return bold;
+  }
+  if (style == ITALIC && italic) {
+    return italic;
+  }
+  if (style == BOLD_ITALIC) {
+    if (boldItalic) {
+      return boldItalic;
+    }
+    if (bold) {
+      return bold;
+    }
+    if (italic) {
+      return italic;
+    }
+  }
+
+  return regular;
+}
+
+void EpdFontFamily::getTextDimensions(const char* string, int* w, int* h, const EpdFontStyle style) const {
+  getFont(style)->getTextDimensions(string, w, h);
+}
+
+bool EpdFontFamily::hasPrintableChars(const char* string, const EpdFontStyle style) const {
+  return getFont(style)->hasPrintableChars(string);
+}
+
+const EpdFontData* EpdFontFamily::getData(const EpdFontStyle style) const { return getFont(style)->data; }
+
+const EpdGlyph* EpdFontFamily::getGlyph(const uint32_t cp, const EpdFontStyle style) const {
+  return getFont(style)->getGlyph(cp);
+};

lib/EpdFont/EpdFontFamily.h

@@ -0,0 +1,24 @@
+#pragma once
+#include "EpdFont.h"
+
+enum EpdFontStyle { REGULAR, BOLD, ITALIC, BOLD_ITALIC };
+
+class EpdFontFamily {
+  const EpdFont* regular;
+  const EpdFont* bold;
+  const EpdFont* italic;
+  const EpdFont* boldItalic;
+
+  const EpdFont* getFont(EpdFontStyle style) const;
+
+ public:
+  explicit EpdFontFamily(const EpdFont* regular, const EpdFont* bold = nullptr, const EpdFont* italic = nullptr,
+                         const EpdFont* boldItalic = nullptr)
+      : regular(regular), bold(bold), italic(italic), boldItalic(boldItalic) {}
+  ~EpdFontFamily() = default;
+  void getTextDimensions(const char* string, int* w, int* h, EpdFontStyle style = REGULAR) const;
+  bool hasPrintableChars(const char* string, EpdFontStyle style = REGULAR) const;
+
+  const EpdFontData* getData(EpdFontStyle style = REGULAR) const;
+  const EpdGlyph* getGlyph(uint32_t cp, EpdFontStyle style = REGULAR) const;
+};

lib/EpdFontRenderer/EpdFontRenderer.hpp

@@ -1,5 +1,5 @@
 #pragma once
-#include <EpdFont.h>
+#include <EpdFontFamily.h>
 #include <HardwareSerial.h>
 #include <Utf8.h>
 #include <miniz.h>
@@ -12,13 +12,14 @@ static tinfl_decompressor decomp;
 template <typename Renderable>
 class EpdFontRenderer {
   Renderable* renderer;
-  void renderChar(uint32_t cp, int* x, const int* y, uint16_t color);
+  void renderChar(uint32_t cp, int* x, const int* y, uint16_t color, EpdFontStyle style = REGULAR);
 
  public:
-  const EpdFont* font;
-  explicit EpdFontRenderer(const EpdFont* font, Renderable* renderer);
+  const EpdFontFamily* fontFamily;
+  explicit EpdFontRenderer(const EpdFontFamily* fontFamily, Renderable* renderer)
+      : fontFamily(fontFamily), renderer(renderer) {}
   ~EpdFontRenderer() = default;
-  void renderString(const char* string, int* x, int* y, uint16_t color);
+  void renderString(const char* string, int* x, int* y, uint16_t color, EpdFontStyle style = REGULAR);
 };
 
 inline int uncompress(uint8_t* dest, size_t uncompressedSize, const uint8_t* source, size_t sourceSize) {
@@ -38,37 +39,33 @@ inline int uncompress(uint8_t* dest, size_t uncompressedSize, const uint8_t* sou
 }
 
 template <typename Renderable>
-EpdFontRenderer<Renderable>::EpdFontRenderer(const EpdFont* font, Renderable* renderer) {
-  this->font = font;
-  this->renderer = renderer;
-}
-
-template <typename Renderable>
-void EpdFontRenderer<Renderable>::renderString(const char* string, int* x, int* y, const uint16_t color) {
+void EpdFontRenderer<Renderable>::renderString(const char* string, int* x, int* y, const uint16_t color,
+                                               const EpdFontStyle style) {
   // cannot draw a NULL / empty string
   if (string == nullptr || *string == '\0') {
     return;
   }
 
   // no printable characters
-  if (!font->hasPrintableChars(string)) {
+  if (!fontFamily->hasPrintableChars(string, style)) {
     return;
   }
 
   uint32_t cp;
   while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&string)))) {
-    renderChar(cp, x, y, color);
+    renderChar(cp, x, y, color, style);
   }
 
-  *y += font->data->advanceY;
+  *y += fontFamily->getData(style)->advanceY;
 }
 
 template <typename Renderable>
-void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const int* y, uint16_t color) {
-  const EpdGlyph* glyph = font->getGlyph(cp);
+void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const int* y, uint16_t color,
+                                             const EpdFontStyle style) {
+  const EpdGlyph* glyph = fontFamily->getGlyph(cp, style);
   if (!glyph) {
     // TODO: Replace with fallback glyph property?
-    glyph = font->getGlyph('?');
+    glyph = fontFamily->getGlyph('?', style);
   }
 
   // no glyph?
@@ -86,17 +83,17 @@ void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const in
   const unsigned long bitmapSize = byteWidth * height;
   const uint8_t* bitmap = nullptr;
 
-  if (font->data->compressed) {
+  if (fontFamily->getData(style)->compressed) {
     auto* tmpBitmap = static_cast<uint8_t*>(malloc(bitmapSize));
     if (tmpBitmap == nullptr && bitmapSize) {
-      // ESP_LOGE("font", "malloc failed.");
+      Serial.println("Failed to allocate memory for decompression buffer");
       return;
     }
 
-    uncompress(tmpBitmap, bitmapSize, &font->data->bitmap[offset], glyph->compressedSize);
+    uncompress(tmpBitmap, bitmapSize, &fontFamily->getData(style)->bitmap[offset], glyph->compressedSize);
     bitmap = tmpBitmap;
   } else {
-    bitmap = &font->data->bitmap[offset];
+    bitmap = &fontFamily->getData(style)->bitmap[offset];
   }
 
   if (bitmap != nullptr) {
@@ -123,7 +120,7 @@ void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const in
       }
     }
 
-    if (font->data->compressed) {
+    if (fontFamily->getData(style)->compressed) {
       free(const_cast<uint8_t*>(bitmap));
     }
   }

lib/EpdRenderer/EpdRenderer.cpp

@@ -5,14 +5,18 @@
 #include "builtinFonts/bookerly_bold.h"
 #include "builtinFonts/bookerly_bold_italic.h"
 #include "builtinFonts/bookerly_italic.h"
+#include "builtinFonts/ubuntu_10.h"
+#include "builtinFonts/ubuntu_bold_10.h"
 
 EpdRenderer::EpdRenderer(XteinkDisplay* display) {
+  const auto bookerlyFontFamily = new EpdFontFamily(new EpdFont(&bookerly), new EpdFont(&bookerly_bold),
+                                                    new EpdFont(&bookerly_italic), new EpdFont(&bookerly_bold_italic));
+  const auto ubuntuFontFamily = new EpdFontFamily(new EpdFont(&ubuntu_10), new EpdFont(&ubuntu_bold_10));
+
   this->display = display;
-  this->regularFont = new EpdFontRenderer<XteinkDisplay>(new EpdFont(&bookerly), display);
-  this->boldFont = new EpdFontRenderer<XteinkDisplay>(new EpdFont(&bookerly_bold), display);
-  this->italicFont = new EpdFontRenderer<XteinkDisplay>(new EpdFont(&bookerly_italic), display);
-  this->bold_italicFont = new EpdFontRenderer<XteinkDisplay>(new EpdFont(&bookerly_bold_italic), display);
-  this->smallFont = new EpdFontRenderer<XteinkDisplay>(new EpdFont(&babyblue), display);
+  this->regularFontRenderer = new EpdFontRenderer<XteinkDisplay>(bookerlyFontFamily, display);
+  this->smallFontRenderer = new EpdFontRenderer<XteinkDisplay>(new EpdFontFamily(new EpdFont(&babyblue)), display);
+  this->uiFontRenderer = new EpdFontRenderer<XteinkDisplay>(ubuntuFontFamily, display);
 
   this->marginTop = 11;
   this->marginBottom = 30;
@@ -21,50 +25,53 @@ EpdRenderer::EpdRenderer(XteinkDisplay* display) {
   this->lineCompression = 0.95f;
 }
 
-EpdFontRenderer<XteinkDisplay>* EpdRenderer::getFontRenderer(const bool bold, const bool italic) const {
-  if (bold && italic) {
-    return bold_italicFont;
-  }
-  if (bold) {
-    return boldFont;
-  }
-  if (italic) {
-    return italicFont;
-  }
-  return regularFont;
-}
-
-int EpdRenderer::getTextWidth(const char* text, const bool bold, const bool italic) const {
+int EpdRenderer::getTextWidth(const char* text, const EpdFontStyle style) const {
   int w = 0, h = 0;
 
-  getFontRenderer(bold, italic)->font->getTextDimensions(text, &w, &h);
+  regularFontRenderer->fontFamily->getTextDimensions(text, &w, &h, style);
 
   return w;
 }
 
-int EpdRenderer::getSmallTextWidth(const char* text) const {
+int EpdRenderer::getUiTextWidth(const char* text, const EpdFontStyle style) const {
   int w = 0, h = 0;
 
-  smallFont->font->getTextDimensions(text, &w, &h);
+  uiFontRenderer->fontFamily->getTextDimensions(text, &w, &h, style);
 
   return w;
 }
 
-void EpdRenderer::drawText(const int x, const int y, const char* text, const bool bold, const bool italic,
-                           const uint16_t color) const {
+int EpdRenderer::getSmallTextWidth(const char* text, const EpdFontStyle style) const {
+  int w = 0, h = 0;
+
+  smallFontRenderer->fontFamily->getTextDimensions(text, &w, &h, style);
+
+  return w;
+}
+
+void EpdRenderer::drawText(const int x, const int y, const char* text, const uint16_t color,
+                           const EpdFontStyle style) const {
   int ypos = y + getLineHeight() + marginTop;
   int xpos = x + marginLeft;
-  getFontRenderer(bold, italic)->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
+  regularFontRenderer->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE, style);
 }
 
-void EpdRenderer::drawSmallText(const int x, const int y, const char* text) const {
-  int ypos = y + smallFont->font->data->advanceY + marginTop;
+void EpdRenderer::drawUiText(const int x, const int y, const char* text, const uint16_t color,
+                             const EpdFontStyle style) const {
+  int ypos = y + uiFontRenderer->fontFamily->getData(style)->advanceY + marginTop;
   int xpos = x + marginLeft;
-  smallFont->renderString(text, &xpos, &ypos, GxEPD_BLACK);
+  uiFontRenderer->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE, style);
+}
+
+void EpdRenderer::drawSmallText(const int x, const int y, const char* text, const uint16_t color,
+                                const EpdFontStyle style) const {
+  int ypos = y + smallFontRenderer->fontFamily->getData(style)->advanceY + marginTop;
+  int xpos = x + marginLeft;
+  smallFontRenderer->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE, style);
 }
 
 void EpdRenderer::drawTextBox(const int x, const int y, const std::string& text, const int width, const int height,
-                              const bool bold, const bool italic) const {
+                              const EpdFontStyle style) const {
   const size_t length = text.length();
   // fit the text into the box
   int start = 0;
@@ -72,7 +79,7 @@ void EpdRenderer::drawTextBox(const int x, const int y, const std::string& text,
   int ypos = 0;
   while (true) {
     if (end >= length) {
-      drawText(x, y + ypos, text.substr(start, length - start).c_str(), bold, italic);
+      drawText(x, y + ypos, text.substr(start, length - start).c_str(), 1, style);
       break;
     }
 
@@ -81,15 +88,15 @@ void EpdRenderer::drawTextBox(const int x, const int y, const std::string& text,
     }
 
     if (text[end - 1] == '\n') {
-      drawText(x, y + ypos, text.substr(start, end - start).c_str(), bold, italic);
+      drawText(x, y + ypos, text.substr(start, end - start).c_str(), 1, style);
       ypos += getLineHeight();
       start = end;
       end = start + 1;
       continue;
     }
 
-    if (getTextWidth(text.substr(start, end - start).c_str(), bold, italic) > width) {
-      drawText(x, y + ypos, text.substr(start, end - start - 1).c_str(), bold, italic);
+    if (getTextWidth(text.substr(start, end - start).c_str(), style) > width) {
+      drawText(x, y + ypos, text.substr(start, end - start - 1).c_str(), 1, style);
       ypos += getLineHeight();
       start = end - 1;
       continue;
@@ -108,44 +115,45 @@ void EpdRenderer::drawRect(const int x, const int y, const int width, const int
   display->drawRect(x + marginLeft, y + marginTop, width, height, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
 }
 
-void EpdRenderer::fillRect(const int x, const int y, const int width, const int height,
-                           const uint16_t color = 0) const {
+void EpdRenderer::fillRect(const int x, const int y, const int width, const int height, const uint16_t color) const {
   display->fillRect(x + marginLeft, y + marginTop, width, height, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
 }
 
+void EpdRenderer::drawCircle(const int x, const int y, const int radius, const uint16_t color) const {
+  display->drawCircle(x + marginLeft, y + marginTop, radius, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
+}
+
+void EpdRenderer::fillCircle(const int x, const int y, const int radius, const uint16_t color) const {
+  display->fillCircle(x + marginLeft, y + marginTop, radius, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
+}
+
+void EpdRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, const int width, const int height,
+                            const bool invert, const bool mirrorY) const {
+  drawImageNoMargin(bitmap, x + marginLeft, y + marginTop, width, height, invert, mirrorY);
+}
+
+void EpdRenderer::drawImageNoMargin(const uint8_t bitmap[], const int x, const int y, const int width, const int height,
+                                    const bool invert, const bool mirrorY) const {
+  display->drawImage(bitmap, x, y, width, height, invert, mirrorY);
+}
+
 void EpdRenderer::clearScreen(const bool black) const {
   Serial.println("Clearing screen");
   display->fillScreen(black ? GxEPD_BLACK : GxEPD_WHITE);
 }
 
-void EpdRenderer::flushDisplay() const { display->display(true); }
+void EpdRenderer::flushDisplay(const bool partialUpdate) const { display->display(partialUpdate); }
 
-void EpdRenderer::flushArea(int x, int y, int width, int height) const {
-  // TODO: Fix
-  display->display(true);
+void EpdRenderer::flushArea(const int x, const int y, const int width, const int height) const {
+  display->displayWindow(x + marginLeft, y + marginTop, width, height);
 }
 
 int EpdRenderer::getPageWidth() const { return display->width() - marginLeft - marginRight; }
 
 int EpdRenderer::getPageHeight() const { return display->height() - marginTop - marginBottom; }
 
-int EpdRenderer::getSpaceWidth() const { return regularFont->font->getGlyph(' ')->advanceX; }
+int EpdRenderer::getSpaceWidth() const { return regularFontRenderer->fontFamily->getGlyph(' ', REGULAR)->advanceX; }
 
-int EpdRenderer::getLineHeight() const { return regularFont->font->data->advanceY * lineCompression; }
-
-// deep sleep helper - persist any state to disk that may be needed on wake
-bool EpdRenderer::dehydrate() {
-  // TODO: Implement
-  return false;
-};
-
-// deep sleep helper - retrieve any state from disk after wake
-bool EpdRenderer::hydrate() {
-  // TODO: Implement
-  return false;
-};
-
-// really really clear the screen
-void EpdRenderer::reset() {
-  // TODO: Implement
-};
+int EpdRenderer::getLineHeight() const {
+  return regularFontRenderer->fontFamily->getData(REGULAR)->advanceY * lineCompression;
+}

lib/EpdRenderer/EpdRenderer.h

@@ -8,32 +8,36 @@
 
 class EpdRenderer {
   XteinkDisplay* display;
-  EpdFontRenderer<XteinkDisplay>* regularFont;
-  EpdFontRenderer<XteinkDisplay>* boldFont;
-  EpdFontRenderer<XteinkDisplay>* italicFont;
-  EpdFontRenderer<XteinkDisplay>* bold_italicFont;
-  EpdFontRenderer<XteinkDisplay>* smallFont;
+  EpdFontRenderer<XteinkDisplay>* regularFontRenderer;
+  EpdFontRenderer<XteinkDisplay>* smallFontRenderer;
+  EpdFontRenderer<XteinkDisplay>* uiFontRenderer;
   int marginTop;
   int marginBottom;
   int marginLeft;
   int marginRight;
   float lineCompression;
-  EpdFontRenderer<XteinkDisplay>* getFontRenderer(bool bold, bool italic) const;
 
  public:
   explicit EpdRenderer(XteinkDisplay* display);
   ~EpdRenderer() = default;
-  int getTextWidth(const char* text, bool bold = false, bool italic = false) const;
-  int getSmallTextWidth(const char* text) const;
-  void drawText(int x, int y, const char* text, bool bold = false, bool italic = false, uint16_t color = 1) const;
-  void drawSmallText(int x, int y, const char* text) const;
-  void drawTextBox(int x, int y, const std::string& text, int width, int height, bool bold = false,
-                   bool italic = false) const;
-  void drawLine(int x1, int y1, int x2, int y2, uint16_t color) const;
-  void drawRect(int x, int y, int width, int height, uint16_t color) const;
-  void fillRect(int x, int y, int width, int height, uint16_t color) const;
+  int getTextWidth(const char* text, EpdFontStyle style = REGULAR) const;
+  int getUiTextWidth(const char* text, EpdFontStyle style = REGULAR) const;
+  int getSmallTextWidth(const char* text, EpdFontStyle style = REGULAR) const;
+  void drawText(int x, int y, const char* text, uint16_t color = 1, EpdFontStyle style = REGULAR) const;
+  void drawUiText(int x, int y, const char* text, uint16_t color = 1, EpdFontStyle style = REGULAR) const;
+  void drawSmallText(int x, int y, const char* text, uint16_t color = 1, EpdFontStyle style = REGULAR) const;
+  void drawTextBox(int x, int y, const std::string& text, int width, int height, EpdFontStyle style = REGULAR) const;
+  void drawLine(int x1, int y1, int x2, int y2, uint16_t color = 1) const;
+  void drawRect(int x, int y, int width, int height, uint16_t color = 1) const;
+  void fillRect(int x, int y, int width, int height, uint16_t color = 1) const;
+  void drawCircle(int x, int y, int radius, uint16_t color = 1) const;
+  void fillCircle(int x, int y, int radius, uint16_t color = 1) const;
+  void drawImage(const uint8_t bitmap[], int x, int y, int width, int height, bool invert = false,
+                 bool mirrorY = false) const;
+  void drawImageNoMargin(const uint8_t bitmap[], int x, int y, int width, int height, bool invert = false,
+                         bool mirrorY = false) const;
   void clearScreen(bool black = false) const;
-  void flushDisplay() const;
+  void flushDisplay(bool partialUpdate = true) const;
   void flushArea(int x, int y, int width, int height) const;
 
   int getPageWidth() const;
@@ -45,12 +49,4 @@ class EpdRenderer {
   void setMarginBottom(const int newMarginBottom) { this->marginBottom = newMarginBottom; }
   void setMarginLeft(const int newMarginLeft) { this->marginLeft = newMarginLeft; }
   void setMarginRight(const int newMarginRight) { this->marginRight = newMarginRight; }
-  // deep sleep helper - persist any state to disk that may be needed on wake
-  bool dehydrate();
-  // deep sleep helper - retrieve any state from disk after wake
-  bool hydrate();
-  // really really clear the screen
-  void reset();
-
-  uint8_t temperature = 20;
 };

lib/Epub/Epub/Section.cpp

@@ -107,11 +107,11 @@ void Section::renderPage() {
     delete p;
   } else if (pageCount == 0) {
     Serial.println("No pages to render");
-    const int width = renderer->getTextWidth("Empty chapter", true);
-    renderer->drawText((renderer->getPageWidth() - width) / 2, 300, "Empty chapter", true);
+    const int width = renderer->getTextWidth("Empty chapter", BOLD);
+    renderer->drawText((renderer->getPageWidth() - width) / 2, 300, "Empty chapter", 1, BOLD);
   } else {
     Serial.printf("Page out of bounds: %d (max %d)\n", currentPage, pageCount);
-    const int width = renderer->getTextWidth("Out of bounds", true);
-    renderer->drawText((renderer->getPageWidth() - width) / 2, 300, "Out of bounds", true);
+    const int width = renderer->getTextWidth("Out of bounds", BOLD);
+    renderer->drawText((renderer->getPageWidth() - width) / 2, 300, "Out of bounds", 1, BOLD);
   }
 }

lib/Epub/Epub/blocks/TextBlock.cpp

@@ -56,7 +56,17 @@ std::list<TextBlock*> TextBlock::splitIntoLines(const EpdRenderer* renderer) {
   uint16_t wordWidths[totalWordCount];
   for (int i = 0; i < words.size(); i++) {
     // measure the word
-    const int width = renderer->getTextWidth(words[i].c_str(), wordStyles[i] & BOLD_SPAN, wordStyles[i] & ITALIC_SPAN);
+    EpdFontStyle fontStyle = REGULAR;
+    if (wordStyles[i] & BOLD_SPAN) {
+      if (wordStyles[i] & ITALIC_SPAN) {
+        fontStyle = BOLD_ITALIC;
+      } else {
+        fontStyle = BOLD;
+      }
+    } else if (wordStyles[i] & ITALIC_SPAN) {
+      fontStyle = ITALIC;
+    }
+    const int width = renderer->getTextWidth(words[i].c_str(), fontStyle);
     wordWidths[i] = width;
   }
 
@@ -182,7 +192,18 @@ void TextBlock::render(const EpdRenderer* renderer, const int x, const int y) co
     // get the style
     const uint8_t wordStyle = wordStyles[i];
     // render the word
-    renderer->drawText(x + wordXpos[i], y, words[i].c_str(), wordStyle & BOLD_SPAN, wordStyle & ITALIC_SPAN);
+    EpdFontStyle fontStyle = REGULAR;
+    if (wordStyles[i] & BOLD_SPAN) {
+      if (wordStyles[i] & ITALIC_SPAN) {
+        fontStyle = BOLD_ITALIC;
+      } else {
+        fontStyle = BOLD;
+      }
+
+    } else if (wordStyles[i] & ITALIC_SPAN) {
+      fontStyle = ITALIC;
+    }
+    renderer->drawText(x + wordXpos[i], y, words[i].c_str(), 1, fontStyle);
   }
 }
 

src/CrossPointState.cpp

@@ -0,0 +1,46 @@
+#include "CrossPointState.h"
+
+#include <HardwareSerial.h>
+#include <SD.h>
+#include <Serialization.h>
+
+#include <fstream>
+
+constexpr uint8_t STATE_VERSION = 1;
+constexpr char STATE_FILE[] = "/sd/.crosspoint/state.bin";
+
+void CrossPointState::serialize(std::ostream& os) const {
+  serialization::writePod(os, STATE_VERSION);
+  serialization::writeString(os, openEpubPath);
+}
+
+CrossPointState* CrossPointState::deserialize(std::istream& is) {
+  const auto state = new CrossPointState();
+
+  uint8_t version;
+  serialization::readPod(is, version);
+  if (version != STATE_VERSION) {
+    Serial.printf("CrossPointState: Unknown version %u\n", version);
+    return state;
+  }
+
+  serialization::readString(is, state->openEpubPath);
+  return state;
+}
+
+void CrossPointState::saveToFile() const {
+  std::ofstream outputFile(STATE_FILE);
+  serialize(outputFile);
+  outputFile.close();
+}
+
+CrossPointState* CrossPointState::loadFromFile() {
+  if (!SD.exists(&STATE_FILE[3])) {
+    return new CrossPointState();
+  }
+
+  std::ifstream inputFile(STATE_FILE);
+  CrossPointState* state = deserialize(inputFile);
+  inputFile.close();
+  return state;
+}

src/CrossPointState.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <iosfwd>
+#include <string>
+
+class CrossPointState {
+  void serialize(std::ostream& os) const;
+  static CrossPointState* deserialize(std::istream& is);
+
+ public:
+  std::string openEpubPath;
+  ~CrossPointState() = default;
+  void saveToFile() const;
+  static CrossPointState* loadFromFile();
+};

src/Input.cpp

@@ -29,15 +29,15 @@ Button getPressedButton() {
   return NONE;
 }
 
-Input getInput(const bool skipWait) {
+Input getInput(const long maxHoldMs) {
   const Button button = getPressedButton();
   if (button == NONE) return {NONE, 0};
 
-  if (skipWait) {
-    return {button, 0};
-  }
-
   const auto start = millis();
-  while (getPressedButton() == button) delay(50);
-  return {button, millis() - start};
+  unsigned long held = 0;
+  while (getPressedButton() == button && (maxHoldMs < 0 || held < maxHoldMs)) {
+    delay(50);
+    held = millis() - start;
+  }
+  return {button, held};
 }

src/Input.h

@@ -10,9 +10,9 @@
 // Button ADC thresholds
 #define BTN_THRESHOLD 100  // Threshold tolerance
 #define BTN_RIGHT_VAL 3
-#define BTN_LEFT_VAL 1470
-#define BTN_CONFIRM_VAL 2655
-#define BTN_BACK_VAL 3470
+#define BTN_LEFT_VAL 1500
+#define BTN_CONFIRM_VAL 2700
+#define BTN_BACK_VAL 3550
 #define BTN_VOLUME_DOWN_VAL 3
 #define BTN_VOLUME_UP_VAL 2305
 
@@ -25,4 +25,4 @@ struct Input {
 
 void setupInputPinModes();
 Button getPressedButton();
-Input getInput(bool skipWait = false);
+Input getInput(long maxHoldMs = -1);

src/images/CrossLarge.h

@@ -0,0 +1,113 @@
+#pragma once
+#include <cstdint>
+
+extern const uint8_t CrossLarge[] = {
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xEF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF7, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC7, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE3, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x83, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xC1, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x7F, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xF8, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x1F,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x0F, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xE0, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x01,
+    0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0xFF, 0xFF, 0xFF,
+    0xFE, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFC, 0x00, 0x00,
+    0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x3F, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xF8, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00,
+    0x00, 0x07, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x03, 0xFF,
+    0xFF, 0x80, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0x00, 0x00,
+    0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF,
+    0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFC, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x1F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x0F, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xC0, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x80, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x03, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF,
+    0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x07, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x0F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFC,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFE, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x0F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x07, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xC0, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x03, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF,
+    0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xF8, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x3F, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF,
+    0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xE0, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xC0, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xE0, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F,
+    0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xF8, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x3F, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x7F, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0x80, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x03, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x01, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xE0, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xF0, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x1F, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFF,
+    0xFF, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1F, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFE, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x3F, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x7F, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF,
+    0x80, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x01, 0xFF, 0xFF, 0xC0, 0x00, 0x00,
+    0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x03, 0xFF, 0xFF, 0xE0, 0x00, 0x00, 0x00, 0x0F, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x07, 0xFF, 0xFF, 0xF0, 0x00, 0x00, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xF8, 0x00, 0x00, 0x00, 0x0F, 0xFF, 0xFF, 0xF8, 0x00, 0x00, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x00,
+    0x00, 0x1F, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x3F, 0xFF,
+    0xFF, 0xFE, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0x00,
+    0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0x00, 0x03, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xE0, 0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xE0, 0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0,
+    0x00, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x0F, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xF8, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC, 0x00, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFC, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x7F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x83, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xC1, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC7, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xE3, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xEF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF7, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+};

src/main.cpp

@@ -6,9 +6,13 @@
 #include <SPI.h>
 
 #include "Battery.h"
+#include "CrossPointState.h"
 #include "Input.h"
+#include "screens/BootLogoScreen.h"
 #include "screens/EpubReaderScreen.h"
+#include "screens/FileSelectionScreen.h"
 #include "screens/FullScreenMessageScreen.h"
+#include "screens/SleepScreen.h"
 
 #define SPI_FQ 40000000
 // Display SPI pins (custom pins for XteinkX4, not hardware SPI defaults)
@@ -28,10 +32,11 @@ GxEPD2_BW<GxEPD2_426_GDEQ0426T82, GxEPD2_426_GDEQ0426T82::HEIGHT> display(GxEPD2
                                                                                                  EPD_RST, EPD_BUSY));
 auto renderer = new EpdRenderer(&display);
 Screen* currentScreen;
+CrossPointState* appState;
 
 // Power button timing
 // Time required to confirm boot from sleep
-constexpr unsigned long POWER_BUTTON_WAKEUP_MS = 1500;
+constexpr unsigned long POWER_BUTTON_WAKEUP_MS = 1000;
 // Time required to enter sleep mode
 constexpr unsigned long POWER_BUTTON_SLEEP_MS = 1000;
 
@@ -47,24 +52,33 @@ Epub* loadEpub(const std::string& path) {
   }
 
   Serial.println("Failed to load epub");
-  free(epub);
+  delete epub;
   return nullptr;
 }
 
-void enterNewScreen(Screen* screen) {
+void exitScreen() {
   if (currentScreen) {
     currentScreen->onExit();
     delete currentScreen;
   }
+}
+
+void enterNewScreen(Screen* screen) {
   currentScreen = screen;
   currentScreen->onEnter();
 }
 
 // Verify long press on wake-up from deep sleep
 void verifyWakeupLongPress() {
-  const auto input = getInput();
+  // Give the user up to 1000ms to start holding the power button, and must hold for POWER_BUTTON_WAKEUP_MS
+  const auto start = millis();
+  auto input = getInput(POWER_BUTTON_WAKEUP_MS);
+  while (input.button != POWER && millis() - start < 1000) {
+    delay(50);
+    input = getInput(POWER_BUTTON_WAKEUP_MS);
+  }
 
-  if (input.button == POWER && input.pressTime > POWER_BUTTON_WAKEUP_MS) {
+  if (input.button != POWER || input.pressTime < POWER_BUTTON_WAKEUP_MS) {
     // Button released too early. Returning to sleep.
     // IMPORTANT: Re-arm the wakeup trigger before sleeping again
     esp_deep_sleep_enable_gpio_wakeup(1ULL << BTN_GPIO3, ESP_GPIO_WAKEUP_GPIO_LOW);
@@ -72,12 +86,19 @@ void verifyWakeupLongPress() {
   }
 }
 
+void waitForNoButton() {
+  while (getInput().button != NONE) {
+    delay(50);
+  }
+}
+
 // Enter deep sleep mode
 void enterDeepSleep() {
-  enterNewScreen(new FullScreenMessageScreen(renderer, "Sleeping", true, false, true));
+  exitScreen();
+  enterNewScreen(new SleepScreen(renderer));
 
   Serial.println("Power button released after a long press. Entering deep sleep.");
-  delay(2000);  // Allow Serial buffer to empty and display to update
+  delay(1000);  // Allow Serial buffer to empty and display to update
 
   // Enable Wakeup on LOW (button press)
   esp_deep_sleep_enable_gpio_wakeup(1ULL << BTN_GPIO3, ESP_GPIO_WAKEUP_GPIO_LOW);
@@ -88,31 +109,39 @@ void enterDeepSleep() {
   esp_deep_sleep_start();
 }
 
-void setupSerial() {
-  Serial.begin(115200);
-  // Wait for serial monitor
-  const unsigned long start = millis();
-  while (!Serial && (millis() - start) < 3000) {
-    delay(10);
+void onGoHome();
+void onSelectEpubFile(const std::string& path) {
+  exitScreen();
+  enterNewScreen(new FullScreenMessageScreen(renderer, "Loading..."));
+
+  Epub* epub = loadEpub(path);
+  if (epub) {
+    appState->openEpubPath = path;
+    appState->saveToFile();
+    exitScreen();
+    enterNewScreen(new EpubReaderScreen(renderer, epub, onGoHome));
+  } else {
+    exitScreen();
+    enterNewScreen(new FullScreenMessageScreen(renderer, "Failed to load epub", REGULAR, false, false));
+    delay(2000);
+    onGoHome();
+  }
 }
 
-  if (Serial) {
-    // delay for monitor to start reading
-    delay(1000);
-  }
+void onGoHome() {
+  exitScreen();
+  enterNewScreen(new FileSelectionScreen(renderer, onSelectEpubFile));
 }
 
 void setup() {
   setupInputPinModes();
-
-  // Check if boot was triggered by the Power Button (Deep Sleep Wakeup)
-  // If triggered by RST pin or Battery insertion, this will be false, allowing
-  // normal boot.
-  if (esp_sleep_get_wakeup_cause() == ESP_SLEEP_WAKEUP_GPIO) {
   verifyWakeupLongPress();
-  }
 
-  setupSerial();
+  // Begin serial only if USB connected
+  pinMode(UART0_RXD, INPUT);
+  if (digitalRead(UART0_RXD) == HIGH) {
+    Serial.begin(115200);
+  }
 
   // Initialize pins
   pinMode(BAT_GPIO0, INPUT);
@@ -127,37 +156,29 @@ void setup() {
   display.setTextColor(GxEPD_BLACK);
   Serial.println("Display initialized");
 
-  enterNewScreen(new FullScreenMessageScreen(renderer, "Loading...", true));
+  exitScreen();
+  enterNewScreen(new BootLogoScreen(renderer));
 
   // SD Card Initialization
   SD.begin(SD_SPI_CS, SPI, SPI_FQ);
 
-  // TODO: Add a file selection screen, for now just load the first file
-  File root = SD.open("/");
-  String filename;
-  while (true) {
-    filename = root.getNextFileName();
-    if (!filename) {
-      break;
-    }
-
-    if (filename.substring(filename.length() - 5) == ".epub") {
-      Serial.printf("Found epub: %s\n", filename.c_str());
-      break;
-    }
-  }
-
-  if (!filename) {
-    enterNewScreen(new FullScreenMessageScreen(renderer, "Could not find epub"));
+  appState = CrossPointState::loadFromFile();
+  if (!appState->openEpubPath.empty()) {
+    Epub* epub = loadEpub(appState->openEpubPath);
+    if (epub) {
+      exitScreen();
+      enterNewScreen(new EpubReaderScreen(renderer, epub, onGoHome));
+      // Ensure we're not still holding the power button before leaving setup
+      waitForNoButton();
       return;
     }
-
-  Epub* epub = loadEpub(std::string(filename.c_str()));
-  if (epub) {
-    enterNewScreen(new EpubReaderScreen(renderer, epub));
-  } else {
-    enterNewScreen(new FullScreenMessageScreen(renderer, "Failed to load epub"));
   }
+
+  exitScreen();
+  enterNewScreen(new FileSelectionScreen(renderer, onSelectEpubFile));
+
+  // Ensure we're not still holding the power button before leaving setup
+  waitForNoButton();
 }
 
 void loop() {

src/screens/BootLogoScreen.cpp

@@ -0,0 +1,14 @@
+#include "BootLogoScreen.h"
+
+#include <EpdRenderer.h>
+
+#include "images/CrossLarge.h"
+
+void BootLogoScreen::onEnter() {
+  const auto pageWidth = renderer->getPageWidth();
+  const auto pageHeight = renderer->getPageHeight();
+
+  renderer->clearScreen();
+  // Location for images is from top right in landscape orientation
+  renderer->drawImage(CrossLarge, (pageHeight - 128) / 2, (pageWidth - 128) / 2, 128, 128);
+}

src/screens/BootLogoScreen.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "Screen.h"
+
+class BootLogoScreen final : public Screen {
+ public:
+  explicit BootLogoScreen(EpdRenderer* renderer) : Screen(renderer) {}
+  void onEnter() override;
+};

src/screens/EpubReaderScreen.cpp

@@ -5,6 +5,7 @@
 
 #include "Battery.h"
 
+constexpr int PAGES_PER_REFRESH = 10;
 constexpr unsigned long SKIP_CHAPTER_MS = 700;
 
 void EpubReaderScreen::taskTrampoline(void* param) {
@@ -13,7 +14,11 @@ void EpubReaderScreen::taskTrampoline(void* param) {
 }
 
 void EpubReaderScreen::onEnter() {
-  sectionMutex = xSemaphoreCreateMutex();
+  if (!epub) {
+    return;
+  }
+
+  renderingMutex = xSemaphoreCreateMutex();
 
   epub->setupCacheDir();
 
@@ -40,14 +45,22 @@ void EpubReaderScreen::onEnter() {
 }
 
 void EpubReaderScreen::onExit() {
+  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
-  xSemaphoreTake(sectionMutex, portMAX_DELAY);
-  vSemaphoreDelete(sectionMutex);
-  sectionMutex = nullptr;
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+  delete section;
+  section = nullptr;
+  delete epub;
+  epub = nullptr;
 }
 
 void EpubReaderScreen::handleInput(const Input input) {
-  if (input.button == VOLUME_UP || input.button == VOLUME_DOWN) {
+  if (input.button == VOLUME_UP || input.button == VOLUME_DOWN || input.button == LEFT || input.button == RIGHT) {
     const bool skipChapter = input.pressTime > SKIP_CHAPTER_MS;
 
     // No current section, attempt to rerender the book
@@ -56,41 +69,45 @@ void EpubReaderScreen::handleInput(const Input input) {
       return;
     }
 
-    if (input.button == VOLUME_UP && skipChapter) {
+    if ((input.button == VOLUME_UP || input.button == LEFT) && skipChapter) {
       nextPageNumber = 0;
       currentSpineIndex--;
       delete section;
       section = nullptr;
-    } else if (input.button == VOLUME_DOWN && skipChapter) {
+    } else if ((input.button == VOLUME_DOWN || input.button == RIGHT) && skipChapter) {
       nextPageNumber = 0;
       currentSpineIndex++;
       delete section;
       section = nullptr;
-    } else if (input.button == VOLUME_UP) {
+    } else if (input.button == VOLUME_UP || input.button == LEFT) {
       if (section->currentPage > 0) {
         section->currentPage--;
       } else {
-        xSemaphoreTake(sectionMutex, portMAX_DELAY);
+        // We don't want to delete the section mid-render, so grab the semaphore
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         nextPageNumber = UINT16_MAX;
         currentSpineIndex--;
         delete section;
         section = nullptr;
-        xSemaphoreGive(sectionMutex);
+        xSemaphoreGive(renderingMutex);
       }
-    } else if (input.button == VOLUME_DOWN) {
+    } else if (input.button == VOLUME_DOWN || input.button == RIGHT) {
       if (section->currentPage < section->pageCount - 1) {
         section->currentPage++;
       } else {
-        xSemaphoreTake(sectionMutex, portMAX_DELAY);
+        // We don't want to delete the section mid-render, so grab the semaphore
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         nextPageNumber = 0;
         currentSpineIndex++;
         delete section;
         section = nullptr;
-        xSemaphoreGive(sectionMutex);
+        xSemaphoreGive(renderingMutex);
       }
     }
 
     updateRequired = true;
+  } else if (input.button == BACK) {
+    onGoHome();
   }
 }
 
@@ -98,7 +115,9 @@ void EpubReaderScreen::displayTaskLoop() {
   while (true) {
     if (updateRequired) {
       updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
       renderPage();
+      xSemaphoreGive(renderingMutex);
     }
     vTaskDelay(10 / portTICK_PERIOD_MS);
   }
@@ -113,19 +132,31 @@ void EpubReaderScreen::renderPage() {
     currentSpineIndex = 0;
   }
 
-  xSemaphoreTake(sectionMutex, portMAX_DELAY);
   if (!section) {
     const auto filepath = epub->getSpineItem(currentSpineIndex);
     Serial.printf("Loading file: %s, index: %d\n", filepath.c_str(), currentSpineIndex);
     section = new Section(epub, currentSpineIndex, renderer);
     if (!section->hasCache()) {
       Serial.println("Cache not found, building...");
+
+      {
+        const int textWidth = renderer->getTextWidth("Indexing...");
+        constexpr int margin = 20;
+        const int x = (renderer->getPageWidth() - textWidth - margin * 2) / 2;
+        constexpr int y = 50;
+        const int w = textWidth + margin * 2;
+        const int h = renderer->getLineHeight() + margin * 2;
+        renderer->fillRect(x, y, w, h, 0);
+        renderer->drawText(x + margin, y + margin, "Indexing...");
+        renderer->drawRect(x + 5, y + 5, w - 10, h - 10);
+        renderer->flushArea(x, y, w, h);
+      }
+
       section->setupCacheDir();
       if (!section->persistPageDataToSD()) {
         Serial.println("Failed to persist page data to SD");
-        free(section);
+        delete section;
         section = nullptr;
-        xSemaphoreGive(sectionMutex);
         return;
       }
     } else {
@@ -142,7 +173,13 @@ void EpubReaderScreen::renderPage() {
   renderer->clearScreen();
   section->renderPage();
   renderStatusBar();
+  if (pagesUntilFullRefresh <= 1) {
+    renderer->flushDisplay(false);
+    pagesUntilFullRefresh = PAGES_PER_REFRESH;
+  } else {
     renderer->flushDisplay();
+    pagesUntilFullRefresh--;
+  }
 
   File f = SD.open((epub->getCachePath() + "/progress.bin").c_str(), FILE_WRITE);
   uint8_t data[4];
@@ -152,46 +189,44 @@ void EpubReaderScreen::renderPage() {
   data[3] = (section->currentPage >> 8) & 0xFF;
   f.write(data, 4);
   f.close();
-
-  xSemaphoreGive(sectionMutex);
 }
 
 void EpubReaderScreen::renderStatusBar() const {
   const auto pageWidth = renderer->getPageWidth();
 
-  std::string progress = std::to_string(section->currentPage + 1) + " / " + std::to_string(section->pageCount);
+  const std::string progress = std::to_string(section->currentPage + 1) + " / " + std::to_string(section->pageCount);
   const auto progressTextWidth = renderer->getSmallTextWidth(progress.c_str());
   renderer->drawSmallText(pageWidth - progressTextWidth, 765, progress.c_str());
 
   const uint16_t percentage = battery.readPercentage();
-  auto percentageText = std::to_string(percentage) + "%";
+  const auto percentageText = std::to_string(percentage) + "%";
   const auto percentageTextWidth = renderer->getSmallTextWidth(percentageText.c_str());
   renderer->drawSmallText(20, 765, percentageText.c_str());
 
   // 1 column on left, 2 columns on right, 5 columns of battery body
   constexpr int batteryWidth = 15;
   constexpr int batteryHeight = 10;
-  const int x = 0;
-  const int y = 772;
+  constexpr int x = 0;
+  constexpr int y = 772;
 
   // Top line
-  renderer->drawLine(x, y, x + batteryWidth - 4, y, 1);
+  renderer->drawLine(x, y, x + batteryWidth - 4, y);
   // Bottom line
-  renderer->drawLine(x, y + batteryHeight - 1, x + batteryWidth - 4, y + batteryHeight - 1, 1);
+  renderer->drawLine(x, y + batteryHeight - 1, x + batteryWidth - 4, y + batteryHeight - 1);
   // Left line
-  renderer->drawLine(x, y, x, y + batteryHeight - 1, 1);
+  renderer->drawLine(x, y, x, y + batteryHeight - 1);
   // Battery end
-  renderer->drawLine(x + batteryWidth - 4, y, x + batteryWidth - 4, y + batteryHeight - 1, 1);
-  renderer->drawLine(x + batteryWidth - 3, y + 2, x + batteryWidth - 3, y + batteryHeight - 3, 1);
-  renderer->drawLine(x + batteryWidth - 2, y + 2, x + batteryWidth - 2, y + batteryHeight - 3, 1);
-  renderer->drawLine(x + batteryWidth - 1, y + 2, x + batteryWidth - 1, y + batteryHeight - 3, 1);
+  renderer->drawLine(x + batteryWidth - 4, y, x + batteryWidth - 4, y + batteryHeight - 1);
+  renderer->drawLine(x + batteryWidth - 3, y + 2, x + batteryWidth - 3, y + batteryHeight - 3);
+  renderer->drawLine(x + batteryWidth - 2, y + 2, x + batteryWidth - 2, y + batteryHeight - 3);
+  renderer->drawLine(x + batteryWidth - 1, y + 2, x + batteryWidth - 1, y + batteryHeight - 3);
 
   // The +1 is to round up, so that we always fill at least one pixel
   int filledWidth = percentage * (batteryWidth - 5) / 100 + 1;
   if (filledWidth > batteryWidth - 5) {
     filledWidth = batteryWidth - 5;  // Ensure we don't overflow
   }
-  renderer->fillRect(x + 1, y + 1, filledWidth, batteryHeight - 2, 1);
+  renderer->fillRect(x + 1, y + 1, filledWidth, batteryHeight - 2);
 
   // Page width minus existing content with 30px padding on each side
   const int leftMargin = 20 + percentageTextWidth + 30;

src/screens/EpubReaderScreen.h

@@ -11,10 +11,12 @@ class EpubReaderScreen final : public Screen {
   Epub* epub;
   Section* section = nullptr;
   TaskHandle_t displayTaskHandle = nullptr;
-  SemaphoreHandle_t sectionMutex = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
   int currentSpineIndex = 0;
   int nextPageNumber = 0;
+  int pagesUntilFullRefresh = 0;
   bool updateRequired = false;
+  const std::function<void()> onGoHome;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -22,8 +24,8 @@ class EpubReaderScreen final : public Screen {
   void renderStatusBar() const;
 
  public:
-  explicit EpubReaderScreen(EpdRenderer* renderer, Epub* epub) : Screen(renderer), epub(epub) {}
-  ~EpubReaderScreen() override { free(section); }
+  explicit EpubReaderScreen(EpdRenderer* renderer, Epub* epub, const std::function<void()>& onGoHome)
+      : Screen(renderer), epub(epub), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void handleInput(Input input) override;

src/screens/FileSelectionScreen.cpp

@@ -0,0 +1,122 @@
+#include "FileSelectionScreen.h"
+
+#include <EpdRenderer.h>
+#include <SD.h>
+
+void FileSelectionScreen::taskTrampoline(void* param) {
+  auto* self = static_cast<FileSelectionScreen*>(param);
+  self->displayTaskLoop();
+}
+
+void FileSelectionScreen::loadFiles() {
+  files.clear();
+  selectorIndex = 0;
+  auto root = SD.open(basepath.c_str());
+  for (File file = root.openNextFile(); file; file = root.openNextFile()) {
+    auto filename = std::string(file.name());
+    if (filename[0] == '.') {
+      file.close();
+      continue;
+    }
+
+    if (file.isDirectory()) {
+      files.emplace_back(filename + "/");
+    } else if (filename.substr(filename.length() - 5) == ".epub") {
+      files.emplace_back(filename);
+    }
+    file.close();
+  }
+  root.close();
+}
+
+void FileSelectionScreen::onEnter() {
+  renderingMutex = xSemaphoreCreateMutex();
+
+  basepath = "/";
+  loadFiles();
+  selectorIndex = 0;
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&FileSelectionScreen::taskTrampoline, "FileSelectionScreenTask",
+              1024,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void FileSelectionScreen::onExit() {
+  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+  files.clear();
+}
+
+void FileSelectionScreen::handleInput(const Input input) {
+  if (input.button == VOLUME_DOWN || input.button == RIGHT) {
+    selectorIndex = (selectorIndex + 1) % files.size();
+    updateRequired = true;
+  } else if (input.button == VOLUME_UP || input.button == LEFT) {
+    selectorIndex = (selectorIndex + files.size() - 1) % files.size();
+    updateRequired = true;
+  } else if (input.button == CONFIRM) {
+    if (files.empty()) {
+      return;
+    }
+
+    if (files[selectorIndex].back() == '/') {
+      if (basepath.back() != '/') basepath += "/";
+      basepath += files[selectorIndex].substr(0, files[selectorIndex].length() - 1);
+      loadFiles();
+      updateRequired = true;
+    } else {
+      onSelect(basepath + files[selectorIndex]);
+    }
+  } else if (input.button == BACK && basepath != "/") {
+    basepath = basepath.substr(0, basepath.rfind('/'));
+    if (basepath.empty()) basepath = "/";
+    loadFiles();
+    updateRequired = true;
+  }
+}
+
+void FileSelectionScreen::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void FileSelectionScreen::render() const {
+  renderer->clearScreen();
+
+  const auto pageWidth = renderer->getPageWidth();
+  const auto titleWidth = renderer->getTextWidth("CrossPoint Reader", BOLD);
+  renderer->drawText((pageWidth - titleWidth) / 2, 0, "CrossPoint Reader", 1, BOLD);
+
+  if (files.empty()) {
+    renderer->drawUiText(10, 50, "No EPUBs found");
+  } else {
+    // Draw selection
+    renderer->fillRect(0, 50 + selectorIndex * 30 + 2, pageWidth - 1, 30);
+
+    for (size_t i = 0; i < files.size(); i++) {
+      const auto file = files[i];
+      renderer->drawUiText(10, 50 + i * 30, file.c_str(), i == selectorIndex ? 0 : 1);
+    }
+  }
+
+  renderer->flushDisplay();
+}

src/screens/FileSelectionScreen.h

@@ -0,0 +1,32 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+#include <string>
+#include <vector>
+
+#include "Screen.h"
+
+class FileSelectionScreen final : public Screen {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  std::string basepath = "/";
+  std::vector<std::string> files;
+  int selectorIndex = 0;
+  bool updateRequired = false;
+  const std::function<void(const std::string&)> onSelect;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+  void loadFiles();
+
+ public:
+  explicit FileSelectionScreen(EpdRenderer* renderer, const std::function<void(const std::string&)>& onSelect)
+      : Screen(renderer), onSelect(onSelect) {}
+  void onEnter() override;
+  void onExit() override;
+  void handleInput(Input input) override;
+};

src/screens/FullScreenMessageScreen.cpp

@@ -3,12 +3,12 @@
 #include <EpdRenderer.h>
 
 void FullScreenMessageScreen::onEnter() {
-  const auto width = renderer->getTextWidth(text.c_str(), bold, italic);
+  const auto width = renderer->getUiTextWidth(text.c_str(), style);
   const auto height = renderer->getLineHeight();
   const auto left = (renderer->getPageWidth() - width) / 2;
   const auto top = (renderer->getPageHeight() - height) / 2;
 
   renderer->clearScreen(invert);
-  renderer->drawText(left, top, text.c_str(), bold, italic, invert ? 0 : 1);
-  renderer->flushDisplay();
+  renderer->drawUiText(left, top, text.c_str(), invert ? 0 : 1, style);
+  renderer->flushDisplay(partialUpdate);
 }

src/screens/FullScreenMessageScreen.h

@@ -2,17 +2,18 @@
 #include <string>
 #include <utility>
 
+#include "EpdFontFamily.h"
 #include "Screen.h"
 
 class FullScreenMessageScreen final : public Screen {
   std::string text;
-  bool bold;
-  bool italic;
+  EpdFontStyle style;
   bool invert;
+  bool partialUpdate;
 
  public:
-  explicit FullScreenMessageScreen(EpdRenderer* renderer, std::string text, const bool bold = false,
-                                   const bool italic = false, const bool invert = false)
-      : Screen(renderer), text(std::move(text)), bold(bold), italic(italic), invert(invert) {}
+  explicit FullScreenMessageScreen(EpdRenderer* renderer, std::string text, const EpdFontStyle style = REGULAR,
+                                   const bool invert = false, const bool partialUpdate = true)
+      : Screen(renderer), text(std::move(text)), style(style), invert(invert), partialUpdate(partialUpdate) {}
   void onEnter() override;
 };

src/screens/SleepScreen.cpp

@@ -0,0 +1,7 @@
+#include "SleepScreen.h"
+
+#include <EpdRenderer.h>
+
+#include "images/SleepScreenImg.h"
+
+void SleepScreen::onEnter() { renderer->drawImageNoMargin(SleepScreenImg, 0, 0, 800, 480, false, true); }

src/screens/SleepScreen.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "Screen.h"
+
+class SleepScreen final : public Screen {
+ public:
+  explicit SleepScreen(EpdRenderer* renderer) : Screen(renderer) {}
+  void onEnter() override;
+};