Merge aa2467de9e into d403044f76

## Rationale 

I have 2 wifi access points with almost identical names, just one has
`_EXT` at the end of it. With the current display limit of 13 characters
before adding ellipsis, I can't tell which is which.

Before device screenshot with masked SSIDs:
<img
src="https://github.com/user-attachments/assets/3c5cbbaa-b2f6-412f-b5a8-6278963bd0f2"
width="300">


## Summary

Adjusted displayed length from 13 characters to 30 in the Wifi selection
screen - I've left some space for potential proportional font changes in
the future

After image with masked SSIDs:
<img
src="https://github.com/user-attachments/assets/c5f0712b-bbd3-4eec-9820-4693fae90c9f"
width="300">

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< NO >**_

lib/Epub/Epub/Page.cpp

@@ -3,8 +3,8 @@
 #include <HardwareSerial.h>
 #include <Serialization.h>
 
-void PageLine::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) {
-  block->render(renderer, fontId, xPos + xOffset, yPos + yOffset);
+void PageLine::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset, const bool black) {
+  block->render(renderer, fontId, xPos + xOffset, yPos + yOffset, black);
 }
 
 bool PageLine::serialize(FsFile& file) {
@@ -25,9 +25,10 @@ std::unique_ptr<PageLine> PageLine::deserialize(FsFile& file) {
   return std::unique_ptr<PageLine>(new PageLine(std::move(tb), xPos, yPos));
 }
 
-void Page::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) const {
+void Page::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset,
+                  const bool black) const {
   for (auto& element : elements) {
-    element->render(renderer, fontId, xOffset, yOffset);
+    element->render(renderer, fontId, xOffset, yOffset, black);
   }
 }
 

lib/Epub/Epub/Page.h

@@ -17,7 +17,7 @@ class PageElement {
   int16_t yPos;
   explicit PageElement(const int16_t xPos, const int16_t yPos) : xPos(xPos), yPos(yPos) {}
   virtual ~PageElement() = default;
-  virtual void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) = 0;
+  virtual void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset, bool black = true) = 0;
   virtual bool serialize(FsFile& file) = 0;
 };
 
@@ -28,7 +28,7 @@ class PageLine final : public PageElement {
  public:
   PageLine(std::shared_ptr<TextBlock> block, const int16_t xPos, const int16_t yPos)
       : PageElement(xPos, yPos), block(std::move(block)) {}
-  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) override;
+  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset, bool black = true) override;
   bool serialize(FsFile& file) override;
   static std::unique_ptr<PageLine> deserialize(FsFile& file);
 };
@@ -37,7 +37,7 @@ class Page {
  public:
   // the list of block index and line numbers on this page
   std::vector<std::shared_ptr<PageElement>> elements;
-  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) const;
+  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset, bool black = true) const;
   bool serialize(FsFile& file) const;
   static std::unique_ptr<Page> deserialize(FsFile& file);
 };

lib/Epub/Epub/blocks/TextBlock.cpp

@@ -3,7 +3,8 @@
 #include <GfxRenderer.h>
 #include <Serialization.h>
 
-void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int x, const int y) const {
+void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int x, const int y,
+                       const bool black) const {
   // Validate iterator bounds before rendering
   if (words.size() != wordXpos.size() || words.size() != wordStyles.size()) {
     Serial.printf("[%lu] [TXB] Render skipped: size mismatch (words=%u, xpos=%u, styles=%u)\n", millis(),
@@ -16,7 +17,7 @@ void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int
   auto wordXposIt = wordXpos.begin();
 
   for (size_t i = 0; i < words.size(); i++) {
-    renderer.drawText(fontId, *wordXposIt + x, y, wordIt->c_str(), true, *wordStylesIt);
+    renderer.drawText(fontId, *wordXposIt + x, y, wordIt->c_str(), black, *wordStylesIt);
 
     std::advance(wordIt, 1);
     std::advance(wordStylesIt, 1);

lib/Epub/Epub/blocks/TextBlock.h

@@ -34,7 +34,7 @@ class TextBlock final : public Block {
   bool isEmpty() override { return words.empty(); }
   void layout(GfxRenderer& renderer) override {};
   // given a renderer works out where to break the words into lines
-  void render(const GfxRenderer& renderer, int fontId, int x, int y) const;
+  void render(const GfxRenderer& renderer, int fontId, int x, int y, bool black = true) const;
   BlockType getType() override { return TEXT_BLOCK; }
   bool serialize(FsFile& file) const;
   static std::unique_ptr<TextBlock> deserialize(FsFile& file);

lib/GfxRenderer/GfxRenderer.cpp

@@ -638,7 +638,7 @@ void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y
               drawPixel(screenX, screenY, black);
             } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
               drawPixel(screenX, screenY, false);
-            } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
+            } else if (renderMode == GRAYSCALE_LSB && bmpVal == (black ? 1 : 2)) {
               drawPixel(screenX, screenY, false);
             }
           } else {
@@ -822,8 +822,8 @@ void GfxRenderer::renderChar(const EpdFontFamily& fontFamily, const uint32_t cp,
             // Light gray (also mark the MSB if it's going to be a dark gray too)
             // We have to flag pixels in reverse for the gray buffers, as 0 leave alone, 1 update
             drawPixel(screenX, screenY, false);
-          } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
-            // Dark gray
+          } else if (renderMode == GRAYSCALE_LSB && bmpVal == (pixelState ? 1 : 2)) {
+            // Dark gray (swap gray level for inverse display)
             drawPixel(screenX, screenY, false);
           }
         } else {

src/CrossPointSettings.cpp

@@ -22,7 +22,7 @@ void readAndValidate(FsFile& file, uint8_t& member, const uint8_t maxValue) {
 namespace {
 constexpr uint8_t SETTINGS_FILE_VERSION = 1;
 // Increment this when adding new persisted settings fields
-constexpr uint8_t SETTINGS_COUNT = 23;
+constexpr uint8_t SETTINGS_COUNT = 24;
 constexpr char SETTINGS_FILE[] = "/.crosspoint/settings.bin";
 }  // namespace
 
@@ -60,6 +60,7 @@ bool CrossPointSettings::saveToFile() const {
   serialization::writeString(outputFile, std::string(opdsUsername));
   serialization::writeString(outputFile, std::string(opdsPassword));
   serialization::writePod(outputFile, sleepScreenCoverFilter);
+  serialization::writePod(outputFile, inverseDisplay);
   // New fields added at end for backward compatibility
   outputFile.close();
 
@@ -148,6 +149,8 @@ bool CrossPointSettings::loadFromFile() {
     if (++settingsRead >= fileSettingsCount) break;
     readAndValidate(inputFile, sleepScreenCoverFilter, SLEEP_SCREEN_COVER_FILTER_COUNT);
     if (++settingsRead >= fileSettingsCount) break;
+    serialization::readPod(inputFile, inverseDisplay);
+    if (++settingsRead >= fileSettingsCount) break;
     // New fields added at end for backward compatibility
   } while (false);
 

src/CrossPointSettings.h

@@ -137,6 +137,8 @@ class CrossPointSettings {
   uint8_t hideBatteryPercentage = HIDE_NEVER;
   // Long-press chapter skip on side buttons
   uint8_t longPressChapterSkip = 1;
+  // Inverse display (white text on black background)
+  uint8_t inverseDisplay = 0;
 
   ~CrossPointSettings() = default;
 

src/activities/network/WifiSelectionActivity.cpp

@@ -546,8 +546,8 @@ void WifiSelectionActivity::renderNetworkList() const {
 
       // Draw network name (truncate if too long)
       std::string displayName = network.ssid;
-      if (displayName.length() > 16) {
-        displayName.replace(13, displayName.length() - 13, "...");
+      if (displayName.length() > 33) {
+        displayName.replace(30, displayName.length() - 30, "...");
       }
       renderer.drawText(UI_10_FONT_ID, 20, networkY, displayName.c_str());
 

src/activities/reader/EpubReaderActivity.cpp

@@ -400,11 +400,12 @@ void EpubReaderActivity::renderScreen() {
     }
   }
 
-  renderer.clearScreen();
+  const bool inverse = SETTINGS.inverseDisplay;
+  renderer.clearScreen(inverse ? 0x00 : 0xFF);
 
   if (section->pageCount == 0) {
     Serial.printf("[%lu] [ERS] No pages to render\n", millis());
-    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Empty chapter", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Empty chapter", !inverse, EpdFontFamily::BOLD);
     renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
     renderer.displayBuffer();
     return;
@@ -412,7 +413,7 @@ void EpubReaderActivity::renderScreen() {
 
   if (section->currentPage < 0 || section->currentPage >= section->pageCount) {
     Serial.printf("[%lu] [ERS] Page out of bounds: %d (max %d)\n", millis(), section->currentPage, section->pageCount);
-    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Out of bounds", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_12_FONT_ID, 300, "Out of bounds", !inverse, EpdFontFamily::BOLD);
     renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
     renderer.displayBuffer();
     return;
@@ -453,7 +454,8 @@ void EpubReaderActivity::saveProgress(int spineIndex, int currentPage, int pageC
 void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int orientedMarginTop,
                                         const int orientedMarginRight, const int orientedMarginBottom,
                                         const int orientedMarginLeft) {
-  page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
+  const bool inverse = SETTINGS.inverseDisplay;
+  page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop, !inverse);
   renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
   if (pagesUntilFullRefresh <= 1) {
     renderer.displayBuffer(HalDisplay::HALF_REFRESH);
@@ -471,13 +473,13 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   if (SETTINGS.textAntiAliasing) {
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
-    page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
+    page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop, !inverse);
     renderer.copyGrayscaleLsbBuffers();
 
     // Render and copy to MSB buffer
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
-    page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
+    page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop, !inverse);
     renderer.copyGrayscaleMsbBuffers();
 
     // display grayscale part

src/activities/reader/TxtReaderActivity.cpp

@@ -393,7 +393,7 @@ void TxtReaderActivity::renderScreen() {
   currentPageLines.clear();
   loadPageAtOffset(offset, currentPageLines, nextOffset);
 
-  renderer.clearScreen();
+  renderer.clearScreen(SETTINGS.inverseDisplay ? 0x00 : 0xFF);
   renderPage();
 
   // Save progress
@@ -412,6 +412,8 @@ void TxtReaderActivity::renderPage() {
   const int lineHeight = renderer.getLineHeight(cachedFontId);
   const int contentWidth = viewportWidth;
 
+  const bool inverse = SETTINGS.inverseDisplay;
+
   // Render text lines with alignment
   auto renderLines = [&]() {
     int y = orientedMarginTop;
@@ -441,7 +443,7 @@ void TxtReaderActivity::renderPage() {
             break;
         }
 
-        renderer.drawText(cachedFontId, x, y, line.c_str());
+        renderer.drawText(cachedFontId, x, y, line.c_str(), !inverse);
       }
       y += lineHeight;
     }

src/activities/settings/SettingsActivity.cpp

@@ -24,7 +24,7 @@ const SettingInfo displaySettings[displaySettingsCount] = {
     SettingInfo::Enum("Refresh Frequency", &CrossPointSettings::refreshFrequency,
                       {"1 page", "5 pages", "10 pages", "15 pages", "30 pages"})};
 
-constexpr int readerSettingsCount = 9;
+constexpr int readerSettingsCount = 10;
 const SettingInfo readerSettings[readerSettingsCount] = {
     SettingInfo::Enum("Font Family", &CrossPointSettings::fontFamily, {"Bookerly", "Noto Sans", "Open Dyslexic"}),
     SettingInfo::Enum("Font Size", &CrossPointSettings::fontSize, {"Small", "Medium", "Large", "X Large"}),
@@ -36,7 +36,8 @@ const SettingInfo readerSettings[readerSettingsCount] = {
     SettingInfo::Enum("Reading Orientation", &CrossPointSettings::orientation,
                       {"Portrait", "Landscape CW", "Inverted", "Landscape CCW"}),
     SettingInfo::Toggle("Extra Paragraph Spacing", &CrossPointSettings::extraParagraphSpacing),
-    SettingInfo::Toggle("Text Anti-Aliasing", &CrossPointSettings::textAntiAliasing)};
+    SettingInfo::Toggle("Text Anti-Aliasing", &CrossPointSettings::textAntiAliasing),
+    SettingInfo::Toggle("Inverse Display", &CrossPointSettings::inverseDisplay)};
 
 constexpr int controlsSettingsCount = 4;
 const SettingInfo controlsSettings[controlsSettingsCount] = {