feat: Current page as QR (#1099)

## Summary

* **What is the goal of this PR?** Implements QR text of the current
page
* **What changes are included?**

## Additional Context

I saw this feature request at #982 
It made sense to me so I implemented. But if the team thinks it is not
necessary please let me know and we can close the PR.

| Page | Menu | QR |
|------|-------|----|
|
![IMG_6601.bmp](https://github.com/user-attachments/files/25473201/IMG_6601.bmp)
|
![IMG_6599.bmp](https://github.com/user-attachments/files/25473202/IMG_6599.bmp)
|
![IMG_6600.bmp](https://github.com/user-attachments/files/25473205/IMG_6600.bmp)
|


---

### AI Usage


Did you use AI tools to help write this code? _** YES

---------

Co-authored-by: Eliz Kilic <elizk@google.com>

src/activities/network/CrossPointWebServerActivity.cpp

@@ -6,7 +6,6 @@
 #include <I18n.h>
 #include <WiFi.h>
 #include <esp_task_wdt.h>
-#include <qrcode.h>
 
 #include <cstddef>
 
@@ -16,6 +15,7 @@
 #include "activities/network/CalibreConnectActivity.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
+#include "util/QrUtils.h"
 
 namespace {
 // AP Mode configuration
@@ -24,8 +24,8 @@ constexpr const char* AP_PASSWORD = nullptr;  // Open network for ease of use
 constexpr const char* AP_HOSTNAME = "crosspoint";
 constexpr uint8_t AP_CHANNEL = 1;
 constexpr uint8_t AP_MAX_CONNECTIONS = 4;
-constexpr int QR_CODE_WIDTH = 6 * 33;
-constexpr int QR_CODE_HEIGHT = 200;
+constexpr int QR_CODE_WIDTH = 198;
+constexpr int QR_CODE_HEIGHT = 198;
 
 // DNS server for captive portal (redirects all DNS queries to our IP)
 DNSServer* dnsServer = nullptr;
@@ -363,28 +363,6 @@ void CrossPointWebServerActivity::render(Activity::RenderLock&&) {
   }
 }
 
-void drawQRCode(const GfxRenderer& renderer, const int x, const int y, const std::string& data) {
-  // Implementation of QR code calculation
-  // The structure to manage the QR code
-  QRCode qrcode;
-  uint8_t qrcodeBytes[qrcode_getBufferSize(4)];
-  LOG_DBG("WEBACT", "QR Code (%lu): %s", data.length(), data.c_str());
-
-  qrcode_initText(&qrcode, qrcodeBytes, 4, ECC_LOW, data.c_str());
-  const uint8_t px = 6;  // pixels per module
-  for (uint8_t cy = 0; cy < qrcode.size; cy++) {
-    for (uint8_t cx = 0; cx < qrcode.size; cx++) {
-      if (qrcode_getModule(&qrcode, cx, cy)) {
-        // Serial.print("**");
-        renderer.fillRect(x + px * cx, y + px * cy, px, px, true);
-      } else {
-        // Serial.print("  ");
-      }
-    }
-    // Serial.print("\n");
-  }
-}
-
 void CrossPointWebServerActivity::renderServerRunning() const {
   const auto& metrics = UITheme::getInstance().getMetrics();
   const auto pageWidth = renderer.getScreenWidth();
@@ -404,7 +382,8 @@ void CrossPointWebServerActivity::renderServerRunning() const {
 
     // Show QR code for Wifi
     const std::string wifiConfig = std::string("WIFI:S:") + connectedSSID + ";;";
-    drawQRCode(renderer, metrics.contentSidePadding, startY, wifiConfig);
+    const Rect qrBoundsWifi(metrics.contentSidePadding, startY, QR_CODE_WIDTH, QR_CODE_HEIGHT);
+    QrUtils::drawQrCode(renderer, qrBoundsWifi, wifiConfig);
 
     // Show network name
     renderer.drawText(UI_10_FONT_ID, metrics.contentSidePadding + QR_CODE_WIDTH + metrics.verticalSpacing, startY + 80,
@@ -421,7 +400,8 @@ void CrossPointWebServerActivity::renderServerRunning() const {
     std::string ipUrl = tr(STR_OR_HTTP_PREFIX) + connectedIP + "/";
 
     // Show QR code for URL
-    drawQRCode(renderer, metrics.contentSidePadding, startY, hostnameUrl);
+    const Rect qrBoundsUrl(metrics.contentSidePadding, startY, QR_CODE_WIDTH, QR_CODE_HEIGHT);
+    QrUtils::drawQrCode(renderer, qrBoundsUrl, hostnameUrl);
 
     // Show IP address as fallback
     renderer.drawText(UI_10_FONT_ID, metrics.contentSidePadding + QR_CODE_WIDTH + metrics.verticalSpacing, startY + 80,
@@ -440,7 +420,8 @@ void CrossPointWebServerActivity::renderServerRunning() const {
 
     // Show QR code for URL
     std::string webInfo = "http://" + connectedIP + "/";
-    drawQRCode(renderer, (pageWidth - QR_CODE_WIDTH) / 2, startY, webInfo);
+    const Rect qrBounds((pageWidth - QR_CODE_WIDTH) / 2, startY, QR_CODE_WIDTH, QR_CODE_HEIGHT);
+    QrUtils::drawQrCode(renderer, qrBounds, webInfo);
     startY += QR_CODE_HEIGHT + metrics.verticalSpacing * 2;
 
     // Show web server URL prominently

src/activities/reader/EpubReaderActivity.cpp

@@ -1,6 +1,7 @@
 #include "EpubReaderActivity.h"
 
 #include <Epub/Page.h>
+#include <Epub/blocks/TextBlock.h>
 #include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <HalStorage.h>
@@ -14,6 +15,7 @@
 #include "KOReaderCredentialStore.h"
 #include "KOReaderSyncActivity.h"
 #include "MappedInputManager.h"
+#include "QrDisplayActivity.h"
 #include "RecentBooksStore.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
@@ -403,6 +405,38 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
           }));
       break;
     }
+    case EpubReaderMenuActivity::MenuAction::DISPLAY_QR: {
+      if (section && section->currentPage >= 0 && section->currentPage < section->pageCount) {
+        auto p = section->loadPageFromSectionFile();
+        if (p) {
+          std::string fullText;
+          for (const auto& el : p->elements) {
+            if (el->getTag() == TAG_PageLine) {
+              const auto& line = static_cast<const PageLine&>(*el);
+              if (line.getBlock()) {
+                const auto& words = line.getBlock()->getWords();
+                for (const auto& w : words) {
+                  if (!fullText.empty()) fullText += " ";
+                  fullText += w;
+                }
+              }
+            }
+          }
+          if (!fullText.empty()) {
+            exitActivity();
+            enterNewActivity(new QrDisplayActivity(renderer, mappedInput, fullText, [this]() {
+              exitActivity();
+              requestUpdate();
+            }));
+            break;
+          }
+        }
+      }
+      // If no text or page loading failed, just close menu
+      exitActivity();
+      requestUpdate();
+      break;
+    }
     case EpubReaderMenuActivity::MenuAction::GO_HOME: {
       // Defer go home to avoid race condition with display task
       pendingGoHome = true;

src/activities/reader/EpubReaderMenuActivity.h

@@ -12,7 +12,16 @@
 class EpubReaderMenuActivity final : public ActivityWithSubactivity {
  public:
   // Menu actions available from the reader menu.
-  enum class MenuAction { SELECT_CHAPTER, GO_TO_PERCENT, ROTATE_SCREEN, SCREENSHOT, GO_HOME, SYNC, DELETE_CACHE };
+  enum class MenuAction {
+    SELECT_CHAPTER,
+    GO_TO_PERCENT,
+    ROTATE_SCREEN,
+    SCREENSHOT,
+    DISPLAY_QR,
+    GO_HOME,
+    SYNC,
+    DELETE_CACHE
+  };
 
   explicit EpubReaderMenuActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, const std::string& title,
                                   const int currentPage, const int totalPages, const int bookProgressPercent,
@@ -39,11 +48,14 @@ class EpubReaderMenuActivity final : public ActivityWithSubactivity {
   };
 
   // Fixed menu layout (order matters for up/down navigation).
-  const std::vector<MenuItem> menuItems = {
-      {MenuAction::SELECT_CHAPTER, StrId::STR_SELECT_CHAPTER}, {MenuAction::ROTATE_SCREEN, StrId::STR_ORIENTATION},
-      {MenuAction::GO_TO_PERCENT, StrId::STR_GO_TO_PERCENT},   {MenuAction::SCREENSHOT, StrId::STR_SCREENSHOT_BUTTON},
-      {MenuAction::GO_HOME, StrId::STR_GO_HOME_BUTTON},        {MenuAction::SYNC, StrId::STR_SYNC_PROGRESS},
-      {MenuAction::DELETE_CACHE, StrId::STR_DELETE_CACHE}};
+  const std::vector<MenuItem> menuItems = {{MenuAction::SELECT_CHAPTER, StrId::STR_SELECT_CHAPTER},
+                                           {MenuAction::ROTATE_SCREEN, StrId::STR_ORIENTATION},
+                                           {MenuAction::GO_TO_PERCENT, StrId::STR_GO_TO_PERCENT},
+                                           {MenuAction::SCREENSHOT, StrId::STR_SCREENSHOT_BUTTON},
+                                           {MenuAction::DISPLAY_QR, StrId::STR_DISPLAY_QR},
+                                           {MenuAction::GO_HOME, StrId::STR_GO_HOME_BUTTON},
+                                           {MenuAction::SYNC, StrId::STR_SYNC_PROGRESS},
+                                           {MenuAction::DELETE_CACHE, StrId::STR_DELETE_CACHE}};
   int selectedIndex = 0;
 
   ButtonNavigator buttonNavigator;

src/activities/reader/QrDisplayActivity.cpp

@@ -0,0 +1,45 @@
+#include "QrDisplayActivity.h"
+
+#include <GfxRenderer.h>
+#include <I18n.h>
+
+#include "MappedInputManager.h"
+#include "components/UITheme.h"
+#include "fontIds.h"
+#include "util/QrUtils.h"
+
+void QrDisplayActivity::onEnter() {
+  Activity::onEnter();
+  requestUpdate();
+}
+
+void QrDisplayActivity::onExit() { Activity::onExit(); }
+
+void QrDisplayActivity::loop() {
+  if (mappedInput.wasReleased(MappedInputManager::Button::Back) ||
+      mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
+    onGoBack();
+    return;
+  }
+}
+
+void QrDisplayActivity::render(Activity::RenderLock&&) {
+  renderer.clearScreen();
+  auto metrics = UITheme::getInstance().getMetrics();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+
+  GUI.drawHeader(renderer, Rect{0, metrics.topPadding, pageWidth, metrics.headerHeight}, tr(STR_DISPLAY_QR), nullptr);
+
+  const int availableWidth = pageWidth - 40;
+  const int availableHeight = pageHeight - metrics.topPadding - metrics.headerHeight - metrics.verticalSpacing * 2 - 40;
+  const int startY = metrics.topPadding + metrics.headerHeight + metrics.verticalSpacing;
+
+  const Rect qrBounds(20, startY, availableWidth, availableHeight);
+  QrUtils::drawQrCode(renderer, qrBounds, textPayload);
+
+  const auto labels = mappedInput.mapLabels(tr(STR_BACK), "", "", "");
+  GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+
+  renderer.displayBuffer();
+}

src/activities/reader/QrDisplayActivity.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <I18n.h>
+
+#include <string>
+
+#include "activities/Activity.h"
+
+class QrDisplayActivity final : public Activity {
+ public:
+  explicit QrDisplayActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, const std::string& textPayload,
+                             const std::function<void()>& onGoBack)
+      : Activity("QrDisplay", renderer, mappedInput), textPayload(textPayload), onGoBack(onGoBack) {}
+
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+  void render(Activity::RenderLock&&) override;
+
+ private:
+  std::string textPayload;
+  const std::function<void()> onGoBack;
+};

src/util/QrUtils.cpp

@@ -0,0 +1,54 @@
+#include "QrUtils.h"
+
+#include <qrcode.h>
+
+#include <algorithm>
+#include <memory>
+
+#include "Logging.h"
+
+void QrUtils::drawQrCode(const GfxRenderer& renderer, const Rect& bounds, const std::string& textPayload) {
+  // Dynamically calculate the QR code version based on text length
+  // Version 4 holds ~114 bytes, Version 10 ~395, Version 20 ~1066, up to 40
+  // qrcode.h max version is 40.
+  // Formula: approx version = size / 26 + 1 (very rough estimate, better to find best fit)
+  const size_t len = textPayload.length();
+  int version = 4;
+  if (len > 114) version = 10;
+  if (len > 395) version = 20;
+  if (len > 1066) version = 30;
+  if (len > 2110) version = 40;
+
+  // Make sure we have a large enough buffer on the heap to avoid blowing the stack
+  uint32_t bufferSize = qrcode_getBufferSize(version);
+  auto qrcodeBytes = std::make_unique<uint8_t[]>(bufferSize);
+
+  QRCode qrcode;
+  // Initialize the QR code. We use ECC_LOW for max capacity.
+  int8_t res = qrcode_initText(&qrcode, qrcodeBytes.get(), version, ECC_LOW, textPayload.c_str());
+
+  if (res == 0) {
+    // Determine the optimal pixel size.
+    const int maxDim = std::min(bounds.width, bounds.height);
+
+    int px = maxDim / qrcode.size;
+    if (px < 1) px = 1;
+
+    // Calculate centering X and Y
+    const int qrDisplaySize = qrcode.size * px;
+    const int xOff = bounds.x + (bounds.width - qrDisplaySize) / 2;
+    const int yOff = bounds.y + (bounds.height - qrDisplaySize) / 2;
+
+    // Draw the QR Code
+    for (uint8_t cy = 0; cy < qrcode.size; cy++) {
+      for (uint8_t cx = 0; cx < qrcode.size; cx++) {
+        if (qrcode_getModule(&qrcode, cx, cy)) {
+          renderer.fillRect(xOff + px * cx, yOff + px * cy, px, px, true);
+        }
+      }
+    }
+  } else {
+    // If it fails (e.g. text too large), log an error
+    LOG_ERR("QR", "Text too large for QR Code version %d", version);
+  }
+}

src/util/QrUtils.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <GfxRenderer.h>
+
+#include <string>
+
+#include "components/themes/BaseTheme.h"
+
+namespace QrUtils {
+
+// Renders a QR code with the given text payload within the specified bounding box.
+void drawQrCode(const GfxRenderer& renderer, const Rect& bounds, const std::string& textPayload);
+
+}  // namespace QrUtils