Merge 55d2c985c1 into e5c0ddc9fa

## Summary

* **What is the goal of this PR?**
Add a debugging script to help developers monitor the ESP32 serial port
directly from a PC.

* **What changes are included?**
Added a new script: scripts/debugging_monitor.py

## Additional Context

While working on a new Crosspoint-Reader feature, it quickly became
clear that watching the ESP32 serial output without any visual cues was
inconvenient and easy to mess up.

This script improves the debugging experience by reading data from the
serial port and providing:

1. A timestamp prefix for every log line (instead of milliseconds since
power-up)
2. Color-coded output for different message types
3. A secondary window displaying a live graph of RAM usage, which is
especially useful for tracking the memory impact of new features

<img width="1916" height="1049" alt="Screenshot_20260126_183811"
src="https://github.com/user-attachments/assets/6291887f-ac17-43ac-9e43-f5dec8a7097e"
/>

---

### AI Usage

Did you use AI tools to help write this code? _**< PARTIALLY >**_
I wrote the initial version of the script. Gemini was used to help add
the Matplotlib-based graphing and threading logic.

.github/workflows/ci.yml

@@ -1,27 +1,22 @@
-name: CI
+name: CI (build)
-'on':
+
+on:
   push:
     branches: [master]
   pull_request:
 
 permissions:
   contents: read
-  pull-requests: write
 
 jobs:
-  label:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/labeler@v5
-
   clang-format:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
 
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.14'
 
@@ -34,16 +29,18 @@ jobs:
           sudo apt-get install -y clang-format-21
 
       - name: Run clang-format
-        run: PATH="/usr/lib/llvm-21/bin:$PATH" ./bin/clang-format-fix && git diff --exit-code || (echo "Please run 'bin/clang-format-fix' to fix formatting issues" && exit 1)
+        run: |
+          PATH="/usr/lib/llvm-21/bin:$PATH" ./bin/clang-format-fix
+          git diff --exit-code || (echo "Please run 'bin/clang-format-fix' to fix formatting issues" && exit 1)
 
   cppcheck:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
 
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.14'
 
@@ -56,11 +53,11 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
 
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.14'
 
@@ -90,62 +87,18 @@ jobs:
             if [ -n "$flash_line" ]; then echo "- ${flash_line}"; else echo "- Flash: not found"; fi
           } >> "$GITHUB_STEP_SUMMARY"
 
+      # Upload both the binary and the stats/log so Stage 2 can read them without checkout.
       - name: Upload firmware.bin artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ github.event_name == 'pull_request' && format('firmware-bin-pr-{0}-{1}', github.event.pull_request.number, steps.short_sha.outputs.short) || format('firmware-bin-{0}', steps.short_sha.outputs.short) }}
+          name: firmware-bin
           path: .pio/build/default/firmware.bin
           if-no-files-found: error
 
-      - name: Comment PR with firmware stats and firmware.bin
+      - name: Upload build metadata artifact
-        if: github.event_name == 'pull_request'
+        uses: actions/upload-artifact@v4
-        uses: actions/github-script@v7
         with:
-          script: |
+          name: build-meta
-            const marker = '<!-- firmware-stats -->';
+          path: |
-            const ram = `${{ steps.fw_stats.outputs.ram_line }}`.trim();
+            pio.log
-            const flash = `${{ steps.fw_stats.outputs.flash_line }}`.trim();
+          if-no-files-found: error
-            const prNumber = context.payload.pull_request?.number;
-            const shortSha = `${{ steps.short_sha.outputs.short }}`.trim() || context.sha.substring(0, 7);
-            const artifactName = prNumber
-              ? `firmware-bin-pr-${prNumber}-${shortSha}`
-              : `firmware-bin-${shortSha}`;
-            let firmwareLine = 'Firmware: artifact not found';
-            try {
-              const { data: artifacts } = await github.rest.actions.listWorkflowRunArtifacts({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                run_id: context.runId,
-              });
-              const firmwareArtifact = artifacts.artifacts.find((artifact) => artifact.name === artifactName);
-              if (firmwareArtifact) {
-                const artifactUiUrl = `https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}/artifacts/${firmwareArtifact.id}`;
-                firmwareLine = `Firmware: [${artifactName}](${artifactUiUrl})`;
-              } else {
-                firmwareLine = `Firmware: artifact not found (${artifactName})`;
-              }
-            } catch (error) {
-              firmwareLine = `Firmware: artifact lookup failed (${error.message})`;
-            }
-            const body = `${marker}\n**Firmware build stats**\n\n\`\`\`\n${ram || 'RAM: not found'}\n${flash || 'Flash: not found'}\n\`\`\`\n\n**Firmware binary**\n${firmwareLine}`;
-            const { data: comments } = await github.rest.issues.listComments({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              issue_number: context.issue.number,
-            });
-            const existing = comments.find((comment) => comment.body && comment.body.includes(marker));
-            if (existing) {
-              await github.rest.issues.updateComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                comment_id: existing.id,
-                body,
-              });
-            } else {
-              await github.rest.issues.createComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number: context.issue.number,
-                body,
-              });
-            }

.github/workflows/pr-formatting-check.yml

@@ -37,10 +37,10 @@ jobs:
               `${{ steps.title_check.outputs.error_message || steps.title_check.outputs.error || '' }}`.trim();
             const details = error ? `\n\n**Error:** ${error}` : '\n\n**Error:** See workflow logs.';
             const body = `${marker}
-            **PR title check failed**
+**PR title check failed**
 
-            Please use a Conventional Commit-style prefix (e.g., \`feat:\`, \`fix:\`, \`docs:\`, \`chore:\`).
+Please use a Conventional Commit-style prefix (e.g., \`feat:\`, \`fix:\`, \`docs:\`, \`chore:\`).
-            If this change should appear in release notes, ensure the title reflects the correct category.${details}`;
+If this change should appear in release notes, ensure the title reflects the correct category.${details}`;
 
             const { data: comments } = await github.rest.issues.listComments({
               owner: context.repo.owner,

.github/workflows/pr-writer.yml

@@ -0,0 +1,145 @@
+comment_firmware:
+  runs-on: ubuntu-latest
+  steps:
+    - name: Find the matching CI run for this PR SHA
+      id: find_run
+      uses: actions/github-script@v8
+      with:
+        script: |
+          const owner = context.repo.owner;
+          const repo = context.repo.repo;
+          const pr = context.payload.pull_request;
+          const headSha = pr.head.sha;
+
+          const { data } = await github.rest.actions.listWorkflowRunsForRepo({
+            owner,
+            repo,
+            event: "pull_request",
+            per_page: 50,
+          });
+
+          const run = data.workflow_runs.find(r => r.head_sha === headSha && r.name === "CI (build)");
+          if (!run) core.setFailed(`No matching CI (build) run found for head_sha=${headSha}.`);
+
+          core.setOutput("run_id", String(run.id));
+          core.setOutput("run_html_url", run.html_url);
+
+    - name: Locate artifact IDs in the CI run
+      id: artifacts
+      uses: actions/github-script@v8
+      with:
+        script: |
+          const owner = context.repo.owner;
+          const repo = context.repo.repo;
+          const runId = Number("${{ steps.find_run.outputs.run_id }}");
+
+          const { data } = await github.rest.actions.listWorkflowRunArtifacts({
+            owner,
+            repo,
+            run_id: runId,
+            per_page: 100,
+          });
+
+          const artifacts = data.artifacts || [];
+          const fw = artifacts.find(a => a.name === "firmware-bin");
+          const meta = artifacts.find(a => a.name === "build-meta");
+
+          if (!meta) core.setFailed("build-meta artifact not found in CI run artifacts.");
+          // firmware-bin is nice-to-have for linking; fail if you want.
+          core.setOutput("fw_id", fw ? String(fw.id) : "");
+          core.setOutput("meta_id", String(meta.id));
+
+    - name: Download build-meta artifact zip and extract pio.log
+      id: parse_log
+      shell: bash
+      env:
+        OWNER: ${{ github.repository_owner }}
+        REPO: ${{ github.event.repository.name }}
+        META_ID: ${{ steps.artifacts.outputs.meta_id }}
+        GH_TOKEN: ${{ github.token }}
+      run: |
+        set -euo pipefail
+
+        # Download artifact zip via GitHub API (will redirect to blob storage; -L follows)
+        api="https://api.github.com/repos/${OWNER}/${REPO}/actions/artifacts/${META_ID}/zip"
+        curl -sSL \
+          -H "Authorization: Bearer ${GH_TOKEN}" \
+          -H "X-GitHub-Api-Version: 2022-11-28" \
+          -o build-meta.zip \
+          "${api}"
+
+        mkdir -p build-meta
+        unzip -q build-meta.zip -d build-meta
+
+        if [[ ! -f build-meta/pio.log ]]; then
+          echo "pio.log not found inside build-meta artifact"
+          echo "ram_line=" >> "$GITHUB_OUTPUT"
+          echo "flash_line=" >> "$GITHUB_OUTPUT"
+          exit 0
+        fi
+
+        ram_line="$(grep -E "RAM:\s" -m1 build-meta/pio.log || true)"
+        flash_line="$(grep -E "Flash:\s" -m1 build-meta/pio.log || true)"
+
+        echo "ram_line=${ram_line}" >> "$GITHUB_OUTPUT"
+        echo "flash_line=${flash_line}" >> "$GITHUB_OUTPUT"
+
+    - name: Post/update PR comment with RAM/Flash + artifact links
+      uses: actions/github-script@v8
+      with:
+        script: |
+          const owner = context.repo.owner;
+          const repo = context.repo.repo;
+          const prNumber = context.payload.pull_request.number;
+
+          const runId = Number("${{ steps.find_run.outputs.run_id }}");
+          const runUrl = "${{ steps.find_run.outputs.run_html_url }}";
+
+          const marker = '<!-- firmware-stats -->';
+          const ram = `${{ steps.parse_log.outputs.ram_line }}`.trim();
+          const flash = `${{ steps.parse_log.outputs.flash_line }}`.trim();
+
+          const fwId = `${{ steps.artifacts.outputs.fw_id }}`.trim();
+          const metaId = `${{ steps.artifacts.outputs.meta_id }}`.trim();
+
+          const fwUrl = fwId ? `https://github.com/${owner}/${repo}/actions/runs/${runId}/artifacts/${fwId}` : null;
+          const metaUrl = metaId ? `https://github.com/${owner}/${repo}/actions/runs/${runId}/artifacts/${metaId}` : null;
+
+          const body =
+`${marker}
+**Firmware build stats**
+
+\`\`\`
+${ram || "RAM: not found"}
+${flash || "Flash: not found"}
+\`\`\`
+
+**Artifacts**
+- CI run: ${runUrl}
+- Firmware binary: ${fwUrl ? `[firmware-bin](${fwUrl})` : "artifact not found"}
+- Build logs: ${metaUrl ? `[build-meta](${metaUrl})` : "artifact not found"}
+`;
+
+          const { data: comments } = await github.rest.issues.listComments({
+            owner,
+            repo,
+            issue_number: prNumber,
+            per_page: 100,
+          });
+
+          const existing = comments.find(c => (c.body || "").includes(marker));
+          if (existing) {
+            await github.rest.issues.updateComment({
+              owner,
+              repo,
+              comment_id: existing.id,
+              body,
+            });
+          } else {
+            await github.rest.issues.createComment({
+              owner,
+              repo,
+              issue_number: prNumber,
+              body,
+            });
+          }

README.md

@@ -95,6 +95,20 @@ Connect your Xteink X4 to your computer via USB-C and run the following command.
 ```sh
 pio run --target upload
 ```
+### Debugging
+
+After flashing the new features, it’s recommended to capture detailed logs from the serial port.
+
+First, make sure all required Python packages are installed:
+
+```python
+python3 -m pip install serial colorama matplotlib
+```
+after that run the script:
+```sh
+python3 scripts/debugging_monitor.py
+```
+This was tested on Debian and should work on most Linux systems. Minor adjustments may be required for Windows or macOS.
 
 ## Internals
 

lib/GfxRenderer/GfxRenderer.cpp

@@ -415,13 +415,21 @@ void GfxRenderer::displayBuffer(const HalDisplay::RefreshMode refreshMode) const
 
 std::string GfxRenderer::truncatedText(const int fontId, const char* text, const int maxWidth,
                                        const EpdFontFamily::Style style) const {
+  if (!text || maxWidth <= 0) return "";
+
   std::string item = text;
-  int itemWidth = getTextWidth(fontId, item.c_str(), style);
+  const char* ellipsis = "...";
-  while (itemWidth > maxWidth && item.length() > 8) {
+  int textWidth = getTextWidth(fontId, item.c_str(), style);
-    item.replace(item.length() - 5, 5, "...");
+  if (textWidth <= maxWidth) {
-    itemWidth = getTextWidth(fontId, item.c_str(), style);
+    // Text fits, return as is
+    return item;
   }
-  return item;
+
+  while (!item.empty() && getTextWidth(fontId, (item + ellipsis).c_str(), style) >= maxWidth) {
+    utf8RemoveLastChar(item);
+  }
+
+  return item.empty() ? ellipsis : item + ellipsis;
 }
 
 // Note: Internal driver treats screen in command orientation; this library exposes a logical orientation

lib/Utf8/Utf8.cpp

@@ -29,3 +29,20 @@ uint32_t utf8NextCodepoint(const unsigned char** string) {
 
   return cp;
 }
+
+size_t utf8RemoveLastChar(std::string& str) {
+  if (str.empty()) return 0;
+  size_t pos = str.size() - 1;
+  while (pos > 0 && (static_cast<unsigned char>(str[pos]) & 0xC0) == 0x80) {
+    --pos;
+  }
+  str.resize(pos);
+  return pos;
+}
+
+// Truncate string by removing N UTF-8 characters from the end
+void utf8TruncateChars(std::string& str, const size_t numChars) {
+  for (size_t i = 0; i < numChars && !str.empty(); ++i) {
+    utf8RemoveLastChar(str);
+  }
+}

lib/Utf8/Utf8.h

@@ -1,7 +1,11 @@
 #pragma once
 
 #include <cstdint>
-
+#include <string>
 #define REPLACEMENT_GLYPH 0xFFFD
 
 uint32_t utf8NextCodepoint(const unsigned char** string);
+// Remove the last UTF-8 codepoint from a std::string and return the new size.
+size_t utf8RemoveLastChar(std::string& str);
+// Truncate string by removing N UTF-8 codepoints from the end.
+void utf8TruncateChars(std::string& str, size_t numChars);

scripts/debugging_monitor.py

@@ -0,0 +1,214 @@
+import sys
+import argparse
+import re
+import threading
+from datetime import datetime
+from collections import deque
+import time
+
+# Try to import potentially missing packages
+try:
+    import serial
+    from colorama import init, Fore, Style
+    import matplotlib.pyplot as plt
+    import matplotlib.animation as animation
+except ImportError as e:
+    missing_package = e.name
+    print("\n" + "!" * 50)
+    print(f" Error: The required package '{missing_package}' is not installed.")
+    print("!" * 50)
+
+    print(f"\nTo fix this, please run the following command in your terminal:\n")
+
+    install_cmd = "pip install "
+    packages = []
+    if 'serial' in str(e): packages.append("pyserial")
+    if 'colorama' in str(e): packages.append("colorama")
+    if 'matplotlib' in str(e): packages.append("matplotlib")
+
+    print(f"    {install_cmd}{' '.join(packages)}")
+
+    print("\nExiting...")
+    sys.exit(1)
+
+# --- Global Variables for Data Sharing ---
+# Store last 50 data points
+MAX_POINTS = 50
+time_data = deque(maxlen=MAX_POINTS)
+free_mem_data = deque(maxlen=MAX_POINTS)
+total_mem_data = deque(maxlen=MAX_POINTS)
+data_lock = threading.Lock() # Prevent reading while writing
+
+# Initialize colors
+init(autoreset=True)
+
+def get_color_for_line(line):
+    """
+    Classify log lines by type and assign appropriate colors.
+    """
+    line_upper = line.upper()
+
+    if any(keyword in line_upper for keyword in ["ERROR", "[ERR]", "[SCT]", "FAILED", "WARNING"]):
+        return Fore.RED
+    if "[MEM]" in line_upper or "FREE:" in line_upper:
+        return Fore.CYAN
+    if any(keyword in line_upper for keyword in ["[GFX]", "[ERS]", "DISPLAY", "RAM WRITE", "RAM COMPLETE", "REFRESH", "POWERING ON", "FRAME BUFFER", "LUT"]):
+        return Fore.MAGENTA
+    if any(keyword in line_upper for keyword in ["[EBP]", "[BMC]", "[ZIP]", "[PARSER]", "[EHP]", "LOADING EPUB", "CACHE", "DECOMPRESSED", "PARSING"]):
+        return Fore.GREEN
+    if "[ACT]" in line_upper or "ENTERING ACTIVITY" in line_upper or "EXITING ACTIVITY" in line_upper:
+        return Fore.YELLOW
+    if any(keyword in line_upper for keyword in ["RENDERED PAGE", "[LOOP]", "DURATION", "WAIT COMPLETE"]):
+        return Fore.BLUE
+    if any(keyword in line_upper for keyword in ["[CPS]", "SETTINGS", "[CLEAR_CACHE]"]):
+        return Fore.LIGHTYELLOW_EX
+    if any(keyword in line_upper for keyword in ["ESP-ROM", "BUILD:", "RST:", "BOOT:", "SPIWP:", "MODE:", "LOAD:", "ENTRY", "[SD]", "STARTING CROSSPOINT", "VERSION"]):
+        return Fore.LIGHTBLACK_EX
+    if "[RBS]" in line_upper:
+        return Fore.LIGHTCYAN_EX
+    if "[KRS]" in line_upper:
+        return Fore.LIGHTMAGENTA_EX
+    if any(keyword in line_upper for keyword in ["EINKDISPLAY:", "STATIC FRAME", "INITIALIZING", "SPI INITIALIZED", "GPIO PINS", "RESETTING", "SSD1677", "E-INK"]):
+        return Fore.LIGHTMAGENTA_EX
+    if any(keyword in line_upper for keyword in ["[FNS]", "FOOTNOTE"]):
+        return Fore.LIGHTGREEN_EX
+    if any(keyword in line_upper for keyword in ["[CHAP]", "[OPDS]", "[COF]"]):
+        return Fore.LIGHTYELLOW_EX
+
+    return Fore.WHITE
+
+def parse_memory_line(line):
+    """
+    Extracts Free and Total bytes from the specific log line.
+    Format: [MEM] Free: 196344 bytes, Total: 226412 bytes, Min Free: 112620 bytes
+    """
+    # Regex to find 'Free: <digits>' and 'Total: <digits>'
+    match = re.search(r"Free:\s*(\d+).*Total:\s*(\d+)", line)
+    if match:
+        try:
+            free_bytes = int(match.group(1))
+            total_bytes = int(match.group(2))
+            return free_bytes, total_bytes
+        except ValueError:
+            return None, None
+    return None, None
+
+def serial_worker(port, baud):
+    """
+    Runs in a background thread. Handles reading serial, printing to console,
+    and updating the data lists.
+    """
+    print(f"{Fore.CYAN}--- Opening {port} at {baud} baud ---{Style.RESET_ALL}")
+
+    try:
+        ser = serial.Serial(port, baud, timeout=0.1)
+        ser.dtr = False
+        ser.rts = False
+    except serial.SerialException as e:
+        print(f"{Fore.RED}Error opening port: {e}{Style.RESET_ALL}")
+        return
+
+    try:
+        while True:
+            try:
+                raw_data = ser.readline().decode('utf-8', errors='replace')
+
+                if not raw_data:
+                    continue
+
+                clean_line = raw_data.strip()
+                if not clean_line:
+                    continue
+
+                # Add PC timestamp
+                pc_time = datetime.now().strftime("%H:%M:%S")
+                formatted_line = re.sub(r"^\[\d+\]", f"[{pc_time}]", clean_line)
+
+                # Check for Memory Line
+                if "[MEM]" in formatted_line:
+                    free_val, total_val = parse_memory_line(formatted_line)
+                    if free_val is not None:
+                        with data_lock:
+                            time_data.append(pc_time)
+                            free_mem_data.append(free_val / 1024) # Convert to KB
+                            total_mem_data.append(total_val / 1024) # Convert to KB
+
+                # Print to console
+                line_color = get_color_for_line(formatted_line)
+                print(f"{line_color}{formatted_line}")
+
+            except OSError:
+                print(f"{Fore.RED}Device disconnected.{Style.RESET_ALL}")
+                break
+    except Exception as e:
+        # If thread is killed violently (e.g. main exit), silence errors
+        pass
+    finally:
+        if 'ser' in locals() and ser.is_open:
+            ser.close()
+
+def update_graph(frame):
+    """
+    Called by Matplotlib animation to redraw the chart.
+    """
+    with data_lock:
+        if not time_data:
+            return
+
+        # Convert deques to lists for plotting
+        x = list(time_data)
+        y_free = list(free_mem_data)
+        y_total = list(total_mem_data)
+
+    plt.cla() # Clear axis
+
+    # Plot Total RAM
+    plt.plot(x, y_total, label='Total RAM (KB)', color='red', linestyle='--')
+
+    # Plot Free RAM
+    plt.plot(x, y_free, label='Free RAM (KB)', color='green', marker='o')
+
+    # Fill area under Free RAM
+    plt.fill_between(x, y_free, color='green', alpha=0.1)
+
+    plt.title("ESP32 Memory Monitor")
+    plt.ylabel("Memory (KB)")
+    plt.xlabel("Time")
+    plt.legend(loc='upper left')
+    plt.grid(True, linestyle=':', alpha=0.6)
+
+    # Rotate date labels
+    plt.xticks(rotation=45, ha='right')
+    plt.tight_layout()
+
+def main():
+    parser = argparse.ArgumentParser(description="ESP32 Monitor with Graph")
+    parser.add_argument("port", nargs="?", default="/dev/ttyACM0", help="Serial port")
+    parser.add_argument("--baud", type=int, default=115200, help="Baud rate")
+    args = parser.parse_args()
+
+    # 1. Start the Serial Reader in a separate thread
+    # Daemon=True means this thread dies when the main program closes
+    t = threading.Thread(target=serial_worker, args=(args.port, args.baud), daemon=True)
+    t.start()
+
+    # 2. Set up the Graph (Main Thread)
+    try:
+        plt.style.use('light_background')
+    except:
+        pass
+
+    fig = plt.figure(figsize=(10, 6))
+
+    # Update graph every 1000ms
+    ani = animation.FuncAnimation(fig, update_graph, interval=1000)
+
+    try:
+        print(f"{Fore.YELLOW}Starting Graph Window... (Close window to exit){Style.RESET_ALL}")
+        plt.show()
+    except KeyboardInterrupt:
+        print(f"\n{Fore.YELLOW}Exiting...{Style.RESET_ALL}")
+        plt.close('all') # Force close any lingering plot windows
+
+if __name__ == "__main__":
+    main()

src/activities/home/HomeActivity.cpp

@@ -4,6 +4,7 @@
 #include <Epub.h>
 #include <GfxRenderer.h>
 #include <SDCardManager.h>
+#include <Utf8.h>
 #include <Xtc.h>
 
 #include <cstring>
@@ -366,7 +367,7 @@ void HomeActivity::render() {
         while (!lines.back().empty() && renderer.getTextWidth(UI_12_FONT_ID, lines.back().c_str()) > maxLineWidth) {
           // Remove "..." first, then remove one UTF-8 char, then add "..." back
           lines.back().resize(lines.back().size() - 3);  // Remove "..."
-          StringUtils::utf8RemoveLastChar(lines.back());
+          utf8RemoveLastChar(lines.back());
           lines.back().append("...");
         }
         break;
@@ -375,7 +376,7 @@ void HomeActivity::render() {
       int wordWidth = renderer.getTextWidth(UI_12_FONT_ID, i.c_str());
       while (wordWidth > maxLineWidth && !i.empty()) {
         // Word itself is too long, trim it (UTF-8 safe)
-        StringUtils::utf8RemoveLastChar(i);
+        utf8RemoveLastChar(i);
         // Check if we have room for ellipsis
         std::string withEllipsis = i + "...";
         wordWidth = renderer.getTextWidth(UI_12_FONT_ID, withEllipsis.c_str());
@@ -428,7 +429,7 @@ void HomeActivity::render() {
       if (!lastBookAuthor.empty()) {
         std::string trimmedAuthor = lastBookAuthor;
         while (renderer.getTextWidth(UI_10_FONT_ID, trimmedAuthor.c_str()) > maxLineWidth && !trimmedAuthor.empty()) {
-          StringUtils::utf8RemoveLastChar(trimmedAuthor);
+          utf8RemoveLastChar(trimmedAuthor);
         }
         if (renderer.getTextWidth(UI_10_FONT_ID, trimmedAuthor.c_str()) <
             renderer.getTextWidth(UI_10_FONT_ID, lastBookAuthor.c_str())) {
@@ -462,14 +463,14 @@ void HomeActivity::render() {
       // Trim author if too long (UTF-8 safe)
       bool wasTrimmed = false;
       while (renderer.getTextWidth(UI_10_FONT_ID, trimmedAuthor.c_str()) > maxLineWidth && !trimmedAuthor.empty()) {
-        StringUtils::utf8RemoveLastChar(trimmedAuthor);
+        utf8RemoveLastChar(trimmedAuthor);
         wasTrimmed = true;
       }
       if (wasTrimmed && !trimmedAuthor.empty()) {
         // Make room for ellipsis
         while (renderer.getTextWidth(UI_10_FONT_ID, (trimmedAuthor + "...").c_str()) > maxLineWidth &&
                !trimmedAuthor.empty()) {
-          StringUtils::utf8RemoveLastChar(trimmedAuthor);
+          utf8RemoveLastChar(trimmedAuthor);
         }
         trimmedAuthor.append("...");
       }

src/activities/reader/EpubReaderActivity.cpp

@@ -570,8 +570,8 @@ void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const in
         availableTitleSpace = rendererableScreenWidth - titleMarginLeft - titleMarginRight;
         titleMarginLeftAdjusted = titleMarginLeft;
       }
-      while (titleWidth > availableTitleSpace && title.length() > 11) {
+      if (titleWidth > availableTitleSpace) {
-        title.replace(title.length() - 8, 8, "...");
+        title = renderer.truncatedText(SMALL_FONT_ID, title.c_str(), availableTitleSpace);
         titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
       }
     }

src/activities/reader/TxtReaderActivity.cpp

@@ -533,8 +533,8 @@ void TxtReaderActivity::renderStatusBar(const int orientedMarginRight, const int
 
     std::string title = txt->getTitle();
     int titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
-    while (titleWidth > availableTextWidth && title.length() > 11) {
+    if (titleWidth > availableTextWidth) {
-      title.replace(title.length() - 8, 8, "...");
+      title = renderer.truncatedText(SMALL_FONT_ID, title.c_str(), availableTextWidth);
       titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
     }
 

src/util/StringUtils.cpp

@@ -61,23 +61,4 @@ bool checkFileExtension(const String& fileName, const char* extension) {
   return localFile.endsWith(localExtension);
 }
 
-size_t utf8RemoveLastChar(std::string& str) {
-  if (str.empty()) return 0;
-  size_t pos = str.size() - 1;
-  // Walk back to find the start of the last UTF-8 character
-  // UTF-8 continuation bytes start with 10xxxxxx (0x80-0xBF)
-  while (pos > 0 && (static_cast<unsigned char>(str[pos]) & 0xC0) == 0x80) {
-    --pos;
-  }
-  str.resize(pos);
-  return pos;
-}
-
-// Truncate string by removing N UTF-8 characters from the end
-void utf8TruncateChars(std::string& str, const size_t numChars) {
-  for (size_t i = 0; i < numChars && !str.empty(); ++i) {
-    utf8RemoveLastChar(str);
-  }
-}
-
 }  // namespace StringUtils

src/util/StringUtils.h

@@ -19,10 +19,4 @@ std::string sanitizeFilename(const std::string& name, size_t maxLength = 100);
 bool checkFileExtension(const std::string& fileName, const char* extension);
 bool checkFileExtension(const String& fileName, const char* extension);
 
-// UTF-8 safe string truncation - removes one character from the end
-// Returns the new size after removing one UTF-8 character
-size_t utf8RemoveLastChar(std::string& str);
-
-// Truncate string by removing N UTF-8 characters from the end
-void utf8TruncateChars(std::string& str, size_t numChars);
 }  // namespace StringUtils