From f1a8e4e00ac33f224d621b39a7c47808d989f969 Mon Sep 17 00:00:00 2001
From: Dave Allie <dave@daveallie.com>
Date: Sun, 21 Dec 2025 17:52:33 +1100
Subject: [PATCH] Add Epub::generateCoverBmp Add Epub::generateCoverBmp, only
 supports JPG for now

---
 lib/Epub/Epub.cpp | 34 +++++++++++++++++++++++++++++++++-
 lib/Epub/Epub.h   |  2 +-
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/lib/Epub/Epub.cpp b/lib/Epub/Epub.cpp
index cc3bc90..b04c771 100644
--- a/lib/Epub/Epub.cpp
+++ b/lib/Epub/Epub.cpp
@@ -1,6 +1,7 @@
 #include "Epub.h"
 
 #include <HardwareSerial.h>
+#include <JpegToBmpConverter.h>
 #include <SD.h>
 #include <ZipFile.h>
 
@@ -218,7 +219,38 @@ const std::string& Epub::getPath() const { return filepath; }
 
 const std::string& Epub::getTitle() const { return title; }
 
-const std::string& Epub::getCoverImageItem() const { return coverImageItem; }
+bool Epub::generateCoverBmp() const {
+  // Already generated, return true
+  if (SD.exists((getCachePath() + "/cover.bmp").c_str())) {
+    return true;
+  }
+
+  if (coverImageItem.empty()) {
+    Serial.printf("[%lu] [EBP] No known cover image\n", millis());
+    return false;
+  }
+
+  if (coverImageItem.substr(coverImageItem.length() - 4) == ".jpg" ||
+      coverImageItem.substr(coverImageItem.length() - 5) == ".jpeg") {
+    Serial.printf("[%lu] [EBP] Generating BMP from JPG cover image\n", millis());
+    File coverJpg = SD.open((getCachePath() + "/.cover.jpg").c_str(), FILE_WRITE, true);
+    readItemContentsToStream(coverImageItem, coverJpg, 1024);
+    coverJpg.close();
+
+    coverJpg = SD.open((getCachePath() + "/.cover.jpg").c_str(), FILE_READ);
+    File coverBmp = SD.open((getCachePath() + "/cover.bmp").c_str(), FILE_WRITE, true);
+    const bool success = JpegToBmpConverter::jpegFileToBmpStream(coverJpg, coverBmp);
+    coverJpg.close();
+    coverBmp.close();
+    SD.remove((getCachePath() + "/.cover.jpg").c_str());
+    Serial.printf("[%lu] [EBP] Generated BMP from JPG cover image, success: %s\n", millis(), success ? "yes" : "no");
+    return success;
+  } else {
+    Serial.printf("[%lu] [EBP] Cover image is not a JPG, skipping\n", millis());
+  }
+
+  return false;
+}
 
 std::string normalisePath(const std::string& path) {
   std::vector<std::string> components;
diff --git a/lib/Epub/Epub.h b/lib/Epub/Epub.h
index 3115303..f11e388 100644
--- a/lib/Epub/Epub.h
+++ b/lib/Epub/Epub.h
@@ -48,7 +48,7 @@ class Epub {
   const std::string& getCachePath() const;
   const std::string& getPath() const;
   const std::string& getTitle() const;
-  const std::string& getCoverImageItem() const;
+  bool generateCoverBmp() const;
   uint8_t* readItemContentsToBytes(const std::string& itemHref, size_t* size = nullptr,
                                    bool trailingNullByte = false) const;
   bool readItemContentsToStream(const std::string& itemHref, Print& out, size_t chunkSize) const;