Recognize css display:none, fixes #1431

lib/Epub/Epub/css/CssParser.cpp

@@ -317,6 +317,9 @@ void CssParser::parseDeclarationIntoStyle(const std::string& decl, CssStyle& sty
       style.imageWidth = len;
       style.defined.imageWidth = 1;
     }
+  } else if (propNameBuf == "display") {
+    style.display = (propValueBuf == "none") ? CssDisplay::None : CssDisplay::Block;
+    style.defined.display = 1;
   }
 }
 
@@ -692,6 +695,7 @@ bool CssParser::saveToCache() const {
     writeLength(style.paddingRight);
     writeLength(style.imageHeight);
     writeLength(style.imageWidth);
+    file.write(static_cast<uint8_t>(style.display));
 
     // Write defined flags as uint16_t
     uint16_t definedBits = 0;
@@ -710,6 +714,7 @@ bool CssParser::saveToCache() const {
     if (style.defined.paddingRight) definedBits |= 1 << 12;
     if (style.defined.imageHeight) definedBits |= 1 << 13;
     if (style.defined.imageWidth) definedBits |= 1 << 14;
+    if (style.defined.display) definedBits |= 1 << 15;
     file.write(reinterpret_cast<const uint8_t*>(&definedBits), sizeof(definedBits));
   }
 
@@ -820,6 +825,15 @@ bool CssParser::loadFromCache() {
       return false;
     }
 
+    // Read display value
+    uint8_t displayVal;
+    if (file.read(&displayVal, 1) != 1) {
+      rulesBySelector_.clear();
+      file.close();
+      return false;
+    }
+    style.display = static_cast<CssDisplay>(displayVal);
+
     // Read defined flags
     uint16_t definedBits = 0;
     if (file.read(&definedBits, sizeof(definedBits)) != sizeof(definedBits)) {
@@ -842,6 +856,7 @@ bool CssParser::loadFromCache() {
     style.defined.paddingRight = (definedBits & 1 << 12) != 0;
     style.defined.imageHeight = (definedBits & 1 << 13) != 0;
     style.defined.imageWidth = (definedBits & 1 << 14) != 0;
+    style.defined.display = (definedBits & 1 << 15) != 0;
 
     rulesBySelector_[selector] = style;
   }

lib/Epub/Epub/css/CssParser.h

@@ -31,7 +31,7 @@
 class CssParser {
  public:
   // Bump when CSS cache format or rules change; section caches are invalidated when this changes
-  static constexpr uint8_t CSS_CACHE_VERSION = 3;
+  static constexpr uint8_t CSS_CACHE_VERSION = 4;
 
   explicit CssParser(std::string cachePath) : cachePath(std::move(cachePath)) {}
   ~CssParser() = default;

lib/Epub/Epub/css/CssStyle.h

@@ -54,6 +54,9 @@ enum class CssFontWeight : uint8_t { Normal = 0, Bold = 1 };
 // Text decoration options
 enum class CssTextDecoration : uint8_t { None = 0, Underline = 1 };
 
+// Display options - only None and Block are relevant for e-ink rendering
+enum class CssDisplay : uint8_t { Block = 0, None = 1 };
+
 // Bitmask for tracking which properties have been explicitly set
 struct CssPropertyFlags {
   uint16_t textAlign : 1;
@@ -71,6 +74,7 @@ struct CssPropertyFlags {
   uint16_t paddingRight : 1;
   uint16_t imageHeight : 1;
   uint16_t imageWidth : 1;
+  uint16_t display : 1;
 
   CssPropertyFlags()
       : textAlign(0),
@@ -87,19 +91,20 @@ struct CssPropertyFlags {
         paddingLeft(0),
         paddingRight(0),
         imageHeight(0),
-        imageWidth(0) {}
+        imageWidth(0),
+        display(0) {}
 
   [[nodiscard]] bool anySet() const {
     return textAlign || fontStyle || fontWeight || textDecoration || textIndent || marginTop || marginBottom ||
            marginLeft || marginRight || paddingTop || paddingBottom || paddingLeft || paddingRight || imageHeight ||
-           imageWidth;
+           imageWidth || display;
   }
 
   void clearAll() {
     textAlign = fontStyle = fontWeight = textDecoration = textIndent = 0;
     marginTop = marginBottom = marginLeft = marginRight = 0;
     paddingTop = paddingBottom = paddingLeft = paddingRight = 0;
-    imageHeight = imageWidth = 0;
+    imageHeight = imageWidth = display = 0;
   }
 };
 
@@ -123,6 +128,7 @@ struct CssStyle {
   CssLength paddingRight;   // Padding right
   CssLength imageHeight;    // Height for img (e.g. 2em) – width derived from aspect ratio when only height set
   CssLength imageWidth;     // Width for img when both or only width set
+  CssDisplay display = CssDisplay::Block;  // display property (Block or None)
 
   CssPropertyFlags defined;  // Tracks which properties were explicitly set
 
@@ -189,6 +195,10 @@ struct CssStyle {
       imageWidth = base.imageWidth;
       defined.imageWidth = 1;
     }
+    if (base.hasDisplay()) {
+      display = base.display;
+      defined.display = 1;
+    }
   }
 
   [[nodiscard]] bool hasTextAlign() const { return defined.textAlign; }
@@ -206,6 +216,7 @@ struct CssStyle {
   [[nodiscard]] bool hasPaddingRight() const { return defined.paddingRight; }
   [[nodiscard]] bool hasImageHeight() const { return defined.imageHeight; }
   [[nodiscard]] bool hasImageWidth() const { return defined.imageWidth; }
+  [[nodiscard]] bool hasDisplay() const { return defined.display; }
 
   void reset() {
     textAlign = CssTextAlign::Left;
@@ -216,6 +227,7 @@ struct CssStyle {
     marginTop = marginBottom = marginLeft = marginRight = CssLength{};
     paddingTop = paddingBottom = paddingLeft = paddingRight = CssLength{};
     imageHeight = imageWidth = CssLength{};
+    display = CssDisplay::Block;
     defined.clearAll();
   }
 };

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -264,6 +264,19 @@ void XMLCALL ChapterHtmlSlimParser::startElement(void* userData, const XML_Char*
         return;
       }
 
+      // Skip image if CSS display:none
+      if (self->cssParser) {
+        CssStyle imgDisplayStyle = self->cssParser->resolveStyle("img", classAttr);
+        if (!styleAttr.empty()) {
+          imgDisplayStyle.applyOver(CssParser::parseInlineStyle(styleAttr));
+        }
+        if (imgDisplayStyle.hasDisplay() && imgDisplayStyle.display == CssDisplay::None) {
+          self->skipUntilDepth = self->depth;
+          self->depth += 1;
+          return;
+        }
+      }
+
       if (!src.empty() && self->imageRendering != 1) {
         LOG_DBG("EHP", "Found image: src=%s", src.c_str());
 
@@ -526,6 +539,13 @@ void XMLCALL ChapterHtmlSlimParser::startElement(void* userData, const XML_Char*
     }
   }
 
+  // Skip elements with display:none
+  if (cssStyle.hasDisplay() && cssStyle.display == CssDisplay::None) {
+    self->skipUntilDepth = self->depth;
+    self->depth += 1;
+    return;
+  }
+
   const float emSize = static_cast<float>(self->renderer.getFontAscenderSize(self->fontId));
   const auto userAlignmentBlockStyle = BlockStyle::fromCssStyle(
       cssStyle, emSize, static_cast<CssTextAlign>(self->paragraphAlignment), self->viewportWidth);