Process lines into pages as they are built

lib/Epub/Epub/ParsedText.cpp

@@ -4,6 +4,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <functional>
 #include <limits>
 #include <vector>
 
@@ -17,10 +18,10 @@ void ParsedText::addWord(std::string word, const EpdFontStyle fontStyle) {
 }
 
 // Consumes data to minimize memory usage
-std::list<std::shared_ptr<TextBlock>> ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fontId,
+void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fontId, const int horizontalMargin,
-                                                                        const int horizontalMargin) {
+                                       const std::function<void(std::shared_ptr<TextBlock>)>& processLine) {
   if (words.empty()) {
-    return {};
+    return;
   }
 
   const size_t totalWordCount = words.size();
@@ -99,8 +100,6 @@ std::list<std::shared_ptr<TextBlock>> ParsedText::layoutAndExtractLines(const Gf
     currentWordIndex = nextBreakIndex;
   }
 
-  std::list<std::shared_ptr<TextBlock>> lines;
-
   // Initialize iterators for consumption
   auto wordStartIt = words.begin();
   auto wordStyleStartIt = wordStyles.begin();
@@ -153,7 +152,7 @@ std::list<std::shared_ptr<TextBlock>> ParsedText::layoutAndExtractLines(const Gf
     std::list<EpdFontStyle> lineWordStyles;
     lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyleStartIt, wordStyleEndIt);
 
-    lines.push_back(
+    processLine(
         std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
 
     // Update pointers/indices for the next line
@@ -162,6 +161,4 @@ std::list<std::shared_ptr<TextBlock>> ParsedText::layoutAndExtractLines(const Gf
     wordWidthIndex += lineWordCount;
     lastBreakAt = lineBreak;
   }
-
-  return lines;
 }

lib/Epub/Epub/ParsedText.h

@@ -3,6 +3,7 @@
 #include <EpdFontFamily.h>
 
 #include <cstdint>
+#include <functional>
 #include <list>
 #include <memory>
 #include <string>
@@ -24,6 +25,6 @@ class ParsedText {
   void setStyle(const TextBlock::BLOCK_STYLE style) { this->style = style; }
   TextBlock::BLOCK_STYLE getStyle() const { return style; }
   bool isEmpty() const { return words.empty(); }
-  std::list<std::shared_ptr<TextBlock>> layoutAndExtractLines(const GfxRenderer& renderer, int fontId,
+  void layoutAndExtractLines(const GfxRenderer& renderer, int fontId, int horizontalMargin,
-                                                              int horizontalMargin);
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
 };

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -245,6 +245,20 @@ bool ChapterHtmlSlimParser::parseAndBuildPages() {
   return true;
 }
 
+void ChapterHtmlSlimParser::addLineToPage(std::shared_ptr<TextBlock> line) {
+  const int lineHeight = renderer.getLineHeight(fontId) * lineCompression;
+  const int pageHeight = GfxRenderer::getScreenHeight() - marginTop - marginBottom;
+
+  if (currentPageNextY + lineHeight > pageHeight) {
+    completePageFn(std::move(currentPage));
+    currentPage.reset(new Page());
+    currentPageNextY = marginTop;
+  }
+
+  currentPage->elements.push_back(std::make_shared<PageLine>(line, marginLeft, currentPageNextY));
+  currentPageNextY += lineHeight;
+}
+
 void ChapterHtmlSlimParser::makePages() {
   if (!currentTextBlock) {
     Serial.printf("[%lu] [EHP] !! No text block to make pages for !!\n", millis());
@@ -257,23 +271,9 @@ void ChapterHtmlSlimParser::makePages() {
   }
 
   const int lineHeight = renderer.getLineHeight(fontId) * lineCompression;
-  const int pageHeight = GfxRenderer::getScreenHeight() - marginTop - marginBottom;
+  currentTextBlock->layoutAndExtractLines(
-
+      renderer, fontId, marginLeft + marginRight,
-  // Long running task, make sure to let other things happen
+      [this](const std::shared_ptr<TextBlock>& textBlock) { addLineToPage(textBlock); });
-  vTaskDelay(1);
+  // Extra paragrpah spacing
-
-  const auto lines = currentTextBlock->layoutAndExtractLines(renderer, fontId, marginLeft + marginRight);
-
-  for (auto&& line : lines) {
-    if (currentPageNextY + lineHeight > pageHeight) {
-      completePageFn(std::move(currentPage));
-      currentPage.reset(new Page());
-      currentPageNextY = marginTop;
-    }
-
-    currentPage->elements.push_back(std::make_shared<PageLine>(line, marginLeft, currentPageNextY));
-    currentPageNextY += lineHeight;
-  }
-  // add some extra line between blocks
   currentPageNextY += lineHeight / 2;
 }

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h

@@ -59,4 +59,5 @@ class ChapterHtmlSlimParser {
         completePageFn(completePageFn) {}
   ~ChapterHtmlSlimParser() = default;
   bool parseAndBuildPages();
+  void addLineToPage(std::shared_ptr<TextBlock> line);
 };