Optimize fold marker highlight. Feature #3282649.

From Jérôme LAFORGE.

3 files changed, 15 insertions, 10 deletions

diff --git a/src/Document.cxx b/src/Document.cxx
index b9b284e96..eb818b515 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -355,16 +355,18 @@ int Document::GetFoldParent(int line) {
 	}
 }
 
-void Document::GetHighlightDelimiters(int line, HighlightDelimiter &highlightDelimiter) {
+void Document::GetHighlightDelimiters(HighlightDelimiter &highlightDelimiter, int line, int topLine, int bottomLine) {
+	int noNeedToParseBefore = Platform::Minimum(line, topLine) - 1;
+	int noNeedToParseAfter = Platform::Maximum(line, bottomLine) + 1;
 	int endLine = LineFromPosition(Length());
-	int beginFoldBlock = -1;
+	int beginFoldBlock = noNeedToParseBefore;
 	int endFoldBlock = -1;
-	int beginMarginCorrectlyDrawnZone = -1;
-	int endMarginCorrectlyDrawnZone = endLine + 1;
+	int beginMarginCorrectlyDrawnZone = noNeedToParseBefore;
+	int endMarginCorrectlyDrawnZone = noNeedToParseAfter;
 	int endOfTailOfWhiteFlag = -1; //endOfTailOfWhiteFlag points the last SC_FOLDLEVELWHITEFLAG if follow a fold block. Otherwise endOfTailOfWhiteFlag points end of fold block.
 	int level = GetLevel(line);
 	int levelNumber = -1;
-	int lineLookLevel = -1;
+	int lineLookLevel = 0;
 	int lineLookLevelNumber = -1;
 	int lineLook = line;
 	bool beginFoldBlockFound = false;
@@ -375,7 +377,7 @@ void Document::GetHighlightDelimiters(int line, HighlightDelimiter &highlightDel
 	/*******************************************************************************/
 	/*      search backward (beginFoldBlock & beginMarginCorrectlyDrawnZone)       */
 	/*******************************************************************************/
-	for (endOfTailOfWhiteFlag = line; lineLook >= 0 && (!beginFoldBlockFound || !beginMarginCorrectlyDrawnZoneFound); --lineLook) {
+	for (endOfTailOfWhiteFlag = line; (lineLook > noNeedToParseBefore || (lineLookLevel & SC_FOLDLEVELWHITEFLAG)) && (!beginFoldBlockFound || !beginMarginCorrectlyDrawnZoneFound); --lineLook) {
 		lineLookLevel = GetLevel(lineLook);
 		if (levelNumber != -1) {
 			lineLookLevelNumber = lineLookLevel & SC_FOLDLEVELNUMBERMASK;
@@ -395,7 +397,8 @@ void Document::GetHighlightDelimiters(int line, HighlightDelimiter &highlightDel
 					beginMarginCorrectlyDrawnZone = lineLook - 1;
 				}
 			} else 	if (!beginFoldBlockFound && lineLookLevelNumber == SC_FOLDLEVELBASE) {
-				beginFoldBlockFound = true; //beginFoldBlock already set to -1.
+				beginFoldBlockFound = true;
+				beginFoldBlock = -1;
 			}
 		} else if (!(lineLookLevel & SC_FOLDLEVELWHITEFLAG)) {
 			endOfTailOfWhiteFlag = lineLook - 1;
@@ -421,7 +424,7 @@ void Document::GetHighlightDelimiters(int line, HighlightDelimiter &highlightDel
 	} else {
 		lineLook = line;
 	}
-	for (; lineLook <= endLine && (!endFoldBlockFound || !endMarginCorrectlyDrawnZoneFound); ++lineLook) {
+	for (; lineLook < noNeedToParseAfter && (!endFoldBlockFound || !endMarginCorrectlyDrawnZoneFound); ++lineLook) {
 		lineLookLevel = GetLevel(lineLook);
 		lineLookLevelNumber = lineLookLevel & SC_FOLDLEVELNUMBERMASK;
 		if (!endFoldBlockFound && !(lineLookLevel & SC_FOLDLEVELWHITEFLAG) && lineLookLevelNumber < levelNumber) {
diff --git a/src/Document.h b/src/Document.h
index 125a4a0a6..274aa0baa 100644
--- a/src/Document.h
+++ b/src/Document.h
@@ -340,7 +340,7 @@ public:
 	void ClearLevels();
 	int GetLastChild(int lineParent, int level=-1);
 	int GetFoldParent(int line);
-	void GetHighlightDelimiters(int line, HighlightDelimiter &hDelimiter);
+	void GetHighlightDelimiters(HighlightDelimiter &hDelimiter, int line, int topLine, int bottomLine);
 
 	void Indent(bool forwards);
 	int ExtendWordSelect(int pos, int delta, bool onlyWordCharacters=false);
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 05531a650..afeffc86f 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -1730,7 +1730,9 @@ void Editor::PaintSelMargin(Surface *surfWindow, PRectangle &rc) {
 				}
 			}
 			if (highlightDelimiter.isEnabled && (vs.ms[margin].mask & SC_MASK_FOLDERS)) {
-				pdoc->GetHighlightDelimiters(pdoc->LineFromPosition(CurrentPosition()), highlightDelimiter);
+				int lineBack = cs.DocFromDisplay(topLine);
+				int lineFront = cs.DocFromDisplay(((rcMargin.bottom - rcMargin.top) / vs.lineHeight) + topLine) + 1;
+				pdoc->GetHighlightDelimiters(highlightDelimiter, pdoc->LineFromPosition(CurrentPosition()), lineBack, lineFront);
 			}
 
 			// Old code does not know about new markers needed to distinguish all cases