From 9ea1c79aa013385f921445395f57fbd45b0ea014 Mon Sep 17 00:00:00 2001
From: Asger Ottar Alstrup <alstrup@lyx.org>
Date: Sun, 27 Jul 2003 10:42:11 +0000
Subject: [PATCH] When calculating fill, exploit data structure to avoid
 superfluous calls to getFont.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@7376 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/ChangeLog   |  5 +++++
 src/paragraph.C | 15 +++++++++++++++
 src/paragraph.h |  7 +++++++
 src/text.C      | 35 ++++++++++++++++++++++++++++++++---
 4 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index c1e29d1852..d03913f0fb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2003-07-27  Asger Alstrup  <alstrup@local>
+
+	* text.C (fill): Optimise algorithm to exploit that we can reuse
+	the LyXFont for many characters.
+
 2003-07-26  Asger Alstrup  <alstrup@local>
 
 	* text2.C (metrics): change a brain-dead algorithm to a smarter one.
diff --git a/src/paragraph.C b/src/paragraph.C
index 84d8b2350d..daeec8dd78 100644
--- a/src/paragraph.C
+++ b/src/paragraph.C
@@ -411,6 +411,21 @@ LyXFont const Paragraph::getFontSettings(BufferParams const & bparams,
 	return retfont;
 }
 
+lyx::pos_type 
+Paragraph::getEndPosOfFontSpan(lyx::pos_type pos) const 
+{
+	Assert(pos <= size());
+
+	Pimpl::FontList::const_iterator cit = pimpl_->fontlist.begin();
+	Pimpl::FontList::const_iterator end = pimpl_->fontlist.end();
+	for (; cit != end; ++cit) {
+		if (cit->pos() >= pos)
+			return cit->pos();
+	}
+	// This should not happen, but if so, we take no chances.
+	return pos;
+}
+
 
 // Gets uninstantiated font setting at position 0
 LyXFont const Paragraph::getFirstFontSettings() const
diff --git a/src/paragraph.h b/src/paragraph.h
index daa2056cb8..6581b639ed 100644
--- a/src/paragraph.h
+++ b/src/paragraph.h
@@ -222,6 +222,13 @@ public:
 				    LyXFont const & outerfont) const;
 	LyXFont const getLabelFont(BufferParams const &,
 				   LyXFont const & outerfont) const;
+	/**
+	 * The font returned by the above functions is the same in a
+	 * span of characters. This method will return the last position
+	 * in the paragraph for which that font is the same.
+	 * This can be used to avoid unnecessary calls to getFont.
+	 */
+	lyx::pos_type getEndPosOfFontSpan(lyx::pos_type pos) const;
 	///
 	value_type getChar(lyx::pos_type pos) const;
 	///
diff --git a/src/text.C b/src/text.C
index 8552f65777..42667d24af 100644
--- a/src/text.C
+++ b/src/text.C
@@ -934,7 +934,10 @@ int LyXText::fill(RowList::iterator row, int paper_width) const
 	pos_type const body_pos = pit->beginningOfBody();
 	pos_type i = row->pos();
 
-	if (! pit->empty()) {
+	if (! pit->empty() && i <= last) {
+		// We re-use the font resolution for the entire span when possible
+		LyXFont font = getFont(bv()->buffer(), pit, i);
+		lyx::pos_type endPosOfFontSpan = pit->getEndPosOfFontSpan(i);
 		while (i <= last) {
 			if (body_pos > 0 && i == body_pos) {
 				w += font_metrics::width(layout->labelsep, getLabelFont(bv()->buffer(), pit));
@@ -944,7 +947,30 @@ int LyXText::fill(RowList::iterator row, int paper_width) const
 				if (w < left_margin)
 					w = left_margin;
 			}
-			w += singleWidth(pit, i);
+			{ // Manual inlined an optimised version of the common case of "w += singleWidth(pit, i);"
+				char const c = pit->getChar(i);
+
+				if (IsPrintable(c)) {
+					if (i > endPosOfFontSpan) {
+						// We need to get the next font
+						font = getFont(bv()->buffer(), pit, i);
+						endPosOfFontSpan = pit->getEndPosOfFontSpan(i);
+					}
+					if (! font.language()->RightToLeft()) {
+						w += font_metrics::width(c, font);
+					} else {
+						// Fall-back to the normal case
+						w += singleWidth(pit, i, c);
+						// And flush font cache
+						endPosOfFontSpan = 0;
+					}
+				} else {
+					// Fall-back to the normal case
+					w += singleWidth(pit, i, c);
+					// And flush font cache
+					endPosOfFontSpan = 0;
+				}
+			}
 			++i;
 		}
 	}
@@ -1096,7 +1122,10 @@ void LyXText::setHeightOfRow(RowList::iterator rit)
 #endif
 				}
 			} else {
-				maxwidth += singleWidth(pit, pos);
+				// Manual inlined optimised version of common case of "maxwidth += singleWidth(pit, pos);"
+				char const c = pit->getChar(pos);
+				maxwidth += singleWidth(pit, pos, c);
+				
 			}
 		}
 	}
-- 
2.39.2