From 3ea0a9e5f451ca35c67adca1ee4ee315e316260b Mon Sep 17 00:00:00 2001
From: John Levon <levon@movementarian.org>
Date: Tue, 18 Mar 2003 16:47:18 +0000
Subject: [PATCH] anchorRow

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@6526 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/ChangeLog |  6 ++++++
 src/lyxtext.h | 11 +++++++----
 src/text.C    | 27 ++++++++++++++++++++-------
 src/text2.C   | 20 ++++++++++++--------
 4 files changed, 45 insertions(+), 19 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index a8f0f528b3..3543415d93 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2003-03-18  Alfredo Braunstein  <abraunst@libero.it>
+
+	* lyxtext.h:
+	* text.C:
+	* text2.C: anchor row on setCursor
+
 2003-03-18  Alfredo Braunstein  <abraunst@libero.it>
  
  	* lyxtext.h: remove almost all mutable keywords
diff --git a/src/lyxtext.h b/src/lyxtext.h
index e880d878c4..a7446769db 100644
--- a/src/lyxtext.h
+++ b/src/lyxtext.h
@@ -84,17 +84,20 @@ public:
 	/// the current font
 	LyXFont real_current_font;
 private:
-	/** the first visible row on screen
+	/** the 'anchor' row: the position of this row remains constant
+	 *  with respect to the top of the screen
 	 */
-	Row * top_row_;
+	Row * anchor_row_;
 	/** the pixel offset with respect to this row of top_y
 	 */
-	int top_row_offset_;
+	int anchor_row_offset_;
 public:
 	/// get the y coord. of the top of the screen (relative to doc start)
 	int top_y() const;
-	/// set it
+	/// set the y coord. of the top of the screen (relative to doc start)
 	void top_y(int newy);
+	/// set the anchoring row. top_y will be computed relative to this
+	void anchor_row(Row * row);
 	///
 	InsetText * inset_owner;
 	///
diff --git a/src/text.C b/src/text.C
index e1239f2878..5235f1611f 100644
--- a/src/text.C
+++ b/src/text.C
@@ -74,14 +74,15 @@ BufferView * LyXText::bv() const
 
 int LyXText::top_y() const
 {
-	if (!top_row_)
+	if (!anchor_row_)
 		return 0;
 
 	int y = 0;
-	for (Row * row = firstrow; row && row != top_row_; row = row->next()) {
+	for (Row * row = firstrow; 
+	     row && row != anchor_row_; row = row->next()) {
 		y += row->height();
 	}
-	return y + top_row_offset_;
+	return y + anchor_row_offset_;
 }
 
 
@@ -92,10 +93,22 @@ void LyXText::top_y(int newy)
 	lyxerr[Debug::GUI] << "setting top y = " << newy << endl;
 
 	int y = newy;
-	top_row_ = getRowNearY(y);
-	top_row_offset_ = newy - y;
-	lyxerr[Debug::GUI] << "changing reference to row: " << top_row_
-	       << " offset: " << top_row_offset_ << endl;
+	anchor_row_ = getRowNearY(y);
+	anchor_row_offset_ = newy - y;
+	lyxerr[Debug::GUI] << "changing reference to row: " << anchor_row_
+	       << " offset: " << anchor_row_offset_ << endl;
+}
+
+
+void LyXText::anchor_row(Row * row)
+{
+	int old_y = top_y();
+	anchor_row_offset_ = 0;
+	anchor_row_ = row; 
+	anchor_row_offset_ = old_y - top_y();
+	lyxerr[Debug::GUI] << "anchor_row(): changing reference to row: " 
+			   << anchor_row_ << " offset: " << anchor_row_offset_ 
+			   << endl;
 }
 
 
diff --git a/src/text2.C b/src/text2.C
index 75126e96c0..29ebcd2d13 100644
--- a/src/text2.C
+++ b/src/text2.C
@@ -52,7 +52,7 @@ using lyx::pos_type;
 
 
 LyXText::LyXText(BufferView * bv)
-	: height(0), width(0), top_row_(0), top_row_offset_(0),
+	: height(0), width(0), anchor_row_(0), anchor_row_offset_(0),
 	  inset_owner(0), the_locking_inset(0), need_break_row(0),
 	  bv_owner(bv), firstrow(0), lastrow(0)
 {
@@ -61,7 +61,7 @@ LyXText::LyXText(BufferView * bv)
 
 
 LyXText::LyXText(BufferView * bv, InsetText * inset)
-	: height(0), width(0), top_row_(0), top_row_offset_(0),
+	: height(0), width(0), anchor_row_(0), anchor_row_offset_(0),
 	  inset_owner(inset), the_locking_inset(0), need_break_row(0),
 	  bv_owner(bv), firstrow(0), lastrow(0)
 {
@@ -331,13 +331,13 @@ void LyXText::removeRow(Row * row)
 		// what about refresh_y
 	}
 
-	if (top_row_ == row) {
-		if (row->next()) {
-			top_row_ = row->next();
-			top_row_offset_ -= row->height();
+	if (anchor_row_ == row) {
+		if (row_prev) {
+			anchor_row_ = row_prev;
+			anchor_row_offset_ = 0;
 		} else {
-			top_row_ = row_prev;
-			top_row_offset_ = 0;
+			anchor_row_ = row->next();
+			anchor_row_offset_ -= row->height();
 		}
 	}
 
@@ -1793,6 +1793,10 @@ void LyXText::setCursor(LyXCursor & cur, Paragraph * par,
 		cur.ix(int(x));
 	} else
 		cur.ix(cur.x());
+	//if the cursor is in a visible row, anchor to it
+	int topy = top_y();
+	if (topy < y && y < topy + bv()->workHeight()) 
+		anchor_row(row);
 }
 
 
-- 
2.39.2