From 8fd209b4de878c718aae2844e87a0fab7cb2feb9 Mon Sep 17 00:00:00 2001
From: Oliver Tappe <zooey@hirschkaefer.de>
Date: Sun, 26 Apr 2009 18:05:42 +0000
Subject: [PATCH] Fixed incompatibility with R5 (and general PITA) -
 LineAt(TextLength()) returned one less than it should, causing unexpected
 moves of the caret, for instance when pressing HOME on the last (empty) line:
 * LineBuffer::OffsetToLine() and LineBuffer::PixelToLine() did not check  
 for the last line in their binary search * removed a special case from
 TextView::PointAt() which now is no longer   necessary (not sure if it was,
 before)

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30435 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/kits/interface/TextView.cpp               | 46 ++++++++-----------
 .../interface/textview_support/LineBuffer.cpp | 19 +++++---
 2 files changed, 31 insertions(+), 34 deletions(-)

diff --git a/src/kits/interface/TextView.cpp b/src/kits/interface/TextView.cpp
index 4dd2bfcaac..d1b86afbf1 100644
--- a/src/kits/interface/TextView.cpp
+++ b/src/kits/interface/TextView.cpp
@@ -1749,7 +1749,6 @@ BPoint
 BTextView::PointAt(int32 inOffset, float *outHeight) const
 {
 	// TODO: Cleanup.
-	const int32 textLength = fText->Length();
 	int32 lineNum = LineAt(inOffset);
 	STELine* line = (*fLines)[lineNum];
 	float height = 0;
@@ -1758,10 +1757,9 @@ BTextView::PointAt(int32 inOffset, float *outHeight) const
 	result.x = 0.0;
 	result.y = line->origin + fTextRect.top;
 
-	// Handle the case where there is only one line
-	// (no text inserted)
+	// Handle the case where we are on the last (always empty) line
 	// TODO: See if we can do this better
-	if (fStyles->NumRuns() == 0) {
+	if (fStyles->NumRuns() == 0 || lineNum == fLines->NumLines()) {
 		const rgb_color *color = NULL;
 		const BFont *font = NULL;
 		fStyles->GetNullStyle(&font, &color);
@@ -1773,32 +1771,24 @@ BTextView::PointAt(int32 inOffset, float *outHeight) const
 	} else {
 		height = (line + 1)->origin - line->origin;
 
-		// special case: go down one line if inOffset is a newline
-		if (inOffset == textLength && fText->RealCharAt(inOffset - 1)
-				== B_ENTER) {
-			result.y += height;
-			height = LineHeight(CountLines() - 1);
+		int32 offset = line->offset;
+		int32 length = inOffset - line->offset;
+		int32 numBytes = length;
+		bool foundTab = false;
+		do {
+			foundTab = fText->FindChar(B_TAB, offset, &numBytes);
+			float width = _StyledWidth(offset, numBytes);
+			result.x += width;
 
-		} else {
-			int32 offset = line->offset;
-			int32 length = inOffset - line->offset;
-			int32 numBytes = length;
-			bool foundTab = false;
-			do {
-				foundTab = fText->FindChar(B_TAB, offset, &numBytes);
-				float width = _StyledWidth(offset, numBytes);
-				result.x += width;
+			if (foundTab) {
+				result.x += _ActualTabWidth(result.x);
+				numBytes++;
+			}
 
-				if (foundTab) {
-					result.x += _ActualTabWidth(result.x);
-					numBytes++;
-				}
-
-				offset += numBytes;
-				length -= numBytes;
-				numBytes = length;
-			} while (foundTab && length > 0);
-		}
+			offset += numBytes;
+			length -= numBytes;
+			numBytes = length;
+		} while (foundTab && length > 0);
 	}
 
 	if (fAlignment != B_ALIGN_LEFT) {
diff --git a/src/kits/interface/textview_support/LineBuffer.cpp b/src/kits/interface/textview_support/LineBuffer.cpp
index 4ff3af2edc..55676bb5c4 100644
--- a/src/kits/interface/textview_support/LineBuffer.cpp
+++ b/src/kits/interface/textview_support/LineBuffer.cpp
@@ -8,7 +8,6 @@
 
 #include "LineBuffer.h"
 
-
 BTextView::LineBuffer::LineBuffer()
 	:	_BTextViewSupportBuffer_<STELine>(20, 2)
 {
@@ -54,7 +53,7 @@ BTextView::LineBuffer::OffsetToLine(int32 offset) const
 	int32 minIndex = 0;
 	int32 maxIndex = fItemCount - 1;
 	int32 index = 0;
-	
+
 	while (minIndex < maxIndex) {
 		index = (minIndex + maxIndex) >> 1;
 		if (offset >= fBuffer[index].offset) {
@@ -65,7 +64,11 @@ BTextView::LineBuffer::OffsetToLine(int32 offset) const
 		} else
 			maxIndex = index;
 	}
-	
+
+	// do check for last line
+	if (minIndex == maxIndex && offset >= fBuffer[maxIndex].offset)
+		index = maxIndex;
+
 	return index;
 }
 
@@ -76,7 +79,7 @@ BTextView::LineBuffer::PixelToLine(float pixel) const
 	int32 minIndex = 0;
 	int32 maxIndex = fItemCount - 1;
 	int32 index = 0;
-	
+
 	while (minIndex < maxIndex) {
 		index = (minIndex + maxIndex) >> 1;
 		if (pixel >= fBuffer[index].origin) {
@@ -87,14 +90,18 @@ BTextView::LineBuffer::PixelToLine(float pixel) const
 		} else
 			maxIndex = index;
 	}
-	
+
+	// do check for last line
+	if (minIndex == maxIndex && pixel >= fBuffer[maxIndex].origin)
+		index = maxIndex;
+
 	return index;
 }
 
 
 void
 BTextView::LineBuffer::BumpOrigin(float delta, long index)
-{	
+{
 	for (long i = index; i < fItemCount; i++)
 		fBuffer[i].origin += delta;
 }