[lyx-cvs] [LyX/master] Fix bad caret position with horizontal scrolling

[Jean-Marc Lasgouttes]

commit bdf58b77e7bebce6e9554151a909a5ee62be439f
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Mon Oct 7 12:31:20 2019 +0200

    Fix bad caret position with horizontal scrolling
    
    Horizontal scrolling used to be taken into account when updating caret
    geometry. This is wrong since it may have changed when time comes to
    draw the caret. This leads to a situation where the first apparition
    of the caret is at a wrong place.
    
    Now the extra horizontal offset is used at drawing time.
    
    Fixes bug #11603.
---
 src/frontends/qt/GuiWorkArea.cpp |   35 +++++++++++++++++------------------
 1 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/src/frontends/qt/GuiWorkArea.cpp b/src/frontends/qt/GuiWorkArea.cpp
index 6a7c995..e2772fb 100644
--- a/src/frontends/qt/GuiWorkArea.cpp
+++ b/src/frontends/qt/GuiWorkArea.cpp
@@ -133,26 +133,30 @@ public:
 		x_(0), caret_width_(0)
 	{}
 
-	void draw(QPainter & painter)
+	/* Draw he caret. Parameter \c horiz_offset is not 0 when there
+	 * has been horizontal scrolling in current row
+	 */
+	void draw(QPainter & painter, int horiz_offset)
 	{
 		if (!rect_.isValid())
 			return;
 
-		int y = rect_.top();
-		int l = x_ - rect_.left();
-		int r = rect_.right() - x_;
-		int bot = rect_.bottom();
+		int const x = x_ - horiz_offset;
+		int const y = rect_.top();
+		int const l = x_ - rect_.left();
+		int const r = rect_.right() - x_;
+		int const bot = rect_.bottom();
 
 		// draw vertical line
-		painter.fillRect(x_, y, caret_width_, rect_.height(), color_);
+		painter.fillRect(x, y, caret_width_, rect_.height(), color_);
 
 		// draw RTL/LTR indication
 		painter.setPen(color_);
 		if (l_shape_) {
 			if (rtl_)
-				painter.drawLine(x_, bot, x_ - l + 1, bot);
+				painter.drawLine(x, bot, x - l + 1, bot);
 			else
-				painter.drawLine(x_, bot, x_ + caret_width_ + r - 1, bot);
+				painter.drawLine(x, bot, x + caret_width_ + r - 1, bot);
 		}
 
 		// draw completion triangle
@@ -160,11 +164,11 @@ public:
 			int m = y + rect_.height() / 2;
 			int d = TabIndicatorWidth - 1;
 			if (rtl_) {
-				painter.drawLine(x_ - 1, m - d, x_ - 1 - d, m);
-				painter.drawLine(x_ - 1, m + d, x_ - 1 - d, m);
+				painter.drawLine(x - 1, m - d, x - 1 - d, m);
+				painter.drawLine(x - 1, m + d, x - 1 - d, m);
 			} else {
-				painter.drawLine(x_ + caret_width_, m - d, x_ + caret_width_ + d, m);
-				painter.drawLine(x_ + caret_width_, m + d, x_ + caret_width_ + d, m);
+				painter.drawLine(x + caret_width_, m - d, x + caret_width_ + d, m);
+				painter.drawLine(x + caret_width_, m + d, x + caret_width_ + d, m);
 			}
 		}
 	}
@@ -633,11 +637,6 @@ void GuiWorkArea::Private::updateCaretGeometry()
 		&& !completer_->inlineVisible();
 	caret_visible_ = true;
 
-	//int cur_x = buffer_view_->getPos(cur).x_;
-	// We may have decided to slide the cursor row so that caret
-	// is visible.
-	point.x_ -= buffer_view_->horizScrollOffset();
-
 	caret_->update(point.x_, point.y_, h, l_shape, isrtl, completable);
 }
 
@@ -1340,7 +1339,7 @@ void GuiWorkArea::paintEvent(QPaintEvent * ev)
 
 	// and the caret
 	if (d->caret_visible_)
-		d->caret_->draw(pain);
+		d->caret_->draw(pain, d->buffer_view_->horizScrollOffset());
 
 	d->updateScreen(ev->rect());