[LyX/master] Get rid of BufferView::scrollUp/Down

[Jean-Marc Lasgouttes]

commit 439b7bb9c97ba2f267a4ccc9ae3d9af5eab100f9
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Tue Sep 3 18:13:02 2024 +0200

    Get rid of BufferView::scrollUp/Down
    
    LFUN_SCROLL was the last user, change it to use only scroll(). Take
    this opportunity to improve a bit this dispatch code.
    
    Also improve somewhat the methods documentation.
---
 src/BufferView.cpp | 32 ++++++++++++--------------------
 src/BufferView.h   | 14 +++++++-------
 2 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 485daf4f31..75d145fa75 100644
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -2168,18 +2168,24 @@ void BufferView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			scroll_step = d->scrollbarParameters_.single_step;
 		else if (scroll_type == "page")
 			scroll_step = d->scrollbarParameters_.page_step;
-		else
+		else {
+			dispatched = false;
 			return;
+		}
+
 		string const scroll_quantity = cmd.getArg(1);
+
 		if (scroll_quantity == "up")
-			scrollUp(scroll_step);
+			scroll(-scroll_step);
 		else if (scroll_quantity == "down")
-			scrollDown(scroll_step);
+			scroll(scroll_step);
+		else if (isStrInt(scroll_quantity))
+			scroll(scroll_step * convert<int>(scroll_quantity));
 		else {
-			int const scroll_value = convert<int>(scroll_quantity);
-			if (scroll_value)
-				scroll(scroll_step * scroll_value);
+			dispatched = false;
+			return;
 		}
+
 		dr.screenUpdate(Update::ForceDraw);
 		dr.forceBufferUpdate();
 		break;
@@ -2859,20 +2865,6 @@ int BufferView::scroll(int pixels)
 }
 
 
-int BufferView::scrollDown(int pixels)
-{
-	d->anchor_ypos_ -= pixels;
-	return -pixels;
-}
-
-
-int BufferView::scrollUp(int pixels)
-{
-	d->anchor_ypos_ += pixels;
-	return pixels;
-}
-
-
 bool BufferView::setCursorFromRow(int row)
 {
 	TexRow::TextEntry start, end;
diff --git a/src/BufferView.h b/src/BufferView.h
index 0b9ade2f3b..57d602de7f 100644
--- a/src/BufferView.h
+++ b/src/BufferView.h
@@ -218,17 +218,17 @@ public:
 	/// Ensure the passed cursor \p dit is visible.
 	/// This method will automatically scroll and update the BufferView
 	/// (metrics+drawing) if needed.
-	/// \param how Use this scroll strategy
+	/// \param how: where the cursor should appear (visible/top/center)
 	void showCursor(DocIterator const & dit, ScrollType how);
 	/// Scroll to the cursor.
-	/// \param how Use this scroll strategy
+	/// This only updates the anchor vertical position, but does not
+	/// recompute metrics nor trigger a screen refresh.
+	/// \param how: where the cursor should appear (visible/top/center)
 	/// \return true if screen was scrolled
 	bool scrollToCursor(DocIterator const & dit, ScrollType how);
-	/// scroll down document by the given number of pixels.
-	int scrollDown(int pixels);
-	/// scroll up document by the given number of pixels.
-	int scrollUp(int pixels);
-	/// scroll document by the given number of pixels.
+	/// scroll the view by the given number of pixels. This only
+	/// updates the anchor vertical position, but does not recompute
+	/// metrics nor trigger a screen refresh.
 	int scroll(int pixels);
 	/// Scroll the view by a number of pixels.
 	void scrollDocView(int pixels);