From ed7e87bfd2dfb8cbbab786b3742385de9d1e6a2a Mon Sep 17 00:00:00 2001
From: Neil <nyamatongwe@gmail.com>
Date: Sun, 25 Sep 2022 11:33:59 +1000
Subject: Draw lines more consistently in SC_PHASES_TWO and SC_PHASES_ONE modes
 by clipping drawing to just the line rectangle.

---
 doc/ScintillaHistory.html | 6 ++++++
 src/EditView.cxx          | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 8f2a6206c..2224ca420 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -589,6 +589,12 @@
 	and was exposed by ScintillaDocument in the Qt implementation of ScintillaEdit.
 	</li>
 	<li>
+	Draw lines more consistently in SC_PHASES_TWO and SC_PHASES_ONE modes by
+	clipping drawing to just the line rectangle.
+	This stops drawing some extreme ascenders, descenders and portions of indicators which
+	may appear and then disappear depending on which lines were drawn.
+	</li>
+	<li>
 	On Win32 implement horizontal scrolling mouse wheel.
 	<a href="https://sourceforge.net/p/scintilla/feature-requests/1450/">Feature #1450</a>.
 	</li>
diff --git a/src/EditView.cxx b/src/EditView.cxx
index 100d3d18b..2290cf8a6 100644
--- a/src/EditView.cxx
+++ b/src/EditView.cxx
@@ -2354,6 +2354,11 @@ void EditView::DrawLine(Surface *surface, const EditModel &model, const ViewStyl
 		return; // No further drawing
 	}
 
+	const bool clipLine = !bufferedDraw && !LinesOverlap();
+	if (clipLine) {
+		surface->SetClip(rcLine);
+	}
+
 	// See if something overrides the line background colour.
 	const std::optional<ColourRGBA> background = vsDraw.Background(model.GetMark(line), model.caret.active, ll->containsCaret);
 
@@ -2429,6 +2434,10 @@ void EditView::DrawLine(Surface *surface, const EditModel &model, const ViewStyl
 	if (FlagSet(phase, DrawPhase::lineTranslucent)) {
 		DrawTranslucentLineState(surface, model, vsDraw, ll, line, rcLine, subLine, Layer::OverText);
 	}
+
+	if (clipLine) {
+		surface->PopClip();
+	}
 }
 
 static void DrawFoldLines(Surface *surface, const EditModel &model, const ViewStyle &vsDraw, const LineLayout *ll,
-- 
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