From ee4e08d81f633437034b05b56a82dc20f474991a Mon Sep 17 00:00:00 2001
From: Neil <nyamatongwe@gmail.com>
Date: Mon, 1 Aug 2022 11:03:53 +1000
Subject: Improve drawing of rounded rectangles with Direct2D. Treat case where
 outline and fill are same colour as single fill call for more uniform
 appearance. In thin rectangles, shift to semi-circular ends when no room for
 full rounded corners. Use different radius for fill and stroke for more
 uniform appearance.

---
 doc/ScintillaHistory.html |  3 +++
 win32/PlatWin.cxx         | 30 ++++++++++++++++++++----------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 7895d131a..e7ac0cc1b 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -596,6 +596,9 @@
 	The translucency of INDIC_COMPOSITIONTHICK can be changed with SCI_INDICSETOUTLINEALPHA.
 	</li>
 	<li>
+	Improve drawing of rounded rectangles on Direct2D.
+	</li>
+	<li>
 	Line state optimized to avoid excess allocations by always allocating for every line.
 	This makes SCI_GETMAXLINESTATE less useful although it can still distinguish cases
 	where line state was never set for any lines.
diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 293e7d3cb..761c00193 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -1651,17 +1651,27 @@ void SurfaceD2D::FillRectangle(PRectangle rc, Surface &surfacePattern) {
 
 void SurfaceD2D::RoundedRectangle(PRectangle rc, FillStroke fillStroke) {
 	if (pRenderTarget) {
-		D2D1_ROUNDED_RECT roundedRectFill = {
-			RectangleFromPRectangle(rc.Inset(1.0)),
-			4, 4};
-		D2DPenColourAlpha(fillStroke.fill.colour);
-		pRenderTarget->FillRoundedRectangle(roundedRectFill, pBrush);
+		const FLOAT minDimension = static_cast<FLOAT>(std::min(rc.Width(), rc.Height())) / 2.0f;
+		const FLOAT radius = std::min(4.0f, minDimension);
+		if (fillStroke.fill.colour == fillStroke.stroke.colour) {
+			D2D1_ROUNDED_RECT roundedRectFill = {
+				RectangleFromPRectangle(rc),
+				radius, radius };
+			D2DPenColourAlpha(fillStroke.fill.colour);
+			pRenderTarget->FillRoundedRectangle(roundedRectFill, pBrush);
+		} else {
+			D2D1_ROUNDED_RECT roundedRectFill = {
+				RectangleFromPRectangle(rc.Inset(1.0)),
+				radius-1, radius-1 };
+			D2DPenColourAlpha(fillStroke.fill.colour);
+			pRenderTarget->FillRoundedRectangle(roundedRectFill, pBrush);
 
-		D2D1_ROUNDED_RECT roundedRect = {
-			RectangleFromPRectangle(rc.Inset(0.5)),
-			4, 4};
-		D2DPenColourAlpha(fillStroke.stroke.colour);
-		pRenderTarget->DrawRoundedRectangle(roundedRect, pBrush, fillStroke.stroke.WidthF());
+			D2D1_ROUNDED_RECT roundedRect = {
+				RectangleFromPRectangle(rc.Inset(0.5)),
+				radius, radius };
+			D2DPenColourAlpha(fillStroke.stroke.colour);
+			pRenderTarget->DrawRoundedRectangle(roundedRect, pBrush, fillStroke.stroke.WidthF());
+		}
 	}
 }
 
-- 
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