Add SCI_MARKERSETLAYER to define layer on which to draw content area markers.

This replaces the use of SC_ALPHA_NOALPHA for markers.

11 files changed, 78 insertions, 29 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 2ba53c837..990868241 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -267,19 +267,18 @@
           This is similar to <a class="seealso" href="#colour">colour</a> but with a byte
           of <a class="seealso" href="#colour">alpha</a> added. They are combined as:
           red | (green &lt;&lt; 8) | (blue &lt;&lt; 16) | (alpha &lt;&lt; 24).
-          Fully opaque uses an alpha of 255. SC_ALPHA_NOALPHA is not possible for
-          colouralpha values.</td>
+          Fully opaque uses an alpha of 255.
         </tr>
 
         <tr>
           <th align="left" id="alpha"><code>alpha</code></th>
 
           <td>Translucency is set using an alpha value.
-                        Alpha ranges from 0 (SC_ALPHA_TRANSPARENT) which is completely transparent to
-                               255 (SC_ALPHA_OPAQUE) which is opaque. The value 256 (SC_ALPHA_NOALPHA)
-                               is opaque and uses code that is not alpha-aware and may be faster. Not all platforms support
-                               translucency and only some Scintilla features implement translucency.
-                               The default alpha value for most features is SC_ALPHA_NOALPHA.</td>
+		Alpha ranges from 0 (SC_ALPHA_TRANSPARENT) which is completely transparent to
+                   255 (SC_ALPHA_OPAQUE) which is opaque.
+		Previous versions used the value 256 (SC_ALPHA_NOALPHA) to indicate that drawing was to be
+		performed opaquely on the base layer. This is now discouraged and code should use the <code>&hellip;LAYER&hellip;</code>
+		methods to choose the layer.</td>
         </tr>
 
         <tr>
@@ -4744,6 +4743,8 @@ struct Sci_TextToFind {
     back)</a><br />
     <a class="message" href="#SCI_MARKERSETSTROKEWIDTH">SCI_MARKERSETSTROKEWIDTH(int markerNumber, int hundredths)</a><br />
     <a class="message" href="#SCI_MARKERENABLEHIGHLIGHT">SCI_MARKERENABLEHIGHLIGHT(bool enabled)</a><br />
+     <a class="message" href="#SCI_MARKERSETLAYER">SCI_MARKERSETLAYER(int markerNumber, int layer)</a><br />
+     <a class="message" href="#SCI_MARKERGETLAYER">SCI_MARKERGETLAYER(int markerNumber) &rarr; int</a><br />
      <a class="message" href="#SCI_MARKERSETALPHA">SCI_MARKERSETALPHA(int markerNumber, alpha alpha)</a><br />
      <a class="message" href="#SCI_MARKERADD">SCI_MARKERADD(line line, int markerNumber) &rarr; int</a><br />
      <a class="message" href="#SCI_MARKERADDSET">SCI_MARKERADDSET(line line, int markerSet)</a><br />
@@ -4974,11 +4975,17 @@ struct Sci_TextToFind {
      <p><b id="SCI_MARKERENABLEHIGHLIGHT">SCI_MARKERENABLEHIGHLIGHT(bool enabled)</b><br />
      This message allows to enable/disable the highlight folding block when it is selected. (i.e. block that contains the caret)</p>
 
-     <p><b id="SCI_MARKERSETALPHA">SCI_MARKERSETALPHA(int markerNumber,
+     <p>
+     <b id="SCI_MARKERSETLAYER">SCI_MARKERSETLAYER(int markerNumber, int layer)</b><br />
+     <b id="SCI_MARKERGETLAYER">SCI_MARKERGETLAYER(int markerNumber) &rarr; int</b><br />
+     <b id="SCI_MARKERSETALPHA">SCI_MARKERSETALPHA(int markerNumber,
      <a class="jump" href="#alpha">alpha</a> alpha)</b><br />
      When markers are drawn in the content area, either because there is no margin for them or
-     they are of <code>SC_MARK_BACKGROUND</code> or <code>SC_MARK_UNDERLINE</code> types, they may be drawn translucently by
-     setting an alpha value. This is only for the content area - in margins, translucency is achieved through the <code>SCI_MARKERSET&hellip;TRANSLUCENT</code>
+     they are of <code>SC_MARK_BACKGROUND</code> or <code>SC_MARK_UNDERLINE</code> types, they may be drawn translucently over text
+     or opaquely on the base layer.
+     The layer to draw on is defined by <code>SCI_MARKERSETLAYER</code>.
+     The degree of translucency can be chosen by setting an alpha value.
+     This is only for the content area - in margins, translucency is achieved through the <code>SCI_MARKERSET&hellip;TRANSLUCENT</code>
      methods.</p>
 
     <p><b id="SCI_MARKERADD">SCI_MARKERADD(line line, int markerNumber) &rarr; int</b><br />
diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 6985807e1..8fdea24bc 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -592,6 +592,10 @@
 	SCI_SETCARETLINEBACKALPHA now discouraged.
 	</li>
 	<li>
+	Add SCI_MARKERSETLAYER to define layer on which to draw conetent area markers.
+	This replaces the use of SC_ALPHA_NOALPHA for markers.
+	</li>
+	<li>
 	Add SCI_GETELEMENTBASECOLOUR to return the default values for element colours.
 	</li>
 	<li>
diff --git a/include/Scintilla.h b/include/Scintilla.h
index d48ad6c5a..de0e37ca7 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -177,6 +177,8 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCI_MARKERDEFINEPIXMAP 2049
 #define SCI_MARKERADDSET 2466
 #define SCI_MARKERSETALPHA 2476
+#define SCI_MARKERGETLAYER 2734
+#define SCI_MARKERSETLAYER 2735
 #define SC_MAX_MARGIN 4
 #define SC_MARGIN_SYMBOL 0
 #define SC_MARGIN_NUMBER 1
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 8a2b0de66..0f1b0fc3c 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -453,6 +453,12 @@ fun void MarkerAddSet=2466(line line, int markerSet)
 # Set the alpha used for a marker that is drawn in the text area, not the margin.
 set void MarkerSetAlpha=2476(int markerNumber, Alpha alpha)
 
+# Get the layer used for a marker that is drawn in the text area, not the margin.
+get Layer MarkerGetLayer=2734(int markerNumber,)
+
+# Set the layer used for a marker that is drawn in the text area, not the margin.
+set void MarkerSetLayer=2735(int markerNumber, Layer layer)
+
 val SC_MAX_MARGIN=4
 
 enu MarginType=SC_MARGIN_
diff --git a/src/EditView.cxx b/src/EditView.cxx
index 2b389ecee..4ae9aecc9 100644
--- a/src/EditView.cxx
+++ b/src/EditView.cxx
@@ -888,12 +888,6 @@ void EditView::DrawIndentGuide(Surface *surface, Sci::Line lineVisible, int line
 		highlight ? *pixmapIndentGuideHighlight : *pixmapIndentGuide);
 }
 
-static void SimpleAlphaRectangle(Surface *surface, PRectangle rc, ColourAlpha fill, int alpha) {
-	if (alpha != SC_ALPHA_NOALPHA) {
-		surface->FillRectangleAligned(rc, ColourAlpha(fill, alpha));
-	}
-}
-
 static void DrawTextBlob(Surface *surface, const ViewStyle &vsDraw, PRectangle rcSegment,
 	std::string_view text, ColourAlpha textBack, ColourAlpha textFore, bool fillBackground) {
 	if (rcSegment.Empty())
@@ -1790,13 +1784,13 @@ static void DrawEdgeLine(Surface *surface, const ViewStyle &vsDraw, const LineLa
 	}
 }
 
-// Draw underline mark as part of background if not transparent
+// Draw underline mark as part of background if on base layer
 static void DrawMarkUnderline(Surface *surface, const EditModel &model, const ViewStyle &vsDraw,
 	Sci::Line line, PRectangle rcLine) {
 	int marks = model.pdoc->GetMark(line);
 	for (int markBit = 0; (markBit < 32) && marks; markBit++) {
 		if ((marks & 1) && (vsDraw.markers[markBit].markType == SC_MARK_UNDERLINE) &&
-			(vsDraw.markers[markBit].alpha == SC_ALPHA_NOALPHA)) {
+			(vsDraw.markers[markBit].layer == Layer::base)) {
 			PRectangle rcUnderline = rcLine;
 			rcUnderline.top = rcUnderline.bottom - 2;
 			surface->FillRectangleAligned(rcUnderline, Fill(vsDraw.markers[markBit].back));
@@ -1883,11 +1877,11 @@ static void DrawTranslucentLineState(Surface *surface, const EditModel &model, c
 	for (int markBit = 0; (markBit < 32) && marksDrawnInText; markBit++) {
 		if (marksDrawnInText & 1) {
 			if (vsDraw.markers[markBit].markType == SC_MARK_BACKGROUND) {
-				SimpleAlphaRectangle(surface, rcLine, vsDraw.markers[markBit].back, vsDraw.markers[markBit].alpha);
+				surface->FillRectangleAligned(rcLine, vsDraw.markers[markBit].BackWithAlpha());
 			} else if (vsDraw.markers[markBit].markType == SC_MARK_UNDERLINE) {
 				PRectangle rcUnderline = rcLine;
 				rcUnderline.top = rcUnderline.bottom - 2;
-				SimpleAlphaRectangle(surface, rcUnderline, vsDraw.markers[markBit].back, vsDraw.markers[markBit].alpha);
+				surface->FillRectangleAligned(rcUnderline, vsDraw.markers[markBit].BackWithAlpha());
 			}
 		}
 		marksDrawnInText >>= 1;
@@ -1895,7 +1889,7 @@ static void DrawTranslucentLineState(Surface *surface, const EditModel &model, c
 	int marksDrawnInLine = marksOfLine & vsDraw.maskInLine;
 	for (int markBit = 0; (markBit < 32) && marksDrawnInLine; markBit++) {
 		if (marksDrawnInLine & 1) {
-			SimpleAlphaRectangle(surface, rcLine, vsDraw.markers[markBit].back, vsDraw.markers[markBit].alpha);
+			surface->FillRectangleAligned(rcLine, vsDraw.markers[markBit].BackWithAlpha());
 		}
 		marksDrawnInLine >>= 1;
 	}
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 694ac2f5f..8b6147a5b 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -6997,10 +6997,26 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 		RedrawSelMargin();
 		break;
 	case SCI_MARKERSETALPHA:
-		if (wParam <= MARKER_MAX)
-			vs.markers[wParam].alpha = static_cast<int>(lParam);
-		InvalidateStyleRedraw();
+		if (wParam <= MARKER_MAX) {
+			if (lParam == SC_ALPHA_NOALPHA) {
+				SetAppearance(vs.markers[wParam].alpha, 0xff);
+				SetAppearance(vs.markers[wParam].layer, Layer::base);
+			} else {
+				SetAppearance(vs.markers[wParam].alpha, static_cast<int>(lParam));
+				SetAppearance(vs.markers[wParam].layer, Layer::over);
+			}
+		}
 		break;
+	case SCI_MARKERSETLAYER:
+		if (wParam <= MARKER_MAX) {
+			SetAppearance(vs.markers[wParam].layer, static_cast<Layer>(lParam));
+		}
+		break;
+	case SCI_MARKERGETLAYER:
+		if (wParam <= MARKER_MAX) {
+			return static_cast<sptr_t>(vs.markers[wParam].layer);
+		}
+		return 0;
 	case SCI_MARKERADD: {
 			const int markerID = pdoc->AddMark(static_cast<Sci::Line>(wParam), static_cast<int>(lParam));
 			return markerID;
diff --git a/src/LineMarker.cxx b/src/LineMarker.cxx
index ed9c1ce7a..a3ab16b1d 100644
--- a/src/LineMarker.cxx
+++ b/src/LineMarker.cxx
@@ -37,6 +37,7 @@ LineMarker::LineMarker(const LineMarker &other) {
 	back = other.back;
 	backSelected = other.backSelected;
 	strokeWidth = other.strokeWidth;
+	layer = other.layer;
 	alpha = other.alpha;
 	if (other.pxpm)
 		pxpm = std::make_unique<XPM>(*other.pxpm);
@@ -57,6 +58,7 @@ LineMarker &LineMarker::operator=(const LineMarker &other) {
 		back = other.back;
 		backSelected = other.backSelected;
 		strokeWidth = other.strokeWidth;
+		layer = other.layer;
 		alpha = other.alpha;
 		if (other.pxpm)
 			pxpm = std::make_unique<XPM>(*other.pxpm);
@@ -71,6 +73,10 @@ LineMarker &LineMarker::operator=(const LineMarker &other) {
 	return *this;
 }
 
+ColourAlpha LineMarker::BackWithAlpha() const noexcept {
+	return ColourAlpha(back, alpha);
+}
+
 void LineMarker::SetXPM(const char *textForm) {
 	pxpm = std::make_unique<XPM>(textForm);
 	markType = SC_MARK_PIXMAP;
diff --git a/src/LineMarker.h b/src/LineMarker.h
index c13d4f4d0..1047d34e9 100644
--- a/src/LineMarker.h
+++ b/src/LineMarker.h
@@ -15,6 +15,8 @@ class RGBAImage;
 
 typedef void (*DrawLineMarkerFn)(Surface *surface, const PRectangle &rcWhole, const Font *fontForCharacter, int tFold, int marginStyle, const void *lineMarker);
 
+enum class Layer { base = 0, over = 10 };
+
 /**
  */
 class LineMarker {
@@ -25,6 +27,7 @@ public:
 	ColourAlpha fore = ColourAlpha(0, 0, 0);
 	ColourAlpha back = ColourAlpha(0xff, 0xff, 0xff);
 	ColourAlpha backSelected = ColourAlpha(0xff, 0x00, 0x00);
+	Layer layer = Layer::base;
 	int alpha = SC_ALPHA_NOALPHA;
 	XYPOSITION strokeWidth = 1.0f;
 	std::unique_ptr<XPM> pxpm;
@@ -42,6 +45,8 @@ public:
 	LineMarker &operator=(LineMarker&&) noexcept = default;
 	virtual ~LineMarker() = default;
 
+	ColourAlpha BackWithAlpha() const noexcept;
+
 	void SetXPM(const char *textForm);
 	void SetXPM(const char *const *linesForm);
 	void SetRGBAImage(Point sizeRGBAImage, float scale, const unsigned char *pixelsRGBAImage);
diff --git a/src/ViewStyle.cxx b/src/ViewStyle.cxx
index 60334c2ea..455a44c1e 100644
--- a/src/ViewStyle.cxx
+++ b/src/ViewStyle.cxx
@@ -483,7 +483,7 @@ std::optional<ColourAlpha> ViewStyle::Background(int marksOfLine, bool caretActi
 		int marks = marksOfLine;
 		for (int markBit = 0; (markBit < 32) && marks; markBit++) {
 			if ((marks & 1) && (markers[markBit].markType == SC_MARK_BACKGROUND) &&
-				(markers[markBit].alpha == SC_ALPHA_NOALPHA)) {
+				(markers[markBit].layer == Layer::base)) {
 				background = markers[markBit].back;
 			}
 			marks >>= 1;
@@ -494,14 +494,18 @@ std::optional<ColourAlpha> ViewStyle::Background(int marksOfLine, bool caretActi
 		if (marksMasked) {
 			for (int markBit = 0; (markBit < 32) && marksMasked; markBit++) {
 				if ((marksMasked & 1) &&
-					(markers[markBit].alpha == SC_ALPHA_NOALPHA)) {
+					(markers[markBit].layer == Layer::base)) {
 					background = markers[markBit].back;
 				}
 				marksMasked >>= 1;
 			}
 		}
 	}
-	return background;
+	if (background) {
+		return background->Opaque();
+	} else {
+		return {};
+	}
 }
 
 bool ViewStyle::SelectionBackgroundDrawn() const noexcept {
diff --git a/src/ViewStyle.h b/src/ViewStyle.h
index 9f3cae123..20325a962 100644
--- a/src/ViewStyle.h
+++ b/src/ViewStyle.h
@@ -63,8 +63,6 @@ struct ForeBackColours {
 	std::optional<ColourAlpha> back;
 };
 
-enum class Layer { base=0, over=10 };
-
 struct SelectionAppearance {
 	// Whether to draw on base layer or over text
 	Layer layer;
diff --git a/test/simpleTests.py b/test/simpleTests.py
index 9ac1c43fd..470b56509 100644
--- a/test/simpleTests.py
+++ b/test/simpleTests.py
@@ -2047,6 +2047,13 @@ class TestElements(unittest.TestCase):
 
 		self.RestoreCaretLine()
 
+	def testMarkerLayer(self):
+		self.assertEquals(self.ed.MarkerGetLayer(1), 0)
+		self.ed.MarkerSetAlpha(1, 23)
+		self.assertEquals(self.ed.MarkerGetLayer(1), 10)
+		self.ed.MarkerSetAlpha(1, 0x100)
+		self.assertEquals(self.ed.MarkerGetLayer(1), 0)
+
 class TestIndices(unittest.TestCase):
 	def setUp(self):
 		self.xite = Xite.xiteFrame