Move DrawStrategy enum to update_flags.h.

Introduce new drawStrategy() and drawStrategyDescription() methods to
frontend::Application.

Show the current draw strategy in About dialog.

src/BufferView.cpp

@@ -58,6 +58,7 @@
 #include "mathed/MathRow.h"
 
 #include "frontends/alert.h"
+#include "frontends/Application.h"
 #include "frontends/CaretGeometry.h"
 #include "frontends/Delegates.h"
 #include "frontends/FontMetrics.h"
@@ -592,7 +593,7 @@ void BufferView::processUpdateFlags(Update::flags flags)
 		flags = (flags & ~Update::FitCursor) | Update::ForceDraw;
 	}
 
-	if (lyxrc.draw_strategy == LyXRC::DS_FULL)
+	if (theApp()->drawStrategy() == DrawStrategy::Full)
 		flags = flags | Update::ForceDraw;
 
 	// Add flags to the the update flags. These will be reset to None

src/LyXRC.cpp

@@ -1144,11 +1144,11 @@ LyXRC::ReturnValues LyXRC::read(Lexer & lexrc, bool check_format)
 			if (lexrc.next()) {
 				string const tmp = lexrc.getString();
 				if (tmp == "partial")
-					draw_strategy = DS_PARTIAL;
+					draw_strategy = DrawStrategy::Partial;
 				else if (tmp == "backingstore")
-					draw_strategy = DS_BACKINGSTORE;
+					draw_strategy = DrawStrategy::Backingstore;
 				else if (tmp == "full")
-					draw_strategy = DS_FULL;
+					draw_strategy = DrawStrategy::Full;
 				else {
 					LYXERR0("Unrecognized draw strategy " << tmp <<'"');
 				}
@@ -2056,13 +2056,13 @@ void LyXRC::write(ostream & os, bool ignore_system_lyxrc, string const & name) c
 			draw_strategy != system_lyxrc.draw_strategy) {
 			string status;
 			switch (draw_strategy) {
-			case DS_FULL:
+			case DrawStrategy::Full:
 				status = "full";
 				break;
-			case DS_PARTIAL:
+			case DrawStrategy::Partial:
 				status = "partial";
 				break;
-			case DS_BACKINGSTORE:
+			case DrawStrategy::Backingstore:
 				status = "backingstore";
 				break;
 			}

src/LyXRC.h

@@ -19,6 +19,7 @@
 #define LYXRC_H
 
 #include "LyX.h"
+#include "update_flags.h"
 
 #include "support/Length.h"
 #include "support/strfwd.h"
@@ -579,16 +580,8 @@ public:
 	///
 	BookmarksVisibility bookmarks_visibility = BMK_NONE;
 
-	enum DrawStrategy {
-		// draw all
-		DS_FULL,
-		// draw only what has changed
-		DS_PARTIAL,
-		// draw in backing store (only what has changed)
-		DS_BACKINGSTORE
-	};
 	///
-	DrawStrategy draw_strategy = DS_PARTIAL;
+	DrawStrategy draw_strategy = DrawStrategy::Partial;
 };
 
 

src/frontends/Application.h

@@ -13,6 +13,7 @@
 
 #include "ColorCode.h"
 #include "FuncCode.h"
+#include "update_flags.h"
 
 #include "support/strfwd.h"
 
@@ -203,6 +204,11 @@ public:
 	/// Like getRgbColor(), but static and slower
 	static bool getRgbColorUncached(ColorCode col, RGBColor & rgbcol);
 
+	/// \returns the draw strategy used by the application
+	virtual DrawStrategy drawStrategy() const = 0;
+	/// \returns the description of the draw strategy used by the application
+	virtual docstring drawStrategyDescription() const = 0;
+
 	/**
 	 * @return true if LyX uses a dark theme
 	 */

src/frontends/qt/GuiAbout.cpp

@@ -298,6 +298,11 @@ static QString version(bool const plain = false)
 		out << "</p><p>";
 #endif
 	out << toqstr(bformat(_("Python detected: %1$s"), from_utf8(os::python_info())));
+	if (plain)
+		out << '\n';
+	else
+		out << "</p><p>";
+	out << toqstr(bformat(_("Draw strategy: %1$s"), guiApp->drawStrategyDescription()));
 	if (!plain)
 		out << toqstr("</p></body></html>");
 	return res;

src/frontends/qt/GuiApplication.cpp

@@ -2730,16 +2730,36 @@ Menus & GuiApplication::menus()
 }
 
 
-bool GuiApplication::noPartialDraw() const
+DrawStrategy GuiApplication::drawStrategy() const
 {
 	/* Qt on macOS and Wayland does not respect the
 	 * Qt::WA_OpaquePaintEvent attribute and resets the widget backing
 	 * store at each update. Therefore, if it not good to use
-	 * "partial" draw strategy in these cases. It is also possible to
-	 * force the use of the backing store for cases like x11 with
+	 * "partial" draw strategy in these cases. It can also be useful
+	 * to force the use of the backing store for cases like X11 with
 	 * transparent WM themes.
 	 */
-	return platformName() == "cocoa" || platformName().contains("wayland");
+	if (lyxrc.draw_strategy == DrawStrategy::Partial
+	     && (platformName() == "cocoa" || platformName().contains("wayland")))
+		return DrawStrategy::Backingstore;
+	else
+		return lyxrc.draw_strategy;
+}
+
+
+docstring GuiApplication::drawStrategyDescription() const
+{
+	switch(drawStrategy()) {
+	case DrawStrategy::Partial:
+		return _("partial draw");
+		break;
+	case DrawStrategy::Backingstore:
+		return _("partial draw on backing store");
+		break;
+	case DrawStrategy::Full:
+		return _("full draw");
+	}
+	return docstring();
 }
 
 

src/frontends/qt/GuiApplication.h

@@ -113,8 +113,9 @@ public:
 	///
 	Menus & menus();
 
-	/// \returns true the "partial" draw strategy is known to be broken
-	bool noPartialDraw() const;
+	/// \returns the draw strategy used by the application
+	DrawStrategy drawStrategy() const;
+	virtual docstring drawStrategyDescription() const override;
 
 	/// \name Methods inherited from QApplication class
 	//@{

src/frontends/qt/GuiWorkArea.cpp

@@ -130,14 +130,8 @@ SyntheticMouseEvent::SyntheticMouseEvent()
 GuiWorkArea::Private::Private(GuiWorkArea * parent)
 	: p(parent), completer_(new GuiCompleter(p, p))
 {
-	use_backingstore_ = lyxrc.draw_strategy == LyXRC::DS_BACKINGSTORE
-		|| (lyxrc.draw_strategy == LyXRC::DS_PARTIAL && guiApp->noPartialDraw());
-	if (use_backingstore_)
-		LYXERR(Debug::WORKAREA, "Drawing strategy: partial draw on backing store");
-	else
-		LYXERR(Debug::WORKAREA, "Drawing strategy: "
-			   << (lyxrc.draw_strategy == LyXRC::DS_PARTIAL ? "partial draw"
-				   : "full draw"));
+	use_backingstore_ = guiApp->drawStrategy() == DrawStrategy::Backingstore;
+	LYXERR(Debug::WORKAREA, "Drawing strategy: " << guiApp->drawStrategyDescription());
 
 	int const time = QApplication::cursorFlashTime() / 2;
 	if (time > 0) {

src/update_flags.h

@@ -51,5 +51,17 @@ inline flags operator~(flags const f)
 
 } // namespace Update
 
+
+// How the work area gets drawn (painted)
+enum class DrawStrategy {
+	// draw all
+	Full,
+	// draw only what has changed
+	Partial,
+	// draw in backing store (only what has changed)
+	Backingstore
+};
+
+
 } // namespace lyx
 #endif