Add support for 4K

examples/sdl/source/app.d

@@ -1,6 +1,7 @@
 module examples.sdl;
 
 import std.datetime : Clock;
+import std.getopt : defaultGetoptPrinter, getopt;
 import arsd.nanovega;
 import nanogui.sdlbackend : SdlBackend;
 import nanogui.widget : Widget;
@@ -179,9 +180,9 @@ class MyGui : SdlBackend
 	Label lblCpuUsage;
 	ProcessCPUWatcher cpuWatcher;
 
-	this(int w, int h, string title)
+	this(int w, int h, string title, int scale)
 	{
-		super(w, h, title);
+		super(w, h, title, scale);
 	}
 
 	override void onVisibleForTheFirstTime()
@@ -551,8 +552,29 @@ union Payload
 }
 alias Item = TaggedAlgebraic!Payload;
 
-void main () {
-	auto gui = new MyGui(1000, 800, "Nanogui using SDL2 backend");
+int main (string[] args)
+{
+	int scale = 1;
+
+	auto helpInformation = getopt(
+		args,
+		"scale", "Scale, 2 for 4K monitors and 1 for the rest", &scale,
+	);
+
+	if (helpInformation.helpWanted)
+	{
+		defaultGetoptPrinter("Usage:", helpInformation.options);
+		return 0;
+	}
+
+	if (scale != 1 && scale != 2)
+	{
+		import std;
+		stderr.writeln("Scale can be 1 or 2 only");
+		return 1;
+	}
+
+	auto gui = new MyGui(1000, 800, "Nanogui using SDL2 backend", scale);
 	gui.onBeforeLoopStart = () {
 		import std.datetime : SysTime, seconds, Clock;
 		static SysTime prevStdTime;
@@ -566,4 +588,6 @@ void main () {
 		}
 	};
 	gui.run();
+
+	return 0;
 }

source/nanogui/glcanvas.d

@@ -86,13 +86,14 @@ public:
 		if (mDrawBorder)
 			drawWidgetBorder(ctx);
 
+		const scale = screen.scale; // TODO PERFORMANCE it can be expensive operation
 		auto mImage = glCreateImageFromOpenGLTexture(ctx, mColorBuf.handle, width, height, NVGImageFlag.NoDelete);
 		assert(mImage.valid);
 		auto mPaint = ctx.imagePattern(
 			mPos.x + 1,
 			mPos.y + 1.0f,
-			mSize.x - 2,
-			mSize.y - 2,
+			mSize.x/scale - 2,
+			mSize.y/scale - 2,
 			0,
 			mImage);
 

source/nanogui/screen.d

@@ -14,7 +14,7 @@ class Screen : Widget
 {
 	import nanogui.window : Window;
 
-	this(int w, int h, long timestamp)
+	this(int w, int h, long timestamp, int scale)
 	{
 		super(null);
 		size = vec2i(w, h);
@@ -23,6 +23,7 @@ class Screen : Widget
 		mCursor = Cursor.Arrow;
 		mPixelRatio = 1.0;
 		mClearEnabled = true;
+		mScale = scale;
 	}
 
 	auto currTime() const { return mTimestamp; }
@@ -38,6 +39,8 @@ class Screen : Widget
 		}
 	}
 
+	auto scale() const { return mScale; }
+
 	auto lastInteraction() { return mLastInteraction; }
 
 	override void draw(ref NanoContext ctx)
@@ -72,11 +75,11 @@ class Screen : Widget
 		// draw the rest
 		if (mClearEnabled)
 		{
-			glViewport(0, 0, size.x, size.y);
+			glViewport(0, 0, size.x*mScale, size.y*mScale);
 			glClearColor(0., 0., 0., 0);
 			glClear(glNVGClearFlags); // use NanoVega API to get flags for OpenGL call
 		}
-		ctx.beginFrame(size.x, size.y); // begin rendering
+		ctx.beginFrame(size.x, size.y, mScale); // begin rendering
 		scope(exit)
 		{
 			if (ctx.inFrame)
@@ -450,4 +453,6 @@ protected:
 	void delegate(Vector2i) mResizeCallback;
 	Array!GLCanvas mGLCanvases;
 	bool         mClearEnabled;
+	/// Integer scale for 4K support
+	int			 mScale;
 }

source/nanogui/sdlapp.d

@@ -12,7 +12,7 @@ class SdlApp
 {
 	alias Event = SDL_Event;
 
-	this(int w, int h, string title)
+	this(int w, int h, string title, int scale = 1)
 	{
 		/* Avoid locale-related number parsing issues */
 		version(Windows) {}
@@ -66,7 +66,7 @@ class SdlApp
 		// create an OpenGL-enabled SDL window
 		window = new SDL2Window(_sdl2,
 								SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-								width, height,
+								width * scale, height * scale,
 								SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN );
 
 		window.setTitle(title);

source/nanogui/sdlbackend.d

@@ -16,9 +16,9 @@ import nanogui.sdlapp : SdlApp;
 
 class SdlBackend : Screen
 {
-	this(int w, int h, string title)
+	this(int w, int h, string title, int scale)
 	{
-		_sdlApp = new SdlApp(w, h, title);
+		_sdlApp = new SdlApp(w, h, title, scale);
 
 		_sdlApp.onBeforeLoopStart = ()
 		{
@@ -77,8 +77,8 @@ class SdlBackend : Screen
 
 			_sdlApp.invalidate;
 
-			ctx.mouse.x = event.motion.x;
-			ctx.mouse.y = event.motion.y;
+			ctx.mouse.x = event.motion.x/scale;
+			ctx.mouse.y = event.motion.y/scale;
 
 			if (event.motion.state & SDL_BUTTON_LMASK)
 				btn = MouseButton.Left;
@@ -168,7 +168,7 @@ class SdlBackend : Screen
 		mCursorSet[Cursor.HResize]   = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEWE);
 		mCursorSet[Cursor.VResize]   = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENS);
 
-		super(w, h, Clock.currTime.stdTime);
+		super(w, h, Clock.currTime.stdTime, scale);
 		theme = new Theme(ctx);
 	}