Added high DPI support. I bought a Macbook Pro Retina for $450 just for this commit!

include/gui.hpp

@@ -14,5 +14,6 @@ void guiCursorUnlock();
 
 extern NVGcontext *gVg;
 extern std::shared_ptr<Font> gGuiFont;
+extern float gPixelRatio;
 
 } // namespace rack

src/gui.cpp

@@ -23,6 +23,7 @@ namespace rack {
 static GLFWwindow *window = NULL;
 std::shared_ptr<Font> gGuiFont;
 NVGcontext *gVg = NULL;
+float gPixelRatio = 0.0;
 
 
 void windowSizeCallback(GLFWwindow* window, int width, int height) {
@@ -136,6 +137,7 @@ static int lastWindowX, lastWindowY, lastWindowWidth, lastWindowHeight;
 void keyCallback(GLFWwindow* window, int key, int scancode, int action, int mods) {
 	if (action == GLFW_PRESS || action == GLFW_REPEAT) {
 		if (key == GLFW_KEY_F11 || key == GLFW_KEY_ESCAPE) {
+			/*
 			// Toggle fullscreen
 			GLFWmonitor *monitor = glfwGetWindowMonitor(window);
 			if (monitor) {
@@ -151,6 +153,7 @@ void keyCallback(GLFWwindow* window, int key, int scancode, int action, int mods
 				const GLFWvidmode *mode = glfwGetVideoMode(monitor);
 				glfwSetWindowMonitor(window, monitor, 0, 0, mode->width, mode->height, mode->refreshRate);
 			}
+			*/
 		}
 		else {
 			if (gSelectedWidget) {
@@ -163,16 +166,20 @@ void keyCallback(GLFWwindow* window, int key, int scancode, int action, int mods
 void renderGui() {
 	int width, height;
 	glfwGetFramebufferSize(window, &width, &height);
-	// glfwGetWindowSize(window, &width, &height);
+	int windowWidth, windowHeight;
+	glfwGetWindowSize(window, &windowWidth, &windowHeight);
+	gPixelRatio = (float)width / windowWidth;
 
 	// Update and render
 	glViewport(0, 0, width, height);
 	glClearColor(0.0, 0.0, 0.0, 1.0);
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
-	nvgBeginFrame(gVg, width, height, 1.0);
+	nvgBeginFrame(gVg, width, height, gPixelRatio);
 
 	nvgSave(gVg);
+	nvgReset(gVg);
+	nvgScale(gVg, gPixelRatio, gPixelRatio);
 	gScene->draw(gVg);
 	nvgRestore(gVg);
 
@@ -220,7 +227,7 @@ void guiInit() {
 	// GLEW generates GL error because it calls glGetString(GL_EXTENSIONS), we'll consume it here.
 	glGetError();
 
-	glfwSetWindowSizeLimits(window, 240, 160, GLFW_DONT_CARE, GLFW_DONT_CARE);
+	glfwSetWindowSizeLimits(window, 640, 480, GLFW_DONT_CARE, GLFW_DONT_CARE);
 
 	// Set up NanoVG
 	gVg = nvgCreateGL2(NVG_ANTIALIAS);

src/widgets/FramebufferWidget.cpp

@@ -10,6 +10,7 @@ namespace rack {
 
 struct FramebufferWidget::Internal {
 	NVGLUframebuffer *fb = NULL;
+	Rect box;
 
 	~Internal() {
 		setFramebuffer(NULL);
@@ -21,6 +22,7 @@ struct FramebufferWidget::Internal {
 	}
 };
 
+
 FramebufferWidget::FramebufferWidget() {
 	internal = new Internal();
 }
@@ -35,7 +37,9 @@ void FramebufferWidget::step() {
 
 	// Render the scene to the framebuffer if dirty
 	if (dirty) {
-		Vec fbSize = box.size.plus(padding.mult(2));
+		internal->box.pos = padding.neg();
+		internal->box.size = box.size.plus(padding.mult(2));
+		Vec fbSize = internal->box.size.mult(gPixelRatio);
 		assert(fbSize.isFinite());
 
 		internal->setFramebuffer(NULL);
@@ -44,14 +48,13 @@ void FramebufferWidget::step() {
 			return;
 		internal->setFramebuffer(fb);
 
-		// TODO Support screens with pixelRatio != 1.0 (e.g. Retina) by using the actual size of the framebuffer, etc.
-		const float pixelRatio = 1.0;
 		nvgluBindFramebuffer(fb);
 		glViewport(0.0, 0.0, fbSize.x, fbSize.y);
 		glClearColor(0.0, 0.0, 0.0, 0.0);
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
-		nvgBeginFrame(gVg, fbSize.x, fbSize.y, pixelRatio);
+		nvgBeginFrame(gVg, fbSize.x, fbSize.y, gPixelRatio);
 
+		nvgScale(gVg, gPixelRatio, gPixelRatio);
 		nvgTranslate(gVg, padding.x, padding.y);
 		Widget::draw(gVg);
 
@@ -67,14 +70,13 @@ void FramebufferWidget::draw(NVGcontext *vg) {
 		return;
 
 	// Draw framebuffer image
-	int width, height;
-	nvgImageSize(vg, internal->fb->image, &width, &height);
 	nvgBeginPath(vg);
-	nvgRect(vg, -padding.x, -padding.y, width, height);
-	NVGpaint paint = nvgImagePattern(vg, -padding.x, -padding.y, width, height, 0.0, internal->fb->image, 1.0);
+	nvgRect(vg, internal->box.pos.x, internal->box.pos.y, internal->box.size.x, internal->box.size.y);
+	NVGpaint paint = nvgImagePattern(vg, internal->box.pos.x, internal->box.pos.y, internal->box.size.x, internal->box.size.y, 0.0, internal->fb->image, 1.0);
 	nvgFillPaint(vg, paint);
 	nvgFill(vg);
 
+	// For debugging bounding box of framebuffer image
 	// nvgFillColor(vg, nvgRGBA(255, 0, 0, 64));
 	// nvgFill(vg);
 }