From 6ffe9ff900038fa0b1df1725ab9214295872a3e8 Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Tue, 22 Jun 2021 16:50:09 -0400
Subject: [PATCH] Don't redraw FramebufferWidget on subpixel change when
 dragging ModuleWidgets.

---
 include/window.hpp               | 2 ++
 src/app/ModuleWidget.cpp         | 5 +++++
 src/widget/FramebufferWidget.cpp | 2 +-
 src/window.cpp                   | 7 +++++++
 4 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/window.hpp b/include/window.hpp
index 04e5194d..2f5b1cee 100644
--- a/include/window.hpp
+++ b/include/window.hpp
@@ -92,6 +92,8 @@ struct Window {
 	DEPRECATED std::shared_ptr<Svg> loadSvg(const std::string& filename) {
 		return Svg::load(filename);
 	}
+
+	INTERNAL bool& fbDirtyOnSubpixelChange();
 };
 
 
diff --git a/src/app/ModuleWidget.cpp b/src/app/ModuleWidget.cpp
index feb8eeaa..9c0d471f 100644
--- a/src/app/ModuleWidget.cpp
+++ b/src/app/ModuleWidget.cpp
@@ -681,6 +681,9 @@ void ModuleWidget::onHoverKey(const HoverKeyEvent& e) {
 
 void ModuleWidget::onDragStart(const DragStartEvent& e) {
 	if (e.button == GLFW_MOUSE_BUTTON_LEFT) {
+		// HACK Disable FramebufferWidget redrawing subpixels while dragging
+		APP->window->fbDirtyOnSubpixelChange() = false;
+
 		// Clear dragRack so dragging in not enabled until mouse is moved a bit.
 		internal->dragRackPos = math::Vec(NAN, NAN);
 
@@ -691,6 +694,8 @@ void ModuleWidget::onDragStart(const DragStartEvent& e) {
 
 void ModuleWidget::onDragEnd(const DragEndEvent& e) {
 	if (e.button == GLFW_MOUSE_BUTTON_LEFT) {
+		APP->window->fbDirtyOnSubpixelChange() = true;
+
 		// The next time the module is dragged, it should always move immediately
 		internal->dragEnabled = true;
 
diff --git a/src/widget/FramebufferWidget.cpp b/src/widget/FramebufferWidget.cpp
index 4b836cc2..b057bcbf 100644
--- a/src/widget/FramebufferWidget.cpp
+++ b/src/widget/FramebufferWidget.cpp
@@ -188,7 +188,7 @@ void FramebufferWidget::draw(const DrawArgs& args) {
 	// If drawing to a new subpixel location, rerender in the next frame.
 	// Anything less than 0.1 pixels isn't noticeable.
 	math::Vec offsetFDelta = internal->offsetF.minus(internal->fbOffsetF);
-	if (dirtyOnSubpixelChange && offsetFDelta.square() >= std::pow(0.1f, 2)) {
+	if (offsetFDelta.square() >= std::pow(0.1f, 2) && dirtyOnSubpixelChange && APP->window->fbDirtyOnSubpixelChange()) {
 		// DEBUG("%p dirty subpixel (%f, %f) (%f, %f)", this, VEC_ARGS(internal->offsetF), VEC_ARGS(internal->fbOffsetF));
 		setDirty();
 	}
diff --git a/src/window.cpp b/src/window.cpp
index cb6c5555..65f1b075 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -88,6 +88,8 @@ struct Window::Internal {
 
 	std::map<std::string, std::shared_ptr<Font>> fontCache;
 	std::map<std::string, std::shared_ptr<Image>> imageCache;
+
+	bool fbDirtyOnSubpixelChange = true;
 };
 
 
@@ -679,6 +681,11 @@ std::shared_ptr<Image> Window::loadImage(const std::string& filename) {
 }
 
 
+bool& Window::fbDirtyOnSubpixelChange() {
+	return internal->fbDirtyOnSubpixelChange;
+}
+
+
 void windowInit() {
 	int err;