From e481d033cbf4ffec105f17c84cb43480fc554ffd Mon Sep 17 00:00:00 2001
From: wangqr <wangqr@wangqr.tk>
Date: Fri, 5 Jun 2020 22:34:06 -0400
Subject: [PATCH] Prevent event queue flooded by wxEVT_PAINT by moving some
 repaint request to OnIdle

---
 src/base_grid.cpp     | 16 ++++++++++++++--
 src/base_grid.h       |  3 +++
 src/video_display.cpp |  4 ++--
 src/video_display.h   |  2 +-
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/base_grid.cpp b/src/base_grid.cpp
index 8c8e1689f..d73f20a39 100644
--- a/src/base_grid.cpp
+++ b/src/base_grid.cpp
@@ -125,6 +125,7 @@ BEGIN_EVENT_TABLE(BaseGrid,wxWindow)
 	EVT_KEY_DOWN(BaseGrid::OnKeyDown)
 	EVT_CHAR_HOOK(BaseGrid::OnCharHook)
 	EVT_MENU_RANGE(MENU_SHOW_COL,MENU_SHOW_COL+15,BaseGrid::OnShowColMenu)
+	EVT_IDLE(BaseGrid::OnIdle)
 END_EVENT_TABLE()
 
 void BaseGrid::OnSubtitlesCommit(int type) {
@@ -136,8 +137,12 @@ void BaseGrid::OnSubtitlesCommit(int type) {
 		Refresh(false);
 		return;
 	}
-	if (type & AssFile::COMMIT_DIAG_TIME)
-		Refresh(false);
+	if (type & AssFile::COMMIT_DIAG_TIME) {
+		// Dragging start / end time in audio display can generate lots of commit in a short period of time.
+		// On the other hand, GDI painting time depends on area, and BaseGrid typically is very large. Therefore repainting BaseGrid can be expensive.
+		// To prevent GUI lag / FPS drop caused by frequent repaint of BaseGrid, we do not call Refresh(false) here. Instead, we set the refresh_on_idle flag, and only repaint BaseGrid when idle.
+		refresh_on_idle = true;
+	}
 	else if (type & AssFile::COMMIT_DIAG_TEXT) {
 		for (auto const& rect : text_refresh_rects)
 			RefreshRect(rect, false);
@@ -263,6 +268,13 @@ void BaseGrid::OnSeek() {
 		Refresh(false);
 }
 
+void BaseGrid::OnIdle(wxIdleEvent&) {
+	if (refresh_on_idle) {
+		refresh_on_idle = false;
+		Refresh(false);
+	}
+}
+
 void BaseGrid::OnPaint(wxPaintEvent &) {
 	// Find which columns need to be repainted
 	std::vector<char> paint_columns;
diff --git a/src/base_grid.h b/src/base_grid.h
index 366189588..809d88a41 100644
--- a/src/base_grid.h
+++ b/src/base_grid.h
@@ -71,6 +71,8 @@ class BaseGrid final : public wxWindow {
 
 	std::vector<wxRect> text_refresh_rects;
 
+	bool refresh_on_idle = false;
+
 	/// Cached brushes used for row backgrounds
 	struct {
 		wxBrush Default;
@@ -93,6 +95,7 @@ class BaseGrid final : public wxWindow {
 
 	void OnContextMenu(wxContextMenuEvent &evt);
 	void OnHighlightVisibleChange(agi::OptionValue const& opt);
+	void OnIdle(wxIdleEvent&);
 	void OnKeyDown(wxKeyEvent &event);
 	void OnCharHook(wxKeyEvent &event);
 	void OnMouseEvent(wxMouseEvent &event);
diff --git a/src/video_display.cpp b/src/video_display.cpp
index 578e3ae01..2fe52c28e 100644
--- a/src/video_display.cpp
+++ b/src/video_display.cpp
@@ -105,7 +105,7 @@ VideoDisplay::VideoDisplay(wxToolBar *toolbar, bool freeSize, wxComboBox *zoomBo
 	});
 
 	Bind(wxEVT_PAINT, std::bind(&VideoDisplay::Render, this));
-	Bind(wxEVT_UPDATE_UI, &VideoDisplay::OnUpdateUIEvent, this);
+	Bind(wxEVT_IDLE, &VideoDisplay::OnIdle, this);
 	Bind(wxEVT_SIZE, &VideoDisplay::OnSizeEvent, this);
 	Bind(wxEVT_CONTEXT_MENU, &VideoDisplay::OnContextMenu, this);
 	Bind(wxEVT_ENTER_WINDOW, &VideoDisplay::OnMouseEvent, this);
@@ -158,7 +158,7 @@ void VideoDisplay::Render() {
 	render_requested = true;
 }
 
-void VideoDisplay::OnUpdateUIEvent(wxUpdateUIEvent&) {
+void VideoDisplay::OnIdle(wxIdleEvent&) {
 	if (render_requested)
 		DoRender();
 }
diff --git a/src/video_display.h b/src/video_display.h
index 653188480..62113e553 100644
--- a/src/video_display.h
+++ b/src/video_display.h
@@ -142,7 +142,7 @@ class VideoDisplay final : public wxGLCanvas {
 	/// @brief Recalculate video positioning and scaling when the available area or zoom changes
 	void OnSizeEvent(wxSizeEvent &event);
 	void OnContextMenu(wxContextMenuEvent&);
-	void OnUpdateUIEvent(wxUpdateUIEvent& event);
+	void OnIdle(wxIdleEvent&);
 	void DoRender();
 
 public: