From e3949cdaa1ccbc074a6cbc4e522ba8e6a48c8008 Mon Sep 17 00:00:00 2001
From: moex3 <46636583+moex3@users.noreply.github.com>
Date: Mon, 23 Nov 2020 20:19:29 +0100
Subject: [PATCH] Add video panning

---
 src/video_display.cpp     | 24 ++++++++++++++++++++++--
 src/video_display.h       |  9 +++++++++
 src/visual_tool_cross.cpp |  4 ++--
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/video_display.cpp b/src/video_display.cpp
index 8d85311a6..73df313ba 100644
--- a/src/video_display.cpp
+++ b/src/video_display.cpp
@@ -113,6 +113,8 @@ VideoDisplay::VideoDisplay(wxToolBar *toolbar, bool freeSize, wxComboBox *zoomBo
 	Bind(wxEVT_LEFT_DCLICK, &VideoDisplay::OnMouseEvent, this);
 	Bind(wxEVT_LEFT_DOWN, &VideoDisplay::OnMouseEvent, this);
 	Bind(wxEVT_LEFT_UP, &VideoDisplay::OnMouseEvent, this);
+	Bind(wxEVT_MIDDLE_DOWN, &VideoDisplay::OnMouseEvent, this);
+	Bind(wxEVT_MIDDLE_UP, &VideoDisplay::OnMouseEvent, this);
 	Bind(wxEVT_MOTION, &VideoDisplay::OnMouseEvent, this);
 	Bind(wxEVT_MOUSEWHEEL, &VideoDisplay::OnMouseWheel, this);
 
@@ -191,7 +193,7 @@ void VideoDisplay::Render() try {
 		PositionVideo();
 
 	videoOut->Render(viewport_left, viewport_bottom, viewport_width, viewport_height);
-	E(glViewport(0, std::min(viewport_bottom, 0), videoSize.GetWidth(), videoSize.GetHeight()));
+	E(glViewport(0, viewport_bottom, videoSize.GetWidth(), videoSize.GetHeight()));
 
 	E(glMatrixMode(GL_PROJECTION));
 	E(glLoadIdentity());
@@ -296,6 +298,9 @@ void VideoDisplay::PositionVideo() {
 		}
 	}
 
+	viewport_left += pan_x;
+	viewport_bottom -= pan_y;
+
 	if (tool)
 		tool->SetDisplayArea(viewport_left / scale_factor, viewport_top / scale_factor,
 		                     viewport_width / scale_factor, viewport_height / scale_factor);
@@ -351,8 +356,23 @@ void VideoDisplay::OnMouseEvent(wxMouseEvent& event) {
 
 	last_mouse_pos = mouse_pos = event.GetPosition();
 
-	if (tool)
+	if (event.GetButton() == wxMOUSE_BTN_MIDDLE) {
+		if ((panning = event.ButtonDown()))
+			pan_last_pos = event.GetPosition();
+	}
+	if (panning && event.Dragging()) {
+		pan_x += event.GetX() - pan_last_pos.X();
+		pan_y += event.GetY() - pan_last_pos.Y();
+		pan_last_pos = event.GetPosition();
+
+		PositionVideo();
+	}
+
+	if (tool) {
+		if (pan_y)
+			event.SetPosition(wxPoint(event.GetX(), event.GetY() - pan_y));
 		tool->OnMouseEvent(event);
+	}
 }
 
 void VideoDisplay::OnMouseLeave(wxMouseEvent& event) {
diff --git a/src/video_display.h b/src/video_display.h
index f0d65edb6..46ed78a69 100644
--- a/src/video_display.h
+++ b/src/video_display.h
@@ -87,6 +87,15 @@ class VideoDisplay final : public wxGLCanvas {
 	/// The current zoom level, where 1.0 = 100%
 	double zoomValue;
 
+	/// The last position of the mouse, when dragging
+	Vector2D pan_last_pos;
+	/// True if middle mouse button is down, and we should update pan_{x,y}
+	bool panning = false;
+	/// The current video pan offset width
+	int pan_x = 0;
+	/// The current video pan offset height
+	int pan_y = 0;
+
 	/// The video renderer
 	std::unique_ptr<VideoOutGL> videoOut;
 
diff --git a/src/visual_tool_cross.cpp b/src/visual_tool_cross.cpp
index ffbf5329b..624cd7613 100644
--- a/src/visual_tool_cross.cpp
+++ b/src/visual_tool_cross.cpp
@@ -69,8 +69,8 @@ void VisualToolCross::Draw() {
 	gl.SetInvert();
 	gl.SetLineColour(*wxWHITE, 1.0, 1);
 	float lines[] = {
-		0.f, mouse_pos.Y(),
-		video_res.X() + video_pos.X() * 2, mouse_pos.Y(),
+		video_pos.X(), mouse_pos.Y(),
+		video_res.X() + video_pos.X(), mouse_pos.Y(),
 		mouse_pos.X(), 0.f,
 		mouse_pos.X(), video_res.Y() + video_pos.Y() * 2
 	};