From 3528e492861ef4db040550071ce35b8d74639126 Mon Sep 17 00:00:00 2001
From: Thomas Goyne <plorkyeran@aegisub.org>
Date: Tue, 15 Apr 2014 08:41:58 -0700
Subject: [PATCH] Make the duration field not completely wrong in frame mode

---
 src/subs_edit_box.cpp | 25 ++++++++++++++++++-------
 src/subs_edit_box.h   |  2 ++
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/src/subs_edit_box.cpp b/src/subs_edit_box.cpp
index 892b82486..7f7de7c1e 100644
--- a/src/subs_edit_box.cpp
+++ b/src/subs_edit_box.cpp
@@ -313,7 +313,7 @@ void SubsEditBox::OnCommit(int type) {
 	if (type & AssFile::COMMIT_DIAG_TIME) {
 		start_time->SetTime(line->Start);
 		end_time->SetTime(line->End);
-		duration->SetTime(line->End - line->Start);
+		SetDurationField();
 	}
 
 	if (type & AssFile::COMMIT_DIAG_TEXT) {
@@ -468,7 +468,7 @@ void SubsEditBox::CommitTimes(TimeField field) {
 
 			case TIME_DURATION:
 				if (by_frame->GetValue())
-					d->End = c->videoController->TimeAtFrame(c->videoController->FrameAtTime(d->Start, agi::vfr::START) + duration->GetFrame(), agi::vfr::END);
+					d->End = c->videoController->TimeAtFrame(c->videoController->FrameAtTime(d->Start, agi::vfr::START) + duration->GetFrame() - 1, agi::vfr::END);
 				else
 					d->End = d->Start + duration->GetTime();
 				initial_times[d].second = d->End;
@@ -479,10 +479,8 @@ void SubsEditBox::CommitTimes(TimeField field) {
 	start_time->SetTime(line->Start);
 	end_time->SetTime(line->End);
 
-	if (by_frame->GetValue())
-		duration->SetFrame(end_time->GetFrame() - start_time->GetFrame() + 1);
-	else
-		duration->SetTime(end_time->GetTime() - start_time->GetTime());
+	if (field != TIME_DURATION)
+		SetDurationField();
 
 	if (field != last_time_commit_type)
 		commit_id = -1;
@@ -493,6 +491,16 @@ void SubsEditBox::CommitTimes(TimeField field) {
 	file_changed_slot.Unblock();
 }
 
+void SubsEditBox::SetDurationField() {
+	// With VFR, the frame count calculated from the duration in time can be
+	// completely wrong (since the duration is calculated as if it were a start
+	// time), so we need to explicitly set it with the correct units.
+	if (by_frame->GetValue())
+		duration->SetFrame(end_time->GetFrame() - start_time->GetFrame() + 1);
+	else
+		duration->SetTime(end_time->GetTime() - start_time->GetTime());
+}
+
 void SubsEditBox::OnSize(wxSizeEvent &evt) {
 	int availableWidth = GetVirtualSize().GetWidth();
 	int midMin = middle_left_sizer->GetMinSize().GetWidth();
@@ -517,12 +525,15 @@ void SubsEditBox::OnSize(wxSizeEvent &evt) {
 }
 
 void SubsEditBox::OnFrameTimeRadio(wxCommandEvent &event) {
+	event.Skip();
+
 	bool byFrame = by_frame->GetValue();
 	start_time->SetByFrame(byFrame);
 	end_time->SetByFrame(byFrame);
 	duration->SetByFrame(byFrame);
 	c->subsGrid->SetByFrame(byFrame);
-	event.Skip();
+
+	SetDurationField();
 }
 
 void SubsEditBox::SetControlsState(bool state) {
diff --git a/src/subs_edit_box.h b/src/subs_edit_box.h
index bc69dda9d..cbb344107 100644
--- a/src/subs_edit_box.h
+++ b/src/subs_edit_box.h
@@ -195,6 +195,8 @@ class SubsEditBox final : public wxPanel {
 	/// Call a command the restore focus to the edit box
 	void CallCommand(const char *cmd_name);
 
+	void SetDurationField();
+
 	SubsTextEditCtrl *edit_ctrl;
 	wxTextCtrl *secondary_editor;
 	std::unique_ptr<TextSelectionController> textSelectionController;