From 26c3e133401eb9e98391bf6e7579bf4f8c859dfa Mon Sep 17 00:00:00 2001
From: Thomas Goyne <plorkyeran@aegisub.org>
Date: Wed, 25 Jan 2012 04:59:17 +0000
Subject: [PATCH] Fix poor synchronization between mouse and keyboard
 modifications to the selection

Combining Shift+Up/Down (or Home/End or Page Up/Page Down) with
shift-clicking had very odd results due to that they used separate
variables to decide where to extend from (and even when only one was
used they were handled incorrectly in some cases).

Closes #1311.

Originally committed to SVN as r6355.
---
 aegisub/src/base_grid.cpp | 69 ++++++++++++++++-----------------------
 aegisub/src/base_grid.h   |  4 +--
 2 files changed, 31 insertions(+), 42 deletions(-)

diff --git a/aegisub/src/base_grid.cpp b/aegisub/src/base_grid.cpp
index 0bbd30a5a..cf0347ff2 100644
--- a/aegisub/src/base_grid.cpp
+++ b/aegisub/src/base_grid.cpp
@@ -89,7 +89,6 @@ static inline void set_difference(const S1 &src1, const S2 &src2, D &dst) {
 BaseGrid::BaseGrid(wxWindow* parent, agi::Context *context, const wxSize& size, long style, const wxString& name)
 : wxWindow(parent, -1, wxDefaultPosition, size, style, name)
 , lineHeight(1) // non-zero to avoid div by 0
-, lastRow(-1)
 , holding(false)
 , scrollBar(new wxScrollBar(this, GRID_SCROLLBAR, wxDefaultPosition, wxDefaultSize, wxSB_VERTICAL))
 , bmp(0)
@@ -349,8 +348,6 @@ void BaseGrid::EndBatch() {
 }
 
 void BaseGrid::MakeCellVisible(int row, int col, bool center) {
-	lastRow = row;
-
 	int w = 0;
 	int h = 0;
 	GetClientSize(&w,&h);
@@ -722,51 +719,45 @@ void BaseGrid::OnMouseEvent(wxMouseEvent &event) {
 
 	// Click
 	if ((click || holding || dclick) && dlg) {
+		int old_extend = extendRow;
+		SetActiveLine(dlg);
+
 		// Toggle selected
 		if (click && ctrl && !shift && !alt) {
 			bool isSel = !!selection.count(dlg);
 			if (isSel && selection.size() == 1) return;
-			SelectRow(row,true,!isSel);
-			if (dlg == GetActiveLine()) {
-				SetActiveLine(GetDialogue(GetFirstSelRow()));
-			}
-			lastRow = row;
+			SelectRow(row, true, !isSel);
 			return;
 		}
 
 		// Normal click
 		if ((click || dclick) && !shift && !ctrl && !alt) {
-			SetActiveLine(dlg);
 			if (dclick) context->videoController->JumpToTime(dlg->Start);
-			SelectRow(row,false);
-			lastRow = row;
+			SelectRow(row, false);
 			return;
 		}
 
-		// Keep selection
+		// Change active line only
 		if (click && !shift && !ctrl && alt) {
-			SetActiveLine(dlg);
 			return;
 		}
 
 		// Block select
 		if ((click && shift && !alt) || (holding && !ctrl && !alt && !shift)) {
-			if (lastRow != -1) {
-				// Set boundaries
-				int i1 = row;
-				int i2 = lastRow;
-				if (i1 > i2) {
-					std::swap(i1, i2);
-				}
+			extendRow = old_extend;
+			int i1 = row;
+			int i2 = extendRow;
 
-				// Toggle each
-				Selection newsel;
-				if (ctrl) newsel = selection;
-				for (int i=i1;i<=i2;i++) {
-					newsel.insert(GetDialogue(i));
-				}
-				SetSelectedSet(newsel);
+			if (i1 > i2)
+				std::swap(i1, i2);
+
+			// Toggle each
+			Selection newsel;
+			if (ctrl) newsel = selection;
+			for (int i = i1; i <= i2; i++) {
+				newsel.insert(GetDialogue(i));
 			}
+			SetSelectedSet(newsel);
 			return;
 		}
 
@@ -1010,38 +1001,36 @@ void BaseGrid::OnKeyDown(wxKeyEvent &event) {
 
 	// Moving
 	if (dir) {
+		int old_extend = extendRow;
+		int next = mid(0, GetDialogueIndex(active_line) + dir * step, GetRows() - 1);
+		SetActiveLine(GetDialogue(next));
+
 		// Move selection
 		if (!ctrl && !shift && !alt) {
-			int next = mid(0, extendRow + dir * step, GetRows() - 1);
-			SetActiveLine(GetDialogue(next));
 			SelectRow(next);
 			return;
 		}
 
 		// Move active only
-		else if (alt && !shift && !ctrl) {
-			int next = mid(0, GetDialogueIndex(GetActiveLine()) + dir * step, GetRows() - 1);
-			SetActiveLine(GetDialogue(next));
+		if (alt && !shift && !ctrl) {
 			Refresh(false);
 			return;
 		}
 
 		// Shift-selection
-		else if (shift && !ctrl && !alt) {
-			extendRow = mid(0, extendRow + dir * step, GetRows() - 1);
-
+		if (shift && !ctrl && !alt) {
+			extendRow = old_extend;
 			// Set range
-			int begin = GetDialogueIndex(GetActiveLine());
+			int begin = next;
 			int end = extendRow;
-			if (end < begin) {
+			if (end < begin)
 				std::swap(begin, end);
-			}
 
 			// Select range
 			Selection newsel;
-			for (int i = begin; i <= end; i++) {
+			for (int i = begin; i <= end; i++)
 				newsel.insert(GetDialogue(i));
-			}
+
 			SetSelectedSet(newsel);
 
 			MakeCellVisible(extendRow, 0, false);
diff --git a/aegisub/src/base_grid.h b/aegisub/src/base_grid.h
index d20f60234..e5ef34295 100644
--- a/aegisub/src/base_grid.h
+++ b/aegisub/src/base_grid.h
@@ -66,14 +66,14 @@ typedef SelectionListener<AssDialogue> SubtitleSelectionListener;
 /// DOCME
 class BaseGrid : public wxWindow, public BaseSelectionController<AssDialogue> {
 	int lineHeight;         ///< Height of a line in pixels in the current font
-	int lastRow;            ///< ?
 	bool holding;           ///< Is a drag selection in process?
 	wxFont font;            ///< Current grid font
 	wxScrollBar *scrollBar; ///< The grid's scrollbar
 	wxBitmap *bmp;          ///< Back buffer which the grid is rendered into
 	bool byFrame;           ///< Should times be displayed as frame numbers
+
 	/// Row from which the selection shrinks/grows from when selecting via the
-	/// keyboard. Equal to the active row except for when using shift+up/down.
+	/// keyboard, shift-clicking or dragging
 	int extendRow;
 
 	Selection selection;      ///< Currently selected lines