Folding: Toggling folds by clicking the indicator

src/base_grid.cpp

@@ -459,6 +459,17 @@ void BaseGrid::OnMouseEvent(wxMouseEvent &event) {
 	AssDialogue *dlg = GetVisDialogue(row);
 	if (!dlg) row = 0;
 
+	// Find the column the mouse is over
+	int colx = event.GetX();
+	int col;
+	for (col = 0; col < columns.size(); col++) {
+		int w = columns[col]->Width();
+		if (colx < w) {
+			break;
+		}
+		colx -= w;
+	}
+
 	if (event.ButtonDown() && OPT_GET("Subtitle/Grid/Focus Allow")->GetBool())
 		SetFocus();
 
@@ -488,6 +499,10 @@ void BaseGrid::OnMouseEvent(wxMouseEvent &event) {
 		CaptureMouse();
 	}
 
+	if (columns[col]->OnMouseEvent(dlg, context, event)) {
+		return;
+	}
+
 	if ((click || holding || dclick) && dlg) {
 		int old_extend = extendRow;
 

src/grid_column.cpp

@@ -147,6 +147,18 @@ struct GridColumnFolds final : GridColumn {
 		return " " + value;
 	}
 
+	bool OnMouseEvent(AssDialogue *d, agi::Context *c, wxMouseEvent &event) const override {
+		if ((event.LeftDown() || event.LeftDClick()) && !event.ShiftDown() && !event.CmdDown() && !event.AltDown()) {
+			if (d->Fold.hasFold() && !d->Fold.isEnd()) {
+				std::vector<AssDialogue *> lines;
+				lines.push_back(d);
+				c->foldController->ToggleFoldsAt(lines);
+				return true;
+			}
+		}
+		return false;
+	}
+
 	int Width(const agi::Context *c, WidthHelper &helper) const override {
 		int maxdepth = c->foldController->GetMaxDepth();
 		if (maxdepth == 0) {

src/grid_column.h

@@ -15,6 +15,7 @@
 // Aegisub Project http://www.aegisub.org/
 
 #include "flyweight_hash.h"
+#include "wx/event.h"
 
 #include <memory>
 #include <string>
@@ -68,6 +69,9 @@ public:
 	virtual wxString const& Description() const = 0;
 	virtual void Paint(wxDC &dc, int x, int y, const AssDialogue *d, const agi::Context *c) const;
 
+	// Returns true if the default action should be skipped
+	virtual bool OnMouseEvent(AssDialogue *d, agi::Context *c, wxMouseEvent &event) const { return false; }
+
 	int Width() const { return width; }
 	bool Visible() const { return visible; }