From 8fe6d2ec950ed1ebdedd776bab125dff90e5a20f Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sun, 30 Apr 2017 10:30:47 +0200
Subject: Add support for rotating the tabs using the scroll-wheel.

---
 plugingui/stackedwidget.cc | 45 +++++++++++++++++++++++++++++++++++++++++++++
 plugingui/stackedwidget.h  | 18 +++++++++++++-----
 plugingui/tabbutton.cc     |  5 +++++
 plugingui/tabbutton.h      |  4 ++++
 plugingui/tabwidget.cc     | 19 +++++++++++++++++++
 plugingui/tabwidget.h      |  2 ++
 6 files changed, 88 insertions(+), 5 deletions(-)

diff --git a/plugingui/stackedwidget.cc b/plugingui/stackedwidget.cc
index 069e80b..05f8f3c 100644
--- a/plugingui/stackedwidget.cc
+++ b/plugingui/stackedwidget.cc
@@ -93,6 +93,51 @@ void StackedWidget::setCurrentWidget(Widget *widget)
 	currentChanged(currentWidget);
 }
 
+Widget* StackedWidget::getWidgetAfter(Widget* widget)
+{
+	bool found_it{false};
+
+	for(auto w : widgets)
+	{
+		if(found_it)
+		{
+			return w;
+		}
+
+		if(w == widget)
+		{
+			found_it = true;
+		}
+	}
+
+	if(found_it)
+	{
+		// widget was the last in the list.
+		return nullptr;
+	}
+
+	// The Widget pointed to by 'widget' was not in the list...
+	return nullptr;
+}
+
+Widget* StackedWidget::getWidgetBefore(Widget* widget)
+{
+	Widget* last{nullptr};
+
+	for(auto w : widgets)
+	{
+		if(w == widget)
+		{
+			return last;
+		}
+
+		last = w;
+	}
+
+	// The Widget pointed to by 'widget' was not in the list...
+	return nullptr;
+}
+
 void StackedWidget::sizeChanged(int width, int height)
 {
 	// Propagate size change to child:
diff --git a/plugingui/stackedwidget.h b/plugingui/stackedwidget.h
index 13d764b..24213f7 100644
--- a/plugingui/stackedwidget.h
+++ b/plugingui/stackedwidget.h
@@ -42,21 +42,29 @@ class StackedWidget
 	: public Widget
 {
 public:
-	StackedWidget(Widget *parent);
+	StackedWidget(Widget* parent);
 	~StackedWidget();
 
 	//! Add a widget to the stack.
-	void addWidget(Widget *widget);
+	void addWidget(Widget* widget);
 
 	//! Remove a widget from the stack.
-	void removeWidget(Widget *widget);
+	void removeWidget(Widget* widget);
 
 	//! Get currently visible widget.
-	Widget *getCurrentWidget() const;
+	Widget* getCurrentWidget() const;
 
 	//! Show widget. Hide all the others.
 	//! If widget is not in the stack nothing happens.
-	void setCurrentWidget(Widget *widget);
+	void setCurrentWidget(Widget* widget);
+
+	//! Returns a pointer to the Widget after the one referenced by 'widget' or
+	//! nullptr if 'widget' is the last in the list.
+	Widget* getWidgetAfter(Widget* widget);
+
+	//! Returns a pointer to the Widget beforer the one referenced by 'widget' or
+	//! nullptr if 'widget' is the first in the list.
+	Widget* getWidgetBefore(Widget* widget);
 
 	//! Reports whn a new widget is shown.
 	Notifier<Widget*> currentChanged;
diff --git a/plugingui/tabbutton.cc b/plugingui/tabbutton.cc
index f46daa4..845dedb 100644
--- a/plugingui/tabbutton.cc
+++ b/plugingui/tabbutton.cc
@@ -106,6 +106,11 @@ void TabButton::repaintEvent(RepaintEvent* e)
 	p.drawText(x, y, font, text, true);
 }
 
+void TabButton::scrollEvent(ScrollEvent* scroll_event)
+{
+	scrollNotifier(scroll_event->delta);
+}
+
 void TabButton::clickHandler()
 {
 	switchTabNotifier(tab_widget);
diff --git a/plugingui/tabbutton.h b/plugingui/tabbutton.h
index 1c4d84b..29e6e05 100644
--- a/plugingui/tabbutton.h
+++ b/plugingui/tabbutton.h
@@ -35,6 +35,8 @@
 namespace GUI
 {
 
+class ScrollEvent;
+
 class TabButton
 	: public ButtonBase
 {
@@ -48,10 +50,12 @@ public:
 	void setActive(bool active);
 
 	Notifier<Widget*> switchTabNotifier;
+	Notifier<float> scrollNotifier; // float delta
 
 protected:
 	// From Widget:
 	virtual void repaintEvent(RepaintEvent* e) override;
+	virtual void scrollEvent(ScrollEvent* scroll_event) override;
 
 private:
 	void clickHandler();
diff --git a/plugingui/tabwidget.cc b/plugingui/tabwidget.cc
index 06e7425..dde2137 100644
--- a/plugingui/tabwidget.cc
+++ b/plugingui/tabwidget.cc
@@ -46,6 +46,7 @@ void TabWidget::addTab(const std::string& title, Widget* widget)
 	button.setText(title);
 	stack.addWidget(widget);
 	CONNECT(&button, switchTabNotifier, this, &TabWidget::switchTab);
+	CONNECT(&button, scrollNotifier, this, &TabWidget::rotateTab);
 	sizeChanged(width(), height());
 }
 
@@ -54,6 +55,24 @@ std::size_t TabWidget::getBarHeight() const
 	return topbar.height();
 }
 
+void TabWidget::rotateTab(float delta)
+{
+	Widget* widget{nullptr};
+	if(delta > 0.0f)
+	{
+		widget = stack.getWidgetAfter(stack.getCurrentWidget());
+	}
+	else
+	{
+		widget = stack.getWidgetBefore(stack.getCurrentWidget());
+	}
+
+	if(widget)
+	{
+		switchTab(widget);
+	}
+}
+
 void TabWidget::switchTab(Widget* tabWidget)
 {
 	stack.setCurrentWidget(tabWidget);
diff --git a/plugingui/tabwidget.h b/plugingui/tabwidget.h
index ca96dc2..3f0e041 100644
--- a/plugingui/tabwidget.h
+++ b/plugingui/tabwidget.h
@@ -52,6 +52,8 @@ private:
 	void sizeChanged(int width, int height);
 
 private:
+	//! Switch to the next tab if delta is > 0 or previous tab if delta is <= 0.
+	void rotateTab(float delta);
 	void switchTab(Widget* tabWidget);
 	void setActiveButtons(Widget* current_widget);
 
-- 
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