Add scroll_container formspec element (redo) (#9101)

New formspec elements:

 - `scroll_container[<X>,<Y>;<W>,<H>;<scrollbar name>;<orientation>;<scroll factor>]`
 - `scroll_container_end[]`

Other elements can be embedded in this element. Scrollbar must be placed manually.

1 files changed, 70 insertions, 0 deletions

diff --git a/src/gui/guiScrollContainer.cpp b/src/gui/guiScrollContainer.cpp
new file mode 100644
index 000000000..88cdc7057
--- /dev/null
+++ b/src/gui/guiScrollContainer.cpp
@@ -0,0 +1,70 @@
+/*
+Minetest
+Copyright (C) 2020 DS
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "guiScrollContainer.h"
+
+GUIScrollContainer::GUIScrollContainer(gui::IGUIEnvironment *env,
+		gui::IGUIElement *parent, s32 id, const core::rect<s32> &rectangle,
+		const std::string &orientation, f32 scrollfactor) :
+		gui::IGUIElement(gui::EGUIET_ELEMENT, env, parent, id, rectangle),
+		m_scrollbar(nullptr), m_scrollfactor(scrollfactor)
+{
+	if (orientation == "vertical")
+		m_orientation = VERTICAL;
+	else if (orientation == "horizontal")
+		m_orientation = HORIZONTAL;
+	else
+		m_orientation = UNDEFINED;
+}
+
+bool GUIScrollContainer::OnEvent(const SEvent &event)
+{
+	if (event.EventType == EET_MOUSE_INPUT_EVENT &&
+			event.MouseInput.Event == EMIE_MOUSE_WHEEL &&
+			!event.MouseInput.isLeftPressed() && m_scrollbar) {
+		Environment->setFocus(m_scrollbar);
+		bool retval = m_scrollbar->OnEvent(event);
+
+		// a hacky fix for updating the hovering and co.
+		IGUIElement *hovered_elem = getElementFromPoint(core::position2d<s32>(
+				event.MouseInput.X, event.MouseInput.Y));
+		SEvent mov_event = event;
+		mov_event.MouseInput.Event = EMIE_MOUSE_MOVED;
+		Environment->postEventFromUser(mov_event);
+		if (hovered_elem)
+			hovered_elem->OnEvent(mov_event);
+
+		return retval;
+	}
+
+	return IGUIElement::OnEvent(event);
+}
+
+void GUIScrollContainer::updateScrolling()
+{
+	s32 pos = m_scrollbar->getPos();
+	core::rect<s32> rect = getRelativePosition();
+
+	if (m_orientation == VERTICAL)
+		rect.UpperLeftCorner.Y = pos * m_scrollfactor;
+	else if (m_orientation == HORIZONTAL)
+		rect.UpperLeftCorner.X = pos * m_scrollfactor;
+
+	setRelativePosition(rect);
+}