iOS: finger scrolling in controls.

(cherry picked from commit ccb5ccd)

src/gui/core/event/distributor.cpp

@@ -125,6 +125,15 @@ mouse_motion::mouse_motion(widget& owner,
 						_5),
 			queue_position);
 
+	owner.connect_signal<event::SDL_TOUCH_MOTION>(
+			std::bind(&mouse_motion::signal_handler_sdl_touch_motion,
+						this,
+						_2,
+						_3,
+						_5,
+						_6),
+			queue_position);
+
 	owner_.connect_signal<event::SDL_WHEEL_UP>(std::bind(
 			&mouse_motion::signal_handler_sdl_wheel, this, _2, _3, _5));
 	owner_.connect_signal<event::SDL_WHEEL_DOWN>(std::bind(
@@ -199,6 +208,25 @@ void mouse_motion::signal_handler_sdl_mouse_motion(const event::ui_event event,
 	handled = true;
 }
 
+void mouse_motion::signal_handler_sdl_touch_motion(const event::ui_event event,
+									 bool& handled,
+									 const point& coordinate,
+									 const point& distance)
+{
+	DBG_GUI_E << LOG_HEADER << event << ".\n";
+
+	if(mouse_captured_) {
+		assert(mouse_focus_);
+		owner_.fire(event, *mouse_focus_, coordinate, distance);
+	} else {
+		widget* mouse_over = owner_.find_at(coordinate, true);
+		if(mouse_over) {
+			owner_.fire(event, *mouse_over, coordinate, distance);
+		}
+	}
+	handled = true;
+}
+
 void mouse_motion::signal_handler_sdl_wheel(const event::ui_event event,
 											 bool& handled,
 											 const point& coordinate)

src/gui/core/event/distributor.hpp

@@ -138,6 +138,11 @@ class mouse_motion
 										 bool& handled,
 										 const point& coordinate);
 
+	void signal_handler_sdl_touch_motion(const event::ui_event event,
+										 bool& handled,
+										 const point& coordinate,
+										 const point& distance);
+
 	void signal_handler_sdl_wheel(const event::ui_event event,
 								  bool& handled,
 								  const point& coordinate);

src/gui/widgets/scrollbar.cpp

@@ -43,6 +43,8 @@ scrollbar_base::scrollbar_base(const implementation::builder_styled_widget& buil
 			&scrollbar_base::signal_handler_mouse_enter, this, _2, _3, _4));
 	connect_signal<event::MOUSE_MOTION>(std::bind(
 			&scrollbar_base::signal_handler_mouse_motion, this, _2, _3, _4, _5));
+	connect_signal<event::SDL_TOUCH_MOTION>(std::bind(
+			&scrollbar_base::signal_handler_mouse_motion, this, _2, _3, _4, _5));
 	connect_signal<event::MOUSE_LEAVE>(std::bind(
 			&scrollbar_base::signal_handler_mouse_leave, this, _2, _3));
 	connect_signal<event::LEFT_BUTTON_DOWN>(std::bind(
@@ -60,6 +62,11 @@ void scrollbar_base::finalize_setup()
 	}
 }
 
+void scrollbar_base::scroll_by(const int pixels)
+{
+	move_positioner(static_cast<int>(pixels_per_step_ * pixels));
+}
+
 void scrollbar_base::scroll(const scroll_mode scroll)
 {
 	switch(scroll) {

src/gui/widgets/scrollbar.hpp

@@ -71,6 +71,8 @@ class scrollbar_base : public styled_widget
 	 * @param scroll              'step size' to scroll.
 	 */
 	void scroll(const scroll_mode scroll);
+
+	void scroll_by(const int pixels);
 
 	/** Is the positioner at the beginning of the scrollbar? */
 	bool at_begin() const

src/gui/widgets/scrollbar_container.cpp

@@ -98,6 +98,15 @@ scrollbar_container::scrollbar_container(
 	connect_signal<event::SDL_WHEEL_RIGHT>(
 		std::bind(&scrollbar_container::signal_handler_sdl_wheel_right, this, _2, _3),
 		event::dispatcher::back_post_child);
+
+	connect_signal<event::SDL_TOUCH_MOTION>(
+			std::bind(&scrollbar_container::signal_handler_sdl_touch_motion,
+						this,
+						_2,
+						_3,
+						_5,
+						_6),
+			event::dispatcher::back_post_child);
 }
 
 void scrollbar_container::layout_initialize(const bool full_initialization)
@@ -1178,4 +1187,39 @@ void scrollbar_container::signal_handler_sdl_wheel_right(const event::ui_event e
 	}
 }
 
+void
+scrollbar_container::signal_handler_sdl_touch_motion(const event::ui_event event,
+													 bool& handled,
+													 const point& position,
+													 const point& distance)
+{
+	(void) position;
+	DBG_GUI_E << LOG_HEADER << event << ".\n";
+
+	bool is_scrollbar_moved = false;
+
+	if (horizontal_scrollbar_grid_ && horizontal_scrollbar_) {
+
+		if(horizontal_scrollbar_grid_->get_visible() == widget::visibility::visible) {
+			horizontal_scrollbar_->scroll_by(-distance.x);
+			is_scrollbar_moved = true;
+		}
+	}
+
+	if (vertical_scrollbar_grid_ && vertical_scrollbar_) {
+
+		if(vertical_scrollbar_grid_->get_visible() == widget::visibility::visible) {
+			vertical_scrollbar_->scroll_by(-distance.y);
+			is_scrollbar_moved = true;
+		}
+	}
+
+	if (is_scrollbar_moved) {
+		scrollbar_moved();
+		handled = true;
+	}
+}
+
+
+
 } // namespace gui2

src/gui/widgets/scrollbar_container.hpp

@@ -540,6 +540,8 @@ class scrollbar_container : public container_base
 	void signal_handler_sdl_wheel_down(const event::ui_event event, bool& handled);
 	void signal_handler_sdl_wheel_left(const event::ui_event event, bool& handled);
 	void signal_handler_sdl_wheel_right(const event::ui_event event, bool& handled);
+	void signal_handler_sdl_touch_motion(const event::ui_event event, bool& handled,
+                                         const point& position, const point& distance);
 
 public:
 	scrollbar_base* horizontal_scrollbar()

src/widgets/scrollarea.cpp

@@ -18,14 +18,15 @@
 
 #include "widgets/scrollarea.hpp"
 #include "sdl/rect.hpp"
+#include "video.hpp"
 
 
 namespace gui {
 
 scrollarea::scrollarea(CVideo &video, const bool auto_join)
 	: widget(video, auto_join), scrollbar_(video),
 	  old_position_(0), recursive_(false), shown_scrollbar_(false),
-	  shown_size_(0), full_size_(0)
+	  shown_size_(0), full_size_(0), swipe_dy_(0)
 {
 	scrollbar_.hide(true);
 }
@@ -153,19 +154,59 @@ void scrollarea::handle_event(const SDL_Event& event)
 	if (mouse_locked() || hidden())
 		return;
 
-	if (event.type != SDL_MOUSEWHEEL)
-		return;
+	if (event.type == SDL_MOUSEWHEEL) {
+		const SDL_MouseWheelEvent &ev = event.wheel;
+		int x, y;
+		SDL_GetMouseState(&x, &y);
+		if (sdl::point_in_rect(x, y, inner_location())) {
+			if (ev.y > 0) {
+				scrollbar_.scroll_up();
+			} else if (ev.y < 0) {
+				scrollbar_.scroll_down();
+			}
+		}
+	}
+
+	if (event.type == SDL_FINGERUP) {
+		swipe_dy_ = 0;
+	}
+
+	if (event.type == SDL_FINGERDOWN || event.type == SDL_FINGERMOTION) {
+		SDL_Rect r = video().screen_area();
+		auto tx = static_cast<int>(event.tfinger.x * r.w);
+		auto ty = static_cast<int>(event.tfinger.y * r.h);
+		auto dy = static_cast<int>(event.tfinger.dy * r.h);
+
+		if (event.type == SDL_FINGERDOWN) {
+			swipe_dy_ = 0;
+			swipe_origin_.x = tx;
+			swipe_origin_.y = ty;
+		}
 
-	const SDL_MouseWheelEvent &ev = event.wheel;
-	int x, y;
-	SDL_GetMouseState(&x, &y);
-	if (sdl::point_in_rect(x, y, inner_location())) {
-		if (ev.y > 0) {
-			scrollbar_.scroll_up();
-		} else if (ev.y < 0) {
-			scrollbar_.scroll_down();
+		if (event.type == SDL_FINGERMOTION) {
+
+			swipe_dy_ += dy;
+			if (scrollbar_.get_max_position() == 0) {
+				return;
+			}
+
+			int scrollbar_step = scrollbar_.height() / scrollbar_.get_max_position();
+			if (scrollbar_step <= 0) {
+				return;
+			}
+
+			if (sdl::point_in_rect(swipe_origin_.x, swipe_origin_.y, inner_location())
+				&& abs(swipe_dy_) >= scrollbar_step)
+			{
+				unsigned int pos = std::max(
+						static_cast<int>(scrollbar_.get_position() - swipe_dy_ / scrollbar_step),
+						0);
+				scrollbar_.set_position(pos);
+				swipe_dy_ %= scrollbar_step;
+			}
 		}
 	}
+
 }
 
 } // end namespace gui

src/widgets/scrollarea.hpp

@@ -60,6 +60,11 @@ class scrollarea : public widget
 	bool recursive_, shown_scrollbar_;
 	unsigned shown_size_;
 	unsigned full_size_;
+	int swipe_dy_;
+	struct {
+		int x;
+		int y;
+	} swipe_origin_;
 
 	void test_scrollbar();
 };