GUI: Set ScrollContainer single step to kLineHeight instead of 1 pixel

The single step is the amount of scroll done when clicking once on
the scrollbar up or down arrow. It used to be 1 entry, but for the
ScrollContainer 1 entry is 1 pixel, which was too litle. Now the
single step can be set to a multiple entries.

3 files changed, 9 insertions, 6 deletions

diff --git a/gui/widgets/scrollbar.cpp b/gui/widgets/scrollbar.cpp
index 38cdc6fda6..c45b4e0ec5 100644
--- a/gui/widgets/scrollbar.cpp
+++ b/gui/widgets/scrollbar.cpp
@@ -47,6 +47,7 @@ ScrollBarWidget::ScrollBarWidget(GuiObject *boss, int x, int y, int w, int h)
 	_numEntries = 0;
 	_entriesPerPage = 0;
 	_currentPos = 0;
+	_singleStep = 1;
 
 	_repeatTimer = 0;
 }
@@ -60,12 +61,12 @@ void ScrollBarWidget::handleMouseDown(int x, int y, int button, int clickCount)
 
 	if (y <= UP_DOWN_BOX_HEIGHT) {
 		// Up arrow
-		_currentPos--;
+		_currentPos -= _singleStep;
 		_repeatTimer = g_system->getMillis() + kRepeatInitialDelay;
 		_draggingPart = kUpArrowPart;
 	} else if (y >= _h - UP_DOWN_BOX_HEIGHT) {
 		// Down arrow
-		_currentPos++;
+		_currentPos += _singleStep;
 		_repeatTimer = g_system->getMillis() + kRepeatInitialDelay;
 		_draggingPart = kDownArrowPart;
 	} else if (y < _sliderPos) {
@@ -93,9 +94,9 @@ void ScrollBarWidget::handleMouseWheel(int x, int y, int direction) {
 		return;
 
 	if (direction < 0) {
-		_currentPos--;
+		_currentPos -= _singleStep;
 	} else {
-		_currentPos++;
+		_currentPos += _singleStep;
 	}
 
 	// Make sure that _currentPos is still inside the bounds
@@ -146,9 +147,9 @@ void ScrollBarWidget::handleTickle() {
 			const int old_pos = _currentPos;
 
 			if (_part == kUpArrowPart)
-				_currentPos -= 3;
+				_currentPos -= 3 * _singleStep;
 			else if (_part == kDownArrowPart)
-				_currentPos += 3;
+				_currentPos += 3 * _singleStep;
 
 			checkBounds(old_pos);
 
diff --git a/gui/widgets/scrollbar.h b/gui/widgets/scrollbar.h
index a1181b9e6c..9fdc94c396 100644
--- a/gui/widgets/scrollbar.h
+++ b/gui/widgets/scrollbar.h
@@ -60,6 +60,7 @@ public:
 	int		_numEntries;
 	int		_entriesPerPage;
 	int		_currentPos;
+	int		_singleStep;
 
 public:
 	ScrollBarWidget(GuiObject *boss, int x, int y, int w, int h);
diff --git a/gui/widgets/scrollcontainer.cpp b/gui/widgets/scrollcontainer.cpp
index 33f7e7f754..3c2e7aae32 100644
--- a/gui/widgets/scrollcontainer.cpp
+++ b/gui/widgets/scrollcontainer.cpp
@@ -73,6 +73,7 @@ void ScrollContainerWidget::recalc() {
 	_verticalScroll->_numEntries = h;
 	_verticalScroll->_currentPos = _scrolledY;
 	_verticalScroll->_entriesPerPage = _limitH;
+	_verticalScroll->_singleStep = kLineHeight;
 	_verticalScroll->setPos(_w - scrollbarWidth, _scrolledY+1);
 	_verticalScroll->setSize(scrollbarWidth, _limitH -2);
 }