[qwaq] Fix various scrollbar related issues

The editor now uses the vertical scrollbar for handling mouse wheel
scrolling, thus keeping the scrollbar in sync.

Scrollbar index can now cover the full range (not sure why I had that
-1), and the potential divide by zero is avoided properly.

Thumb-tab now positioned properly when the range is 0.

ruamoko/qwaq/editor/editor.h

@@ -37,8 +37,6 @@
 -(string)filepath;
 -(Point)cursor;
 -setStatusView:(EditStatus *)status;
--scrollUp:(unsigned) count;
--scrollDown:(unsigned) count;
 -scrollLeft:(unsigned) count;
 -scrollRight:(unsigned) count;
 -pageUp;

ruamoko/qwaq/editor/editor.r

@@ -154,11 +154,11 @@ handleEvent (Editor *self, qwaq_event_t *event)
 	if (event.what & qe_mouse) {
 		if (event.what == qe_mouseclick) {
 			if (event.mouse.buttons & (1 << 3)) {
-				[self scrollUp: 1];
+				[self.vScrollBar page:1 dir:0];
 				return 1;
 			}
 			if (event.mouse.buttons & (1 << 4)) {
-				[self scrollDown: 1];
+				[self.vScrollBar page:1 dir:1];
 				return 1;
 			}
 			if (event.mouse.buttons & (1 << 5)) {
@@ -243,40 +243,6 @@ handleEvent (Editor *self, qwaq_event_t *event)
 	return self;
 }
 
--scrollUp:(unsigned) count
-{
-	unsigned    index;
-	unsigned    lines;
-	if (count == 1) {
-		index = [buffer prevLine: base_index];
-	} else {
-		index = [buffer prevLine: base_index :count];
-	}
-	lines = [buffer countLines: {index, base_index - index}];
-	base.y -= lines;
-	base_index = index;
-	[self redraw];
-	[self moveCursor: {cursor.x - base.x, cursor.y - base.y}];
-	return self;
-}
-
--scrollDown:(unsigned) count
-{
-	unsigned    index;
-	unsigned    lines;
-	if (count == 1) {
-		index = [buffer nextLine: base_index];
-	} else {
-		index = [buffer nextLine: base_index :count];
-	}
-	lines = [buffer countLines: {base_index, index - base_index}];
-	base.y += lines;
-	base_index = index;
-	[self redraw];
-	[self moveCursor: {cursor.x - base.x, cursor.y - base.y}];
-	return self;
-}
-
 -scrollLeft:(unsigned) count
 {
 	if (base.x > count) {

ruamoko/qwaq/ui/scrollbar.h

@@ -35,6 +35,7 @@
 -setSingleStep:(unsigned)singleStep;
 -setIndex:(unsigned)index;
 -(unsigned)index;
+-page:(unsigned)step dir:(unsigned) dir;
 @end
 
 #endif//__qwaq_ui_scrollbar_h

ruamoko/qwaq/ui/scrollbar.r

@@ -45,6 +45,8 @@
 	thumbTab = [Button withPos:thumbPos
 				  releasedIcon:icons[2] pressedIcon:icons[2]];
 
+	[forwardButton setGrowMode:gfGrowAll];
+
 	[[backButton onClick] addListener:self :@selector(scrollBack:)];
 	[[forwardButton onClick] addListener:self :@selector(scrollForward:)];
 	[[thumbTab onPress] addListener:self :thumbSel];
@@ -110,15 +112,20 @@ static void
 position_tab (ScrollBar *self)
 {
 	Point       p = {0, 0};
-	Point       o = [self.thumbTab origin];
 	if (self.range > 0) {
 		if (self.vertical) {
-			p.y = 1 + self.index * (self.ylen - 3) / (self.range - 1);
+			p.y = 1 + self.index * (self.ylen - 3) / self.range;
 		} else {
-			p.x = 1 + self.index * (self.xlen - 3) / (self.range - 1);
+			p.x = 1 + self.index * (self.xlen - 3) / self.range;
+		}
+	} else {
+		if (self.vertical) {
+			p.y = 1;
+		} else {
+			p.x = 1;
 		}
 	}
-	[self.thumbTab move:{p.x - o.x, p.y - o.y}];
+	[self.thumbTab moveTo:p];
 	[self redraw];
 }
 
@@ -138,8 +145,8 @@ position_tab (ScrollBar *self)
 	unsigned    oind = index;
 
 	if (dir) {
-		if (range - 1 - index < step) {
-			step = range - 1 - index;
+		if (range - index < step) {
+			step = range - index;
 		}
 		index += step;
 	} else {