Function DrawVerticalScrollbar

src/widget.cpp:519–549

* Draw a vertical scrollbar. * @param r Rectangle of the scrollbar widget. * @param colour Colour of the scrollbar widget. * @param up_clicked Up-arrow is clicked. * @param bar_dragged Bar is dragged. * @param down_clicked Down-arrow is clicked. * @param scrollbar Scrollbar size, offset, and capacity information. */

 * @param scrollbar    Scrollbar size, offset, and capacity information.
 */
static inline void DrawVerticalScrollbar(const Rect &r, Colours colour, bool up_clicked, bool bar_dragged, bool down_clicked, const Scrollbar *scrollbar)
{
	int height = NWidgetScrollbar::GetVerticalDimension().height;

	/* draw up/down buttons */
	DrawImageButtons(r.WithHeight(height, false),  NWID_VSCROLLBAR, colour, up_clicked,   SPR_ARROW_UP,   SA_CENTER);
	DrawImageButtons(r.WithHeight(height, true),   NWID_VSCROLLBAR, colour, down_clicked, SPR_ARROW_DOWN, SA_CENTER);

	PixelColour c1 = GetColourGradient(colour, SHADE_DARK);
	PixelColour c2 = GetColourGradient(colour, SHADE_LIGHTEST);

	/* draw "shaded" background */
	Rect bg = r.Shrink(0, height);
	GfxFillRect(bg, c2);
	GfxFillRect(bg, c1, FILLRECT_CHECKER);

	/* track positions. These fractions are based on original 1x dimensions, but scale better. */
	int left  = r.left + r.Width() * 3 / 11; /*  left track is positioned 3/11ths from the left */
	int right = r.left + r.Width() * 8 / 11; /* right track is positioned 8/11ths from the left */
	const uint8_t bl = WidgetDimensions::scaled.bevel.left;
	const uint8_t br = WidgetDimensions::scaled.bevel.right;

	/* draw shaded lines */
	GfxFillRect(bg.WithX(left - bl,  left       - 1), c1);
	GfxFillRect(bg.WithX(left,       left + br  - 1), c2);
	GfxFillRect(bg.WithX(right - bl, right      - 1), c1);
	GfxFillRect(bg.WithX(right,      right + br - 1), c2);

	auto [top, bottom] = HandleScrollbarHittest(scrollbar, r.top, r.bottom, false);
	DrawFrameRect(r.left, top, r.right, bottom, colour, bar_dragged ? FrameFlag::Lowered : FrameFlags{});
}

/**
 * Draw a horizontal scrollbar.