lighttroupe/luz-next

#
# GuiScrollbar shows progress in scroll, plus allows dragging and scroll wheel operation
#
class GuiScrollbarScroller < GuiObject
    HOVER_COLOR = [0.7,0.7,0.0,0.8]
    INACTIVE_COLOR = [0.08,0.08,0.08,0.4]
    ACTIVE_COLOR = [0.15,0.15,0.15,0.9]

    def initialize(scrollbar)
        super()
        @scrollbar = scrollbar
    end

    def gui_render
        with_positioning {
            with_color(scroller_color) {
                unit_square
            }
        }
    end

    def scroller_color
        if @scrollbar.can_move?
            if @scrollbar.pointer_hovering?
                HOVER_COLOR
            else
                ACTIVE_COLOR
            end
        else
            INACTIVE_COLOR
        end
    end
end

class GuiScrollbar < GuiBox
    WELL_COLOR = [0.05,0.05,0.05,0.4]

    # target should support:
    # scroll_velocity
    # scroll_percentage
    # visible_percentage

    def initialize(target)
        super()
        @target = target
        draggable!
    end

    def gui_tick
        unless @scroller
            self << (@scroller = GuiScrollbarScroller.new(self).set(:scale_x => 0.50, :scale_y => 1.0))
        end

        scroller_size = @target.visible_percentage
        scroller_half_size = scroller_size / 2.0
        scroller_progress = @target.scroll_percentage
        space = (1.0 - scroller_size)

        @scroller.set(:scale_y => scroller_size * 0.95, :offset_y => (0.5 - scroller_half_size) - (scroller_progress * space))
    end

    def gui_render
        with_positioning {
            with_color(WELL_COLOR) {
                unit_square
            }
        }
        super
    end

    def hit_test_render!
        return if hidden?
        with_positioning {
            render_hit_test_unit_square
        }
    end

    #
    def can_move?
        @target.visible_percentage < 1.0
    end

    def update_drag(pointer)
        @target.scroll_by(pointer, -(pointer.drag_delta_y * 2.0))
    end

    def scroll_up!(pointer)
        @target.scroll_up!(pointer)
    end

    def scroll_down!(pointer)
        @target.scroll_down!(pointer)
    end
end