Rearranged and renamed Animation Editor-related script files

Data/Scripts/801_UI controls/001_UIControls.rb

@@ -0,0 +1,2 @@
+# Container module for control classes.
+module UIControls; end

Data/Scripts/801_UI controls/002_ControlsContainer.rb

@@ -0,0 +1,192 @@
+#===============================================================================
+# Controls are arranged in a list in self's bitmap. Each control is given a
+# "self's bitmap's width" x LINE_SPACING area of self's bitmap to draw itself
+# in.
+# TODO: The act of "capturing" a control makes other controls in this container
+#       not update themselves, i.e. they won't colour themselves with a hover
+#       highlight if the mouse happens to move over it while another control is
+#       captured. Is there a better way of dealing with this? I'm leaning
+#       towards the control itself deciding if it's captured, and it being
+#       treated as uncaptured once it says its value has changed, but I think
+#       this would require manually telling all other controls in this container
+#       that something else is captured and they shouldn't show a hover
+#       highlight when updated (perhaps as a parameter in def update), which I
+#       don't think is ideal.
+#===============================================================================
+class UIControls::ControlsContainer
+  attr_reader :x, :y
+  attr_reader :controls
+  attr_reader :values
+  attr_reader :visible
+
+  LINE_SPACING        = 28
+  OFFSET_FROM_LABEL_X = 90
+  OFFSET_FROM_LABEL_Y = 0
+
+  def initialize(x, y, width, height)
+    @viewport = Viewport.new(x, y, width, height)
+    @viewport.z = 99999
+    @x = x
+    @y = y
+    @width = width
+    @height = height
+    @controls = []
+    @control_rects = []
+    @row_count = 0
+    @captured = nil
+    @visible = true
+  end
+
+  def dispose
+    @controls.each { |c| c[1]&.dispose }
+    @controls.clear
+    @viewport.dispose
+  end
+
+  def busy?
+    return !@captured.nil?
+  end
+
+  def changed?
+    return !@values.nil?
+  end
+
+  def clear_changed
+    @values = nil
+  end
+
+  def visible=(value)
+    @visible = value
+    @controls.each { |c| c[1].visible = value }
+    repaint if @visible
+  end
+
+  def get_control(id)
+    ret = nil
+    @controls.each do |c|
+      ret = c[1] if c[0] == id
+      break if ret
+    end
+    return ret
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def add_label(id, label, has_label = false)
+    id = (id.to_s + "_label").to_sym
+    add_control(id, UIControls::Label.new(*control_size(has_label), @viewport, label), has_label)
+  end
+
+  def add_checkbox(id, value, has_label = false)
+    add_control(id, UIControls::Checkbox.new(*control_size(has_label), @viewport, value), has_label)
+  end
+
+  def add_labelled_checkbox(id, label, value)
+    add_label(id, label)
+    add_checkbox(id, value, true)
+  end
+
+  def add_text_box(id, value, has_label = false)
+    add_control(id, UIControls::TextBox.new(*control_size(has_label), @viewport, value), has_label)
+  end
+
+  def add_labelled_text_box(id, label, value)
+    add_label(id, label)
+    add_text_box(id, value, true)
+  end
+
+  def add_number_slider(id, min_value, max_value, value, has_label = false)
+    add_control(id, UIControls::NumberSlider.new(*control_size(has_label), @viewport, min_value, max_value, value), has_label)
+  end
+
+  def add_labelled_number_slider(id, label, min_value, max_value, value)
+    add_label(id, label)
+    add_number_slider(id, min_value, max_value, value, true)
+  end
+
+  def add_number_text_box(id, min_value, max_value, value, has_label = false)
+    add_control(id, UIControls::NumberTextBox.new(*control_size(has_label), @viewport, min_value, max_value, value), has_label)
+  end
+
+  def add_labelled_number_text_box(id, label, min_value, max_value, value)
+    add_label(id, label)
+    add_number_text_box(id, min_value, max_value, value, true)
+  end
+
+  def add_button(id, button_text, has_label = false)
+    add_control(id, UIControls::Button.new(*control_size(has_label), @viewport, button_text), has_label)
+  end
+
+  def add_labelled_button(id, label, button_text)
+    add_label(id, label)
+    add_button(id, button_text, true)
+  end
+
+  def add_dropdown_list(id, options, value, has_label = false)
+    add_control(id, UIControls::DropdownList.new(*control_size(has_label), @viewport, options, value), has_label)
+  end
+
+  def add_labelled_dropdown_list(id, label, options, value)
+    add_label(id, label)
+    add_dropdown_list(id, options, value, true)
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def repaint
+    @controls.each { |ctrl| ctrl[1].repaint }
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def update
+    return if !@visible
+    # Update controls
+    if @captured
+      # TODO: Ideally all controls will be updated here, if only to redraw
+      #       themselves if they happen to be invalidated somehow. But that
+      #       involves telling each control whether any other control is busy,
+      #       to ensure that they don't show their hover colours or anything,
+      #       which is fiddly and I'm not sure if it's the best approach.
+      @captured.update
+      @captured = nil if !@captured.busy?
+    else
+      @controls.each do |ctrl|
+        ctrl[1].update
+        @captured = ctrl[1] if ctrl[1].busy?
+      end
+    end
+    # Check for updated controls
+    @controls.each do |ctrl|
+      next if !ctrl[1].changed?
+      @values ||= {}
+      @values[ctrl[0]] = ctrl[1].value
+      ctrl[1].clear_changed
+    end
+    # Redraw controls if needed
+    repaint
+  end
+
+  #-----------------------------------------------------------------------------
+
+  private
+
+  def control_size(has_label = false)
+    if has_label
+      return @width - OFFSET_FROM_LABEL_X, LINE_SPACING - OFFSET_FROM_LABEL_Y
+    end
+    return @width, LINE_SPACING
+  end
+
+  def add_control(id, control, add_offset = false)
+    i = @controls.length
+    control_y = (add_offset ? @row_count - 1 : @row_count) * LINE_SPACING
+    @control_rects[i] = Rect.new(0, control_y, control.width, control.height)
+    control.x = @control_rects[i].x + (add_offset ? OFFSET_FROM_LABEL_X : 0)
+    control.y = @control_rects[i].y + (add_offset ? OFFSET_FROM_LABEL_Y : 0)
+    control.set_interactive_rects
+    @controls[i] = [id, control]
+    @row_count += 1 if !add_offset
+    repaint
+  end
+end

Data/Scripts/801_UI controls/Control elements/001_BaseControl.rb

@@ -0,0 +1,185 @@
+# TODO: Add "disabled" greying out/non-editable.
+# TODO: Add indicator of whether the control's value is "lerping" between frames
+#       (use yellow somehow?).
+
+#===============================================================================
+#
+#===============================================================================
+class UIControls::BaseControl < BitmapSprite
+  attr_reader :value
+#  attr_accessor :disabled   # TODO: Make use of this.
+
+  TEXT_COLOR    = Color.black
+  TEXT_SIZE     = 18           # Default is 22 if size isn't explicitly set
+  HOVER_COLOR   = Color.cyan   # For clickable area when hovering over it
+  CAPTURE_COLOR = Color.pink   # For area you clicked in but aren't hovering over
+
+  def initialize(width, height, viewport)
+    super(width, height, viewport)
+    self.bitmap.font.color = TEXT_COLOR
+    self.bitmap.font.size = TEXT_SIZE
+
+#    @disabled = false   # TODO: Make use of this.
+    @hover_area = nil   # Is a symbol from the keys for @interactions if the mouse is hovering over that interaction
+    @captured_area = nil   # Is a symbol from the keys for @interactions (or :none) if this control is clicked in
+    clear_changed
+    invalidate
+  end
+
+  def width
+    return self.bitmap.width
+  end
+
+  def height
+    return self.bitmap.height
+  end
+
+  def mouse_pos
+    mouse_coords = Mouse.getMousePos
+    return nil, nil if !mouse_coords
+    ret_x = mouse_coords[0] - self.viewport.rect.x - self.x
+    ret_y = mouse_coords[1] - self.viewport.rect.y - self.y
+    return ret_x, ret_y
+  end
+
+  def set_interactive_rects
+    @interactions = {}
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def invalid?
+    return @invalid
+  end
+
+  # Marks that the control must be redrawn to reflect current logic.
+  def invalidate
+    @invalid = true
+  end
+
+  # Makes the control no longer invalid.
+  def validate
+    @invalid = false
+  end
+
+  def busy?
+    return !@captured_area.nil?
+  end
+
+  def changed?
+    return @changed
+  end
+
+  def set_changed
+    @changed = true
+  end
+
+  def clear_changed
+    @changed = false
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def draw_text(this_bitmap, text_x, text_y, this_text)
+    text_size = this_bitmap.text_size(this_text)
+    this_bitmap.draw_text(text_x, text_y, text_size.width, text_size.height, this_text, 0)
+  end
+
+  def draw_text_centered(this_bitmap, text_x, text_y, wid, this_text)
+    text_size = this_bitmap.text_size(this_text)
+    this_bitmap.draw_text(text_x, text_y, wid, text_size.height, this_text, 1)
+  end
+
+  # Redraws the control only if it is invalid.
+  def repaint
+    return if !invalid?
+    refresh
+    validate
+  end
+
+  def refresh
+    # Paint over control to erase contents (intentionally not using self.bitmap.clear)
+    self.bitmap.clear
+    draw_area_highlight
+  end
+
+  def draw_area_highlight
+    return if !@interactions || @interactions.empty?
+    if !@captured_area || @hover_area == @captured_area
+      # Draw mouse hover over area highlight
+      rect = @interactions[@hover_area]
+      self.bitmap.fill_rect(rect.x, rect.y, rect.width, rect.height, HOVER_COLOR) if rect
+    elsif @captured_area
+      # Draw captured area highlight
+      rect = @interactions[@captured_area]
+      self.bitmap.fill_rect(rect.x, rect.y, rect.width, rect.height, CAPTURE_COLOR) if rect
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  # This method is only called if the mouse is in the game window and this
+  # control has interactive elements.
+  def on_mouse_press
+    return if !@interactions || @interactions.empty?
+    return if @captured_area
+    @captured_area = nil
+    mouse_x, mouse_y = mouse_pos
+    return if !mouse_x || !mouse_y
+    @interactions.each_pair do |area, rect|
+      next if !rect.contains?(mouse_x, mouse_y)
+      @captured_area = area
+      invalidate
+      break
+    end
+  end
+
+  def on_mouse_release
+    @captured_area = nil
+    invalidate
+  end
+
+  def update_hover_highlight
+    # Remove the hover highlight if there are no interactions for this control
+    # or if the mouse is off-screen
+    mouse_x, mouse_y = mouse_pos
+    if !@interactions || @interactions.empty? || !mouse_x || !mouse_y
+      invalidate if @hover_area
+      @hover_area = nil
+      return
+    end
+    # Check each interactive area for whether the mouse is hovering over it, and
+    # set @hover_area accordingly
+    in_area = false
+    @interactions.each_pair do |area, rect|
+      next if !rect.contains?(mouse_x, mouse_y)
+      invalidate if @hover_area != area
+      @hover_area = area
+      in_area = true
+      break
+    end
+    if !in_area
+      invalidate if @hover_area
+      @hover_area = nil
+    end
+  end
+
+  # Updates the logic on the control, invalidating it if necessary.
+  def update
+    return if !self.visible
+    # TODO: Disabled control stuff.
+#    return if self.disabled
+
+    update_hover_highlight
+
+    # Detect a mouse press/release
+    if @interactions && !@interactions.empty?
+      if Input.trigger?(Input::MOUSELEFT)
+        on_mouse_press
+      elsif busy? && Input.release?(Input::MOUSELEFT)
+        on_mouse_release
+      end
+    end
+
+  end
+end

Data/Scripts/801_UI controls/Control elements/002_Label.rb

@@ -0,0 +1,24 @@
+#===============================================================================
+#
+#===============================================================================
+class UIControls::Label < UIControls::BaseControl
+  attr_reader :label
+
+  LABEL_END_X   = 80
+  TEXT_OFFSET_Y = 5
+
+  def initialize(width, height, viewport, label)
+    super(width, height, viewport)
+    @label = label
+  end
+
+  def label=(value)
+    @label = value
+    refresh
+  end
+
+  def refresh
+    super
+    draw_text(self.bitmap, 4, TEXT_OFFSET_Y, @label)
+  end
+end

Data/Scripts/801_UI controls/Control elements/003_Checkbox.rb

@@ -0,0 +1,68 @@
+#===============================================================================
+# NOTE: Strictly speaking, this is a toggle switch and not a checkbox.
+#===============================================================================
+class UIControls::Checkbox < UIControls::BaseControl
+  CHECKBOX_X         = 2
+  CHECKBOX_WIDTH     = 40
+  CHECKBOX_HEIGHT    = 24
+  CHECKBOX_FILL_SIZE = CHECKBOX_HEIGHT - 4
+
+  UNCHECKED_COLOR = Color.gray
+  CHECKED_COLOR   = Color.new(64, 255, 64)   # Green
+
+  def initialize(width, height, viewport, value = false)
+    super(width, height, viewport)
+    @value = value
+  end
+
+  def value=(new_value)
+    return if @value == new_value
+    @value = new_value
+    invalidate
+  end
+
+  def set_interactive_rects
+    @checkbox_rect = Rect.new(CHECKBOX_X, (height - CHECKBOX_HEIGHT) / 2,
+                              CHECKBOX_WIDTH, CHECKBOX_HEIGHT)
+    @interactions = {
+      :checkbox => @checkbox_rect
+    }
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def refresh
+    super
+    # Draw checkbox outline
+    self.bitmap.outline_rect(@checkbox_rect.x, @checkbox_rect.y,
+                             @checkbox_rect.width, @checkbox_rect.height,
+                             self.bitmap.font.color)
+    # Draw checkbox fill
+    if @value   # If checked
+      self.bitmap.fill_rect(@checkbox_rect.x + @checkbox_rect.width - CHECKBOX_FILL_SIZE - 2, @checkbox_rect.y + 2,
+                            CHECKBOX_FILL_SIZE, CHECKBOX_FILL_SIZE, CHECKED_COLOR)
+      self.bitmap.outline_rect(@checkbox_rect.x + @checkbox_rect.width - CHECKBOX_FILL_SIZE - 2, @checkbox_rect.y + 2,
+                               CHECKBOX_FILL_SIZE, CHECKBOX_FILL_SIZE, self.bitmap.font.color)
+    else
+      self.bitmap.fill_rect(@checkbox_rect.x + 2, @checkbox_rect.y + 2,
+                            CHECKBOX_FILL_SIZE, CHECKBOX_FILL_SIZE, UNCHECKED_COLOR)
+      self.bitmap.outline_rect(@checkbox_rect.x + 2, @checkbox_rect.y + 2,
+                               CHECKBOX_FILL_SIZE, CHECKBOX_FILL_SIZE, self.bitmap.font.color)
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_release
+    return if !@captured_area   # Wasn't captured to begin with
+    # Change this control's value
+    if @captured_area == :checkbox
+      mouse_x, mouse_y = mouse_pos
+      if mouse_x && mouse_y &&  @interactions[@captured_area].contains?(mouse_x, mouse_y)
+        @value = !@value   # The actual change of this control's value
+        set_changed
+      end
+    end
+    super   # Make this control not busy again
+  end
+end

Data/Scripts/801_UI controls/Control elements/004_TextBox.rb

@@ -0,0 +1,293 @@
+#===============================================================================
+# TODO: Support selecting part of the text by remembering the initial
+#       cursor position and using it and the current cursor position to
+#       decide which characters are selected. Maybe? Note that this method
+#       is only triggered upon the initial mouse press, and isn't repeated
+#       while it's still held down.
+#===============================================================================
+class UIControls::TextBox < UIControls::BaseControl
+  TEXT_BOX_X       = 2
+  TEXT_BOX_WIDTH   = 172
+  TEXT_BOX_HEIGHT  = 24
+  TEXT_BOX_PADDING = 4   # Gap between sides of text box and text
+  TEXT_OFFSET_Y    = 5
+
+  def initialize(width, height, viewport, value = "")
+    super(width, height, viewport)
+    @value        = value
+    @cursor_pos   = -1
+    @display_pos  = 0
+    @cursor_timer = nil
+    @cursor_shown = false
+  end
+
+  def value=(new_value)
+    return if @value == new_value
+    @value = new_value
+    invalidate
+  end
+
+  def insert_char(ch)
+    @value.insert(@cursor_pos, ch)
+    @cursor_pos += 1
+    @cursor_timer = System.uptime
+    @cursor_shown = true
+    invalidate
+  end
+
+  def delete_at(index)
+    @value.slice!(index)
+    @cursor_pos -= 1 if @cursor_pos > index
+    @cursor_timer = System.uptime
+    @cursor_shown = true
+    invalidate
+  end
+
+  def cursor_pos=(val)
+    @cursor_pos = val
+    reset_display_pos
+    @cursor_timer = System.uptime
+    @cursor_shown = true
+    invalidate
+  end
+
+  def set_interactive_rects
+    @text_box_rect = Rect.new(TEXT_BOX_X, (height - TEXT_BOX_HEIGHT) / 2,
+                              [TEXT_BOX_WIDTH, width].min, TEXT_BOX_HEIGHT)
+    @interactions = {
+      :text_box => @text_box_rect
+    }
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def busy?
+    return @cursor_pos >= 0 if @captured_area == :text_box
+    return super
+  end
+
+  def reset_interaction
+    @cursor_pos = -1
+    @display_pos = 0
+    @cursor_timer = nil
+    @initial_value = nil
+    Input.text_input = false
+    invalidate
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def get_cursor_index_from_mouse_position
+    char_widths = []
+    @value.to_s.length.times { |i| char_widths[i] = self.bitmap.text_size(@value.to_s[i]).width }
+    mouse_x, mouse_y = mouse_pos
+    mouse_x -= @text_box_rect.x + TEXT_BOX_PADDING
+    return 0 if mouse_x < 0
+    (@display_pos...char_widths.length).each do |i|
+      mouse_x -= char_widths[i]
+      if mouse_x <= 0
+        return (mouse_x.abs >= char_widths[i] / 2) ? i : i + 1
+      end
+    end
+    return @value.to_s.length
+  end
+
+  def reset_display_pos
+    box_width = @text_box_rect.width - (TEXT_BOX_PADDING * 2)
+    char_widths = []
+    @value.to_s.length.times { |i| char_widths[i] = self.bitmap.text_size(@value.to_s[i]).width }
+    # Text isn't wider than the box
+    if char_widths.sum <= box_width
+      return false if @display_pos == 0
+      @display_pos = 0
+      return true
+    end
+    display_pos_changed = false
+    # Ensure the cursor hasn't gone off the left side of the text box
+    if @cursor_pos < @display_pos
+      @display_pos = @cursor_pos
+      display_pos_changed = true
+    end
+    # Ensure the cursor hasn't gone off the right side of the text box
+    if @cursor_pos > @display_pos
+      loop do
+        cursor_x = 0
+        (@display_pos...@cursor_pos).each do |i|
+          cursor_x += char_widths[i] if char_widths[i]
+        end
+        break if cursor_x < box_width
+        @display_pos += 1
+        display_pos_changed = true
+        break if @display_pos == @cursor_pos
+      end
+    end
+    # Ensure there isn't empty space on the right if the text can be moved to
+    # the right to fill it
+    if @display_pos > 0
+      cursor_x = 0
+      (@display_pos...char_widths.length).each do |i|
+        cursor_x += char_widths[i] if char_widths[i]
+      end
+      loop do
+        cursor_x += char_widths[@display_pos - 1]
+        break if cursor_x >= box_width
+        @display_pos -= 1
+        display_pos_changed = true
+        break if @display_pos == 0
+      end
+    end
+    return display_pos_changed
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def draw_area_highlight
+    return if @captured_area == :text_box && (@hover_area == @captured_area || !Input.press?(Input::MOUSELEFT))
+    super
+  end
+
+  def draw_cursor(cursor_x)
+    return if !@cursor_shown || @cursor_pos < 0
+    cursor_y_offset = ((height - TEXT_BOX_HEIGHT) / 2) + 2
+    cursor_height = height - (cursor_y_offset * 2)
+    bitmap.fill_rect(cursor_x, cursor_y_offset, 2, cursor_height, self.bitmap.font.color)
+  end
+
+  def refresh
+    super
+    # Draw text box outline
+    self.bitmap.outline_rect(@text_box_rect.x, @text_box_rect.y,
+                             @text_box_rect.width, @text_box_rect.height,
+                             self.bitmap.font.color)
+    # Draw value
+    char_x = @text_box_rect.x + TEXT_BOX_PADDING
+    last_char_index = @display_pos
+    (@value.to_s.length - @display_pos).times do |i|
+      char = @value.to_s[@display_pos + i]
+      char_width = self.bitmap.text_size(char).width
+      cannot_display_next_char = char_x + char_width > @text_box_rect.x + @text_box_rect.width - TEXT_BOX_PADDING
+      draw_text(self.bitmap, char_x, TEXT_OFFSET_Y, char) if !cannot_display_next_char
+      # Draw cursor
+      draw_cursor(char_x - 1) if @display_pos + i == @cursor_pos
+      break if cannot_display_next_char
+      last_char_index = @display_pos + i
+      char_x += char_width
+    end
+    # Draw cursor at end
+    draw_cursor(char_x - 1) if @cursor_pos == @value.to_s.length
+    # Draw left/right arrows to indicate more text beyond the text box sides
+    if @display_pos > 0
+      bitmap.fill_rect(@text_box_rect.x, (height / 2) - 4, 1, 8, Color.white)
+      5.times do |i|
+        bitmap.fill_rect(@text_box_rect.x - 2 + i, (height / 2) - (i + 1), 1, 2 * (i + 1), self.bitmap.font.color)
+      end
+    end
+    if last_char_index < @value.to_s.length - 1
+      bitmap.fill_rect(@text_box_rect.x + @text_box_rect.width - 1, (height / 2) - 4, 1, 8, Color.white)
+      5.times do |i|
+        bitmap.fill_rect(@text_box_rect.x + @text_box_rect.width + 1 - i, (height / 2) - (i + 1), 1, 2 * (i + 1), self.bitmap.font.color)
+      end
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_press
+    @captured_area = nil
+    super
+    if @captured_area == :text_box
+      # Clicked into the text box; put the text cursor in there
+      @cursor_pos = get_cursor_index_from_mouse_position
+      @cursor_timer = System.uptime
+      invalidate
+    else
+      @value.strip! if @value.respond_to?("strip!")
+      set_changed if @initial_value && @value != @initial_value
+      reset_interaction
+    end
+  end
+
+  def on_mouse_release
+    return if !@captured_area   # Wasn't captured to begin with
+    # Start text entry if clicked and released mouse button in the text box
+    if @captured_area == :text_box
+      mouse_x, mouse_y = mouse_pos
+      if mouse_x && mouse_y && @interactions[@captured_area].contains?(mouse_x, mouse_y)
+        @initial_value = @value.clone
+        Input.text_input = true
+        invalidate
+        return   # This control is still captured
+      end
+    end
+    # Released mouse button outside of text box, or initially clicked outside of
+    # text box; end interaction with this control
+    @value.strip! if @value.respond_to?("strip!")
+    set_changed if @initial_value && @value != @initial_value
+    reset_interaction
+    super   # Make this control not busy again
+  end
+
+  def update_special_inputs
+    # Left/right to move cursor
+    if Input.triggerex?(:LEFT) || Input.repeatex?(:LEFT)
+      self.cursor_pos = @cursor_pos - 1 if @cursor_pos > 0
+    elsif Input.triggerex?(:RIGHT) || Input.repeatex?(:RIGHT)
+      self.cursor_pos = @cursor_pos + 1 if @cursor_pos < @value.to_s.length
+    end
+    # Home/End to jump to start/end of the text
+    if Input.triggerex?(:HOME) || Input.repeatex?(:HOME)
+      self.cursor_pos = 0
+    elsif Input.triggerex?(:END) || Input.repeatex?(:END)
+      self.cursor_pos = @value.to_s.length
+    end
+    # Backspace/Delete to remove text
+    if Input.triggerex?(:BACKSPACE) || Input.repeatex?(:BACKSPACE)
+      delete_at(@cursor_pos - 1) if @cursor_pos > 0
+    elsif Input.triggerex?(:DELETE) || Input.repeatex?(:DELETE)
+      delete_at(@cursor_pos) if @cursor_pos < @value.to_s.length
+    end
+    # Return/Escape to end text input (Escape undoes the change)
+    if Input.triggerex?(:RETURN) || Input.repeatex?(:RETURN) ||
+       Input.triggerex?(:KP_ENTER) || Input.repeatex?(:KP_ENTER)
+      @value.strip! if @value.respond_to?("strip!")
+      set_changed if @initial_value && @value != @initial_value
+      reset_interaction
+      @captured_area = nil
+    elsif Input.triggerex?(:ESCAPE) || Input.repeatex?(:ESCAPE)
+      @value = @initial_value if @initial_value
+      reset_interaction
+      @captured_area = nil
+    end
+  end
+
+  def update_text_entry
+    ret = false
+    Input.gets.each_char do |ch|
+      insert_char(ch)
+      ret = true
+    end
+    return ret
+  end
+
+  def update
+    return if !self.visible
+    super
+    # TODO: Disabled control stuff.
+#    return if self.disabled
+    # Make the cursor flash
+    if @captured_area == :text_box
+      cursor_to_show = ((System.uptime - @cursor_timer) / 0.35).to_i.even?
+      if cursor_to_show != @cursor_shown
+        @cursor_shown = cursor_to_show
+        invalidate
+      end
+      old_cursor_pos = @cursor_pos
+      # Update cursor movement, deletions and ending text input
+      update_special_inputs
+      return if @cursor_pos != old_cursor_pos || !busy?
+      # Detect character input and add them to @value
+      char_inserted = update_text_entry
+      invalidate if reset_display_pos || char_inserted
+    end
+  end
+end

Data/Scripts/801_UI controls/Control elements/005_NumberSlider.rb

@@ -0,0 +1,131 @@
+#===============================================================================
+#
+#===============================================================================
+class UIControls::NumberSlider < UIControls::BaseControl
+  attr_reader :min_value
+  attr_reader :max_value
+
+  PLUS_MINUS_SIZE = 16
+  SLIDER_PADDING  = 6   # Gap between sides of interactive area for slider and drawn slider bar
+
+  MINUS_X       = 0
+  SLIDER_X      = MINUS_X + PLUS_MINUS_SIZE + SLIDER_PADDING
+  SLIDER_LENGTH = 128
+  PLUS_X        = SLIDER_X + SLIDER_LENGTH + SLIDER_PADDING
+  VALUE_X       = PLUS_X + PLUS_MINUS_SIZE + 5
+  TEXT_OFFSET_Y = 5
+
+  # TODO: Is there a better knob design than a big black rectangle? I'd rather
+  #       it not be a different colour.
+  SLIDER_KNOB_COLOR = Color.black
+
+  def initialize(width, height, viewport, min_value, max_value, value)
+    super(width, height, viewport)
+    @min_value = min_value
+    @max_value = max_value
+    self.value = value
+  end
+
+  def value=(new_value)
+    old_val = @value
+    @value = new_value.to_i.clamp(self.min_value, self.max_value)
+    self.invalidate if @value != old_val
+  end
+
+  def min_value=(new_min)
+    return if new_min == @min_value
+    @min_value = new_min
+    @value = @value.clamp(self.min_value, self.max_value)
+    self.invalidate
+  end
+
+  def max_value=(new_max)
+    return if new_max == @max_value
+    @max_value = new_max
+    @value = @value.clamp(self.min_value, self.max_value)
+    self.invalidate
+  end
+
+  def set_interactive_rects
+    @slider_rect = Rect.new(SLIDER_X - SLIDER_PADDING, (self.height - PLUS_MINUS_SIZE) / 2, SLIDER_LENGTH + (SLIDER_PADDING * 2), PLUS_MINUS_SIZE)
+    @minus_rect = Rect.new(MINUS_X, (self.height - PLUS_MINUS_SIZE) / 2, PLUS_MINUS_SIZE, PLUS_MINUS_SIZE)
+    @plus_rect = Rect.new(PLUS_X, (self.height - PLUS_MINUS_SIZE) / 2, PLUS_MINUS_SIZE, PLUS_MINUS_SIZE)
+    @interactions = {
+      :slider => @slider_rect,
+      :minus  => @minus_rect,
+      :plus   => @plus_rect
+    }
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def draw_area_highlight
+    # Don't want to ever highlight the slider with the capture color, because
+    # the mouse doesn't need to be on the slider to change this control's value
+    if @captured_area == :slider
+      rect = @interactions[@captured_area]
+      self.bitmap.fill_rect(rect.x, rect.y, rect.width, rect.height, HOVER_COLOR) if rect
+    else
+      super
+    end
+  end
+
+  def refresh
+    super
+    # Draw minus button
+    self.bitmap.fill_rect(@minus_rect.x + 2, @minus_rect.y + (@minus_rect.height / 2) - 2, @minus_rect.width - 4, 4, self.bitmap.font.color)
+    # Draw slider bar
+    self.bitmap.fill_rect(SLIDER_X, (self.height / 2) - 1, SLIDER_LENGTH, 2, self.bitmap.font.color)
+    # Draw notches on slider bar
+    5.times do |i|
+      self.bitmap.fill_rect(SLIDER_X - 1 + (i * SLIDER_LENGTH / 4), (self.height / 2) - 2, 2, 4, self.bitmap.font.color)
+    end
+    # Draw slider knob
+    fraction = (self.value - self.min_value) / self.max_value.to_f
+    knob_x = (SLIDER_LENGTH * fraction).to_i
+    self.bitmap.fill_rect(SLIDER_X + knob_x - 4, (self.height / 2) - 6, 8, 12, SLIDER_KNOB_COLOR)
+    # Draw plus button
+    self.bitmap.fill_rect(@plus_rect.x + 2, @plus_rect.y + (@plus_rect.height / 2) - 2, @plus_rect.width - 4, 4, self.bitmap.font.color)
+    self.bitmap.fill_rect(@plus_rect.x + (@plus_rect.width / 2) - 2, @plus_rect.y + 2, 4, @plus_rect.height - 4, self.bitmap.font.color)
+    # Draw value text
+    draw_text(self.bitmap, VALUE_X, TEXT_OFFSET_Y, self.value.to_s)
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_press
+    super
+    @initial_value = @value if @captured_area
+  end
+
+  def on_mouse_release
+    return if !@captured_area   # Wasn't captured to begin with
+    set_changed if @initial_value && @value != @initial_value
+    @initial_value = nil
+    super
+  end
+
+  def update
+    return if !self.visible
+    super
+    # TODO: Disabled control stuff.
+#    return if self.disabled
+    case @captured_area
+    when :minus
+      # Constant decrement of value while pressing the minus button
+      if @hover_area == @captured_area && Input.repeat?(Input::MOUSELEFT)
+        self.value -= 1
+      end
+    when :plus
+      # Constant incrementing of value while pressing the plus button
+      if @hover_area == @captured_area && Input.repeat?(Input::MOUSELEFT)
+        self.value += 1
+      end
+    when :slider
+      # Constant updating of value depending on mouse's x position
+      mouse_x, mouse_y = mouse_pos
+      return if !mouse_x || !mouse_y
+      self.value = lerp(self.min_value, self.max_value + (self.max_value & 1), SLIDER_LENGTH, mouse_x - SLIDER_X)
+    end
+  end
+end

Data/Scripts/801_UI controls/Control elements/006_NumberTextBox.rb

@@ -0,0 +1,140 @@
+#===============================================================================
+#
+#===============================================================================
+class UIControls::NumberTextBox < UIControls::TextBox
+  attr_reader :min_value
+  attr_reader :max_value
+
+  PLUS_MINUS_SIZE = 16
+  CONTROL_PADDING = 2   # Gap between buttons and text box
+
+  MINUS_X         = 0
+  TEXT_BOX_X      = MINUS_X + PLUS_MINUS_SIZE + CONTROL_PADDING
+  TEXT_BOX_WIDTH  = 64
+  TEXT_BOX_HEIGHT = 24
+  PLUS_X          = TEXT_BOX_X + TEXT_BOX_WIDTH + CONTROL_PADDING
+
+  def initialize(width, height, viewport, min_value, max_value, value)
+    super(width, height, viewport, value)
+    @min_value = min_value
+    @max_value = max_value
+    self.value = value
+  end
+
+  def value=(new_value)
+    old_val = @value
+    @value = new_value.to_i.clamp(self.min_value, self.max_value)
+    self.invalidate if @value != old_val
+  end
+
+  def min_value=(new_min)
+    return if new_min == @min_value
+    @min_value = new_min
+    @value = @value.clamp(self.min_value, self.max_value)
+    self.invalidate
+  end
+
+  def max_value=(new_max)
+    return if new_max == @max_value
+    @max_value = new_max
+    @value = @value.clamp(self.min_value, self.max_value)
+    self.invalidate
+  end
+
+  # TODO: If current value is 0, replace it with ch instead of inserting ch?
+  def insert_char(ch)
+    self.value = @value.to_s.insert(@cursor_pos, ch).to_i
+    @cursor_pos += 1
+    @cursor_pos = @cursor_pos.clamp(0, @value.to_s.length)
+    @cursor_timer = System.uptime
+    @cursor_shown = true
+    invalidate
+  end
+
+  def delete_at(index)
+    new_val = @value.to_s
+    new_val.slice!(index)
+    self.value = new_val.to_i
+    @cursor_pos -= 1 if @cursor_pos > index
+    @cursor_pos = @cursor_pos.clamp(0, @value.to_s.length)
+    @cursor_timer = System.uptime
+    @cursor_shown = true
+    invalidate
+  end
+
+  def set_interactive_rects
+    @text_box_rect = Rect.new(TEXT_BOX_X, (height - TEXT_BOX_HEIGHT) / 2,
+                              TEXT_BOX_WIDTH, TEXT_BOX_HEIGHT)
+    @minus_rect = Rect.new(MINUS_X, (self.height - PLUS_MINUS_SIZE) / 2, PLUS_MINUS_SIZE, PLUS_MINUS_SIZE)
+    @plus_rect = Rect.new(PLUS_X, (self.height - PLUS_MINUS_SIZE) / 2, PLUS_MINUS_SIZE, PLUS_MINUS_SIZE)
+    @interactions = {
+      :text_box => @text_box_rect,
+      :minus    => @minus_rect,
+      :plus     => @plus_rect
+    }
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def refresh
+    super
+    # Draw minus button
+    self.bitmap.fill_rect(@minus_rect.x + 2, @minus_rect.y + (@minus_rect.height / 2) - 2, @minus_rect.width - 4, 4, self.bitmap.font.color)
+    # Draw plus button
+    self.bitmap.fill_rect(@plus_rect.x + 2, @plus_rect.y + (@plus_rect.height / 2) - 2, @plus_rect.width - 4, 4, self.bitmap.font.color)
+    self.bitmap.fill_rect(@plus_rect.x + (@plus_rect.width / 2) - 2, @plus_rect.y + 2, 4, @plus_rect.height - 4, self.bitmap.font.color)
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_press
+    @captured_area = nil
+    super
+    if @captured_area == :text_box
+      # Clicked into the text box; put the text cursor in there
+      @cursor_pos = get_cursor_index_from_mouse_position
+      @cursor_timer = System.uptime
+      invalidate
+    elsif @captured_area
+      @initial_value = @value
+    else
+      set_changed if @initial_value && @value != @initial_value
+      reset_interaction
+    end
+  end
+
+  def update_text_entry
+    ret = false
+    Input.gets.each_char do |ch|
+      next if !["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "-"].include?(ch)
+      if ch == "-"
+        next if @min_value >= 0 || @cursor_pos > 1 || (@cursor_pos > 0 && @value >= 0)
+        if @value < 0
+          delete_at(0)   # Remove the negative sign
+          ret = true
+          next
+        end
+      end
+      insert_char(ch)
+      ret = true
+    end
+    return ret
+  end
+
+  def update
+    return if !self.visible
+    super
+    case @captured_area
+    when :minus
+      # Constant decrement of value while pressing the minus button
+      if @hover_area == @captured_area && Input.repeat?(Input::MOUSELEFT)
+        self.value -= 1
+      end
+    when :plus
+      # Constant incrementing of value while pressing the plus button
+      if @hover_area == @captured_area && Input.repeat?(Input::MOUSELEFT)
+        self.value += 1
+      end
+    end
+  end
+end

Data/Scripts/801_UI controls/Control elements/007_Button.rb

@@ -0,0 +1,75 @@
+#===============================================================================
+#
+#===============================================================================
+class UIControls::Button < UIControls::BaseControl
+  BUTTON_X           = 2
+  BUTTON_Y           = 2
+  BUTTON_PADDING     = 10
+  BUTTON_HEIGHT      = 28
+  # TODO: This will also depend on the font size.
+  TEXT_BASE_OFFSET_Y = 18   # Text is centred vertically in the button
+
+  def initialize(width, height, viewport, text = "")
+    super(width, height, viewport)
+    @text = text
+    @fixed_size = false
+  end
+
+  def set_fixed_size
+    @fixed_size = true
+  end
+
+  def set_interactive_rects
+    button_width = (@fixed_size) ? width - (BUTTON_X * 2) : self.bitmap.text_size(@text).width + (BUTTON_PADDING * 2)
+    button_height = (@fixed_size) ? height - (2 * BUTTON_Y) : BUTTON_HEIGHT
+    button_height = [button_height, height - (2 * BUTTON_Y)].min
+    @button_rect = Rect.new(BUTTON_X, (height - button_height) / 2, button_width, button_height)
+    @interactions = {
+      :button => @button_rect
+    }
+  end
+
+  def set_changed
+    @value = true
+    super
+  end
+
+  def clear_changed
+    @value = false
+    super
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def refresh
+    super
+    # Draw button outline
+    self.bitmap.outline_rect(@button_rect.x, @button_rect.y,
+                             @button_rect.width, @button_rect.height,
+                             self.bitmap.font.color)
+    # TODO: Make buttons look more different to text boxes?
+    # shade = self.bitmap.font.color.clone
+    # shade.alpha = 96
+    # self.bitmap.outline_rect(@button_rect.x + 1, @button_rect.y + 1,
+    #                          @button_rect.width - 2, @button_rect.height - 2,
+    #                          shade, 3)
+    # Draw button text
+    draw_text_centered(self.bitmap, @button_rect.x,
+                       @button_rect.y + (@button_rect.height - TEXT_BASE_OFFSET_Y) / 2,
+                       @button_rect.width, @text)
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_release
+    return if !@captured_area   # Wasn't captured to begin with
+    # Change this control's value
+    if @captured_area == :button
+      mouse_x, mouse_y = mouse_pos
+      if mouse_x && mouse_y &&  @interactions[@captured_area].contains?(mouse_x, mouse_y)
+        set_changed
+      end
+    end
+    super   # Make this control not busy again
+  end
+end

Data/Scripts/801_UI controls/Control elements/008_List.rb

@@ -0,0 +1,207 @@
+#===============================================================================
+# TODO: Do I need to split self's bitmap into two (one for highlights and one
+#       for text)? This would be to reduce lag caused by redrawing text even if
+#       you're just waving the mouse over the control. There doesn't seem to be
+#       any lag at the moment with a tall list.
+# TODO: Make a viewport for the list, and allow scrolling positions halfway
+#       through a line? Nah.
+#===============================================================================
+class UIControls::List < UIControls::BaseControl
+  LIST_X         = 0
+  LIST_Y         = 0
+  ROW_HEIGHT     = 24
+  TEXT_PADDING_X = 4
+  TEXT_OFFSET_Y  = 3
+
+  SELECTED_ROW_COLOR = Color.green
+
+  def initialize(width, height, viewport, values = [])
+    super(width, height, viewport)
+    @scrollbar = UIControls::Scrollbar.new(LIST_X + width - UIControls::Scrollbar::SLIDER_WIDTH, LIST_Y, height, viewport)
+    @scrollbar.set_interactive_rects
+    @scrollbar.range = ROW_HEIGHT
+    @scrollbar.z = self.z + 1
+    @rows_count = (height / ROW_HEIGHT).floor   # Number of rows visible at once
+    @top_row  = 0
+    @selected = -1
+    self.values = values
+  end
+
+  def dispose
+    @scrollbar.dispose
+    @scrollbar = nil
+    super
+  end
+
+  def x=(new_val)
+    super(new_val)
+    @scrollbar.x = new_val + LIST_X + width - UIControls::Scrollbar::SLIDER_WIDTH
+  end
+
+  def y=(new_val)
+    super(new_val)
+    @scrollbar.y = new_val + LIST_Y
+  end
+
+  # Each value in @values is an array: [id, text].
+  def values=(new_vals)
+    @values = new_vals
+    set_interactive_rects
+    @scrollbar.range = @values.length * ROW_HEIGHT
+    if @scrollbar.visible
+      self.top_row = (@scrollbar.position.to_f / ROW_HEIGHT).round
+    else
+      self.top_row = 0
+    end
+    self.selected = -1 if @selected >= @values.length
+    invalidate
+  end
+
+  def top_row=(val)
+    old_val = @top_row
+    @top_row = val
+    if @scrollbar.visible
+      @top_row = @top_row.clamp(0, @values.length - @rows_count)
+    else
+      @top_row = 0
+    end
+    invalidate if @top_row != old_val
+  end
+
+  def selected=(val)
+    return if @selected == val
+    @selected = val
+    invalidate
+  end
+
+  # Returns the ID of the selected row.
+  def value
+    return nil if @selected < 0
+    return @values[@selected][0]
+  end
+
+  def set_interactive_rects
+    @interactions = {}
+    @values.length.times do |i|
+      @interactions[i] = Rect.new(LIST_X, LIST_Y + (ROW_HEIGHT * i), width - LIST_X, ROW_HEIGHT)
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def busy?
+    return !@captured_area.nil?
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def draw_area_highlight
+    # If a row is captured, it will automatically be selected and the selection
+    # colour will be drawn over the highlight. There's no point drawing a
+    # highlight at all if anything is captured.
+    return if @captured_area
+    # Draw mouse hover over row highlight
+    rect = @interactions[@hover_area]
+    if rect
+      rect_y = rect.y
+      rect_y -= @top_row * ROW_HEIGHT if @hover_area.is_a?(Integer)
+      self.bitmap.fill_rect(rect.x, rect_y, rect.width, rect.height, HOVER_COLOR)
+    end
+  end
+
+  def repaint
+    @scrollbar.repaint if @scrollbar.invalid?
+    super if invalid?
+  end
+
+  def refresh
+    super
+    # Draw text options
+    @values.each_with_index do |val, i|
+      next if i < @top_row || i >= @top_row + @rows_count
+      if @selected == i
+        self.bitmap.fill_rect(
+           @interactions[i].x,
+           @interactions[i].y - (@top_row * ROW_HEIGHT),
+           @interactions[i].width, @interactions[i].height,
+           SELECTED_ROW_COLOR
+         )
+      end
+      draw_text(self.bitmap,
+                @interactions[i].x + TEXT_PADDING_X,
+                @interactions[i].y + TEXT_OFFSET_Y - (@top_row * ROW_HEIGHT),
+                val[1])
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_press
+    @captured_area = nil
+    mouse_x, mouse_y = mouse_pos
+    return if !mouse_x || !mouse_y
+    return if @scrollbar.visible && (@scrollbar.busy? || mouse_x >= @scrollbar.x - self.x)
+    # Check for mouse presses on rows
+    mouse_y += @top_row * ROW_HEIGHT
+    @interactions.each_pair do |area, rect|
+      next if !area.is_a?(Integer) || area < @top_row || area >= @top_row + @rows_count
+      next if !rect.contains?(mouse_x, mouse_y)
+      @captured_area = area
+      invalidate
+      break
+    end
+  end
+
+  def on_mouse_release
+    return if !@captured_area   # Wasn't captured to begin with
+    set_changed
+    super
+  end
+
+  def update_hover_highlight
+    # Remove the hover highlight if there are no interactions for this control
+    # or if the mouse is off-screen
+    mouse_x, mouse_y = mouse_pos
+    if !@interactions || @interactions.empty? || !mouse_x || !mouse_y
+      invalidate if @hover_area
+      @hover_area = nil
+      return
+    end
+    # Don't update the highlight if the mouse is using the scrollbar
+    if @scrollbar.visible && (@scrollbar.busy? || mouse_x >= @scrollbar.x - self.x)
+      invalidate if @hover_area
+      @hover_area = nil
+      return
+    end
+    # Check each interactive area for whether the mouse is hovering over it, and
+    # set @hover_area accordingly
+    in_area = false
+    mouse_y += @top_row * ROW_HEIGHT
+    @interactions.each_pair do |area, rect|
+      next if !area.is_a?(Integer) || area < @top_row || area >= @top_row + @rows_count
+      next if !rect.contains?(mouse_x, mouse_y)
+      invalidate if @hover_area != area
+      @hover_area = area
+      in_area = true
+      break
+    end
+    if !in_area
+      invalidate if @hover_area
+      @hover_area = nil
+    end
+  end
+
+  def update
+    return if !self.visible
+    @scrollbar.update
+    super
+    # TODO: Disabled control stuff.
+#    return if self.disabled
+    # Refresh the list's position if changed by moving the scrollbar
+    self.top_row = (@scrollbar.position.to_f / ROW_HEIGHT).round
+    # Set the selected row to the row the mouse is over, if clicked on
+    if @captured_area
+      @selected = @hover_area if @hover_area.is_a?(Integer)
+    end
+  end
+end

Data/Scripts/801_UI controls/Control elements/009_DropdownList.rb

@@ -0,0 +1,9 @@
+#===============================================================================
+# TODO
+#===============================================================================
+class UIControls::DropdownList < UIControls::BaseControl
+  def initialize(width, height, viewport, options, value)
+    # NOTE: options is a hash: keys are symbols, values are display names.
+    super(width, height, viewport)
+  end
+end

Data/Scripts/801_UI controls/Control elements/101_Scrollbar.rb

@@ -0,0 +1,156 @@
+#===============================================================================
+# TODO: Make the slider a separate sprite that moves, instead of redrawing this
+#       sprite's bitmap whenever it moves? Intended to reduce lag. There doesn't
+#       seem to be any lag at the moment with a tall scrollbar.
+#===============================================================================
+class UIControls::Scrollbar < UIControls::BaseControl
+  SLIDER_WIDTH    = 16
+  WIDTH_PADDING   = 0
+  SCROLL_DISTANCE = 16
+  TRAY_COLOR      = Color.white
+  SLIDER_COLOR    = Color.black
+  GRAB_COLOR      = HOVER_COLOR   # Cyan
+
+  attr_reader :slider_top
+
+  def initialize(x, y, size, viewport, horizontal = false, always_visible = false)
+    if horizontal
+      super(size, SLIDER_WIDTH, viewport)
+    else
+      super(SLIDER_WIDTH, size, viewport)
+    end
+    self.x = x
+    self.y = y
+    @horizontal     = horizontal   # Is vertical if not horizontal
+    @tray_size      = size   # Number of pixels the scrollbar can move around in
+    @slider_size    = size
+    @range          = size   # Total distance of the area this scrollbar is for
+    @slider_top     = 0      # Top pixel within @size of the scrollbar
+    @always_visible = always_visible
+    self.visible    = @always_visible
+  end
+
+  def position
+    return 0 if @range <= @tray_size
+    return (@range - @tray_size) * @slider_top / (@tray_size - @slider_size)
+  end
+
+  # Range is the total size of the large area that the scrollbar is able to
+  # show part of.
+  def range=(new_val)
+    raise "Can't set a scrollbar's range to 0!" if new_val == 0
+    @range = new_val
+    @slider_size = (@tray_size * [@tray_size.to_f / @range, 1].min).round
+    if @horizontal
+      @slider.width = @slider_size
+    else   # Vertical
+      @slider.height = @slider_size
+    end
+    self.slider_top = @slider_top
+    self.visible = (@always_visible || @range > @tray_size)
+    invalidate
+  end
+
+  def slider_top=(new_val)
+    old_val = @slider_top
+    @slider_top = new_val.clamp(0, @tray_size - @slider_size)
+    if @horizontal
+      @slider.x = @slider_top
+    else   # Vertical
+      @slider.y = @slider_top
+    end
+    invalidate if @slider_top != old_val
+  end
+
+  def set_interactive_rects
+    @interactions = {}
+    if @horizontal
+      @slider = Rect.new(@slider_top, WIDTH_PADDING, @slider_size, height - (WIDTH_PADDING * 2))
+    else   # Vertical
+      @slider = Rect.new(WIDTH_PADDING, @slider_top, width - (WIDTH_PADDING * 2), @slider_size)
+    end
+    @interactions[:slider] = @slider
+    @slider_tray = Rect.new(0, 0, width, height)
+    @interactions[:slider_tray] = @slider_tray
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def refresh
+    super
+    return if !self.visible
+    # Draw the tray
+    self.bitmap.fill_rect(@slider_tray.x, @slider_tray.y, @slider_tray.width, @slider_tray.height, TRAY_COLOR)
+    # Draw the slider
+    if @slider_size < @tray_size
+      bar_color = SLIDER_COLOR
+      if @captured_area == :slider || (!@captured_area && @hover_area == :slider)
+        bar_color = GRAB_COLOR
+      end
+      self.bitmap.fill_rect(@slider.x, @slider.y, @slider.width, @slider.height, bar_color)
+    end
+  end
+
+  #-----------------------------------------------------------------------------
+
+  def on_mouse_press
+    @captured_area = nil
+    mouse_x, mouse_y = mouse_pos
+    return if !mouse_x || !mouse_y
+    # Check for mouse presses on slider/slider tray
+    @interactions.each_pair do |area, rect|
+      next if !rect.contains?(mouse_x, mouse_y)
+      @captured_area = area
+      if area == :slider
+        if @horizontal
+          @slider_mouse_offset = mouse_x - rect.x
+        else
+          @slider_mouse_offset = mouse_y - rect.y
+        end
+      end
+      invalidate
+      break
+    end
+  end
+
+  def on_mouse_release
+    super if @captured_area
+  end
+
+  def update
+    return if !self.visible
+    super
+    # TODO: Disabled control stuff.
+#    return if self.disabled
+    if @captured_area == :slider
+      # TODO: Have a display y position for the slider bar which is in pixels,
+      #       and round it to the nearest row when setting @top_row? This is
+      #       just to make the slider bar movement smoother.
+      mouse_x, mouse_y = mouse_pos
+      return if !mouse_x || !mouse_y
+      long_coord = (@horizontal) ? mouse_x : mouse_y
+      self.slider_top = long_coord - @slider_mouse_offset
+    elsif @captured_area == :slider_tray
+      if Input.repeat?(Input::MOUSELEFT) && @hover_area == :slider_tray
+        mouse_x, mouse_y = mouse_pos
+        return if !mouse_x || !mouse_y
+        long_coord = (@horizontal) ? mouse_x : mouse_y
+        if long_coord < @slider_top
+          self.slider_top = @slider_top - ((@tray_size - @slider_size) / 4.0).ceil
+        else
+          self.slider_top = @slider_top + ((@tray_size - @slider_size) / 4.0).ceil
+        end
+      end
+    else
+      mouse_x, mouse_y = mouse_pos
+      if mouse_x && mouse_y && @interactions[:slider_tray].contains?(mouse_x, mouse_y)
+        wheel_v = Input.scroll_v
+        if wheel_v > 0   # Scroll up
+          self.slider_top -= SCROLL_DISTANCE
+        elsif wheel_v < 0   # Scroll down
+          self.slider_top += SCROLL_DISTANCE
+        end
+      end
+    end
+  end
+end