Vital gauges control

require("CLRPackage")
--
import("System.Drawing")
import("System.Drawing.Drawing2D")
import("System.Drawing.Text")
import("System.Windows.Forms")
--
gauges = {}
--
function gauges.ctor( loc ) -- application object creator
    --
    -- private variables
    --
    local self = {} -- method and property container.

    local pos = loc or Point( 10, 10 ) -- control starting location in parent container.

    local this = GroupBox() -- display surface.

    local bars = {} -- bar values savearea.

    local pointerLocation  = Point( 0, 0 ) -- current location of the mouse pointer.
    local clientPosition   = Point( 0, 0 ) -- current location of control relative to the parent.
    local adjustedLocation = Point( 0, 0 ) -- resultant control location after move.

    local current, cIndex = {}, 0 -- this stack is used to maintain the cursor being used.

    local moving = false -- if set, the control is being dragged.

    local sf = StringFormat() -- text formatter for our percentage values.

    sf.Alignment     = StringAlignment.Far  -- set horizontal alignment.
    sf.LineAlignment = StringAlignment.Near -- set vertical alignment.

    local textFont = Font( "Miriam Fixed", 12, GraphicsUnit.Pixel ) -- percentage font.

    local hpRect = Rectangle( Point( 10, 20 ), Size( 100, 10 ) ) -- hp    bar
    local mnRect = Rectangle( Point( 10, 40 ), Size( 100, 10 ) ) -- mana  bar
    local mvRect = Rectangle( Point( 10, 60 ), Size( 100, 10 ) ) -- moves bar

    local barRect = { hp = hpRect, mn = mnRect, mv = mvRect } -- reference table for bar rectangles.

    local hptRect = RectangleF( PointF( 115, 20 ), SizeF( 30, 10 ) ) -- hp    pct
    local mntRect = RectangleF( PointF( 115, 40 ), SizeF( 30, 10 ) ) -- mana  pct
    local mvtRect = RectangleF( PointF( 115, 60 ), SizeF( 30, 10 ) ) -- moves pct

    local textRect = { hp = hptRect, mn = mntRect, mv = mvtRect } -- reference table for text rectangles.

    local colors = {
                        Color.DodgerBlue   -- value is over  100%
                       ,Color.SpringGreen  -- value is over   75%
                       ,Color.Yellow       -- value is over   50%
                       ,Color.Orchid       -- value is over   25%
                       ,Color.Red          -- value is under  26%
                   }
    --
    -- private methods
    --
    local function getIndex( value ) -- determine which color to use to paint the bar.

               if type( value ) == "number" then
                   local i = 5
                   if value > 100 then i = 1
                      elseif value > 75 then i = 2
                          elseif value > 50 then i = 3
                              elseif value > 25 then i = 4
                   end
                   return i
               else
                    return nil
               end

          end

    local function move( p ) -- This function moves the control while it is being dragged.

               if self.Movable then
                   local r = this.Parent.ClientRectangle
                   local x, y = p.X, p.Y
                   if x > r.Right  - this.Width  then x = r.Right  - this.Width  end
                   if y > r.Bottom - this.Height then y = r.Bottom - this.Height end
                   if x < r.Left then x = r.Left end
                   if y < r.Top  then y = r.Top  end
                   this.Location = Point ( x, y ) -- relocate control to new position.
               end

          end

    local function parent_Resize( sender, e )

               move( this.Location ) -- make sure the control stays within the parent visible area.

          end

    local function gauges_MouseDown( sender, e )

               if self.Movable then
                   if e.Button == MouseButtons.Left then
                       cIndex = cIndex + 1 -- update stack pointer.
                       current[cIndex] = this.Cursor -- push current cursor into stack.
                       this.Cursor = Cursors.SizeAll -- show move cursor.
                       pointerLocation = e.Location -- remember where the mouse pointer is.
                       this.ForeColor = Color.FromArgb( 255, 224, 224, 224 )
                       this.BackColor = Color.FromArgb( 255, 105, 105, 105 )
                       moving = true
                   end
               end

          end

    local function gauges_MouseEnter( sender, e )

               if self.Movable then
                   cIndex = cIndex + 1 -- update stack pointer.
                   current[cIndex] = this.Cursor -- push current cursor into stack.
                   this.Cursor = Cursors.Hand -- display hand cursor as draggable hint.
               end

          end

          local function gauges_MouseLeave( sender, e )

               if self.Movable then
                   if cIndex > 0 then
                       this.Cursor = current[cIndex] -- pop stack and restore cursor.
                       cIndex = cIndex - 1 -- update stack pointer.
                   end
               end

          end

          local function gauges_MouseMove( sender, e )

               if self.Movable then
                   if moving then
                       clientPosition   = this.Parent:PointToClient( Cursor.Position )
                       adjustedLocation = Point( clientPosition.X - pointerLocation.X, clientPosition.Y - pointerLocation.Y )
                       move( adjustedLocation ) -- move the control while the mouse pointer is in motion.
                   end
               end

          end

    local function gauges_MouseUp( sender, e )

               if self.Movable then
                   if cIndex > 0 then
                       this.Cursor = current[cIndex] -- pop stack and restore cursor.
                       cIndex = cIndex - 1 -- update stack pointer.
                   end
                   if moving then
                       moving = false -- indicate dragging has stopped.
                       this.ForeColor = Color.White
                       this.BackColor = Color.Black
                       this:Invalidate( false ) -- force the repainting of the control.
                   end
               end

          end

    local function gauges_Paint( sender, e )

              local g = e.Graphics -- fetch the graphics object for this control.

              for k, w in pairs( bars )
                    do
                        local i = getIndex( w ) -- obtain color index.
                            if i then
                                if w > 100 then w = 100 end -- take care of possible overflow.
                                local r1 = Rectangle.FromLTRB( barRect[k].Left,     barRect[k].Top, barRect[k].Left + w, barRect[k].Bottom )
                                local r2 = Rectangle.FromLTRB( barRect[k].Left + w, barRect[k].Top, barRect[k].Right,    barRect[k].Bottom )
                                g:FillRectangle( SolidBrush( colors[i] ),  r1 ) -- paint the active bar segment.
                                g:FillRectangle( SolidBrush( Color.Gray ), r2 ) -- paint the unused bar segement.
                                g:DrawString( tostring( bars[k] ), textFont, SolidBrush( colors[i] ), textRect[k], sf )
                            end
                    end

              g:Dispose() -- destroy graphics object.

          end

    local function gauges_ParentChanged( sender, e )

               pcall( function() this.Parent.Resize:Add( parent_Resize ) end )
               -- piggyback on the parent's resize event if it has one.
          end
    --
    -- public methods
    --
    function self.setBars( data )
        -- data is a table containing one or more k/v pairs representing the value for a bar.
        if type( data ) == "table" then
            for k, v in pairs( data )
                do
                    bars[k] = v -- stow the bar value
                end
            this:Invalidate( false ) -- force the repainting of the control.
        end

    end

    this:SuspendLayout()
    --
    -- GroupBox
    --
    this.AutoSize  = false
    this.BackColor = Color.Black
    this.Dock      = DockStyle.None
    this.Font      = Font( "Lucinda Console", 8.25 )
    this.FlatStyle = FlatStyle.Standard
    this.ForeColor = Color.White
    this.Location  = pos
    this.Name      = "gauges"
    this.Size      = Size( 160, 83 )
    this.TabIndex  = 0
    this.Text      = "Vitals"

    this.MouseDown:Add( gauges_MouseDown )

    this.MouseEnter:Add( gauges_MouseEnter )

    this.MouseLeave:Add( gauges_MouseLeave )

    this.MouseMove:Add( gauges_MouseMove )

    this.MouseUp:Add( gauges_MouseUp )

    this.Paint:Add( gauges_Paint )

    this.ParentChanged:Add( gauges_ParentChanged )
    --
    --
    --
    this:ResumeLayout(false)

    self.Control = this -- publish a reference to the control

    self.Movable = true -- allow control relocation as default.

    return self

end
--
setmetatable( gauges, { __call = function( _, ... ) return gauges.ctor( ... ) end } )