How avoid flickering using powerpacks

Question

Hi , I have a problem using power packs. I set in a panel about 70 rectangle shape and when I try to update their "label" , there is a little flickering. Can you help me to avoid this behaviour ? Here my sample code

Imports System.Drawing

Public Class Form1

 Dim arrTavoli(-1) As MyRectangleWithText
 Dim i As Integer = 0
 Dim shapeContainer1 As New Microsoft.VisualBasic.PowerPacks.ShapeContainer

 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
  For i As Integer = 0 To 96
   AvvaloraTavolo(i, i Mod 12, Math.Floor(i / 12))
  Next
  PanelControl1.Controls.Add(shapeContainer1)
 End Sub

 Sub AvvaloraTavolo(ByVal i As Integer, ByVal intRiga As Integer, ByVal intcolonna As Integer)
  ReDim Preserve arrTavoli(i)
  arrTavoli(i) = New MyRectangleWithText
  arrTavoli(i).Location = New Point(intRiga * 50, intcolonna * 50)
  arrTavoli(i).Size = New Drawing.Size(50, 50)
  arrTavoli(i).Visible = True
  arrTavoli(i).Text = "Tav " & i & Environment.NewLine & " T.0"
  arrTavoli(i).FillColor = Color.AliceBlue
  arrTavoli(i).FillStyle = PowerPacks.FillStyle.Solid
  shapeContainer1.Shapes.Add(arrTavoli(i))
 End Sub



 Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
  i += 1
  i = i Mod 96
  For j As Integer = 0 To 95
   arrTavoli(j).Text = "Tav " & j & Environment.NewLine & " T." & i * j
   arrTavoli(i).FillColor = Color.FromArgb(-i * j)

  Next
 End Sub

 Private Sub SimpleButton2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SimpleButton2.Click
  Dim _frm2 As New Form2
  _frm2.ShowDialog()
 End Sub
End Class

---

Carlo

Answer 1

How do you implement the MyRectangleWithText class. This could be the cause I guess, I played your code without the text, works OK to me (You can try to remove the text and see if there is a difference).

And how bad is the flickering? On the full form or in the rectangle.

 

---

John Chen

Answer 2

Sorry for my delay

I forgot to write myRectanglewithtext class. Here you are

Imports System.Drawing

Public Class MyRectangleWithText
  Inherits PowerPacks.RectangleShape

  Private FText As String = String.Empty

  Private FFont As Font = Nothing

  Private FTextLocation As Point = New Point(0, 0)

  Private FTextColour As Color = Color.Black

  Private CanDrawText As Boolean = False

  Public Property Text() As String

    Get

      Return FText

    End Get

    Set(ByVal value As String)

      FText = value

      RedrawText()

    End Set

  End Property


  Public Property Font() As Font

    Get

      Return FFont

    End Get

    Set(ByVal value As Font)

      FFont = value

      RedrawText()

    End Set

  End Property


  Public Property TextLocation() As Point

    Get

      Return FTextLocation

    End Get

    Set(ByVal value As Point)

      FTextLocation = value

      RedrawText()

    End Set

  End Property


  Public Property TextColor() As Color

    Get

      Return FTextColour

    End Get

    Set(ByVal value As Color)

      FTextColour = value

      RedrawText()

    End Set

  End Property


  Private Sub RedrawText()

    CanDrawText = FText <> String.Empty AndAlso FFont IsNot Nothing

    If CanDrawText Then Invalidate()

  End Sub


  Private Sub MyRectangleWithText_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

    If Not CanDrawText Then Exit Sub

    Dim g As Graphics = e.Graphics

    g.DrawString(FText, FFont, New SolidBrush(FTextColour), Location.X + FTextLocation.X, Location.Y + FTextLocation.Y)

    Me.FillColor = Me.FillColor
  End Sub


  Public Sub New()
    Me.Font = New Font("Tahoma", 10)
  End Sub

End Class

The flickering is in the set of rectangle . It seems like a white flash

Thanks

---

Carlo

Answer 3

It seems you can simply use a Label (instead of you own Retangle with Text control) to achieve what you are doing:

Like this code, where in the form assuming you have a Panel1 control as the container control.

Public Class Form1

    Dim arrTavoli(-1) As Label
    Dim i As Integer = 0

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        For i As Integer = 0 To 96
            AvvaloraTavolo(i, i Mod 12, Math.Floor(i / 12))
        Next
        Timer1.Start()
    End Sub

    Sub AvvaloraTavolo(ByVal i As Integer, ByVal intRiga As Integer, ByVal intcolonna As Integer)
        ReDim Preserve arrTavoli(i)
        arrTavoli(i) = New Label
        arrTavoli(i).Location = New Point(intRiga * 50, intcolonna * 50)
        arrTavoli(i).Size = New Drawing.Size(50, 50)
        arrTavoli(i).Visible = True
        arrTavoli(i).Text = "Tav " & i & Environment.NewLine & " T.0"
        arrTavoli(i).BackColor = Color.AliceBlue
        Panel1.Controls.Add(arrTavoli(i))
    End Sub

    Private Sub Timer1_Tick_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        i += 1
        i = i Mod 96
        For j As Integer = 0 To 95

            arrTavoli(j).Text = "Tav " & j & Environment.NewLine & " T." & i * j
            arrTavoli(i).BackColor = Color.FromArgb(-i * j)
        Next
    End Sub
End Class

  

---

John Chen

Answer 4

Yes , It works, but I choose power packs because they are clickable, I can choose between oval and rectangle shape...

In this way how can I display an ellipse?

---

Carlo