Redraw images when lost focus

[Bloged]

He everyone!

I'm using this function to draw images on my pictureBox

Dim gr As Graphics = pctBox.CreateGraphics
gr.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)

As you know when you minimize your application all those things you drew on it are gone so I searched for the GotFocus or something and found/created this:

Public Sub frmMain_Activated(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Activated
        Dim iLoop, iX, iY As Integer
 
        For iLoop = 0 To 29
            iX = Coordinate2Pixel(pioPion(iLoop).GetCoordinateX())
            iY = Coordinate2Pixel(pioPion(iLoop).GetCoordinateY())
 
            Dim gr As Graphics = pctBox.CreateGraphics
            gr.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)
        Next
End Sub

To draw them back whenever my app lost focus... Now does this work when I popup an messagebox... but not when I minimize & maximize my application anyone with good ideas?!

Thnx in advance,

Bloged

[MrPolite]

Originally posted by Bloged
He everyone!

I'm using this function to draw images on my pictureBox

Dim gr As Graphics = pctBox.CreateGraphics
gr.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)

As you know when you minimize your application all those things you drew on it are gone so I searched for the GotFocus or something and found/created this:

Public Sub frmMain_Activated(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Activated
        Dim iLoop, iX, iY As Integer
 
        For iLoop = 0 To 29
            iX = Coordinate2Pixel(pioPion(iLoop).GetCoordinateX())
            iY = Coordinate2Pixel(pioPion(iLoop).GetCoordinateY())
 
            Dim gr As Graphics = pctBox.CreateGraphics
            gr.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)
        Next
End Sub

To draw them back whenever my app lost focus... Now does this work when I popup an messagebox... but not when I minimize & maximize my application anyone with good ideas?!

Thnx in advance,

Bloged

two answers: you can make the image to stay forever if you draw it on the picturebox's image.

instead of
Dim gr As Graphics = pctBox.CreateGraphics
you could use
Dim gr As Graphics = Graphics.FromImage(pctBox.Image)
This way the actual image contained within the picturebox will be modified. You will only have to draw the grahpics ONCE and wont need to call your code again.


other way: if for some other reason you need to use the method that you are using right now (Grahpics.CreateGrahpics), you should put your code in the Paint event of your picturebox. The paint even is fired everytime the control is to be redrawn. Put this code in the Paint event of pctBox:
e.Graphics.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)

notice the e.Graphics.... in the paint event a graphics object is provided already so you dont need to make your own graphics object.

[Bloged]

Thanks MrPolite

Will try it as soon as I'm home!


Edit:
Tried it here with an simple test... But it won't work it looks like it redraws them but then 'removes' them directly after... (Same thing happend when using frmMain_Activated).

Any ideas


Grtz,

Bloged

[MrPolite]

hmm post the code you have in the paint event. You're not clearing or refreshing the form or anything ?

[Bloged]

Sorry for the delay but here is the code I'm using:

'If map is (redraw) draw the pions back on it
Private Sub pctMap_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pctMap.Paint
    'If game is started
    If booStarted = True Then
        Map.DrawAllPions(pioPion, pctMap)
    End If
End Sub

and the DrawAllPions function:

'(Re)draws all the pions on the map
Public Shared Function DrawAllPions(ByRef pioPion() As Pion, ByVal pctBox As PictureBox)
    Dim iLoop, iX, iY As Integer
 
    For iLoop = 0 To 29
        iX = Coordinate2Pixel(pioPion(iLoop).GetCoordinateX())
        iY = Coordinate2Pixel(pioPion(iLoop).GetCoordinateY())
 
        Dim gr As Graphics = pctBox.CreateGraphics
        gr.DrawImage(New Bitmap("c:\pion.gif"), iX, iY)
    Next
End Function

Grtz,

Bloged

[Bloged]

*bump*

Anyone?

Grtz,

Bloged