Hi

I recently learnt how to do crash collision based on colours. So you can use something like img.getpixel(0,0) to retrieve the colour of the pixel at (0,0) on the picture "img." I have experimented quite a lot with it and have managed to make some programs that draw a rectangular box the same colour as the pixel on an image I am highlighting.

How do you do the same to a polygon or a rectangle. I can't seem to be able to use the getpixel command with any sort of shape, though for the purposes of my program I would like to. Is there any way for this or do I have to use an image for colour detection?

Thanks

Hi,

Here's an example how to create an Ellipse and show the same color as the pixel color.

Public Class Form1

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

    End Sub

    Private Sub PictureBox1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseClick
        PictureBox1.Image = My.Resources. your picturename
        Dim TempBitmap As New Bitmap(PictureBox1.Image)
        MyColor = TempBitmap.GetPixel(e.X, e.Y)
        Me.Invalidate()
        End Sub
    
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

        Dim g As Graphics = e.Graphics
        Dim brs As SolidBrush
        brs = New SolidBrush(MyColor)
        g.FillEllipse(brs, 20, 20, 50, 50)
        
    End Sub
End Class

Edited 6 Years Ago by Luc001: n/a

Hi

Sorry, I was probably a bit ambiguous, but thanks for posting anyway. What I meant was that I could get a colour from another picture and draw a shape based on this colour. What I want to be able to do is get a colour from a SHAPE (which is filled with a colour) and use this for crash collision. I know what to do except for how to get a colour from a shape.

getpixel only seems to get colours from a picture, not a shape unfortunatly.

Thanks

Hi,

Here's a way how to detect the color in a shape.
Add a label to show the color.

Public Class Form1
    Public path As New System.Drawing.Drawing2D.GraphicsPath
    Public thecolor As Color = Color.Aqua
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        path.AddEllipse(20, 160, 50, 50)

    End Sub

    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        If path.IsVisible(e.X, e.Y) Then
            Label1.BackColor = thecolor
        End If
    End Sub
    
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim brl As SolidBrush
        brl = New SolidBrush(thecolor)
        e.Graphics.FillPath(brl, path)
                
    End Sub
End Class
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