asked on

Add zoom to picturebox

Hi,
How add a functionality of zoom in and out on picturebox in vb.net (desktop).
Code for adding image to picturebox

 Protected Friend Sub ScaleImage(ByVal p As PictureBox, ByVal i As Bitmap)
        Try
         
        
            p.SizeMode = PictureBoxSizeMode.AutoSize
            p.Image = i

            FrmMain.Panel1.AutoScroll = True


        Catch ex As Exception
            MessageBox.Show(ex.ToString)
        End Try




    End Sub

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Misha

Try this code:

Public Class Form1

    Private _originalSize As Size = Nothing
    Private _scale As Single = 1
    Private _scaleDelta As Single = 0.0005

    Private Sub Form_MouseWheel(sender As System.Object, e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseWheel

        'if very sensitive mouse, change 0.00005 to something even smaller   
        _scaleDelta = Math.Sqrt(PictureBox1.Width * PictureBox1.Height) * 0.00005

        If e.Delta < 0 Then
            _scale -= _scaleDelta
        ElseIf e.Delta > 0 Then
            _scale += _scaleDelta
        End If

        If e.Delta <> 0 Then _
        PictureBox1.Size = New Size(CInt(Math.Round(_originalSize.Width * _scale)), _
                                    CInt(Math.Round(_originalSize.Height * _scale)))

    End Sub

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
        If PictureBox1.Image IsNot Nothing Then
            PictureBox1.Size = Panel1.Size
            _originalSize = Panel1.Size
        End If
    End Sub
End Class

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Source:
https://stackoverflow.com/questions/13496706/how-to-zoom-in-a-picturebox-with-scrollwheel-in-vb-net

Chinmay Patel

Hi RIAS,

Are you using Winforms or WPF? Also you want to Zoom In/Out using Mouse wheel or buttons?

Regards,
Chinmay.

RIAS

ASKER

Hi,
I am using winforms vb.net desktop 2017.
On a button click it willbe great!

RIAS

ASKER

Misha,Thanks that code doesnt work for me.

Misha

What does not work? What is the errors?

RIAS

ASKER

The image just disappear on mouse roll event

Misha

Set properties

 PictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom
Panel1.AutoScroll = True

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and try this code with buttons:

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        PictureBox1.Height *= 1.2
        PictureBox1.Width *= 1.2
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        PictureBox1.Height *= 0.8
        PictureBox1.Width *= 0.8
    End Sub

    Private Sub PictureBox1_LoadCompleted(sender As Object, e As System.ComponentModel.AsyncCompletedEventArgs) Handles PictureBox1.LoadCompleted
        PictureBox1.Height = PictureBox1.Image.Height
        PictureBox1.Width = PictureBox1.Image.Width
    End Sub
End Class

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