how to zoom in the image inside a scrollable panel in vb - vb.net

Question

I have a scrollable panel with an image/picture box inside.
I wanted to zoom in and zoom out the image without the buttons disappearing on the lower left of the panel. by the way, the image is in it's actual size.
If I make it a scrollable panel that can be zoomed in and out, will i still be able to get the coordinates of the image by not using the coordinates of the screen but the coordinates of the actual image?
Pls help me

Answer 1

I'm not sure what you mean by
zoom in and zoom out the image without the buttons disappearing
But you can use this control created by Bob Powell. His site seems to be offline now but I found this code:
Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
Namespace bobpowell.net
'/ <summary>
'/ ZoomPicBox does what it says on the wrapper.
'/ </summary>
'/ <remarks>
'/ PictureBox doesn't lend itself well to overriding. Why not start with something basic and do the job properly?
'/ </remarks>
Public Class ZoomPicBox
Inherits ScrollableControl
Private _image As Image
<Category("Appearance"), Description("The image to be displayed")> _
Public Property Image() As Image
Get
Return _image
End Get
Set
_image = value
UpdateScaleFactor()
Invalidate()
End Set
End Property
Private _zoom As Single = 1F
<Category("Appearance"), Description("The zoom factor. Less than 1 to reduce. More than 1 to magnify.")> _
Public Property Zoom() As Single
Get
Return _zoom
End Get
Set
If value < 0 OrElse value < 1E-05 Then
value = 1E-05F
End If
_zoom = value
UpdateScaleFactor()
Invalidate()
End Set
End Property
Private Sub UpdateScaleFactor()
If _image Is Nothing Then
Me.AutoScrollMargin = Me.Size
Else
Me.AutoScrollMinSize = New Size(CInt(Me._image.Width * _zoom + 0.5F), CInt(Me._image.Height * _zoom + 0.5F))
End If
End Sub 'UpdateScaleFactor
Private _interpolationMode As InterpolationMode = InterpolationMode.High
<Category("Appearance"), Description("The interpolation mode used to smooth the drawing")> _
Public Property InterpolationMode() As InterpolationMode
Get
Return _interpolationMode
End Get
Set
_interpolationMode = value
End Set
End Property
Protected Overrides Sub OnPaintBackground(pevent As PaintEventArgs)
End Sub 'OnPaintBackground
' do nothing.
Protected Overrides Sub OnPaint(e As PaintEventArgs)
'if no image, don't bother
If _image Is Nothing Then
MyBase.OnPaintBackground(e)
Return
End If
'Set up a zoom matrix
Dim mx As New Matrix(_zoom, 0, 0, _zoom, 0, 0)
mx.Translate(Me.AutoScrollPosition.X / _zoom, Me.AutoScrollPosition.Y / _zoom)
e.Graphics.Transform = mx
e.Graphics.InterpolationMode = _interpolationMode
e.Graphics.DrawImage(_image, New Rectangle(0, 0, Me._image.Width, Me._image.Height), 0, 0, _image.Width, _image.Height, GraphicsUnit.Pixel)
MyBase.OnPaint(e)
End Sub 'OnPaint
Public Sub New()
'Double buffer the control
Me.SetStyle(ControlStyles.AllPaintingInWmPaint Or ControlStyles.UserPaint Or ControlStyles.ResizeRedraw Or ControlStyles.UserPaint Or ControlStyles.DoubleBuffer, True)
Me.AutoScroll = True
End Sub 'New
End Class 'ZoomPicBox
End Namespace 'bobpowell.net