I did a resizeable picture box as an user control some time ago. The picture box (= user control) maintains it's size, but you can zoom in and out the image with Zoom property.
Option Explicit On
Option Strict On
Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
Public Class CPictureBox
Inherits ScrollableControl
'--------------------------------------------------------
' CPictureBox.vb
'--------------------------------------------------------
'--------------------------------------------------------
' CPictureBox Control
'--------------------------------------------------------
'--------------------------------------------------------
' Copyright © 2007-2008 xxx
'
' Language: Visual Basic 2005.NET
'
' Version: 1.0.0
'
' Created: 10.12.2007 xxx
'
' Modified: 29.4.2008 xxx
'--------------------------------------------------------
'--------------------------------------------------------
' Public data
'--------------------------------------------------------
'--------------------------------------------------------
' Private data
'--------------------------------------------------------
Private m_Image As Image
Private m_Zoom As Single = 1.0F
Private m_InterpolationMode As InterpolationMode = InterpolationMode.High
'--------------------------------------------------------
' Private procedures
'--------------------------------------------------------
Private Sub InitComponent()
'
' Init component
'
Try
Me.SetStyle(ControlStyles.AllPaintingInWmPaint Or ControlStyles.UserPaint Or ControlStyles.ResizeRedraw Or ControlStyles.UserPaint Or ControlStyles.DoubleBuffer, True)
Me.AutoScroll = True
'Me.BackColor = Color.White
m_InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High
m_Zoom = 1.0!
m_Image = Nothing
Catch ex As Exception
End Try
End Sub
Private Sub UpdateScaleFactor()
'
' Update scale factor
'
Try
If m_Image Is Nothing Then
Me.AutoScrollMargin = Me.Size
Else
Me.AutoScrollMinSize = New Size(CInt(Me.m_Image.Width * m_Zoom + 0.5F), CInt(Me.m_Image.Height * m_Zoom + 0.5F))
End If
Catch ex As Exception
End Try
End Sub
'--------------------------------------------------------
' Event handlers
'--------------------------------------------------------
Public Sub New()
'
' Initialize
'
Try
InitComponent()
Catch ex As Exception
End Try
End Sub
Protected Overrides Sub Finalize()
'
' Terminate control
'
Try
MyBase.Finalize()
Catch ex As Exception
End Try
End Sub
Protected Overrides Sub OnPaintBackground(ByVal e As PaintEventArgs)
'
' Do nothing
'
Try
' Do nothing
Catch ex As Exception
End Try
End Sub
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
'
' If no image, don't bother
'
Try
If m_Image Is Nothing Then
MyBase.OnPaintBackground(e)
Exit Sub
End If
' Set up a zoom matrix
Dim mx As New Matrix(m_Zoom, 0, 0, m_Zoom, 0, 0)
mx.Translate(Me.AutoScrollPosition.X / m_Zoom, Me.AutoScrollPosition.Y / m_Zoom)
e.Graphics.Transform = mx
e.Graphics.InterpolationMode = m_InterpolationMode
e.Graphics.DrawImage(m_Image, New Rectangle(0, 0, Me.m_Image.Width, Me.m_Image.Height), 0, 0, m_Image.Width, m_Image.Height, GraphicsUnit.Pixel)
MyBase.OnPaint(e)
Catch ex As Exception
End Try
End Sub
'--------------------------------------------------------
' Public procedures
'--------------------------------------------------------
''' <summary>
''' Sets or gets the image in CPictureBox
''' </summary>
''' <value>Image</value>
''' <returns>Image</returns>
''' <remarks></remarks>
Public Property Image() As Image
'
Get
Return m_Image
End Get
Set(ByVal value As Image)
m_Image = value
If m_Image IsNot Nothing Then
If m_Image.Height > 0 Then
m_Zoom = CSng(Me.Height / m_Image.Height)
Else
m_Zoom = 1.0!
End If
End If
UpdateScaleFactor()
Invalidate()
End Set
End Property
''' <summary>
''' Sets or gets the zoom factor
''' </summary>
''' <value>Zoom factor</value>
''' <returns>Zoom factor</returns>
''' <remarks>Zoom factor should be between 0-5</remarks>
Public Property Zoom() As Single
'
Get
Return m_Zoom
End Get
Set(ByVal value As Single)
If value < 0 OrElse value < 0.00001 Then
value = 0.00001F
End If
m_Zoom = value
UpdateScaleFactor()
Invalidate()
End Set
End Property
''' <summary>
''' Sets or gets the interpolation mode used in the drawing
''' </summary>
''' <value>System.Drawing.Drawing2D.InterpolationMode</value>
''' <returns>System.Drawing.Drawing2D.InterpolationMode</returns>
''' <remarks></remarks>
Public Property InterpolationMode() As InterpolationMode
' The interpolation mode used to smooth the drawing
Get
Return m_InterpolationMode
End Get
Set(ByVal value As InterpolationMode)
m_InterpolationMode = value
End Set
End Property
End Class
Haven't used the control for a while and it surely misses features :) But I hope that the zooming functionality helps you.
The code was written with VB 2005 and VB 2008 may have some of the functionality "built-in".
