ZoomPictureBox: picture control with mouse-centred zooming

[boops boops]

Hi Paul, welcome to VBForums.

The ZoomPictureBox allows you to set the Image to Nothing and to call its Invalidate method in much the same way as a PictureBox. In both cases, the image source file remains locked. The safest way to avoid this is to read the image as a Stream instead of opening it with Image.FromFile(filename) or New Bitmap(filename).

    Using stream As IO.Stream = IO.File.OpenRead(filename)
         ZoomPictureBoxName.Image = Image.FromStream(stream)
      End Using

The source file is closed at the end of the Using block, so you are free to delete it independently of the image.

BB

[davidgarnett]

I would like to contact the author of this library. I'm using the library in an application and need some information that I hope he can provide

[.paul.]

I would like to contact the author of this library. I'm using the library in an application and need some information that I hope he can provide

BoopsBoops is the author of this software. This thread is the place to ask your questions

[davidgarnett]

BoopsBoops is the author of this software. This thread is the place to ask your questions

Paul,

Thank you for your reply ... I'm new to VBForums. I thought I replied with my question to this thread.

If I didn't, please let me know how to reply.

[.paul.]

Paul,

Thank you for your reply ... I'm new to VBForums. I thought I replied with my question to this thread.

If I didn't, please let me know how to reply.

Yeah you're posting in the right place, but you haven't given any details with your comment. Boops Boops will need to know what it is you need to know....

[davidgarnett]

Yeah you're posting in the right place, but you haven't given any details with your comment. Boops Boops will need to know what it is you need to know....

There is no license information for ZPLib that I can find. Can the developer associate a license with the library? ... perhaps MIT?

[boops boops]

There is no license information for ZPLib that I can find. Can the developer associate a license with the library? ... perhaps MIT?

That question applies to any code library, not just ZPLib. And it's not something I know much about. Please address your question to another forum such as Visual Basic .Net or C#.

BB

[Delaney]

Boops Boops, I think Davidgarnett want to know what is the license associated with your library/class to know if he can use it freely or not in his own applications.

[boops boops]

As far as I know all code posted in the CodeBank is unlicensed, so you are free use it however you like. if you include the code in a licensed project, it would be polite to add a comment referring to this thread or to my authorship. BB

[john_g33]

Hello, thank you for providing such great code.
Unfortunately, the main post directs to post #75 to get the February 2019 version, but post #75 redirects back to the main post, which are two zip files, both from 2012, none of them with the newly added "DragMargin" property. There may have been a mix-up when editing posts. Would it be possible for OP to upload the new version? Thanks a lot.

[boops boops]

Hi John, you are right. When I posted the last link nearly 3 years ago, I intended move it to post #1 where anyone could find it. But I discovered some errors and never got around to fixing them. Life got in the way... And then a month ago - even worse - I decided to clear out what seemed to be obsolete links in the thread. I forgot that the link in post #1 wasn't updated. What a mess: it took me quite a while to sort it out but now at least I have a new version with the following changes:

1. SafeMargin works OK.
2. The two separate files for the ZoomPictureBox class (Main and Properties) are now merged into one. Separating them seemed like a good idea at first but no longer.
3. The panning and zooming for very large images works smoothly, but they can be very slow to load. There must be a better way. And very large images seem prone to throw OutOfMemory exceptions in Visual Studio 2022. That will take some work
4. There was a problem with transparent backgrounds. I don't know if anyone noticed but it's fixed now.

Here's an interim version of the ZoomPictureBox Class you may care try out:
ZoomPictureBox_Jan2022.vb
Questions, suggestions and criticism are welcome.

BB

[nkvb]

Dear Boops Boops, The authour of this thread
After downloading the files as per the instructions. I was so much thrilled as this was required
Indeed Great work and remarkable achievement.

Then i tried to develop an application but below coding generates error
in ZoomPictureBox_Main1 DoubleClick Event and btnGetFrontImg_Click Event

I've marked in Coding with Red mark and also pointed out the Error messages in quotes

Will appreciate your help for the right corrections as i am using vb.net VS2019

Public Class ZoomingMovingImages

    Private _BaseImage As Image
    Private _AddImage As Image

    Public EmptyBitmapSize As New Size(500, 500)

    Private Sub ZoomingMovingImages_Load(sender As Object, e As EventArgs) Handles MyBase.Load
      Call FormLayout()
    End Sub

    Private Sub FormLayout()
        'Set the PictureBox and ZoomPictureBox properties:
        PictureBox1.SizeMode = PictureBoxSizeMode.AutoSize
        PictureBox1.BorderStyle = BorderStyle.Fixed3D
        ZoomPictureBox_Main1.Parent = PictureBox1
        ZoomPictureBox_Main1.BackColor = Color.Transparent
        ZoomPictureBox_Main1.BorderStyle = BorderStyle.None
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle

        Dim zRect As Rectangle = ZoomPictureBox_Main1.ClientRectangle 'ZoomPictureBox1.ClientRectangle
        Dim bmp As New Bitmap(zRect.Width, zRect.Height)
        ZoomPictureBox_Main1.DrawToBitmap(bmp, zRect) 'ZoomPictureBox1.DrawToBitmap(bmp, zRect)

    End Sub

    Private Sub PictureBox1_SizeChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle
    End Sub

    Private Sub ZoomPictureBox_Main1_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles ZoomPictureBox_Main1.DoubleClick
        PictureBox1.Image = SuperimposeImage(_BaseImage, _AddImage, ZoomPictureBox_Main1.ImagePosition, ZoomPictureBox_Main1.ZoomFactor)
        ZoomPictureBox_Main1.ImagePosition = New Point(ZoomPictureBox_Main1.ImagePosition.X - 2, ZoomPictureBox_Main1.ImagePosition.Y - 2)
        Cursor.Position = New Point(Cursor.Position.X - 2, Cursor.Position.Y - 2)
    End Sub


    'Get an image from file or an empty bitmap:
    Private Function GetImage(ByVal currentImage As Image, ByVal emptyBitmapSize As Size, ByVal caption As String) As Image
        Dim bmp As Bitmap
        If currentImage Is Nothing Then
            bmp = New Bitmap(emptyBitmapSize.Width, emptyBitmapSize.Height)
        Else
            bmp = New Bitmap(currentImage)
        End If
        Using ofd As New OpenFileDialog
            ofd.Title = caption
            If ofd.ShowDialog = Windows.Forms.DialogResult.OK Then
                Try
                    bmp = New Bitmap(ofd.FileName)
                Catch
                    MessageBox.Show("Invalid image file " & ofd.FileName)
                End Try
            End If
        End Using
        Return bmp
    End Function
    Private Function SuperimposeImage(ByVal baseImage As Image, ByVal addImage As Image, ByVal location As Point, ByVal zoomFactor As Double) As Image
        If baseImage IsNot Nothing AndAlso addImage IsNot Nothing Then
            Using g As Graphics = Graphics.FromImage(baseImage)
                g.DrawImage(addImage, location.X, location.Y,
                  CInt(addImage.Width * zoomFactor),
                  CInt(addImage.Height * zoomFactor))
            End Using
        End If
        Return baseImage
    End Function

    Private Sub SaveImage(ByVal img As Image)
        Using sfd As New SaveFileDialog
            sfd.Filter = "Image Files (*.png, *.jpg)|*.png;*.jpg"
            If sfd.ShowDialog = Windows.Forms.DialogResult.OK Then
                If sfd.FileName.ToUpper.EndsWith("PNG") Then
                    _BaseImage.Save(sfd.FileName, Imaging.ImageFormat.Png)
                ElseIf sfd.FileName.ToUpper.EndsWith("JPG") Then
                    _BaseImage.Save(sfd.FileName, Imaging.ImageFormat.Jpeg)
                Else
                    MessageBox.Show("Please give a PNG or JPG extension. Other formats are not yet supported.")
                End If
            End If
        End Using
    End Sub

    Private Sub btnGetImgFile_Click(sender As Object, e As EventArgs) Handles btnGetImgFile.Click
        _BaseImage = GetImage(PictureBox1.Image, EmptyBitmapSize, "Select base image")
        PictureBox1.Image = _BaseImage
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle
    End Sub

    Private Sub btnGetFrontImg_Click(sender As Object, e As EventArgs) Handles btnGetFrontImg.Click
        _AddImage = GetImage(ZoomPictureBox_Main1.Image, EmptyBitmapSize, "Select zoomable image")
        ZoomPictureBox_Main1.Image = _AddImage

    End Sub
End Class

I get Totally 8 errors

ie below single single
Handles ZoomPictureBox_Main1.DoubleClick : Handle Clause requires a with events variable defined in the containing type or one of its base types

and below 7 with repeated messages in respective lines of syntaxes
ImagePosition is is not a member of ZoomPictureBox_Main1
ZoomFactor is not a member of ZoomPictureBox_Main1
Image is is not a member of ZoomPictureBox_Main1

Thankx
nkvb

[nkvb]

Boops Boops

I've succeeded in resolving the issues as per #92.

Wherever Errors cropping up have marked in RED and Underlined

But now I am not able to access ZPBLib
Imports ZPBlib GreenLine displaying under ZPBlib Although ZPBlib Project file Exists in Solution Explorer

Now I've error coming up BC42025: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated at following line in below code

Also GreenLine dispalying ZoomPictureBox_Main1.ZoomType

'Below Trackbar I've used to Zoom the ZoomPicturebox

Imports ZPBlib
Public Class ZoomingMovingImages

    Private _BaseImage As Image
    Private _AddImage As Image

    Public EmptyBitmapSize As New Size(500, 500)

    Private Sub ZoomingMovingImages_Load(sender As Object, e As EventArgs) Handles MyBase.Load
      Call FormLayout()
    End Sub

    Private Sub FormLayout()
        'Set the PictureBox and ZoomPictureBox properties:
        PictureBox1.SizeMode = PictureBoxSizeMode.AutoSize
        PictureBox1.BorderStyle = BorderStyle.Fixed3D
        ZoomPictureBox_Main1.Parent = PictureBox1
        ZoomPictureBox_Main1.BackColor = Color.Transparent
        ZoomPictureBox_Main1.BorderStyle = BorderStyle.None
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle

        Dim zRect As Rectangle = ZoomPictureBox_Main1.ClientRectangle 'ZoomPictureBox1.ClientRectangle
        Dim bmp As New Bitmap(zRect.Width, zRect.Height)
        ZoomPictureBox_Main1.DrawToBitmap(bmp, zRect) 'ZoomPictureBox1.DrawToBitmap(bmp, zRect)

    End Sub

    Private Sub PictureBox1_SizeChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle
    End Sub

    Private Sub ZoomPictureBox_Main1_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles ZoomPictureBox_Main1.DoubleClick
        PictureBox1.Image = SuperimposeImage(_BaseImage, _AddImage, ZoomPictureBox_Main1.ImagePosition, ZoomPictureBox_Main1.ZoomFactor)
        ZoomPictureBox_Main1.ImagePosition = New Point(ZoomPictureBox_Main1.ImagePosition.X - 2, ZoomPictureBox_Main1.ImagePosition.Y - 2)
        Cursor.Position = New Point(Cursor.Position.X - 2, Cursor.Position.Y - 2)
    End Sub


    'Get an image from file or an empty bitmap:
    Private Function GetImage(ByVal currentImage As Image, ByVal emptyBitmapSize As Size, ByVal caption As String) As Image
        Dim bmp As Bitmap
        If currentImage Is Nothing Then
            bmp = New Bitmap(emptyBitmapSize.Width, emptyBitmapSize.Height)
        Else
            bmp = New Bitmap(currentImage)
        End If
        Using ofd As New OpenFileDialog
            ofd.Title = caption
            If ofd.ShowDialog = Windows.Forms.DialogResult.OK Then
                Try
                    bmp = New Bitmap(ofd.FileName)
                Catch
                    MessageBox.Show("Invalid image file " & ofd.FileName)
                End Try
            End If
        End Using
        Return bmp
    End Function
    Private Function SuperimposeImage(ByVal baseImage As Image, ByVal addImage As Image, ByVal location As Point, ByVal zoomFactor As Double) As Image
        If baseImage IsNot Nothing AndAlso addImage IsNot Nothing Then
            Using g As Graphics = Graphics.FromImage(baseImage)
                g.DrawImage(addImage, location.X, location.Y,
                  CInt(addImage.Width * zoomFactor),
                  CInt(addImage.Height * zoomFactor))
            End Using
        End If
        Return baseImage
    End Function

    Private Sub SaveImage(ByVal img As Image)
        Using sfd As New SaveFileDialog
            sfd.Filter = "Image Files (*.png, *.jpg)|*.png;*.jpg"
            If sfd.ShowDialog = Windows.Forms.DialogResult.OK Then
                If sfd.FileName.ToUpper.EndsWith("PNG") Then
                    _BaseImage.Save(sfd.FileName, Imaging.ImageFormat.Png)
                ElseIf sfd.FileName.ToUpper.EndsWith("JPG") Then
                    _BaseImage.Save(sfd.FileName, Imaging.ImageFormat.Jpeg)
                Else
                    MessageBox.Show("Please give a PNG or JPG extension. Other formats are not yet supported.")
                End If
            End If
        End Using
    End Sub

    Private Sub btnGetImgFile_Click(sender As Object, e As EventArgs) Handles btnGetImgFile.Click
        _BaseImage = GetImage(PictureBox1.Image, EmptyBitmapSize, "Select base image")
        PictureBox1.Image = _BaseImage
        ZoomPictureBox_Main1.Bounds = PictureBox1.ClientRectangle
    End Sub

    Private Sub btnGetFrontImg_Click(sender As Object, e As EventArgs) Handles btnGetFrontImg.Click
        _AddImage = GetImage(ZoomPictureBox_Main1.Image, EmptyBitmapSize, "Select zoomable image")
        ZoomPictureBox_Main1.Image = _AddImage

    End Sub

Private Sub ZoomSlider_Scroll(sender As Object, e As EventArgs) Handles ZoomSlider.Scroll

    ZoomPictureBox_Main1.EnableMouseWheelZooming = False
    ZoomPictureBox_Main1.EnableMouseDragging = False

    ZoomPictureBox_Main1.ZoomMode = ZoomPictureBox_Main1.ZoomType.ControlCenter

        If ZoomSlider.Value = 1 Then ZoomPictureBox_Main1.ZoomFactor = 1
        If ZoomSlider.Value = 2 Then ZoomPictureBox_Main1.ZoomFactor = 1.25
        If ZoomSlider.Value = 3 Then ZoomPictureBox_Main1.ZoomFactor = 1.5
        If ZoomSlider.Value = 4 Then ZoomPictureBox_Main1.ZoomFactor = 2
        If ZoomSlider.Value = 5 Then ZoomPictureBox_Main1.ZoomFactor = 2.5

End Sub
End Class

Some Observations when trackbar scrolled No Doubt ZoomPictureBox_Main1 Displays all the images with respective zoomFactor
and does not resemble as if zooming because smaller to larger all the images zoomed sized are displayed. How can all these Images with zoomed sized be cleared and resemble as Zooming

your guidance and help shall be appreciated

nkvb