Zoom picturebox with static edges (for report)

[projecttoday]

My report is an image in a picturebox. I want it so if the user clicks on it it will zoom larger --- while the picturebox remains the same size. That's important. The examples I've found for picturebox zooming cause the picturebox to get bigger and smaller. I need it to be like an Access report. Click on the report and it gets bigger. Click again and it goes back to the full image. Of cours when you're zoomed in, the perimeter of the report is not visible. So I'd like to be able to drag the image as well so the unseen portions can be seen. Does anyone know of an example or tutorial in VB.Net for this type of picturebox function?

[.paul.]

here's a custom control that zooms the image when you doubleclick it + allows you to drag the image.
needs a bit more work on the location after resizing:

Imports System.Runtime.InteropServices
 
Public Class dragMoveZoomPicturebox
    Inherits Panel
 
    <DllImport("user32.dll")> _
    Public Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
    End Function
 
    <DllImport("user32.dll")> _
   Public Shared Function ReleaseCapture() As Boolean
    End Function
 
    Private Const WM_NCLBUTTONDOWN As Integer = &HA1
    Private Const HTCAPTION As Integer = 2
 
    Dim standard As Size
 
    Private WithEvents pb1 As New PictureBox
 
    Private _image As Image
    Public Property Image() As Image
        Get
            Return _image
        End Get
        Set(ByVal value As Image)
            _image = value
            pb1.Image = _image
        End Set
    End Property
 
    Public Sub New()
        MyBase.BorderStyle = Windows.Forms.BorderStyle.FixedSingle
        MyBase.Controls.Add(pb1)
        pb1.SizeMode = PictureBoxSizeMode.AutoSize
    End Sub
 
    Private Sub pb1_MouseDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles pb1.MouseDoubleClick
        If pb1.SizeMode = PictureBoxSizeMode.AutoSize Then
            standard = pb1.Size
            Dim p As Point = pb1.Location
            pb1.SizeMode = PictureBoxSizeMode.StretchImage
            pb1.Size = New Size(CInt(standard.Width * 1.5), CInt(standard.Height * 1.5))
            pb1.Location = New Point(CInt(p.X * 1.5), CInt(p.Y * 1.5))
        Else
            pb1.SizeMode = PictureBoxSizeMode.AutoSize
            pb1.Size = standard
        End If
    End Sub
 
    Private Sub pb1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles pb1.MouseMove
        If e.Button = Windows.Forms.MouseButtons.Left Then
            ReleaseCapture()
            SendMessage(pb1.Handle, WM_NCLBUTTONDOWN, HTCAPTION, 0)
        End If
    End Sub
 
End Class

[projecttoday]

I'm looking for code that will work with a picturebox.

[boops boops]

Put the PictureBox inside a Panel and set the Panel's AutoScroll property to True. Then use one of the methods you already have for zooming the picture box complete with the image. Only the part of the PictureBox which is inside the panel will be visible. The panel will show scroll bars when necessary to allow the image to be scrolled.

BB

[.paul.]

I'm looking for code that will work with a picturebox.

my custom control is a picturebox inside a panel

[projecttoday]

I tried putting the picture in a panel and made the changes in the program but there's a problem. When the picturebox is clicked the previous image on the upsized picturebox is upsized correctly but it is cut off on the right and on the bottom.

Now the picturebox is inside a panel. On clicking the picturebox, the height and width of the picturebox are doubled, causing scroll bars to appear, and the contents of the picture box are regenerated with an adjusted font size and adjusted coordinates. The part that does appear is correct. But it is cut off on the right and on the bottom.

This is the code that prints one of the lines which is cutoff on the right:

            Try
                gr.DrawString(text, New Font(printFont, printFontSize, printfontstyle, GraphicsUnit.Pixel), printbrush, xadjusted, yadjusted)
            Finally
                gr.Dispose()
            End Try

The field text contains a string of characters. In the upsized picturebox the text from text gets cut off on the right. It's cutoff about 4/5 of the way over. The area that's okay is still larger that the original picturebox. That's what's so strange about it. The original report prior to clicking the picturebox appears okay. Any idea why it's doing this? Unless I'm wrong, the DrawString prints the given text at the given coordinate. There is no end point specified. Why should it just quit at some point?

[boops boops]

@ProjectToday. (EDIT) What happens when you leave out the Try-End Try? It may be masking some coding error. Apart from that, it will be hard to help without seeing more code and maybe a screenshot.

@.Paul. Of course, the method I mentioned is similar in broad respects to your class: a PictureBox in a Panel. The main difference is that I suggest using the Panel scroll bars instead of Interop to drag the picture box. It may not work as smoothly in some circumstances but it is simpler.



BB

[projecttoday]

I took a look at .Paul.'s post but was concerned about trying something which he says "needs a bit more work".

Unfortunately when I took out Try, End, Finally the result was the same. This is the subroutine which prints the line which is cut off on the right

    Private Sub Println(ByVal text As String, ByVal x As Single, ByVal y As Single, _
        ByVal printFont As String, ByVal printfontstyle As FontStyle, _
        ByVal fontsize As Single, ByVal brushcolor As Color, _
        ByVal printstatus As String, ByVal gr As Graphics, ByVal ev As PrintPageEventArgs)
        Dim printbrush As Brush      
        printbrush = New SolidBrush(brushcolor)

        Dim printFontSize As Double, xadjusted As Single, yadjusted As Single
        If printstatus = "preview" Then
            ' the parameters must be adjusted to fit the size of the output
            printFontSize = fontsize * dRatio         'scale font size for picture box
            xadjusted = x * dRatio
            yadjusted = y * dRatio
            'Try
            gr.DrawString(text, New Font(printFont, printFontSize, printfontstyle, GraphicsUnit.Pixel), printbrush, xadjusted, yadjusted)
            'Catch exc As Exception
            'MsgBox(exc.Message)
            'Finally
            'gr.Dispose()
            'End Try
        ElseIf printstatus = "print" Then
            Dim prntfont As Font = New System.Drawing.Font(printFont, fontsize, _
                System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
            ev.Graphics.DrawString(text, prntfont, printbrush, x, y)
        End If
        printbrush.Dispose()
    End Sub

This is the line which calls it

            Println(str, 2.84 * pointsperinch, 0.6 * pointsperinch, "Eras Bold ITC", _
                FontStyle.Regular, 18, namecolor, printstatus, Graphics.FromImage(bmp), ev)

str contains "abcdefghijklmnopqrstuvwxyz1234567890" and this appears in the picturebox before the upsizing. After the upsizing only abcdefghijklmnopqrstuvwxyz12" appears even though there's plenty of room for the rest of it and the full string makes it into the subroutine (I checked). The entire rest of the document is cut off at that same point and it is also cut off at the bottom.

2.84 is the number of inches from the left the line appears (on the actual paper) and 0.8 is the number of inches from the top the line appears.

[boops boops]

Are you sure the bitmap is getting resized correctly to match the PictureBox when you zoom it? You could check that quickly by giving the bitmap a contrasting background colour. For example, you could add this line for testing purposes (before gr.DrawString):

gr.Clear(Color.Red)

I have to come back on my suggestion of using the Panel scrollbars to scroll the PictureBox. I haven't been able to get it to work really well -- the scrollbars themselves cause lots of jerking and flashing. So it would be better to drag the PictureBox with the mouse, and that comes down to practically the same as .Paul's method (although there are other ways of dragging). I suspect a "bit more work" refers the adjustments needed to keep the Image centred reliably during zooming.

In fact I already have made a custom image zoom/pan control. Everything works perfectly, including zooming to the cursor position. At present it's overcomplicated (too many options) but I think I could boil it down to essentials. Zooming and dragging are done by changing the size and position of a rectangle, and the image is painted into that rectangle. Let me know if you are interested.

BB

[.paul.]

I suspect a "bit more work" refers the adjustments needed to keep the Image centred reliably during zooming.

yep. spot on

[projecttoday]

The red does the same thing. It's cut off on the side and the bottom.

This picturebox was actually downsized once earlier. The original was a larger form. I decided to reduce the size of the form and the picture box and because the code multiplies everything by a scaling factor it worked. But the image is too small to see detail. So I decided to add a click to upsize it. The current viewable area of the upsized image looks suspiciously like the size of the old/original picturebox.

In any case it must be a setting somewhere but I can't find it. I am not at all expert in VB.Net drawing code.

The scroll bars are working fine.

Also, the hard copy print works fine.

[boops boops]

The red does the same thing. It's cut off on the side and the bottom.

This picturebox was actually downsized once earlier. The original was a larger form. I decided to reduce the size of the form and the picture box and because the code multiplies everything by a scaling factor it worked. But the image is too small to see detail. So I decided to add a click to upsize it. The current viewable area of the upsized image looks suspiciously like the size of the old/original picturebox.

In any case it must be a setting somewhere but I can't find it. I am not at all expert in VB.Net drawing code.

The scroll bars are working fine.

Also, the hard copy print works fine.

Well I'm sorry, I can't find it either. I wonder why? BB

[projecttoday]

Thanks for trying.

Anybody?

[boops boops]

I'm sorry if I was sarcastic. I have to guess that you are using the bitmap as the PictureBox.Image. It's clear that your bitmap is smaller than you expect. You haven't said how you are resizing the PictureBox or how you are setting the size of the bitmap. How can anyone debug that if you don't show the relevant code?

The normal (simple) approach is to set the PictureBox.SizeMode to AutoSize and zoom by changing the size of its Image. Have you tried it that way?

BB

[projecttoday]

Autosize didn't work. I'm doing my own zooming and it works. It's just cut off for some reason. This is the code

        Picturebox1.Height =* 2
       standardratio = 8.5 / 11.0
        pictureboxheight = PictureBox1.Height
        PictureBox1.Width = pictureboxheight * standardratio
        pointsperinch = 98
        'scale the report on the screen to an 8.5 by 11 sheet of paper
        dRatio = (pictureboxheight / pointsperinch) / 11.0

[boops boops]

1. where are you changing the size of the bitmap?
2. what is the SizeMode of the PictureBox?
BB

[projecttoday]

1. Everywhere. Everything, including the fonts, gets multiplied by dRatio.
2. Normal

[boops boops]

1. Everywhere. Everything, including the fonts, gets multiplied by dRatio.

Everywhere? That's tough, because it's where you need to look to find what you are doing wrong. My psychic debugging powers have run out for today. If you want someone to help you, I suggest you take the time to figure out what code shows exactly what you are doing and post it. BB

[boops boops]

You may find it interesting to try out the ZoomPictureBox control I have just posted to the VB.Net code bank. The approach is clearly different from what you are doing but maybe it would serve your purposes. BB

[Promocom]

I made this in VB6 that sounds like what you want to do... maybe you can convert it to .net?

[projecttoday]

Thanks for your trouble but my form is basically working except for some reason the drawing is clipped off. When I get a chance I'm going to recreate the whole thing, checking it along the way, and that will probably solve the problem. In the meantime I'm using a zoom factor of 1.5 instead of 2.