将放大的图像保存在图片框中？

Question

I'm a newbie in vb.net (windows app) programming. How can I save a zoomed image in a picturebox.

See, I have a panel and put a picturebox (set to zoom) inside and set the panel to autoscroll to accomodate the size of the image. I can zoom in and out of the image. I can save the picture as is using a memorystream and save it to the database (access). But the thing I don't know is how to save the current size of the image to the size and current position of the image relative to the size of the panel.

This is what my project looks like. See I can load an image and save the picture as is to the database.

What my project looks like

My question is, how to save the current location and size relative to the panel size of the image if I zoom it?

How to save this image and resize the picturebox to the size of the panel and the current location of the zoomed image and the image itself

I hope you understand my question (sorry if my english is bad, it is not my native language).

------edit------

UPDATE: I was able to save the zoomed image from the picturebox inside the panel. I used @dr.null and @jtxkopt suggestion and it works somehow. BUT the problem is, the output has also drawn the scrollbars on the panel.

Output: This is my current output

This is my code:

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    SaveFileDialog1.Filter = "Image Files|*.jpg; *.png; *.bmp"
    Panel3.HorizontalScroll.Visible = False
    Panel3.VerticalScroll.Visible = False
    If SaveFileDialog1.ShowDialog = DialogResult.OK Then
        Dim imageRectangle = New Rectangle(Point.Empty, picUser.Image.Size)
        Dim safeCropRectangle = Rectangle.Intersect(imageRectangle, Panel3.DisplayRectangle)
        Dim bmp As Bitmap = New Bitmap(Panel3.Width, Panel3.Height, picUser.Image.PixelFormat)
        Panel3.DrawToBitmap(bmp, safeCropRectangle)
        bmp.Save(SaveFileDialog1.FileName)
    End If
End Sub

What can I do to remove the scroll bars? I already used the panel.VerticalScroll.Visible = false before the lines of code but it doesn't work.

Answer 1

You can use the function DrawToBitmap to save modified image inside PictureBox. Follow the below procedure.

1. Create a new bitmap with the same size and Pixel Format as the picturebox.
2. Call the DrawToBitmap function of the picturebox.

For more details, examine the following example program.

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks
Imports System.Windows.Forms

Namespace PictureboxZoomSave
    Public Class MainForm
        Inherits Form

        Public Sub New()
            InitializeComponent()
        End Sub

        Private openFileDialog As OpenFileDialog = New OpenFileDialog()
        Private saveFileDialog As SaveFileDialog = New SaveFileDialog()
        Private image As Image

        Private Sub OpenImageButton_click(ByVal sender As Object, ByVal e As EventArgs)
            openFileDialog.Filter = "Image Files|*.jpg; *.png"

            If openFileDialog.ShowDialog() = DialogResult.OK Then
                If image IsNot Nothing Then image.Dispose()
                image = Image.FromFile(openFileDialog.FileName)
                pictureBox1.Image = image
            End If
        End Sub

        Private Sub SaveImageButton_click(ByVal sender As Object, ByVal e As EventArgs)
            saveFileDialog.Filter = "Image Files|*.jpg; *.png"

            If saveFileDialog.ShowDialog() = DialogResult.OK Then
                Dim bitmap As Bitmap = New Bitmap(pictureBox1.Width, pictureBox1.Height, image.PixelFormat)
                pictureBox1.DrawToBitmap(bitmap, New Rectangle(0, 0, pictureBox1.Width, pictureBox1.Height))
                bitmap.Save(saveFileDialog.FileName)
            End If
        End Sub

        <STAThread>
        Private Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            Application.Run(New MainForm())
        End Sub

        Private components As System.ComponentModel.IContainer = Nothing

        Protected Overrides Sub Dispose(ByVal disposing As Boolean)
            If disposing AndAlso (components IsNot Nothing) Then
                components.Dispose()
            End If

            MyBase.Dispose(disposing)
        End Sub

        Private Sub InitializeComponent()
            Me.pictureBox1 = New System.Windows.Forms.PictureBox()
            Me.OpenImageButton = New System.Windows.Forms.Button()
            Me.SaveImageButton = New System.Windows.Forms.Button()
            (CType((Me.pictureBox1), System.ComponentModel.ISupportInitialize)).BeginInit()
            Me.SuspendLayout()
            Me.pictureBox1.Location = New System.Drawing.Point(12, 12)
            Me.pictureBox1.Name = "pictureBox1"
            Me.pictureBox1.Size = New System.Drawing.Size(200, 191)
            Me.pictureBox1.TabIndex = 0
            Me.pictureBox1.TabStop = False
            Me.OpenImageButton.Location = New System.Drawing.Point(229, 12)
            Me.OpenImageButton.Name = "button1"
            Me.OpenImageButton.Size = New System.Drawing.Size(75, 23)
            Me.OpenImageButton.TabIndex = 1
            Me.OpenImageButton.Text = "Open"
            Me.OpenImageButton.UseVisualStyleBackColor = True
            AddHandler Me.OpenImageButton.Click, New System.EventHandler(AddressOf Me.OpenImageButton_click)
            Me.SaveImageButton.Location = New System.Drawing.Point(229, 42)
            Me.SaveImageButton.Name = "button2"
            Me.SaveImageButton.Size = New System.Drawing.Size(75, 23)
            Me.SaveImageButton.TabIndex = 2
            Me.SaveImageButton.Text = "Save"
            Me.SaveImageButton.UseVisualStyleBackColor = True
            AddHandler Me.SaveImageButton.Click, New System.EventHandler(AddressOf Me.SaveImageButton_click)
            Me.AutoScaleDimensions = New System.Drawing.SizeF(6F, 13F)
            Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
            Me.ClientSize = New System.Drawing.Size(800, 450)
            Me.Controls.Add(Me.SaveImageButton)
            Me.Controls.Add(Me.OpenImageButton)
            Me.Controls.Add(Me.pictureBox1)
            Me.Name = "PictureBoxZoomSave"
            Me.Text = "PictureBoxZoomSave"
            (CType((Me.pictureBox1), System.ComponentModel.ISupportInitialize)).EndInit()
            Me.ResumeLayout(False)
        End Sub

        Private pictureBox1 As System.Windows.Forms.PictureBox
        Private OpenImageButton As System.Windows.Forms.Button
        Private SaveImageButton As System.Windows.Forms.Button
    End Class
End Namespace

Answer 2

I understand that you need to crop the displayed region of a zoomed in image. If so, you can achieve that through many ways and techniques, DrawToBitmap is the easiest approach. Please note:

• Using the PictureBox draw method and size doesn't output the required result because it's size changes when you apply the zoom/scale factor. In other words, the result is either a smaller or bigger image of the original one according to the zoom factor.

• The output image size is the Panel client size (WYSIWYG).

Hence, you just need to do:

Dim imgRect = pnl.ClientRectangle
Dim bmp = New Bitmap(imgRect.Width, imgRect.Height, pbox.Image.PixelFormat)
pnl.DrawToBitmap(bmp, imgRect)
'Save it...

where pbox is the PictureBox and pnl is it's parent Panel .

That's it all if that is what you are after.