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I have been trying to calculate the right side of my rectangle so that it avoids mouse going over a specific area within a picture box. This works fine when zoom factor is on, after zoom is increased right side becomes smaller than the Picturebox's width hence I can not move the mouse over the whole Picturebox area (this also happens when calculating the bottom of rectangle)

This is the code I have written, any help would be appreciated. PIC_SMALL_CLICK_1 function is where I do the calculations please advise, Thanks!

Public Class Form1
    Private selectedArea As Rectangle
    Private loadedImage As Image
    Private thumbnail As Image
    Private selectionColor As Color

    Public Sub New()
           InitializeComponent()
           loadedImage = My.Resources.UPsafety_e_citation_lg

           'the zoom area in the thumbnail
           selectedArea = New Rectangle(0, 0, 80, 60)
           tZoom.Value = 1

           resizePictureArea()
           updateZoom()
           frmMagnifier.Show()
    End Sub



    ''' <summary>
    ''' Stretches out a selected zoom area of an image
    ''' </summary>

    Private Function ZoomImage(ByVal input As Image, ByVal zoomArea As Rectangle, ByVal sourceArea As Rectangle) As Image
        Dim newBmp As New Bitmap(sourceArea.Width, sourceArea.Height)

        Using g As Graphics = Graphics.FromImage(newBmp)
            'high interpolation
            g.InterpolationMode = InterpolationMode.HighQualityBicubic

            g.DrawImage(input, sourceArea, zoomArea, GraphicsUnit.Pixel)
        End Using

        Return newBmp
    End Function

    ''' <summary>
    ''' Draws the selection rectangle on an image
    ''' </summary>
    Private Function MarkImage(ByVal input As Image, ByVal selectedArea As Rectangle, ByVal selectColor As Color) As Image
        Dim newImg As New Bitmap(input.Width, input.Height)

        Using g As Graphics = Graphics.FromImage(newImg)
            'Prevent using images internal thumbnail
            input.RotateFlip(RotateFlipType.Rotate180FlipNone)
            input.RotateFlip(RotateFlipType.Rotate180FlipNone)

            g.DrawImage(input, 0, 0)

            'Draw the selection rect
            Using p As New Pen(Brushes.Black, 4)
                g.DrawRectangle(p, selectedArea)
            End Using
        End Using

        Return DirectCast(newImg, Image)
    End Function

    ''' <summary>
    ''' Resizes an image
    ''' </summary>
    Private Function ResizeImage(ByVal input As Image, ByVal newSize As Size, ByVal interpolation As InterpolationMode) As Image
        Dim newImg As New Bitmap(newSize.Width, newSize.Height)

        Using g As Graphics = Graphics.FromImage(newImg)
            'Prevent using images internal thumbnail
            input.RotateFlip(RotateFlipType.Rotate180FlipNone)
            input.RotateFlip(RotateFlipType.Rotate180FlipNone)

            'Interpolation
            g.InterpolationMode = interpolation

            'Draw the image with the new dimensions
            g.DrawImage(input, 0, 0, newSize.Width, newSize.Height)

        End Using

        Return DirectCast(newImg, Image)
    End Function


    ''' <summary>
    ''' Calculates the opposite color of a given color. 
    ''' Source: 
    ''' </summary>
    ''' <param name="clr"></param>
    ''' <returns></returns>
    Private Function CalculateOppositeColor(ByVal clr As Color) As Color
        Return Color.FromArgb(255 - clr.R, 255 - clr.G, 255 - clr.B)
    End Function

    ''' <summary>
    ''' Constricts a set of given dimensions while keeping aspect ratio.
    ''' </summary>
    Private Function ShrinkToDimensions(ByVal originalWidth As Integer, ByVal originalHeight As Integer, ByVal maxWidth As Integer, ByVal maxHeight As Integer) As Size
        Dim newWidth As Integer = 0
        Dim newHeight As Integer = 0

        If originalWidth >= originalHeight Then
            'Match area width to max width
            If originalWidth <= maxWidth Then
                newWidth = originalWidth
                newHeight = originalHeight
            Else
                newWidth = maxWidth
                newHeight = originalHeight * maxWidth \ originalWidth
            End If
        Else
            'Match area height to max height
            If originalHeight <= maxHeight Then
                newWidth = originalWidth
                newHeight = originalHeight
            Else
                newWidth = originalWidth * maxHeight \ originalHeight
                newHeight = maxHeight
            End If
        End If

        Return New Size(newWidth, newHeight)
    End Function

    Private Sub resizePictureArea()
        'Create a thumbnail image (maintaining aspect ratio)

        Dim newSize As Size = ShrinkToDimensions(loadedImage.Width, loadedImage.Height, 160, 130)

        'use low interpolation
        'thumbnail = ResizeImage(loadedImage, New Size(newSize.Width, newSize.Height), InterpolationMode.Low)
        thumbnail = ResizeImage(loadedImage, New Size(400, 700), InterpolationMode.Low)

        picSmall.Invalidate()
    End Sub

    Private Sub updateZoom()
        If loadedImage IsNot Nothing Then
            'Map the area selected in the thumbail to the actual image size
            Dim zoomArea As New Rectangle()
            zoomArea.X = selectedArea.X * loadedImage.Width / thumbnail.Width
            zoomArea.Y = selectedArea.Y * loadedImage.Height / thumbnail.Height
            zoomArea.Width = selectedArea.Width * loadedImage.Width / thumbnail.Width
            zoomArea.Height = selectedArea.Height * loadedImage.Height / thumbnail.Height

            'Adjust the selected area to the current zoom value
            zoomArea.Width /= tZoom.Value
            zoomArea.Height /= tZoom.Value

            frmMagnifier.picZoom.Image = ZoomImage(loadedImage, zoomArea, frmMagnifier.picZoom.ClientRectangle)
            frmMagnifier.picZoom.Refresh()
        End If
    End Sub


    Private Sub tZoom_Scroll(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tZoom.Scroll
        updateZoom()
    End Sub

    Private Sub picSmall_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles picSmall.Click
        'Update the selected area when the user clicks on the thumbnail
        Dim mouseLoc As Point = picSmall.PointToClient(Cursor.Position)

        selectedArea.X = mouseLoc.X - ((selectedArea.Width / tZoom.Value) / 2)
        selectedArea.Y = mouseLoc.Y - ((selectedArea.Height / tZoom.Value) / 2)

        'Bound the box to the picture area bounds
        If selectedArea.Left < 0 Then
            selectedArea.X = 0
        ElseIf selectedArea.Right > picSmall.Width Then
            selectedArea.X = picSmall.Width - selectedArea.Width - 1
        End If

        If selectedArea.Top < 0 Then
            selectedArea.Y = 0
        ElseIf selectedArea.Bottom > picSmall.Height Then
            selectedArea.Y = picSmall.Height - selectedArea.Height - 1
        End If

        picSmall.Invalidate()
        updateZoom()
    End Sub

    Private Sub picSmall_Paint_1(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles picSmall.Paint
        If loadedImage IsNot Nothing Then
            'Adjust the selected area to reflect the zoom value
            Dim adjustedArea As New Rectangle()
            adjustedArea.X = selectedArea.X
            adjustedArea.Y = selectedArea.Y
            adjustedArea.Width = selectedArea.Width / tZoom.Value
            adjustedArea.Height = selectedArea.Height / tZoom.Value

            'Draw the selected area on the thumbnail
            picSmall.Image = MarkImage(thumbnail, adjustedArea, selectionColor)
        End If
    End Sub
End Class
Posted 27-Feb-14 15:24pm
DROB08350

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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