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 1, 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
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 = picSmall.Image
'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(picSmall.Width, picSmall.Height), 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
