[RESOLVED] Why does rotated Transparent image is not saved at its rotated degree with bg image

[nkvb]

Hello

Why does rotated Transparent image is not saved at its rotated degree with background image below it ?
Why does the following does not save as combination of two images into One ?

Able to rotate the Transparent image in Picturebox1. How to save the same as modfied/Rotated image with desired degree ?

1.) First of all How do i save the Transparent image(.PNG) with rotated as desired degree ?

2.) I've also loaded another picture(.JPG) in Picturebox1 to represent as background.

Ultimately the Transparent image rotates above the represented Background image

I was trying to save both the images but only the represented Background Image is Saved and not with Transparent image.
Why does Transparent Image which is on top of represented Background image does not get saved ?

Public Class Frm
Private imgTransp As String = "C:\Images\imgTrans.png"
Private myBGimg As String = "C:\BG-Images\BgImg1.JPG"


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

Private Sub FormLayout()
        PictureBox1.Size = New Size(800, 700)  
        PictureBox1.Image = Image.FromFile(imgTransp)
        PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
End Sub

Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
  Dim dgr As Double
  If dgr = 360 Then dgr = 0
     dgr += Val(txtBxDegrees.Text) 
     PictureBox1.Invalidate()    
  
  With e.Graphics
            .TranslateTransform(PictureBox1.Width \ 2, PictureBox1.Height \ 2)
            .RotateTransform(CSng(dgr))
            Dim imgBmp = New Bitmap(imgTransp)
            imgBmp = ResizeImage(imgBmp, PictureBox1.Width, PictureBox1.Height)
            .DrawImage(imgBmp, -imgBmp.Width \ 2, -imgBmp.Height \ 2)
           'above rotating Transparent image
'Below Background Image 
            Dim newImgBmp = New Bitmap(myBGimg)
            newImgBmp = ResizeImage(newImgBmp, PictureBox1.Width, PictureBox1.Height)
            .DrawImage(newImgBmp, newImgBmp.Width, newImgBmp.height)
        End With

End Sub

Public Shared Function ResizeImage(ByVal InputBitmap As Bitmap, width As Integer, height As Integer) As Bitmap
        Return New Bitmap(InputBitmap, New Size(width, height))
End Function

I am completely lost here because First of all How to save the Rotated(at desired degree) Transparent image(.PNG) over the background image
Display both the images ie Rotated Image with Background in Picturebox1 and save as ".JPG"

The below saves only the background image because I thought Image or combination of images in Picture1Box will save as is.

Private Sub btnSaveImg_Click(sender As Object, e As EventArgs) Handles btnSaveRotatedImg.Click

     Dim savedPath As String = "C:\SavedImages"
     Dim modifiedImage As New Bitmap(PictureBox1.Width, PictureBox1.Height)
     Dim gr As Graphics = Graphics.FromImage(modifiedImage)

     modifiedImage = PictureBox1.Image
     PictureBox1.Image.Save(savedPath & "\" & txtBxSaveFileName.Text & ".JPG", Drawing.Imaging.ImageFormat.JPG)

End Sub

What would be your take in saving both the images into one into which format?

I went thru. the following links which i thought i could get insights and implement the appropriate but somehow did not succeed
Stackoverflow:combing Two Images 1
Vbforums:Rotaing Picture Saving it 2
Vbforums: Overlapping images 3

Thanks
nkvb

[.paul.]

You’re painting an overlay image ON your picturebox. I advised you not to do that…

[nkvb]

.Paul
You’re painting an overlay image ON your picturebox. I advised you not to do that…

Agreed. Revised code below completely removed that part in Paint_Event

Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
  Dim dgr As Double
  If dgr = 360 Then dgr = 0
     dgr += Val(txtBxDegrees.Text) 
     PictureBox1.Invalidate()    
  
  With e.Graphics
            .TranslateTransform(PictureBox1.Width \ 2, PictureBox1.Height \ 2)
            .RotateTransform(CSng(dgr))
            Dim imgBmp = New Bitmap(imgTransp)
            imgBmp = ResizeImage(imgBmp, PictureBox1.Width, PictureBox1.Height)
            .DrawImage(imgBmp, -imgBmp.Width \ 2, -imgBmp.Height \ 2)
           'above rotating Transparent image
        End With
End Sub

Why is the rotated image not being taken into a/c when saving it
How do i save the image with desired degree rotated ?

nkvb

[.paul.]

Painting ON the PictureBox is NOT the same as painting on a Bitmap IN the PictureBox

Don't even touch the PictureBox1_Paint eventhandler. This is how to do it...

Public Class Form3

    Dim dgr As Single = 0
    Dim img1 As Bitmap = Nothing

    Private Sub txtBxDegrees_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtBxDegrees.TextChanged
        Dim s As Single
        If Single.TryParse(txtBxDegrees.Text, s) Then
            If dgr = 360 Then dgr = 0
            dgr += s

            img1 = New Bitmap([your background image path])
            img1 = ResizeImage(img1, PictureBox1.Width, PictureBox1.Height)
            Dim gr As Graphics = Graphics.FromImage(img1)
            
            With gr
                .TranslateTransform(PictureBox1.Width \ 2, PictureBox1.Height \ 2)
                .RotateTransform(dgr)
                Dim img2 = New Bitmap([your foreground image path])
                img2 = ResizeImage(img2, PictureBox1.Width, PictureBox1.Height)
                .DrawImage(img2, -img2.Width, -img2.height)
            End With

            PictureBox1.Image = img1
        End If
    End Sub

    Public Shared Function ResizeImage(ByVal InputBitmap As Bitmap, ByVal width As Integer, ByVal height As Integer) As Bitmap
        Return New Bitmap(InputBitmap, New Size(width, height))
    End Function

    Private Sub btnSaveImg_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSaveRotatedImg.Click

        Dim savedPath As String = "C:\SavedImages"
        If Not img1 Is Nothing Then
            img1.Save(savedPath & "\" & txtBxSaveFileName.Text & ".JPG", Drawing.Imaging.ImageFormat.JPG)
        End If

    End Sub

End Class

[nkvb]

.Paul

Indeed more clarity has been explained. You are right Sir,

Painting ON the PictureBox is NOT the same as painting on a Bitmap IN the PictureBox

Don't even touch the PictureBox1_Paint eventhandler. This is how to do it...

Before implementing your code with TextChanged Event.

the doubt raised Why TextChanged Event ?

Won't the Front image(img2) rotate as per the ADDED numeric value in txtBxdegrees.Text
Deep Observation made here is
for eg
When I enter 9 the img2 moves to 9 degrees then enter 0 to make it 90 the Img2 rotates to 99 degrees. Instead of rotating to 90. You may check
Then ones clear the textbox and Enter 45 it rotates to 144 ie (99+45=144) instead of rotating back to 0 degrees and then to 45

FYI as per Paint Event, which I've deleted now, above comments were not existing. You have empty textbox then img2 to rotate back to 0 degrees.

Can we control this ?

Saved One image with above oversight added degrees rotation and observation was made after that

nkvb

[.paul.]

dgr isn't reset to 0 when you clear your textbox

[nkvb]

dgr isn't reset to 0 when you clear your textbox

This is my first time coming across .TryParse. Did Explore many examples but was not successful
I tried in the below following manner

    If Single.TryParse(txtBxDegrees.Text, s) Then
            If String.IsNullOrEmpty(txtBxDegrees.Text) Then
                dgr = 0
            Else
                dgr += s 
            End If
      ......
   End if

nkvb

[.paul.]

If Single.TryParse(txtBxDegrees.Text, s) Then
    dgr += s

    img1 = New Bitmap([your background image path])
    img1 = ResizeImage(img1, PictureBox1.Width, PictureBox1.Height)
    Dim gr As Graphics = Graphics.FromImage(img1)
            
    With gr
        .TranslateTransform(PictureBox1.Width \ 2, PictureBox1.Height \ 2)
        .RotateTransform(dgr)
        Dim img2 = New Bitmap([your foreground image path])
        img2 = ResizeImage(img2, PictureBox1.Width, PictureBox1.Height)
        .DrawImage(img2, -img2.Width, -img2.height)
    End With

    PictureBox1.Image = img1
Else
    dgr = 0 
End If

[nkvb]

.Paul Sir

Thank you so much for helping me for resolving my issue

Thank you once more.

nkvb