[VB6] - the Graphics Class

[joaquim]

heres my class on attachments files...
heres how use it:

Set ImageData = New Graphics
    ImageData.GetImageData Picture2
    ImageData.BackColor = vbYellow
    ImageData.Rotate = 45
    ImageData.Mirror = HorizontalVertical
    
    ImageData.DrawImageData Picture1, 40, 40
    Set ImageData = Nothing

i have 2 errors:
1 - the BackColor isn't changed and i don't see why

'change image backcolor
            If ImageDataChanged(X + 2, Y) <> clrBackColor.Red And ImageDataChanged(X + 1, Y) <> clrBackColor.Green And ImageDataChanged(X, Y) <> clrBackColor.Blue Then
                ImageDataChanged(X + 2, Y) = clrBackColor.Red
                ImageDataChanged(X + 1, Y) = clrBackColor.Green
                ImageDataChanged(X, Y) = clrBackColor.Blue
            End If

2 - by some reason the rotation values\results aren't corrected

For X = 0 To ByteAlignOnWord(bmi.bmHeader.bmBitCount, lngWidthImage) - 3 Step 3
        For Y = 0 To lngHeigthImage - 1
            'Rotate an image
            If lngRotate <> 0 Then
                RC = InvRotateCoord(X, Y, lngWidthImage / 2, lngHeigthImage / 2, lngRotate)
                If RC.RotatedX <= 0 Or RC.RotatedX >= bm.bmWidth Or RC.RotatedY <= 0 Or RC.RotatedY >= bm.bmHeight Then
                    'do nothing
                Else
                    ImageDataChanged(X + 2, Y) = ImageData(RC.RotatedX + 2, RC.RotatedY)
                    ImageDataChanged(X + 1, Y) = ImageData(RC.RotatedX + 1, RC.RotatedY)
                    ImageDataChanged(X, Y) = ImageData(RC.RotatedX, RC.RotatedY)
                    If RGB(ImageDataChanged(X + 2, Y), ImageDataChanged(X + 1, Y), ImageDataChanged(X, Y)) = &HFFFF Or X >= bm.bmWidth Or Y >= bm.bmHeight Then
                        ImageDataChanged(X + 2, Y) = clrOldBackColor.Red
                        ImageDataChanged(X + 1, Y) = clrOldBackColor.Green
                        ImageDataChanged(X, Y) = clrOldBackColor.Blue
                    End If
                End If
            Else
                ImageDataChanged(X + 2, Y) = ImageData(X + 2, Y)
                ImageDataChanged(X + 1, Y) = ImageData(X + 1, Y)
                ImageDataChanged(X, Y) = ImageData(X, Y)
            End If

ca anyone advice me?

[Jacob Roman]

Without having to download it, the backcolor doesnt change cause all 3 cases must pass in your If statement. So lets say the backcolor is black which is 0 0 0. Lets just let X and Y be just one pixel, at (0, 0). If ImageDataChanged(0 + 2, 0) is not equal to clrBackColor.Red And so on and so forth for Green and Blue, it won't change.

Also for rotation, be sure you are using radians and not degrees, and also be sure you are doing it from the center of the image when something like this:

Vertex(0).X = Center.X - Half_Img_Size.X: Vertex(0).Y = Center.Y - Half_Img_Size.Y
    Vertex(1).X = Center.X + Half_Img_Size.X: Vertex(1).Y = Center.Y - Half_Img_Size.Y
    Vertex(2).X = Center.X - Half_Img_Size.X: Vertex(2).Y = Center.Y + Half_Img_Size.Y
    Vertex(3).X = Center.X + Half_Img_Size.X: Vertex(3).Y = Center.Y + Half_Img_Size.Y
    
    New_Vertex(0).X = X + (Vertex(0).X * Cos(Angle * (PI / 180)) - Vertex(0).Y * Sin(Angle * (PI / 180)))
    New_Vertex(0).Y = Y + (Vertex(0).X * Sin(Angle * (PI / 180)) + Vertex(0).Y * Cos(Angle * (PI / 180)))
    
    New_Vertex(1).X = X + (Vertex(1).X * Cos(Angle * (PI / 180)) - Vertex(1).Y * Sin(Angle * (PI / 180)))
    New_Vertex(1).Y = Y + (Vertex(1).X * Sin(Angle * (PI / 180)) + Vertex(1).Y * Cos(Angle * (PI / 180)))
    
    New_Vertex(2).X = X + (Vertex(2).X * Cos(Angle * (PI / 180)) - Vertex(2).Y * Sin(Angle * (PI / 180)))
    New_Vertex(2).Y = Y + (Vertex(2).X * Sin(Angle * (PI / 180)) + Vertex(2).Y * Cos(Angle * (PI / 180)))
    
    New_Vertex(3).X = X + (Vertex(3).X * Cos(Angle * (PI / 180)) - Vertex(3).Y * Sin(Angle * (PI / 180)))
    New_Vertex(3).Y = Y + (Vertex(3).X * Sin(Angle * (PI / 180)) + Vertex(3).Y * Cos(Angle * (PI / 180)))

Well in this case I'm doing it as vertices. But I do have some old code to literally "Perspective Correct Texture Map" an image regardless of angle correctly, or you'll end up with cracks and holes. This scanlines the image from top to bottom. Unfortunately its in 3D in pure VB, but if you remove the Z's it'll still work in 2D for 2D rotation:

[Mikle]

joaquim
The procedure DrawImageData, when you call StretchDIBits bmi structure contains options of ImageData array, but must ImageDataChanged.

[joaquim]

joaquim
The procedure DrawImageData, when you call StretchDIBits bmi structure contains options of ImageData array, but must ImageDataChanged.

thanks. i found that error and more. that's why some properties results wasn't corrects lol.
thanks for the help my friend.
but what you can tell me about the rotation effect?
(if the rotate property is 0(zero), the image is showed normaly. and the other effects works normaly too. but what isn't right with our rotate effect?)

[joaquim]

heres the class updated... but with rotate problem
only, when, rotate diferent 0(zero), the bad results are showed. if the rotate is 0(zero), the image is showed normaly

[joaquim]

i think i know where is the error:

If lngRotate <> 0 Then
                RC = InvRotateCoord(X, Y, lngWidthImage / (3 * bmi.bmHeader.bmBitCount) / 2, lngHeigthImage / 2, lngRotate)
                If RC.RotatedX < 0 Or RC.RotatedX >= bm.bmWidth Or RC.RotatedY < 0 Or RC.RotatedY >= bm.bmHeight Then
                    'do nothing
                Else
                    ImageDataChanged(X + 2, Y) = ImageData(RC.RotatedX / (3 * bmi.bmHeader.bmBitCount) + 2, RC.RotatedY)
                    ImageDataChanged(X + 1, Y) = ImageData(RC.RotatedX / (3 * bmi.bmHeader.bmBitCount) + 1, RC.RotatedY)
                    ImageDataChanged(X, Y) = ImageData(RC.RotatedX / (3 * bmi.bmHeader.bmBitCount), RC.RotatedY)
                End If

Private Function ByteAlignOnWord(ByVal bitDepth As Byte, ByVal Width As Long) As Long
    ' function to align any bit depth on dWord boundaries
    ByteAlignOnWord = (((Width * bitDepth) + &H1F&) And Not &H1F&) \ &H8&
End Function

because i know that x limite isByteAlignOnWord(bmi.bmHeader.bmBitCount, lngWidthImage), i must found X0(center of X) and then convert it, i belive. that's why i have the bad results. any advices for fix these problem?

[joaquim]

for test: can anyone explain to me how can i use normal X,Y positions... without RGB way?
(normal 2D array)