rotation

[jayantkumble]

hi,
i would like to know how to rotate an image in vb using the APIs not with DirectX.
plz help

[Amithran]

Use neck to tilt head in a clock wise or counter clock wise fashion.

[Mushroom Realm]

use bitblt, and if u dont know how either search the forum, or ask a more specific question (not meant in a mean way)

[Sastraxi]

It was my belief that PlgBlt (a sister API to BitBlt) would rotate images.

[/\/\isanThr0p]

go to www.ur.co.nz
there is a good tutorial about this.

[MXAlPhA]

Originally posted by jayantkumble
i don't need to know how u do it.
if u don't know something then shut ur dam mouth!

how rude

[CornedBee]

A rude way to say something correct.

[BodwadUK]

Const Pi = 3.14159265359
Private Declare Function GetPixel Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, ByVal Y As Long) As Long
Private Declare Function SetPixel Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, ByVal Y As Long, ByVal crColor As Long) As Long

Public Sub rotate(ByRef pic1 As Control, ByRef pic2 As Control, theta As Double)
Dim c1x As Integer ' Center of pic1.
Dim c1y As Integer ' "
Dim c2x As Integer ' Center of pic2.
Dim c2y As Integer ' "
Dim a As Single ' Angle of c2 to p2.
Dim r As Integer ' Radius from c2 to p2.

Dim p1x As Integer ' Position on pic1.
Dim p1y As Integer ' "
Dim p2x As Integer ' Position on pic2.
Dim p2y As Integer ' "
Dim n As Integer ' Max width or height of pic2.

blnDone = False
' Compute the centers.
c1x = pic1.ScaleWidth / 2
c1y = pic1.ScaleHeight / 2
c2x = pic1.ScaleWidth / 2
c2y = pic1.ScaleHeight / 2

theta = theta * (Pi / 180)
theta = theta - (2 * theta)

' Compute the image size.
n = pic2.ScaleWidth
If n < pic2.ScaleHeight Then n = pic2.ScaleHeight
n = n / 2 - 1
' For each pixel position on pic2.
For p2x = 0 To n
For p2y = 0 To n
' Compute polar coordinate of p2.
If p2x = 0 Then
a = Pi / 2
Else
a = Atn(p2y / p2x)
End If
r = Sqr(1& * p2x * p2x + 1& * p2y * p2y)

' Compute rotated position of p1.
p1x = r * Cos(a + theta)
p1y = r * Sin(a + theta)

' Copy pixels, 4 quadrants at once.
c0& = GetPixel(frmBattle.pbSource.hdc, c1x + p1x, c1y + p1y)
c1& = GetPixel(frmBattle.pbSource.hdc, c1x - p1x, c1y - p1y)

c2& = pic1.Point(c1x + p1y, c1y - p1x)
c3& = pic1.Point(c1x - p1y, c1y + p1x)
If c0& <> -1 Then SetPixel frmBattle.PBDest.hdc, c2x + p2x, c2y + p2y, c0&
If c1& <> -1 Then SetPixel frmBattle.PBDest.hdc, c2x - p2x, c2y - p2y, c1&
If c2& <> -1 Then SetPixel frmBattle.PBDest.hdc, c2x + p2y, c2y - p2x, c2&
If c3& <> -1 Then SetPixel frmBattle.PBDest.hdc, c2x - p2y, c2y + p2x, c3&
Next
Next

blnDone = True
End Sub


Some Code Changes Are Required In Regard To PictureBoxes but That us all Then you call this function

Theta is Angle in degrees