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+---- Thread: Does QB64 have a rotate command? (/showthread.php?tid=271)
Does QB64 have a rotate command? - mangurian - 04-29-2022
Does QB64 have a rotate command?
I want to rotate a small .png file through an arbitrary angle.
Thanks
RE: Does QB64 have a rotate command? - bplus - 04-29-2022
Yes, yes we have a thing called RotoZoom and you can scale on independednt x, y axis as well as rotate. 3 for the price of 1 sub routine.
zip has bas source, an image .png and Windows exe already compiled, but as a practice one should compile their own.
Code: (Select All)
' Description:
' Started from a mod of Galleon's in Wiki that both scales and rotates an image.
' This version scales the x-axis and y-axis independently allowing rotations of image just by changing X or Y Scales
' making this tightly coded routine a very powerful and versatile image tool.
Sub RotoZoom3 (X As Long, Y As Long, Image As Long, xScale As Single, yScale As Single, radianRotation As Single)
' This assumes you have set your drawing location with _DEST or default to screen.
' X, Y - is where you want to put the middle of the image
' Image - is the handle assigned with _LOADIMAGE
' xScale, yScale - are shrinkage < 1 or magnification > 1 on the given axis, 1 just uses image size.
' These are multipliers so .5 will create image .5 size on given axis and 2 for twice image size.
' radianRotation is the Angle in Radian units to rotate the image
' note: Radian units for rotation because it matches angle units of other Basic Trig functions
' and saves a little time converting from degree.
' Use the _D2R() function if you prefer to work in degree units for angles.
Dim px(3) As Single: Dim py(3) As Single ' simple arrays for x, y to hold the 4 corners of image
Dim W&, H&, sinr!, cosr!, i&, x2&, y2& ' variables for image manipulation
W& = _Width(Image&): H& = _Height(Image&)
px(0) = -W& / 2: py(0) = -H& / 2 'left top corner
px(1) = -W& / 2: py(1) = H& / 2 ' left bottom corner
px(2) = W& / 2: py(2) = H& / 2 ' right bottom
px(3) = W& / 2: py(3) = -H& / 2 ' right top
sinr! = Sin(-radianRotation): cosr! = Cos(-radianRotation) ' rotation helpers
For i& = 0 To 3 ' calc new point locations with rotation and zoom
x2& = xScale * (px(i&) * cosr! + sinr! * py(i&)) + X: y2& = yScale * (py(i&) * cosr! - px(i&) * sinr!) + Y
px(i&) = x2&: py(i&) = y2&
Next
_MapTriangle _Seamless(0, 0)-(0, H& - 1)-(W& - 1, H& - 1), Image To(px(0), py(0))-(px(1), py(1))-(px(2), py(2))
_MapTriangle _Seamless(0, 0)-(W& - 1, 0)-(W& - 1, H& - 1), Image To(px(0), py(0))-(px(3), py(3))-(px(2), py(2))
End SubRadian Angle is an angle expressed in multiples of Pi, if you prefer to use Degree Angles then you can use the Conversion Functions _R2D() = Radians to Degrees or _D2R() = Degrees to Radians.
@mangurian Congrats! You are our 100th member!
Welcome to the Forum!
RE: Does QB64 have a rotate command? - mangurian - 04-29-2022
Exactly what I needed. In fact, I was planning on scaling also.
Thanks