Declaration
procedure Rotate(Angle: Double; AntiAliasMode: TIEAntialiasMode = ierFast; BackgroundColor: TColor = -1);
Description
Rotate the current image by the specified angle (negative or positive degrees counter-clockwise).
AntialiasMode specifies the algorithm used to improve rotation quality:
ierNone : No anti-aliasing (lowest quality)
ierFast : Fast but lower quality
ierBilinear : Bilinear, high quality
ierBicubic : Bicubic, highest quality
BackgroundColor specifies an alternative background color. If it is -1, Rotate uses the default background.
This is a common image from a digital camera that was not held correctly causing the horizon not to be level.

After calling
ImageEnView1.Proc.Rotate( 5 ):

Note:
- If the image has an
alpha channel then the null area is filled with transparency (so you will not see the background color). To prevent the transparent area, and force a background color fill,
remove the alpha channel- To crop the image caused by rotation, use
RotateAndCrop- To allow the user to interactively rotate the image, use
RotateTool- If
PdfViewer is enabled, this will redirect to
PageRotation- This function is also available to the user in the
Image Processing dialogExamples
// Rotate the image 45° clockwise at highest quality and using the ImageEnView background color
ImageEnView1.Proc.Rotate( 315, ierBicubic, -1 );
// Rotate the image 90° clockwise (Note: AntialiasMode is irrelevant for 90 deg. rotations)
ImageEnView1.Proc.Rotate( 270 );
// Rotate the image 180° clockwise
ImageEnView1.Proc.Rotate( 180 );
// Rotate the image 90° counter-clockwise
ImageEnView1.Proc.Rotate( 90 );
// Rotate the image 45° clockwise, with good quality, and the null area created by the rotation set as transparent
ImageEnView1.IEBitmap.AlphaChannel; // Create an alpha channel if one does not exist
ImageEnView1.Proc.Rotate( -45, ierBicubic );
// Rotate the image 45° clockwise, with good quality, and the null area created by the rotation set as black
ImageEnView1.IEBitmap.RemoveAlphaChannel; // Remove alpha channel if there is one
ImageEnView1.Proc.Rotate( -45, ierBicubic, clBlack );
See Also
-
Global Image Methods-
AngleToImageEnRotateAngle