I have improved the help documentation with a better explanation...
The Rotate and Crop overload rotates the whole image and the crops to a region of interest by adjusting the crop region to account for the rotation.
Consider this image:
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And these parameters:
const
Rotation_Angle = 10;
Crop_Left = 220;
Crop_Top = 70;
Crop_Right = 220 + 170;
Crop_Bottom = 70 + 160;
Cropping then rotating:
ImageEnView1.IO.LoadFromFile( 'D:\Tiger.jpg' );
ImageEnView1.Proc.Crop( Crop_Left, Crop_Top, Crop_Right, Crop_Bottom );
ImageEnView1.Proc.Rotate( Rotation_Angle, ierBicubic, clBlack );
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Rotating then cropping:
ImageEnView1.IO.LoadFromFile( 'D:\Tiger.jpg' );
// Note the negative rotation value
ImageEnView1.Proc.Crop( Rect( Crop_Left, Crop_Top, Crop_Right, Crop_Bottom ), -Rotation_Angle, ierBicubic );
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Nigel
Xequte Software
www.imageen.com