rotate.java

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// Rotate - rotate an image by some angle
//
// Copyright (C) 1997 by Jef Poskanzer <[e-mail]>.  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//
// Visit the ACME Labs Java page for up-to-date versions of this and other
// fine Java utilities: http://www.acme.com/java/

package Acme.JPM.Filters;

import java.awt.image.*;

/// Rotate an image by some angle.
// <P>
// Rotates an image by the specified angle.
// The angle is in degrees measured counter-clockwise.
// It can be negative, but it should be between -90 and 90
// or the resulting image will be unreasonably large.
// Staying between -45 and 45 is best.
// <P>
// The rotation algorithm is Alan Paeth's three-shear method, described
// in "A Fast Algorithm for General Raster Rotation", Graphics Interface
// '86, pp. 77-81.
// <P>
// This filter is slow.
// <P>
// <A HREF="/resources/classes/Acme/JPM/Filters/Rotate.java">Fetch the software.</A><BR>
// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>

public class Rotate extends CompositeFilter
    {

    private double angle;

    /// Constructor.
    public Rotate(  ImageProducer producer, double angle )
	{
	super( producer, new Shear( null, angle ), new Flip( null, Flip.FLIP_XY ) );
	this.angle = angle * Math.PI / 180.0;
	double xshearfac = Math.tan( angle / 2.0 );
	double yshearfac = Math.sin( angle );
	}


    // Main routine for command-line interface.
    public static void main( String[] args )
	{
	if ( args.length != 1 )
	    usage();
	ImageFilterPlus filter = new Rotate( null, Integer.parseInt( args[0] ) );
	System.exit( 
	    ImageFilterPlus.filterStream( System.in, System.out, filter ) );
	}
    
    private static void usage()
	{
	System.err.println( "usage: Rotate <angle>" );
	System.exit( 1 );
	}

    }