plantuml/src/jcckit/renderer/Transformation.java

108 lines
3.7 KiB
Java

/*
* Copyright 2003-2004, Franz-Josef Elmer, All rights reserved
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details
* (http://www.gnu.org/copyleft/lesser.html).
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package jcckit.renderer;
import java.awt.Graphics2D;
import jcckit.graphic.Anchor;
import jcckit.graphic.ClippingRectangle;
import jcckit.graphic.GraphPoint;
/**
* Transformation between device-independent coordinates
* and standard Java coordinates. The aspect-ratio will
* be the same. The position in the canvas is determined by a
* {@link jcckit.graphic.Rectangle Rectangle} defining a (virtual)
* paper which is placed in the canvas according to an anchor point.
* Depending on the aspect ratio of the canvas the paper width or
* height occupies the canvas width or height.
*
* @author Franz-Josef Elmer
*/
public class Transformation {
private final double _scale, _x0, _y0;
public String toString() {
return "_scale=" + _scale + " _x0=" + _x0 + " _y0=" + _y0;
}
/**
* Creates an instance for the specified canvas size, paper size,
* and anchor points of the paper.
* @param width Width of the canvas.
* @param height Height of the canvas.
* @param paper Rectangle defining the paper in device-independent
* coordinates.
* @param horizontalAnchor Horizontal anchor of the paper in the canvas.
* @param verticalAnchor Vertical anchor of the paper in the canvas.
*/
public Transformation(int width, int height, ClippingRectangle paper,
Anchor horizontalAnchor, Anchor verticalAnchor) {
double pWidth = paper.getMaxX() - paper.getMinX();
double pHeight = paper.getMaxY() - paper.getMinY();
_scale = Math.min(width / pWidth, height / pHeight);
_x0 = 0.5 * horizontalAnchor.getFactor() * (width - _scale * pWidth)
- _scale * paper.getMinX();
_y0 = 0.5 * verticalAnchor.getFactor() * (_scale * pHeight - height)
+ height + _scale * + paper.getMinY();
}
/** Transforms the device-independent x coordinate into Java coordinates. */
public int transformX(double x) {
return trim(_scale * x + _x0);
}
/** Transforms the device-independent y coordinate into Java coordinates. */
public int transformY(double y) {
return trim(_y0 - _scale * y);
}
/** Transforms the device-independent width into Java width. */
public int transformWidth(double width) {
return trim(_scale * width + 0.5);
}
/** Transforms the device-independent height into Java height. */
public int transformHeight(double height) {
return trim(_scale * height + 0.5);
}
private static int trim(double number)
{
return number > Short.MAX_VALUE
? Short.MAX_VALUE
: (number < Short.MIN_VALUE ? Short.MIN_VALUE : (int) number);
}
/**
* Transforms a point in Java coordinates back into device-independent
* coordinates.
*/
public GraphPoint transformBack(int x, int y) {
return new GraphPoint((x - _x0) / _scale, (_y0 - y) / _scale);
}
public void apply(Graphics2D g) {
g.translate(_x0, _y0);
g.scale(_scale, -_scale);
}
}