Application: gvSIG desktop » gvSIG Document Layout

import java.awt.geom.Area;

import java.awt.geom.NoninvertibleTransformException;

    /**

     * Gets the visible rectangle of the frame, taking rotation into

     * consideration. The result of this method is the rectangular area

     * of the unrotated frame that will be visible when the frame gets

     * rotated.

     * 

     * @param visibleLayoutDocRect

     * 			The visible area of the layout document

     * @param frame

     * 			The bounding box of this frame

     * @return

     * 			the rectangular area of the unrotated frame that will be

     * visible when the frame gets rotated, measured in screen coordinates  

     */

    protected Rectangle2D getVisibleRect(Rectangle2D visibleLayoutDocRect, Rectangle2D frame) {

    	if (getRotation()>0) {

    		Area area = new Area(frame);

    		AffineTransform at = new AffineTransform();

    		at.rotate(Math.toRadians(getRotation()), frame.getCenterX(), frame.getCenterY());

    		Area rotatedArea = area.createTransformedArea(at);

    		Area visibleArea = new Area(visibleLayoutDocRect);

    		// this is the visible rectangle of the rotated fframeview in layout coordinates

    		visibleArea.intersect(rotatedArea);

    		if (visibleArea.isEmpty()) {

    			return null;

    		}

    		// now we need to calculate the corresponding visible area of the fframeview before rotating,

    		// in order to know which area of the non-rotated fframeview must be drawn

    		try {

	    		Area nonRotatedVisibleArea = visibleArea.createTransformedArea(at.createInverse());

	    		Rectangle2D nonRotatedVisibleBounds = nonRotatedVisibleArea.getBounds2D();

	    		return nonRotatedVisibleBounds;

			} catch (NoninvertibleTransformException e) {

				LoggerFactory.getLogger(FFrame.class).error(e.getMessage(), e);

				return null;

			}

    	}

    	else {

    		Rectangle2D.Double visibleArea = new Rectangle2D.Double();

    		Rectangle2D.intersect(visibleLayoutDocRect, frame, visibleArea);

    		if (visibleArea.isEmpty()) {

    			return null;

    		}

    		return visibleArea;

    	}

    }