/*******************************************************************************
* Copyright (c) 2013 EclipseSource and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* EclipseSource - initial API and implementation
******************************************************************************/
package org.eclipse.swt.graphics;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.SWTException;
/**
* Instances of this class represent paths through the two-dimensional
* coordinate system. Paths do not have to be continuous, and can be
* described using lines, rectangles, arcs, cubic or quadratic bezier curves,
* glyphs, or other paths.
* <p>
* Application code must explicitly invoke the <code>Path.dispose()</code>
* method to release the operating system resources managed by each instance
* when those instances are no longer required.
* </p>
*
* @since 2.1
*/
public class Path extends Resource {
private PointF currentPoint;
private PointF startPoint;
private byte[] types;
private float[] points;
/**
* Constructs a new empty Path.
* <p>
* This operation requires the operating system's advanced
* graphics subsystem which may not be available on some
* platforms.
* </p>
*
* @param device the device on which to allocate the path
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the device is null and there is no current device</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available</li>
* </ul>
* @exception SWTError <ul>
* <li>ERROR_NO_HANDLES if a handle for the path could not be obtained</li>
* </ul>
*
* @see #dispose()
*/
public Path( Device device ) {
super( device );
currentPoint = new PointF();
startPoint = new PointF();
types = new byte[ 0 ];
points = new float[ 0 ];
moveTo( 0, 0 );
}
/**
* Constructs a new Path with the specified PathData.
* <p>
* This operation requires the operating system's advanced
* graphics subsystem which may not be available on some
* platforms.
* </p>
*
* @param device the device on which to allocate the path
* @param data the data for the path
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the device is null and there is no current device</li>
* <li>ERROR_NULL_ARGUMENT - if the data is null</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available</li>
* </ul>
* @exception SWTError <ul>
* <li>ERROR_NO_HANDLES if a handle for the path could not be obtained</li>
* </ul>
*
* @see #dispose()
*/
public Path( Device device, PathData data ) {
this( device );
if( data == null ) {
SWT.error( SWT.ERROR_NULL_ARGUMENT );
}
appendData( data );
}
/**
* Adds to the receiver the path described by the parameter.
*
* @param path the path to add to the receiver
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the parameter is null</li>
* <li>ERROR_INVALID_ARGUMENT - if the parameter has been disposed</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void addPath( Path path ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
if( path == null ) {
SWT.error( SWT.ERROR_NULL_ARGUMENT );
}
if( path.isDisposed() ) {
SWT.error( SWT.ERROR_INVALID_ARGUMENT );
}
appendData( path.getPathData() );
if( currentPoint.x != path.currentPoint.x || currentPoint.y != path.currentPoint.y ) {
moveTo( path.currentPoint.x, path.currentPoint.y );
}
}
/**
* Adds to the receiver the rectangle specified by x, y, width and height.
*
* @param x the x coordinate of the rectangle to add
* @param y the y coordinate of the rectangle to add
* @param width the width of the rectangle to add
* @param height the height of the rectangle to add
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void addRectangle( float x, float y, float width, float height ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
moveTo( x, y );
lineTo( x + width, y );
lineTo( x + width, y + height );
lineTo( x, y + height );
close();
currentPoint.x = x;
currentPoint.y = y;
}
/**
* Sets the current point of the receiver to the point
* specified by (x, y). Note that this starts a new
* sub path.
*
* @param x the x coordinate of the new end point
* @param y the y coordinate of the new end point
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void moveTo( float x, float y ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
addPoint( SWT.PATH_MOVE_TO, x, y );
currentPoint.x = x;
currentPoint.y = y;
startPoint.x = x;
startPoint.y = y;
}
/**
* Adds to the receiver a line from the current point to
* the point specified by (x, y).
*
* @param x the x coordinate of the end of the line to add
* @param y the y coordinate of the end of the line to add
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void lineTo( float x, float y ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
addPoint( SWT.PATH_LINE_TO, x, y );
currentPoint.x = x;
currentPoint.y = y;
}
/**
* Adds to the receiver a quadratic curve based on the parameters.
*
* @param cx the x coordinate of the control point of the spline
* @param cy the y coordinate of the control point of the spline
* @param x the x coordinate of the end point of the spline
* @param y the y coordinate of the end point of the spline
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void quadTo( float cx, float cy, float x, float y ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
addPoint( SWT.PATH_QUAD_TO, cx, cy, x, y );
currentPoint.x = x;
currentPoint.y = y;
}
/**
* Adds to the receiver a cubic bezier curve based on the parameters.
*
* @param cx1 the x coordinate of the first control point of the spline
* @param cy1 the y coordinate of the first control of the spline
* @param cx2 the x coordinate of the second control of the spline
* @param cy2 the y coordinate of the second control of the spline
* @param x the x coordinate of the end point of the spline
* @param y the y coordinate of the end point of the spline
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void cubicTo( float cx1, float cy1, float cx2, float cy2, float x, float y ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
addPoint( SWT.PATH_CUBIC_TO, cx1, cy1, cx2, cy2, x, y );
currentPoint.x = x;
currentPoint.y = y;
}
/**
* Closes the current sub path by adding to the receiver a line
* from the current point of the path back to the starting point
* of the sub path.
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void close() {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
addPoint( SWT.PATH_CLOSE );
currentPoint.x = startPoint.x;
currentPoint.y = startPoint.y;
}
/**
* Returns a device independent representation of the receiver.
*
* @return the PathData for the receiver
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*
* @see PathData
*/
public PathData getPathData() {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
int typesLength = types.length;
int pointsLength = points.length;
if( getLastPointType() == SWT.PATH_MOVE_TO ) {
typesLength--;
pointsLength -= 2;
}
PathData result = new PathData();
result.types = new byte[ typesLength ];
result.points = new float[ pointsLength ];
System.arraycopy( types, 0, result.types, 0, typesLength );
System.arraycopy( points, 0, result.points, 0, pointsLength );
return result;
}
/**
* Replaces the first two elements in the parameter with values that
* describe the current point of the path.
*
* @param point the array to hold the result
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the parameter is null</li>
* <li>ERROR_INVALID_ARGUMENT - if the parameter is too small to hold the end point</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void getCurrentPoint( float[] point ) {
if( isDisposed() ) {
SWT.error( SWT.ERROR_GRAPHIC_DISPOSED );
}
if( point == null ) {
SWT.error( SWT.ERROR_NULL_ARGUMENT );
}
if( point.length < 2 ) {
SWT.error( SWT.ERROR_INVALID_ARGUMENT );
}
point[ 0 ] = currentPoint.x;
point[ 1 ] = currentPoint.y;
}
@Override
void destroy() {
types = null;
points = null;
}
private void appendData( PathData data ) {
byte[] types = data.types;
float[] points = data.points;
for( int i = 0, j = 0; i < types.length; i++ ) {
switch( types[ i ] ) {
case SWT.PATH_MOVE_TO:
moveTo( points[ j++ ], points[ j++ ] );
break;
case SWT.PATH_LINE_TO:
lineTo( points[ j++ ], points[ j++ ] );
break;
case SWT.PATH_CUBIC_TO:
cubicTo( points[ j++ ],
points[ j++ ],
points[ j++ ],
points[ j++ ],
points[ j++ ],
points[ j++ ] );
break;
case SWT.PATH_QUAD_TO:
quadTo( points[ j++ ], points[ j++ ], points[ j++ ], points[ j++ ] );
break;
case SWT.PATH_CLOSE:
close();
break;
default:
dispose();
SWT.error( SWT.ERROR_INVALID_ARGUMENT );
}
}
}
private void addPoint( int type, float... coords ) {
if( type != SWT.PATH_MOVE_TO || getLastPointType() != SWT.PATH_MOVE_TO ) {
enlargeArrays( 1, coords.length );
}
types[ types.length - 1 ] = ( byte )type;
for( int i = coords.length; i > 0; i-- ) {
points[ points.length - i ] = coords[ coords.length - i ];
}
}
private int getLastPointType() {
return types.length > 0 ? types[ types.length - 1 ] : SWT.NONE;
}
private void enlargeArrays( int typesAmount, int pointsAmount ) {
if( typesAmount > 0 ) {
byte[] newTypes = new byte[ types.length + typesAmount ];
System.arraycopy( types, 0, newTypes, 0, types.length );
types = newTypes;
}
if( pointsAmount > 0 ) {
float[] newPoints = new float[ points.length + pointsAmount ];
System.arraycopy( points, 0, newPoints, 0, points.length );
points = newPoints;
}
}
private final class PointF {
public float x;
public float y;
}
}