/*******************************************************************************
* Copyright (c) 2000, 2012 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.graphics;
import org.eclipse.swt.*;
import org.eclipse.swt.internal.gdip.*;
/**
* Instances of this class represent transformation matrices for
* points expressed as (x, y) pairs of floating point numbers.
* <p>
* Application code must explicitly invoke the <code>Transform.dispose()</code>
* method to release the operating system resources managed by each instance
* when those instances are no longer required.
* </p>
* <p>
* This class requires the operating system's advanced graphics subsystem
* which may not be available on some platforms.
* </p>
*
* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: GraphicsExample</a>
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*
* @since 3.1
*/
public class Transform extends Resource {
/**
* the OS resource for the Transform
* (Warning: This field is platform dependent)
* <p>
* <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT
* public API. It is marked public only so that it can be shared
* within the packages provided by SWT. It is not available on all
* platforms and should never be accessed from application code.
* </p>
*
* @noreference This field is not intended to be referenced by clients.
*/
public long /*int*/ handle;
/**
* Constructs a new identity Transform.
* <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 Transform
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if 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 Transform could not be obtained</li>
* </ul>
*
* @see #dispose()
*/
public Transform (Device device) {
this(device, 1, 0, 0, 1, 0, 0);
}
/**
* Constructs a new Transform given an array of elements that represent the
* matrix that describes the transformation.
* <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 Transform
* @param elements an array of floats that describe the transformation matrix
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device, or the elements array is null</li>
* <li>ERROR_INVALID_ARGUMENT - if the elements array is too small to hold the matrix values</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 Transform could not be obtained</li>
* </ul>
*
* @see #dispose()
*/
public Transform(Device device, float[] elements) {
this (device, checkTransform(elements)[0], elements[1], elements[2], elements[3], elements[4], elements[5]);
}
/**
* Constructs a new Transform given all of the elements that represent the
* matrix that describes the transformation.
* <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 Transform
* @param m11 the first element of the first row of the matrix
* @param m12 the second element of the first row of the matrix
* @param m21 the first element of the second row of the matrix
* @param m22 the second element of the second row of the matrix
* @param dx the third element of the first row of the matrix
* @param dy the third element of the second row of the matrix
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if 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 Transform could not be obtained</li>
* </ul>
*
* @see #dispose()
*/
public Transform (Device device, float m11, float m12, float m21, float m22, float dx, float dy) {
super(device);
this.device.checkGDIP();
handle = Gdip.Matrix_new(m11, m12, m21, m22, dx, dy);
if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);
init();
}
static float[] checkTransform(float[] elements) {
if (elements == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
if (elements.length < 6) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
return elements;
}
void destroy() {
Gdip.Matrix_delete(handle);
handle = 0;
}
/**
* Fills the parameter with the values of the transformation matrix
* that the receiver represents, in the order {m11, m12, m21, m22, dx, dy}.
*
* @param elements array to hold the matrix values
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
* @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 matrix values</li>
* </ul>
*/
public void getElements(float[] elements) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
if (elements == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
if (elements.length < 6) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
Gdip.Matrix_GetElements(handle, elements);
}
/**
* Modifies the receiver such that the matrix it represents becomes the
* identity matrix.
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*
* @since 3.4
*/
public void identity() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_SetElements(handle, 1, 0, 0, 1, 0, 0);
}
/**
* Modifies the receiver such that the matrix it represents becomes
* the mathematical inverse of the matrix it previously represented.
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_CANNOT_INVERT_MATRIX - if the matrix is not invertible</li>
* </ul>
*/
public void invert() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
if (Gdip.Matrix_Invert(handle) != 0) SWT.error(SWT.ERROR_CANNOT_INVERT_MATRIX);
}
/**
* Returns <code>true</code> if the Transform has been disposed,
* and <code>false</code> otherwise.
* <p>
* This method gets the dispose state for the Transform.
* When a Transform has been disposed, it is an error to
* invoke any other method (except {@link #dispose()}) using the Transform.
*
* @return <code>true</code> when the Transform is disposed, and <code>false</code> otherwise
*/
public boolean isDisposed() {
return handle == 0;
}
/**
* Returns <code>true</code> if the Transform represents the identity matrix
* and false otherwise.
*
* @return <code>true</code> if the receiver is an identity Transform, and <code>false</code> otherwise
*/
public boolean isIdentity() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
return Gdip.Matrix_IsIdentity(handle);
}
/**
* Modifies the receiver such that the matrix it represents becomes the
* the result of multiplying the matrix it previously represented by the
* argument.
*
* @param matrix the matrix to multiply the receiver by
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
* @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>
*/
public void multiply(Transform matrix) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
if (matrix == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
if (matrix.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
Gdip.Matrix_Multiply(handle, matrix.handle, Gdip.MatrixOrderPrepend);
}
/**
* Modifies the receiver so that it represents a transformation that is
* equivalent to its previous transformation rotated by the specified angle.
* The angle is specified in degrees and for the identity transform 0 degrees
* is at the 3 o'clock position. A positive value indicates a clockwise rotation
* while a negative value indicates a counter-clockwise rotation.
*
* @param angle the angle to rotate the transformation by
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void rotate(float angle) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_Rotate(handle, angle, Gdip.MatrixOrderPrepend);
}
/**
* Modifies the receiver so that it represents a transformation that is
* equivalent to its previous transformation scaled by (scaleX, scaleY).
*
* @param scaleX the amount to scale in the X direction
* @param scaleY the amount to scale in the Y direction
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void scale(float scaleX, float scaleY) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_Scale(handle, scaleX, scaleY, Gdip.MatrixOrderPrepend);
}
/**
* Modifies the receiver to represent a new transformation given all of
* the elements that represent the matrix that describes that transformation.
*
* @param m11 the first element of the first row of the matrix
* @param m12 the second element of the first row of the matrix
* @param m21 the first element of the second row of the matrix
* @param m22 the second element of the second row of the matrix
* @param dx the third element of the first row of the matrix
* @param dy the third element of the second row of the matrix
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void setElements(float m11, float m12, float m21, float m22, float dx, float dy) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_SetElements(handle, m11, m12, m21, m22, dx, dy);
}
/**
* Modifies the receiver so that it represents a transformation that is
* equivalent to its previous transformation sheared by (shearX, shearY).
*
* @param shearX the shear factor in the X direction
* @param shearY the shear factor in the Y direction
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*
* @since 3.4
*/
public void shear(float shearX, float shearY) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_Shear(handle, shearX, shearY, Gdip.MatrixOrderPrepend);
}
/**
* Given an array containing points described by alternating x and y values,
* modify that array such that each point has been replaced with the result of
* applying the transformation represented by the receiver to that point.
*
* @param pointArray an array of alternating x and y values to be transformed
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the point array is null</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void transform(float[] pointArray) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
if (pointArray == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
Gdip.Matrix_TransformPoints(handle, pointArray, pointArray.length / 2);
}
/**
* Modifies the receiver so that it represents a transformation that is
* equivalent to its previous transformation translated by (offsetX, offsetY).
*
* @param offsetX the distance to translate in the X direction
* @param offsetY the distance to translate in the Y direction
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public void translate(float offsetX, float offsetY) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
Gdip.Matrix_Translate(handle, offsetX, offsetY, Gdip.MatrixOrderPrepend);
}
/**
* Returns a string containing a concise, human-readable
* description of the receiver.
*
* @return a string representation of the receiver
*/
public String toString() {
if (isDisposed()) return "Transform {*DISPOSED*}";
float[] elements = new float[6];
getElements(elements);
return "Transform {" + elements [0] + "," + elements [1] + "," +elements [2] + "," +elements [3] + "," +elements [4] + "," +elements [5] + "}";
}
}