org.eclipse.swt.graphics.Transform Maven / Gradle / Ivy
The newest version!
/*******************************************************************************
* Copyright (c) 2000, 2010, 2012 IBM Corporation, Gerhardt Informatics Kft. 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
* Gerhardt Informatics Kft. - GEFGWT port
*******************************************************************************/
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 transformation matrices for points
* expressed as (x, y) pairs of floating point numbers.
*
* Application code must explicitly invoke the Transform.dispose()
* method to release the operating system resources managed by each instance
* when those instances are no longer required.
*
*
* This class requires the operating system's advanced graphics subsystem which
* may not be available on some platforms.
*
*
* @see SWT Example:
* GraphicsExample
* @see Sample code and further
* information
*
* @since 3.1
*/
public class Transform extends Resource {
/**
* the OS resource for the Transform (Warning: This field is platform
* dependent)
*
* IMPORTANT: This field is not 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.
*
*
* @noreference This field is not intended to be referenced by clients.
*/
public double[] handle;
/**
* Constructs a new identity Transform.
*
* This operation requires the operating system's advanced graphics
* subsystem which may not be available on some platforms.
*
*
* @param device
* the device on which to allocate the Transform
*
* @exception IllegalArgumentException
*
* - ERROR_NULL_ARGUMENT - if device is null and there is
* no current device
*
* @exception SWTException
*
* - ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are
* not available
*
* @exception SWTError
*
* - ERROR_NO_HANDLES if a handle for the Transform could
* not be obtained
*
*
* @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.
*
* This operation requires the operating system's advanced graphics
* subsystem which may not be available on some platforms.
*
*
* @param device
* the device on which to allocate the Transform
* @param elements
* an array of floats that describe the transformation matrix
*
* @exception IllegalArgumentException
*
* - ERROR_NULL_ARGUMENT - if device is null and there is
* no current device, or the elements array is null
* - ERROR_INVALID_ARGUMENT - if the elements array is too
* small to hold the matrix values
*
* @exception SWTException
*
* - ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are
* not available
*
* @exception SWTError
*
* - ERROR_NO_HANDLES if a handle for the Transform could
* not be obtained
*
*
* @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.
*
* This operation requires the operating system's advanced graphics
* subsystem which may not be available on some platforms.
*
*
* @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
*
* - ERROR_NULL_ARGUMENT - if device is null and there is
* no current device
*
* @exception SWTException
*
* - ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are
* not available
*
* @exception SWTError
*
* - ERROR_NO_HANDLES if a handle for the Transform could
* not be obtained
*
*
* @see #dispose()
*/
public Transform(Device device, float m11, float m12, float m21, float m22,
float dx, float dy) {
setElements(m11, m12, m21, m22, dx, dy);
}
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() {
handle = null;
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
* @exception IllegalArgumentException
*
* - ERROR_NULL_ARGUMENT - if the parameter is null
* - ERROR_INVALID_ARGUMENT - if the parameter is too small
* to hold the matrix values
*
*/
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);
elements[0] = (float) handle[0];
elements[1] = (float) handle[1];
elements[2] = (float) handle[2];
elements[3] = (float) handle[3];
elements[4] = (float) handle[4];
elements[5] = (float) handle[5];
}
/**
* Modifies the receiver such that the matrix it represents becomes the
* identity matrix.
*
* @exception SWTException
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*
* @since 3.4
*/
public void identity() {
setElements(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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
* - ERROR_CANNOT_INVERT_MATRIX - if the matrix is not
* invertible
*
*/
public void invert() {
}
/**
* Returns true if the Transform has been disposed, and
* false otherwise.
*
* 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 true when the Transform is disposed, and
* false otherwise
*/
public boolean isDisposed() {
// return handle == null;
return false;
}
/**
* Returns true if the Transform represents the identity matrix
* and false otherwise.
*
* @return true if the receiver is an identity Transform, and
* false otherwise
*/
public boolean isIdentity() {
if (isDisposed())
SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
float[] m = new float[6];
getElements(m);
return m[0] == 1 && m[1] == 0 && m[2] == 0 && m[3] == 1 && m[4] == 0
&& m[5] == 0;
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
* @exception IllegalArgumentException
*
* - ERROR_NULL_ARGUMENT - if the parameter is null
* - ERROR_INVALID_ARGUMENT - if the parameter has been
* disposed
*
*/
public void multiply(Transform matrix) {
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*/
public void rotate(float angle) {
double[] rotate = new double[4];
double radians = -Math.toRadians(angle);
rotate[0] = Math.cos(radians);
rotate[1] = Math.sin(radians);
rotate[2] = -Math.sin(radians);
rotate[3] = Math.cos(radians);
double a = handle[0] * rotate[0] + handle[1] * rotate[2];
double b = handle[0] * rotate[1] + handle[1] * rotate[3];
double c = handle[2] * rotate[0] + handle[3] * rotate[2];
double d = handle[2] * rotate[1] + handle[3] * rotate[3];
handle[0] = a;
handle[1] = b;
handle[2] = c;
handle[3] = d;
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*/
public void scale(float scaleX, float scaleY) {
handle[0] = handle[0] * scaleX;
handle[2] = handle[2] * scaleX;
handle[1] = handle[1] * scaleY;
handle[3] = handle[3] * scaleY;
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*/
public void setElements(float m11, float m12, float m21, float m22,
float dx, float dy) {
if (handle == null) {
handle = new double[6];
}
handle[0] = m11;
handle[1] = m12;
handle[2] = m21;
handle[3] = m22;
handle[4] = dx;
handle[5] = 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*
* @since 3.4
*/
public void shear(float shearX, float shearY) {
}
/**
* 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
*
* - ERROR_NULL_ARGUMENT - if the point array is null
*
* @exception SWTException
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*/
public void transform(float[] pointArray) {
}
/**
* 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
*
* - ERROR_GRAPHIC_DISPOSED - if the receiver has been
* disposed
*
*/
public void translate(float offsetX, float offsetY) {
handle[4] = handle[0] * offsetX + handle[1] * offsetY + handle[4];
handle[5] = handle[2] * offsetX + handle[3] * offsetY + handle[5];
}
/**
* 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] + "}";
}
public double[] getMatrix() {
return handle;
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy