/*******************************************************************************
 * Copyright (c) 2000, 2008 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module org.eclipse.swt.graphics.Transform;

import java.lang.all;

import org.eclipse.swt.SWT;
import org.eclipse.swt.internal.Compatibility;
import org.eclipse.swt.internal.cairo.Cairo;
import org.eclipse.swt.graphics.Resource;
import org.eclipse.swt.graphics.Device;


/**
 * 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 : 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>
     */
    public double[] 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 this (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 this(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 this (Device device, float m11, float m12, float m21, float m22, float dx, float dy) {
    super(device);
    this.device.checkCairo();
    handle = new double[6];
    if (handle is null) SWT.error(SWT.ERROR_NO_HANDLES);
    Cairo.cairo_matrix_init( cast(cairo_matrix_t*)handle.ptr, m11, m12, m21, m22, dx, dy);
    init_();
}

static float[] checkTransform(float[] elements) {
    if (elements is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    if (elements.length < 6) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    return elements;
}

override
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 <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 is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    if (elements.length < 6) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    elements[0] = cast(float)handle[0];
    elements[1] = cast(float)handle[1];
    elements[2] = cast(float)handle[2];
    elements[3] = cast(float)handle[3];
    elements[4] = cast(float)handle[4];
    elements[5] = cast(float)handle[5];
}

/**
 * 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);
    Cairo.cairo_matrix_init(cast(cairo_matrix_t*)handle.ptr, 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 (Cairo.cairo_matrix_invert(cast(cairo_matrix_t*)handle.ptr) !is 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 using the Transform.
 *
 * @return <code>true</code> when the Transform is disposed, and <code>false</code> otherwise
 */
public override bool isDisposed() {
    return handle is null;
}

/**
 * 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 bool isIdentity() {
    if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
    float[] m  = new float[6];
    getElements(m);
    return m[0] is 1 && m[1] is 0 && m[2] is 0 && m[3] is 1 && m[4] is 0 && m[5] is 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 <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 is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    if (matrix.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    Cairo.cairo_matrix_multiply(cast(cairo_matrix_t*)handle.ptr,cast(cairo_matrix_t*)matrix.handle.ptr, cast(cairo_matrix_t*)handle.ptr);
}

/**
 * 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);
    Cairo.cairo_matrix_rotate(cast(cairo_matrix_t*)handle.ptr, angle * cast(float)Compatibility.PI / 180);
}

/**
 * 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);
    Cairo.cairo_matrix_scale(cast(cairo_matrix_t*)handle.ptr, scaleX, 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 <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);
    Cairo.cairo_matrix_init(cast(cairo_matrix_t*)handle.ptr, 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);
    double[] matrix = [ 1.0, shearX, shearY, 1, 0, 0];
    Cairo.cairo_matrix_multiply(cast(cairo_matrix_t*)handle.ptr, cast(cairo_matrix_t*)matrix.ptr, cast(cairo_matrix_t*)handle.ptr);
}

/**
 * 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 is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    double dx = 0, dy = 0;
    auto length = pointArray.length / 2;
    for (int i = 0, j = 0; i < length; i++, j += 2) {
        dx = pointArray[j];
        dy = pointArray[j + 1];
        Cairo.cairo_matrix_transform_point(cast(cairo_matrix_t*)handle.ptr, &dx, &dy);
        pointArray[j] = cast(float)dx;
        pointArray[j + 1] = cast(float)dy;
    }
}

/**
 * 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);
    Cairo.cairo_matrix_translate(cast(cairo_matrix_t*)handle.ptr, offsetX, offsetY);
}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the receiver
 */
public override String toString() {
    if (isDisposed()) return "Transform {*DISPOSED*}";
    float[] elements = new float[6];
    getElements(elements);
    return Format( "Transform {{{}}", elements );
}

}