| /******************************************************************************* |
| * 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 |
| *******************************************************************************/ |
| package org.eclipse.swt.layout; |
| |
| import org.eclipse.swt.*; |
| import org.eclipse.swt.widgets.*; |
| |
| /** |
| * Instances of this class are used to define the edges of a control |
| * within a <code>FormLayout</code>. |
| * <p> |
| * <code>FormAttachments</code> are set into the top, bottom, left, |
| * and right fields of the <code>FormData</code> for a control. |
| * For example: |
| * <pre> |
| * FormData data = new FormData(); |
| * data.top = new FormAttachment(0,5); |
| * data.bottom = new FormAttachment(100,-5); |
| * data.left = new FormAttachment(0,5); |
| * data.right = new FormAttachment(100,-5); |
| * button.setLayoutData(data); |
| * </pre> |
| * </p> |
| * <p> |
| * A <code>FormAttachment</code> defines where to attach the side of |
| * a control by using the equation, y = ax + b. The "a" term represents |
| * a fraction of the parent composite's width (from the left) or height |
| * (from the top). It can be defined using a numerator and denominator, |
| * or just a percentage value. If a percentage is used, the denominator |
| * is set to 100. The "b" term in the equation represents an offset, in |
| * pixels, from the attachment position. For example: |
| * <pre> |
| * FormAttachment attach = new FormAttachment (20, -5); |
| * </pre> |
| * specifies that the side to which the <code>FormAttachment</code> |
| * object belongs will lie at 20% of the parent composite, minus 5 pixels. |
| * </p> |
| * <p> |
| * Control sides can also be attached to another control. |
| * For example: |
| * <pre> |
| * FormAttachment attach = new FormAttachment (button, 10); |
| * </pre> |
| * specifies that the side to which the <code>FormAttachment</code> |
| * object belongs will lie in the same position as the adjacent side of |
| * the <code>button</code> control, plus 10 pixels. The control side can |
| * also be attached to the opposite side of the specified control. |
| * For example: |
| * <pre> |
| * FormData data = new FormData (); |
| * data.left = new FormAttachment (button, 0, SWT.LEFT); |
| * </pre> |
| * specifies that the left side of the control will lie in the same position |
| * as the left side of the <code>button</code> control. The control can also |
| * be attached in a position that will center the control on the specified |
| * control. For example: |
| * <pre> |
| * data.left = new FormAttachment (button, 0, SWT.CENTER); |
| * </pre> |
| * specifies that the left side of the control will be positioned so that it is |
| * centered between the left and right sides of the <code>button</code> control. |
| * If the alignment is not specified, the default is to attach to the adjacent side. |
| * </p> |
| * |
| * @see FormLayout |
| * @see FormData |
| * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> |
| * |
| * @since 2.0 |
| */ |
| public final class FormAttachment { |
| /** |
| * numerator specifies the numerator of the "a" term in the |
| * equation, y = ax + b, which defines the attachment. |
| */ |
| public int numerator; |
| |
| /** |
| * denominator specifies the denominator of the "a" term in the |
| * equation, y = ax + b, which defines the attachment. |
| * |
| * The default value is 100. |
| */ |
| public int denominator = 100; |
| |
| /** |
| * offset specifies the offset, in pixels, of the control side |
| * from the attachment position. |
| * If the offset is positive, then the control side is offset |
| * to the right of or below the attachment position. If it is |
| * negative, then the control side is offset to the left of or |
| * above the attachment position. |
| * |
| * This is equivalent to the "b" term in the equation y = ax + b. |
| * The default value is 0. |
| */ |
| public int offset; |
| |
| /** |
| * control specifies the control to which the control side is |
| * attached. |
| */ |
| public Control control; |
| |
| /** |
| * alignment specifies the alignment of the control side that is |
| * attached to a control. |
| * <p> |
| * For top and bottom attachments, TOP, BOTTOM and CENTER are used. For left |
| * and right attachments, LEFT, RIGHT and CENTER are used. If any other case |
| * occurs, the default will be used instead. |
| * </p> |
| * |
| * <br>Possible values are: <ul> |
| * <li>{@link SWT#TOP}: Attach the side to the top side of the specified control.</li> |
| * <li>{@link SWT#BOTTOM}: Attach the side to the bottom side of the specified control.</li> |
| * <li>{@link SWT#LEFT}: Attach the side to the left side of the specified control.</li> |
| * <li>{@link SWT#RIGHT}: Attach the side to the right side of the specified control.</li> |
| * <li>{@link SWT#CENTER}: Attach the side at a position which will center the control on the specified control.</li> |
| * <li>{@link SWT#DEFAULT}: Attach the side to the adjacent side of the specified control.</li> |
| * </ul> |
| */ |
| public int alignment; |
| |
| /** |
| * Constructs a new instance of this class. |
| * Since no numerator, denominator or offset is specified, |
| * the attachment is treated as a percentage of the form. |
| * The numerator is zero, the denominator is 100 and the |
| * offset is zero. |
| * |
| * @since 3.2 |
| */ |
| public FormAttachment () { |
| } |
| |
| /** |
| * Constructs a new instance of this class given a numerator |
| * Since no denominator or offset is specified, the default |
| * is to treat the numerator as a percentage of the form, with a |
| * denominator of 100. The offset is zero. |
| * |
| * @param numerator the percentage of the position |
| * |
| * @since 3.0 |
| */ |
| public FormAttachment (int numerator) { |
| this (numerator, 100, 0); |
| } |
| |
| /** |
| * Constructs a new instance of this class given a numerator |
| * and an offset. Since no denominator is specified, the default |
| * is to treat the numerator as a percentage of the form, with a |
| * denominator of 100. |
| * |
| * @param numerator the percentage of the position |
| * @param offset the offset of the side from the position |
| */ |
| public FormAttachment (int numerator, int offset) { |
| this (numerator, 100, offset); |
| } |
| |
| /** |
| * Constructs a new instance of this class given a numerator |
| * and denominator and an offset. The position of the side is |
| * given by the fraction of the form defined by the numerator |
| * and denominator. |
| * |
| * @param numerator the numerator of the position |
| * @param denominator the denominator of the position |
| * @param offset the offset of the side from the position |
| */ |
| public FormAttachment (int numerator, int denominator, int offset) { |
| if (denominator == 0) SWT.error (SWT.ERROR_CANNOT_BE_ZERO); |
| this.numerator = numerator; |
| this.denominator = denominator; |
| this.offset = offset; |
| } |
| |
| /** |
| * Constructs a new instance of this class given a control. |
| * Since no alignment is specified, the default alignment is |
| * to attach the side to the adjacent side of the specified |
| * control. Since no offset is specified, an offset of 0 is |
| * used. |
| * |
| * @param control the control the side is attached to |
| */ |
| public FormAttachment (Control control) { |
| this (control, 0, SWT.DEFAULT); |
| } |
| |
| /** |
| * Constructs a new instance of this class given a control |
| * and an offset. Since no alignment is specified, the default |
| * alignment is to attach the side to the adjacent side of the |
| * specified control. |
| * |
| * @param control the control the side is attached to |
| * @param offset the offset of the side from the control |
| */ |
| public FormAttachment (Control control, int offset) { |
| this (control, offset, SWT.DEFAULT); |
| } |
| |
| /** |
| * Constructs a new instance of this class given a control, |
| * an offset and an alignment. The possible alignment values are: |
| * <dl> |
| * <dt><b>{@link SWT#TOP}</b></dt> |
| * <dd>the side will be attached to the top side of the specified control</dd> |
| * <dt><b>{@link SWT#BOTTOM}</b></dt> |
| * <dd>the side will be attached to the bottom side of the specified control</dd> |
| * <dt><b>{@link SWT#LEFT}</b></dt> |
| * <dd>the side will be attached to the left side of the specified control</dd> |
| * <dt><b>{@link SWT#RIGHT}</b></dt> |
| * <dd>the side will be attached to the right side of the specified control</dd> |
| * <dt><b>{@link SWT#CENTER}</b></dt> |
| * <dd>the side will be centered on the same side of the specified control</dd> |
| * <dt><b>{@link SWT#DEFAULT}</b></dt> |
| * <dd>the side will be attached to the adjacent side of the specified control</dd> |
| * </dl> |
| * |
| * @param control the control the side is attached to |
| * @param offset the offset of the side from the control |
| * @param alignment the alignment of the side to the control it is attached to, |
| * one of TOP, BOTTOM, LEFT, RIGHT, CENTER, or DEFAULT |
| */ |
| public FormAttachment (Control control, int offset, int alignment) { |
| this.control = control; |
| this.offset = offset; |
| this.alignment = alignment; |
| } |
| |
| FormAttachment divide (int value) { |
| return new FormAttachment (numerator, denominator * value, offset / value); |
| } |
| |
| int gcd (int m, int n) { |
| int temp; |
| m = Math.abs (m); |
| n = Math.abs (n); |
| if (m < n) { |
| temp = m; |
| m = n; |
| n = temp; |
| } |
| while (n != 0){ |
| temp = m; |
| m = n; |
| n = temp % n; |
| } |
| return m; |
| } |
| |
| FormAttachment minus (FormAttachment attachment) { |
| FormAttachment solution = new FormAttachment (); |
| solution.numerator = numerator * attachment.denominator - denominator * attachment.numerator; |
| solution.denominator = denominator * attachment.denominator; |
| int gcd = gcd (solution.denominator, solution.numerator); |
| solution.numerator = solution.numerator / gcd; |
| solution.denominator = solution.denominator / gcd; |
| solution.offset = offset - attachment.offset; |
| return solution; |
| } |
| |
| FormAttachment minus (int value) { |
| return new FormAttachment (numerator, denominator, offset - value); |
| } |
| |
| FormAttachment plus (FormAttachment attachment) { |
| FormAttachment solution = new FormAttachment (); |
| solution.numerator = numerator * attachment.denominator + denominator * attachment.numerator; |
| solution.denominator = denominator * attachment.denominator; |
| int gcd = gcd (solution.denominator, solution.numerator); |
| solution.numerator = solution.numerator / gcd; |
| solution.denominator = solution.denominator / gcd; |
| solution.offset = offset + attachment.offset; |
| return solution; |
| } |
| |
| FormAttachment plus (int value) { |
| return new FormAttachment (numerator, denominator, offset + value); |
| } |
| |
| int solveX (int value) { |
| if (denominator == 0) SWT.error (SWT.ERROR_CANNOT_BE_ZERO); |
| return ((numerator * value) / denominator) + offset; |
| } |
| |
| int solveY (int value) { |
| if (numerator == 0) SWT.error (SWT.ERROR_CANNOT_BE_ZERO); |
| return (value - offset) * denominator / numerator; |
| } |
| |
| /** |
| * Returns a string containing a concise, human-readable |
| * description of the receiver. |
| * |
| * @return a string representation of the FormAttachment |
| */ |
| public String toString () { |
| String string = control != null ? control.toString () : numerator + "/" + denominator; |
| return "{y = (" + string + (offset >= 0 ? ")x + " + offset: ")x - " + (-offset))+"}"; |
| } |
| |
| } |