| /******************************************************************************* |
| * Copyright (c) 2005 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.bpel.common.ui.flatui; |
| |
| import org.eclipse.swt.SWT; |
| import org.eclipse.swt.graphics.Point; |
| import org.eclipse.swt.graphics.Rectangle; |
| import org.eclipse.swt.widgets.Composite; |
| import org.eclipse.swt.widgets.Control; |
| |
| public final class FlatFormLayout extends BorderLayout { |
| /** |
| * marginWidth specifies the number of pixels of horizontal margin |
| * that will be placed along the left and right edges of the layout. |
| * |
| * The default value is 0. |
| */ |
| public int marginWidth = 0; |
| /** |
| * marginHeight specifies the number of pixels of vertical margin |
| * that will be placed along the top and bottom edges of the layout. |
| * |
| * The default value is 0. |
| */ |
| public int marginHeight = 0; |
| |
| /** |
| * Constructs a new instance of this class. |
| */ |
| public FlatFormLayout () { |
| } |
| |
| /** |
| * Computes the preferred height of the form with |
| * respect to the preferred height of the control. |
| * |
| * Given that the equations for top (T) and bottom (B) |
| * of the control in terms of the height of the form (X) |
| * are: |
| * T = AX + B |
| * B = CX + D |
| * |
| * The equation for the height of the control (H) |
| * is bottom (B) minus top (T) or (H = B - T) or: |
| * |
| * H = (CX + D) - (AX + B) |
| * |
| * Solving for (X), the height of the form, we get: |
| * |
| * X = (H + B - D) / (C - A) |
| * |
| * When (A = C), (C - A = 0) and the equation has no |
| * solution for X. This is a special case meaning that |
| * the control does not constrain the height of the |
| * form. In this case, we need to arbitrarily define |
| * the height of the form (X): |
| * |
| * Case 1: A = C, A = 0, C = 0 |
| * |
| * Let X = D, the distance from the top of the form |
| * to the bottom edge of the control. In this case, |
| * the control was attatched to the top of the form |
| * and the form needs to be large enough to show the |
| * bottom edge of the control. |
| * |
| * Case 2: A = C, A = 1, C = 1 |
| * |
| * Let X = -B, the distance from the bottom of the |
| * form to the top edge of the control. In this case, |
| * the control was attached to the bottom of the form |
| * and the only way that the control would be visible |
| * is if the offset is negative. If the offset is |
| * positive, there is no possible height for the form |
| * that will show the control as it will always be |
| * below the bottom edge of the form. |
| * |
| * Case 3: A = C, A != 0, C != 0 and A != 1, C != 0 |
| * |
| * Let X = D / (1 - C), the distance from the top of the |
| * form to the bottom edge of the control. In this case, |
| * since C is not 0 or 1, it must be a fraction, U / V. |
| * The offset D is the distance from CX to the bottom edge |
| * of the control. This represents a fraction of the form |
| * (1 - C)X. Since the height of a fraction of the form is |
| * known, the height of the entire form can be found by setting |
| * (1 - C)X = D. We solve this equation for X in terms of U |
| * and V, giving us X = (U * D) / (U - V). Similarily, if the |
| * offset D is negative, the control is positioned above CX. |
| * The offset -B is the distance from the top edge of the control |
| * to CX. We can find the height of the entire form by setting |
| * CX = -B. Solving in terms of U and V gives us X = (-B * V) / U. |
| */ |
| int computeHeight (FlatFormData data) { |
| FlatFormAttachment top = data.getTopAttachment (); |
| FlatFormAttachment bottom = data.getBottomAttachment (); |
| FlatFormAttachment height = bottom.minus (top); |
| if (height.numerator == 0) { |
| if (bottom.numerator == 0) return bottom.offset; |
| if (bottom.numerator == bottom.denominator) return -top.offset; |
| if (bottom.offset <= 0) { |
| return -top.offset * top.denominator / bottom.numerator; |
| } |
| int divider = bottom.denominator - bottom.numerator; |
| return bottom.denominator * bottom.offset / divider; |
| } |
| return height.solveY (data.cacheHeight); |
| } |
| |
| @Override |
| protected Point computeSize (Composite composite, int wHint, int hHint, boolean flushCache) { |
| Point size = layout (composite, false, 0, 0, 0, 0, flushCache); |
| size.x += marginWidth * 2; |
| size.y += marginHeight * 2; |
| return size; |
| } |
| |
| /** |
| * Computes the preferred height of the form with |
| * respect to the preferred height of the control. |
| */ |
| int computeWidth (FlatFormData data) { |
| FlatFormAttachment left = data.getLeftAttachment (); |
| FlatFormAttachment right = data.getRightAttachment (); |
| FlatFormAttachment width = right.minus (left); |
| if (width.numerator == 0) { |
| if (right.numerator == 0) return right.offset; |
| if (right.numerator == right.denominator) return -left.offset; |
| if (right.offset <= 0) { |
| return -left.offset * left.denominator / left.numerator; |
| } |
| int divider = right.denominator - right.numerator; |
| return right.denominator * right.offset / divider; |
| } |
| return width.solveY (data.cacheWidth); |
| } |
| |
| Point getSize (Control control, boolean flushCache) { |
| int wHint = SWT.DEFAULT, hHint = SWT.DEFAULT; |
| FlatFormData data = (FlatFormData) control.getLayoutData (); |
| if (data != null) { |
| wHint = data.width; |
| hHint = data.height; |
| } |
| /* Reserve additional space here for the border! */ |
| Point pt = control.computeSize (wHint, hHint, flushCache); |
| int bshape = BorderShape[getBorderType( |
| (data==null)? BORDER_DEFAULT : data.borderType, control)]; |
| pt.x += LeftBorderSize[bshape] + RightBorderSize[bshape]; |
| pt.y += TopBorderSize[bshape] + BottomBorderSize[bshape]; |
| return pt; |
| } |
| |
| @Override |
| protected void layout (Composite composite, boolean flushCache) { |
| Rectangle rect = composite.getClientArea (); |
| int x = rect.x + marginWidth; |
| int y = rect.y + marginHeight; |
| int width = Math.max (0, rect.width - 2 * marginWidth); |
| int height = Math.max (0, rect.height - 2 * marginHeight); |
| layout (composite, true, x, y, width, height, flushCache); |
| } |
| |
| Point layout (Composite composite, boolean move, int x, int y, int width, int height, boolean flushCache) { |
| Control [] children = composite.getChildren (); |
| for (int i = 0; i < children.length; i++) { |
| Control child = children [i]; |
| Point pt = getSize (child, false); |
| FlatFormData data = (FlatFormData) child.getLayoutData (); |
| if (data == null) { |
| child.setLayoutData (data = new FlatFormData ()); |
| } |
| data.cacheWidth = pt.x; |
| data.cacheHeight = pt.y; |
| } |
| for (int i=0; i<children.length; i++) { |
| Control child = children [i]; |
| FlatFormData data = (FlatFormData) child.getLayoutData (); |
| /* Adjust the child's position according to its border type! */ |
| int bshape = BorderShape[getBorderType( |
| (data==null)? BORDER_DEFAULT : data.borderType, child)]; |
| |
| if( data != null ) { |
| if( move ) { |
| int x1 = data.getLeftAttachment ().solveX (width) + LeftBorderSize[bshape]; |
| int y1 = data.getTopAttachment ().solveX (height) + TopBorderSize[bshape]; |
| int x2 = data.getRightAttachment ().solveX (width) - RightBorderSize[bshape]; |
| int y2 = data.getBottomAttachment ().solveX (height) - BottomBorderSize[bshape]; |
| child.setBounds (x + x1, y + y1, x2 - x1, y2 - y1); |
| } else { |
| width = Math.max (computeWidth (data), width); |
| height = Math.max (computeHeight (data), height); |
| } |
| } |
| } |
| |
| return move ? null : new Point (width, height); |
| } |
| |
| |
| @Override |
| public String toString () { |
| String string = getClass().getName ()+" {"; |
| if (marginWidth != 0) string += "marginWidth=" + marginWidth + " " ; |
| if (marginHeight != 0) string += "marginHeight="+marginHeight+" "; |
| |
| string = string.trim(); |
| string += "}"; |
| return string; |
| } |
| |
| } |