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static char help_text[] ="\n"
"Introduction\n"
"\n"
" OO-Browser Graphical Interface\n"
"\n"
" This program demonstrates a dynamic tree-drawing \n"
" algorithm developed by Sven Moen. The algorithm is \n"
" published in \"IEEE Software\", July 1990, pp. 21-28.\n"
" If you desire more information than the description\n"
" given below, see the above-referenced article. \n"
"\n"
" A number of the features mentioned herein are not\n"
" included in this version of the program.\n"
"\n"
"Algorithm\n"
"\n"
" Unlike other algorithms, Moen's algorithm uses an \n"
" explicit representation of node and subtree contours\n"
" and it stores each contour as a polygon. \n"
"\n"
" Trees with nodes of any polygonal shape can be drawn\n"
" compactly, and the data structure supports insert and\n"
" delete operations on subtrees. The results are tidy\n"
" trees and efficient relayouts when the tree changes.\n"
"\n"
" In the Layout step, the tree is traversed in depth-first\n"
" fashion until the leaf nodes are reached. The contour\n"
" of each leaf node is formed by creating a linked list of\n"
" lines that wrap around the node's shape. This is the \n"
" LayoutLeaf step. As the return trip is made back to the\n"
" root, the contour of each interior node is formed by\n"
" joining the individual contours of each child. This Join\n"
" step involves a Merge step where the offset between\n"
" two neighboring contours is computed to avoid overlap. \n"
" Since the width of each subtree contour is known at\n"
" each step, each interior node is centered over its\n"
" children, and the subtree contour is extended to include\n"
" the interior node. This is the AttachParent step.\n"
"\n"
" In a dynamic update operation (insert or delete), the\n"
" algorithm reuses the contours not influenced by the\n"
" change and updates them efficiently. When a given \n"
" node changes, subtree contours at higher levels must\n"
" be disassembled before the change. This is called\n"
" the Unzip step, which call RuboutLeaf, Split, and\n"
" DetachParent, all inverses of LayoutLeaf, Join, and\n"
" AttachParent, respectively. After the change is made,\n"
" the Zip step reassembles the contours by again calling\n"
" Layout, Join, and AttachParent.\n"
"\n"
"User Interface\n"
" \n"
" This program offers an interactive environment for \n"
" creating and updating trees of arbitrary size. Trees\n"
" can be loaded from a file or created on-the-fly. You\n"
" can also save trees, and specify various layout and\n"
" animation options. Each feature is associated with \n"
" a menu item which is explained in the next section.\n"
"\n"
" When invoking the program, you may specify a single\n"
" argument indicating the name of a tree file. This file\n"
" will be loaded upon startup. If you start the program\n"
" without arguments, the canvas will be blank.\n"
"\n"
"Tree Menu\n"
"\n"
" New Tree... Create a new tree. You specify \n"
" a new root, and the existing tree, \n"
" if any, is deleted.\n"
"\n"
" Load Tree... Load a tree specification file.\n"
" (see the File Format section)\n"
"\n"
" Save Tree... Save a tree specification file.\n"
" (see the File Format section)\n"
"\n"
" Quit Exits the program.\n"
"\n"
#if 0
"Layout Menu\n"
"\n"
" Layout Spacing...\n"
" Displays a dialog that allows you\n"
" to change the spacing between nodes\n"
" on the same level and the spacing\n"
" between levels. \n"
"\n"
" Align Nodes on Level\n"
" Adds a constraint to the layout\n"
" algorithm that forces all nodes\n"
" on the same level to have the same\n"
" x-position. This leads to truncation\n"
" of nodes if necessary. The maximum\n"
" node width is controlled by the\n"
" Level Spacing. By default, this is\n"
" disabled.\n"
"\n"
#endif
"Node Menu\n"
"\n"
" This popup menu is invoked by pressing and holding\n"
" the left mouse button on a node. This menu offers\n"
" several actions that can be performed on nodes.\n"
"\n"
#if 0
" Add Child Add a child to the node. The new child\n"
" is added after the bottommost child.\n"
"\n"
" Add Sibling Before\n"
" Add a sibling before this node.\n"
"\n"
" Add Sibling After\n"
" Add a sibling after this node.\n"
"\n"
#endif
" Collapse Node Collapses or expands the subtree\n"
" Expand Node beginning at the specified node.\n"
" This operation is similiar to a\n"
" Delete operation, except that the\n"
" subtree is preserved so that you\n"
" can display it again. Collapsed\n"
" nodes are marked with a gray box.\n"
"\n"
" Delete Node Delete the subtree beginning at the\n"
" specified node.\n"
"\n"
"Tree File Format\n"
"\n"
" If you wish to load a file, you can load a file created\n"
" by the OO-Browser with the {M-d} or {M-g} commands within\n"
" a browser listing buffer.\n"
"\n"
" Node labels are sequences of characters delimited by\n"
" newlines or end-of-file. \n"
"\n"
" Files must begin with an OO-Browser Environment path\n"
" name. The next line must be a label, which indicates the\n"
" root node. Optionally, lists containing labels may\n"
" follow. Each child label is indented two spaces more \n"
" its parent. Lists of labels are nested to produce trees. \n"
"\n"
" For example, a three-level binary tree is as follows:\n"
"\n"
" ^^c++-^^~/OOBR\n"
" root node level1\n"
" level2-1\n"
" level3-1\n"
" level3-2\n"
" level2-2\n"
" level3-3\n"
" level3-4\n"
"\n"
"X11 Resources\n"
"\n"
" Various settings in the program can be manipulated by \n"
" using X11 resources, specified either on the command\n"
" line or in a resource setting file. The supported \n"
" resources are:\n"
"\n"
" tree.font: Sets the font of the label nodes.\n"
" Default is \"fixed\".\n"
"\n"
" tree.backgroundColor:\n"
" Sets the background color of the \n"
" canvas. Default is \"white\".\n"
"\n"
" tree.treeColor: Sets the color of the displayed tree.\n"
" Default is \"black\".\n"
"\n"
" tree.splitColor:\n"
" Sets the color of split contours which\n"
" appear during a dynamic update.\n"
" Default is \"goldenrod\".\n"
" \n"
" tree.highlightColor:\n"
" Sets the color of highlighted nodes.\n"
" Default is \"OrangeRed\".\n"
"\n"
"Help\n"
"\n"
" If you are reading this, chances are that you found the\n"
" Help button on the menubar. \n"
"\n"
"Author\n"
" \n"
" A number of people have contributed to the evolution of this\n"
" tree handling program: Mark L. Stern, Stephan Zachwieja,\n"
" Torgeir Veimo, Bob Weiner, Martin Buchholz, Steve Baur and\n"
" Kirill Katsnelson. The other authors have granted Bob Weiner\n"
" rights to distribute any of their work in this code as part of\n"
" the OO-Browser.\n";
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