/usr/share/ada/adainclude/gtkada/glib-graphs-layouts.adb is in libgtkada16.1.0-dev 17.0.2017-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 | ------------------------------------------------------------------------------
-- GtkAda - Ada95 binding for Gtk+/Gnome --
-- --
-- Copyright (C) 2014-2017, AdaCore --
-- --
-- This library is free software; you can redistribute it and/or modify it --
-- under terms of the GNU General Public License as published by the Free --
-- Software Foundation; either version 3, or (at your option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- --
-- --
-- --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
------------------------------------------------------------------------------
with Ada.Containers.Doubly_Linked_Lists;
with Ada.Tags; use Ada.Tags;
with Ada.Unchecked_Deallocation;
with GNAT.Heap_Sort_G;
package body Glib.Graphs.Layouts is
Preferred_Length : constant := 1;
-- Number of layers between edge ends (this is for future extension, so
-- that some edges might be forced to span layers.
Add_Dummy_Nodes : constant Boolean := True;
-- Whether to add dummy (invisible node) for edges that span multiple
-- layers.
Dummy_Node_Size : constant Gdouble := 4.0;
-- Size of the dummy nodes (since we also have margins, we might as well
-- keep those nodes small).
Default_Layer : constant Integer := 0;
type Integer_Array is array (Integer range <>) of Integer;
type Integer_Array_Access is access Integer_Array;
-- maps vertices to some data
procedure Make_Acyclic (G : in out Graph);
-- Make sure the graph is acyclic
package Vertex_Lists is new Ada.Containers.Doubly_Linked_Lists
(Vertex_Access);
use Vertex_Lists;
type Layer_Info_Array is array (Integer range <>) of Vertex_Lists.List;
type Layer_Info_Array_Access is access Layer_Info_Array;
type Layout_Info is record
Horizontal : Boolean;
Space_Between_Layers : Gdouble;
Space_Between_Items : Gdouble;
Min_Layer, Max_Layer : Integer;
In_Layers : Layer_Info_Array_Access;
-- The ordered list of items in each layer
Layers : Integer_Array_Access;
-- For each vertex, its assigned layer
end record;
procedure Free (Self : in out Layout_Info);
-- Free memory used by Self
function Slack (Info : Layout_Info; Edge : Edge_Access) return Integer;
-- Returns the slack for an edge. When greater than 0, the edge could
-- be tightened to lead to a nicer layer
function Layer (Info : Layout_Info; V : Vertex_Access) return Integer;
-- Return the layer for a vertex
procedure Adjust_Positions
(G : Graph;
Info : Layout_Info);
-- Adjust the position of the items within their layer.
-- Items must hav already been ordered, and they are moved a little so that
-- they tend to align with their parent and child nodes
procedure Sort_Nodes_Within_Layers
(G : Graph;
Info : in out Layout_Info);
-- Sort the nodes within each layer so as to minimize crossing of edges.
-- To do this, we use a Median or Barycenter Heuristic.
-- This is also similar to what graphize uses to reorder nodes within a
-- layer to minimize edge crossing. See for instance:
-- "The barycenter Heuristic and the reorderable matrix"
-- Erkki Makinen, Harri Siirtola
-- http://www.informatica.si/PDF/29-3/
-- 13_Makinen-The%20Barycenter%20Heuristic....pdf
--
-- See also
-- http://www.graphviz.org/Documentation/TSE93.pdf
--
-- Basically, for each layer, we order the nodes based on the barycenter
-- of their neighbor nodes, and repeat for each layer.
type Weight_Info is record
Weight : Gdouble;
Vertex : Vertex_Access;
end record;
type Weight_Array is array (Integer range <>) of Weight_Info;
procedure Sort (W : in out Weight_Array);
-- sort the array by weight
-- Precondition: W'First = 0
-- Sorts 1 .. W'Last elements
procedure Init_Rank
(G : Graph;
Info : in out Layout_Info);
-- Computes an initial feasible ranking (i.e where nodes are
-- organized such that children nodes are in layers higher than their
-- parents). This always assigns root nodes (with no in-edges) to
-- layer 0. This might result in non-tight edges, for instance:
-- /--F
-- A -> B -> C -> D
-- E -----------/
--
-- ??? This algorithm requires computation of in-edges, which is
-- not always available for all types of graphs. Seems that we could
-- replace it with a DFS, where leaf nodes are assigned to layer 0
-- (so the ordering would be different, but since we are tightening
-- edges afterward it doesn't really matter).
procedure Organize_Nodes
(G : Graph;
Info : in out Layout_Info);
-- Compute the position of nodes within each layer.
-- We provide an initial ordering for elements: starting from nodes
-- at the lowest layer (rightmost or topmost item depending on
-- layout), we do a breadth-first-search, and add each child in to
-- its respective layer. This ensures that for the spanning tree at
-- least there are no edge crossings.
procedure Rank_Items (G : in out Graph; Info : in out Layout_Info);
-- Compute the layer for each item
----------
-- Tree --
----------
package Edge_Lists is new Ada.Containers.Doubly_Linked_Lists (Edge_Access);
use Edge_Lists;
type Edge_Array is array (Integer range <>) of Edge_Lists.List;
type Tree (Max_Index : Natural) is record
Node_Count : Natural := 0;
Node_In_Tree : Integer_Array (Min_Vertex_Index .. Max_Index) :=
(others => -1);
-- This is used to test whether the corresponding node from the graph is
-- in the tree.
-- Since the graph might include several disjoint components, the value
-- in this array indicates which component the node is part of.
Edges : Edge_Array (Min_Vertex_Index .. Max_Index);
-- For each vertex, the list of tree edges that start from it.
Disjoint_Components : Natural := 0;
-- Number of disjoint sets in thetree
end record;
-- A spanning tree for the graph.
procedure Add_Edge (Self : in out Tree; E : Edge_Access);
procedure Add_Vertex (Self : in out Tree; V : Vertex_Access);
-- Add a new edge or vertex to the tree.
function In_Tree (Self : Tree; V : Vertex_Access) return Boolean;
-- Whether the vertex is already in the tree
function Is_Spanning (Self : Tree) return Boolean;
-- Whether all nodes are in the tree (i.e we have a full spanning tree for
-- the graph).
procedure Normalize_Layers (Spanning : Tree; Info : in out Layout_Info);
-- Normalize the layers so that each independenct component starts at
-- layer 0. This leads to nicer layout, since independent components
-- are aligned
procedure Feasible_Tree
(G : Graph;
Info : in out Layout_Info;
Spanning : out Tree);
-- Computes an initial feasible tree. This is a spanning tree for the
-- graph so that all of its edges are tight (which for instance will
-- tighten the link E->D in the example above).
-- This changes layer assignment for the vertices.
----------
-- Free --
----------
procedure Free (Self : in out Layout_Info) is
procedure Unchecked_Free is new Ada.Unchecked_Deallocation
(Integer_Array, Integer_Array_Access);
procedure Unchecked_Free is new Ada.Unchecked_Deallocation
(Layer_Info_Array, Layer_Info_Array_Access);
begin
Unchecked_Free (Self.In_Layers);
Unchecked_Free (Self.Layers);
end Free;
-----------
-- Slack --
-----------
function Slack (Info : Layout_Info; Edge : Edge_Access) return Integer is
begin
return Info.Layers (Get_Index (Get_Dest (Edge)))
- Info.Layers (Get_Index (Get_Src (Edge)))
- Preferred_Length;
end Slack;
-----------
-- Layer --
-----------
function Layer (Info : Layout_Info; V : Vertex_Access) return Integer is
begin
if V.all in Base_Dummy_Vertex'Class then
return Base_Dummy_Vertex (V.all).Layer;
else
return Info.Layers (Get_Index (V));
end if;
end Layer;
--------------
-- Add_Edge --
--------------
procedure Add_Edge (Self : in out Tree; E : Edge_Access) is
Sindex : constant Integer := Get_Index (Get_Src (E));
begin
Add_Vertex (Self, Get_Src (E));
Add_Vertex (Self, Get_Dest (E));
Self.Edges (Sindex).Append (E);
end Add_Edge;
----------------
-- Add_Vertex --
----------------
procedure Add_Vertex (Self : in out Tree; V : Vertex_Access) is
begin
if not In_Tree (Self, V) then
Self.Node_Count := Self.Node_Count + 1;
Self.Node_In_Tree (Get_Index (V)) := Self.Disjoint_Components;
end if;
end Add_Vertex;
-------------
-- In_Tree --
-------------
function In_Tree (Self : Tree; V : Vertex_Access) return Boolean is
begin
return Self.Node_In_Tree (Get_Index (V)) /= -1;
end In_Tree;
-----------------
-- Is_Spanning --
-----------------
function Is_Spanning (Self : Tree) return Boolean is
begin
return Self.Node_Count = Self.Node_In_Tree'Length;
end Is_Spanning;
------------------
-- Make_Acyclic --
------------------
procedure Make_Acyclic (G : in out Graph) is
Acyclic : aliased Boolean;
Sorted : constant Depth_Vertices_Array := Depth_First_Search
(G => G,
Acyclic => Acyclic'Access,
Reverse_Edge_Cb => Revert_Edge'Access);
pragma Unreferenced (Sorted);
begin
null;
end Make_Acyclic;
----------
-- Sort --
----------
procedure Sort (W : in out Weight_Array) is
procedure Move (From, To : Natural);
function Lt (Op1, Op2 : Natural) return Boolean;
procedure Move (From, To : Natural) is
begin
W (To) := W (From);
end Move;
function Lt (Op1, Op2 : Natural) return Boolean is
begin
return W (Op1).Weight < W (Op2).Weight;
end Lt;
package HS is new GNAT.Heap_Sort_G (Move, Lt);
begin
HS.Sort (W'Last);
end Sort;
----------------------
-- Normalize_Layers --
----------------------
procedure Normalize_Layers (Spanning : Tree; Info : in out Layout_Info) is
Min_Layer : Integer_Array (1 .. Spanning.Disjoint_Components) :=
(others => Integer'Last);
-- The minimal layer used for each of the independent components
Component : Integer;
begin
for V in Spanning.Node_In_Tree'Range loop
Component := Spanning.Node_In_Tree (V);
Min_Layer (Component) :=
Integer'Min (Min_Layer (Component), Info.Layers (V));
end loop;
for V in Spanning.Node_In_Tree'Range loop
Component := Spanning.Node_In_Tree (V);
Info.Layers (V) := Info.Layers (V) - Min_Layer (Component);
end loop;
end Normalize_Layers;
------------------------------
-- Sort_Nodes_Within_Layers --
------------------------------
procedure Sort_Nodes_Within_Layers
(G : Graph;
Info : in out Layout_Info)
is
Max_Iterations : constant := 8;
Max_I : constant Integer := Max_Index (G);
Position : Integer_Array (Min_Vertex_Index .. Max_I);
procedure Do_Iteration (Layer : Integer; Downward : Boolean);
procedure Do_Iteration (Layer : Integer; Downward : Boolean) is
Weights : Weight_Array (0 .. Max_I + 1);
C : Vertex_Lists.Cursor := Info.In_Layers (Layer).First;
Src, Dest : Vertex_Access;
Current_C : Integer := Weights'First + 1;
Eit : Edge_Iterator;
Total, Count : Integer;
begin
while Has_Element (C) loop
Dest := Element (C);
Total := 0;
Count := 0;
if Downward then
Eit := First (G, Src => Dest);
else
Eit := First (G, Dest => Dest);
end if;
while not At_End (Eit) loop
if Downward then
Src := Get_Dest (Get (Eit));
else
Src := Get_Src (Get (Eit));
end if;
-- ignore self-links.
-- Only take into account tight edges (where nodes are in
-- adjacent layers), which is the default if we added dummy
-- nodes.
if Src /= Dest
and then (Add_Dummy_Nodes
or else Slack (Info, Get (Eit)) = 0)
then
Total := Total + Position (Get_Index (Src));
Count := Count + 1;
end if;
Next (Eit);
end loop;
if Count = 0 then
-- leave the item in place
Weights (Current_C) :=
(Gdouble (Position (Get_Index (Dest))), Dest);
else
Weights (Current_C) :=
(Gdouble (Total) / Gdouble (Count), Dest);
end if;
Current_C := Current_C + 1;
Next (C);
end loop;
-- Now sort based on weights
Sort (Weights (0 .. Current_C - 1));
Info.In_Layers (Layer).Clear;
for W in 1 .. Current_C - 1 loop
Position (Get_Index (Weights (W).Vertex)) := W;
Info.In_Layers (Layer).Append (Weights (W).Vertex);
end loop;
end Do_Iteration;
C : Vertex_Lists.Cursor;
Current_C : Integer;
begin
-- Store the position of elements within each layer
for L in Info.In_Layers'Range loop
C := Info.In_Layers (L).First;
Current_C := 1;
while Has_Element (C) loop
Position (Get_Index (Element (C))) := Current_C;
Current_C := Current_C + 1;
Next (C);
end loop;
end loop;
for Iteration in 0 .. Max_Iterations - 1 loop
if Iteration mod 2 = 0 then
for L in reverse Info.In_Layers'First .. Info.In_Layers'Last - 1
loop
Do_Iteration (L, Downward => True);
end loop;
else
for L in Info.In_Layers'First + 1 .. Info.In_Layers'Last loop
Do_Iteration (L, Downward => False);
end loop;
end if;
end loop;
end Sort_Nodes_Within_Layers;
----------------------
-- Adjust_Positions --
----------------------
procedure Adjust_Positions
(G : Graph;
Info : Layout_Info)
is
type Box is record
X, Y, W, H : Gdouble;
Space_After : Gdouble; -- between item and the next
end record;
Boxes : array (Min_Vertex_Index .. Max_Index (G)) of Box;
procedure Do_Iteration (Layer : Integer; Downward : Boolean);
procedure Do_Iteration (Layer : Integer; Downward : Boolean) is
C : Vertex_Lists.Cursor := Info.In_Layers (Layer).First;
Lowest : Gdouble := Gdouble'First;
Highest : Gdouble;
Total : Gdouble;
Count : Integer;
New_Pos : Gdouble;
Src : Vertex_Access;
Eit : Edge_Iterator;
Current, Next_Item : Vertex_Access;
Current_B : Box; -- size for Current
Next_B : Box; -- size for Next_Item
Child_B : Box;
begin
if Has_Element (C) then
Next_Item := Element (C);
Next_B := Boxes (Get_Index (Next_Item));
end if;
while Next_Item /= null loop
Total := 0.0;
Count := 0;
-- Find the range of coordinates allowed for the current item
Current := Next_Item;
Current_B := Next_B;
Next (C);
if Has_Element (C) then
Next_Item := Element (C);
Next_B := Boxes (Get_Index (Next_Item));
if Info.Horizontal then
Highest := Next_B.Y;
else
Highest := Next_B.X;
end if;
else
Next_Item := null;
Highest := Gdouble'Last;
end if;
-- Now take a look at all its neighbors, either in previous
-- or later layers, depending on the iteration
if Downward then
Eit := First (G, Src => Current);
else
Eit := First (G, Dest => Current);
end if;
while not At_End (Eit) loop
if Downward then
Src := Get_Dest (Get (Eit));
else
Src := Get_Src (Get (Eit));
end if;
-- ignore self-links.
-- Only take into account tight edges (where nodes are in
-- adjacent layers), which is the default if we added dummy
-- nodes.
if Src /= Current
and then (Add_Dummy_Nodes
or else Slack (Info, Get (Eit)) = 0)
then
Child_B := Boxes (Get_Index (Src));
Count := Count + 1;
if Info.Horizontal then
Total := Total + Child_B.Y + Child_B.H / 2.0;
else
Total := Total + Child_B.X + Child_B.W / 2.0;
end if;
end if;
Next (Eit);
end loop;
if Count /= 0 then
New_Pos := Total / Gdouble (Count);
if Info.Horizontal then
-- When we compute the highest possible position, we
-- do not include space_between_items. This gives a
-- chance to still move a vertex that would be blocked
-- between two others (which will also move the next
-- vertices)
New_Pos := New_Pos - Current_B.H / 2.0;
New_Pos := Gdouble'Min (New_Pos, Highest - Current_B.H);
else
New_Pos := New_Pos - Current_B.W / 2.0;
New_Pos := Gdouble'Min (New_Pos, Highest - Current_B.W);
end if;
else
if Info.Horizontal then
New_Pos := Current_B.Y;
else
New_Pos := Current_B.X;
end if;
end if;
New_Pos := Gdouble'Max (Lowest, New_Pos);
if Info.Horizontal then
Boxes (Get_Index (Current)).Y := New_Pos;
Lowest := New_Pos + Current_B.H + Current_B.Space_After;
else
Boxes (Get_Index (Current)).X := New_Pos;
Lowest := New_Pos + Current_B.W + Current_B.Space_After;
end if;
end loop;
end Do_Iteration;
C2 : Vertex_Lists.Cursor;
Pos : Gdouble := 0.0;
Lowest : Gdouble;
Max_Size : Gdouble;
V : Vertex_Access;
Current_B : Box; -- size for Current
begin
-- Compute the coordinates for each layer, and an initial position for
-- items within each layer.
for P in Info.In_Layers'Range loop
Lowest := 0.0;
Max_Size := 0.0;
C2 := Info.In_Layers (P).First;
while Has_Element (C2) loop
V := Element (C2);
if V.all in Base_Dummy_Vertex'Class then
Current_B.W := Dummy_Node_Size;
Current_B.H := Dummy_Node_Size;
Current_B.Space_After := 0.0;
else
Get_Size (V, Width => Current_B.W, Height => Current_B.H);
Current_B.Space_After := Info.Space_Between_Items;
end if;
if Info.Horizontal then
Max_Size := Gdouble'Max (Max_Size, Current_B.W);
Current_B.X := Pos;
Current_B.Y := Lowest;
Lowest := Lowest + Current_B.H + Current_B.Space_After;
else
Max_Size := Gdouble'Max (Max_Size, Current_B.H);
Current_B.X := Lowest;
Current_B.Y := Pos;
Lowest := Lowest + Current_B.W + Current_B.Space_After;
end if;
Boxes (Get_Index (V)) := Current_B;
Next (C2);
end loop;
Pos := Pos + Max_Size + Info.Space_Between_Layers;
end loop;
-- Try to adjust position of nodes to align with parents and children
for Iteration in 0 .. 8 loop
if Iteration mod 2 = 0 then
for P in
reverse Info.In_Layers'First .. Info.In_Layers'Last - 1
loop
Do_Iteration (P, Downward => True);
end loop;
else
for P in Info.In_Layers'First + 1 .. Info.In_Layers'Last loop
Do_Iteration (P, Downward => False);
end loop;
end if;
end loop;
declare
Vit : Vertex_Iterator := First (G);
V : Vertex_Access;
begin
while not At_End (Vit) loop
V := Get (Vit);
if V'Tag /= Base_Dummy_Vertex'Tag then
Current_B := Boxes (Get_Index (V));
Set_Position (V, Current_B.X, Current_B.Y);
end if;
Next (Vit);
end loop;
end;
end Adjust_Positions;
---------------
-- Init_Rank --
---------------
procedure Init_Rank
(G : Graph;
Info : in out Layout_Info)
is
Max_I : constant Integer := Max_Index (G);
Vit : Vertex_Iterator := First (G);
Queue : array (0 .. Max_I) of Vertex_Access;
Q_Index : Integer := Queue'First;
Q_Last : Integer := Queue'First;
-- The queue of nodes to visit
S, D : Vertex_Access;
In_Degree : array (0 .. Max_I) of Integer := (others => 0);
-- Number of remaining in-edges that have not been analyzed for
-- each node.
Layer : Integer;
Eit : Edge_Iterator;
Edge : Edge_Access;
Deg : Natural;
begin
Info.Min_Layer := Default_Layer;
Info.Max_Layer := Default_Layer;
while not At_End (Vit) loop
S := Get (Vit);
Deg := 0;
Eit := First (G, Dest => S);
while not At_End (Eit) loop
-- Ignore self links
if Get_Src (Get (Eit)) /= S then
Deg := Deg + 1;
end if;
Next (Eit);
end loop;
In_Degree (Get_Index (S)) := Deg;
if In_Degree (Get_Index (S)) = 0 then
Queue (Q_Last) := S;
Q_Last := Q_Last + 1;
end if;
Next (Vit);
end loop;
while Q_Index < Q_Last loop
S := Queue (Q_Index);
Q_Index := Q_Index + 1;
-- Compute layer based on ancestors' own layers
Layer := Default_Layer;
Eit := First (G, Dest => S);
while not At_End (Eit) loop
Edge := Get (Eit);
Layer := Integer'Max
(Layer,
Info.Layers (Get_Index (Get_Src (Edge)))
+ Preferred_Length);
Next (Eit);
end loop;
Info.Layers (Get_Index (S)) := Layer;
Info.Max_Layer := Integer'Max (Info.Max_Layer, Layer);
-- Mark all outgoing edges as scanned, which might lead to new
-- nodes to analyze.
Eit := First (G, Src => S);
while not At_End (Eit) loop
Edge := Get (Eit);
D := Get_Dest (Edge);
In_Degree (Get_Index (D)) := In_Degree (Get_Index (D)) - 1;
if In_Degree (Get_Index (D)) = 0 then
Queue (Q_Last) := D;
Q_Last := Q_Last + 1;
end if;
Next (Eit);
end loop;
end loop;
end Init_Rank;
--------------------
-- Organize_Nodes --
--------------------
procedure Organize_Nodes
(G : Graph;
Info : in out Layout_Info)
is
Nodes : constant Depth_Vertices_Array := Depth_First_Search (G);
V : Vertex_Access;
begin
Info.In_Layers := new Layer_Info_Array
(Info.Min_Layer .. Info.Max_Layer);
for N in Nodes'Range loop
V := Nodes (N).Vertex;
Info.In_Layers (Layer (Info, V)).Append (V);
end loop;
Sort_Nodes_Within_Layers (G, Info);
Adjust_Positions (G, Info);
end Organize_Nodes;
-------------------
-- Feasible_Tree --
-------------------
procedure Feasible_Tree
(G : Graph;
Info : in out Layout_Info;
Spanning : out Tree)
is
function Add_Edge_And_Recurse
(E : Edge_Access; V : Vertex_Access) return Boolean;
function Search (V : Vertex_Access) return Boolean;
-- These functions return True if the tree is complete at this
-- point, and therefore we should stop searching.
procedure Add_Adjacent_Edge;
-- Add one adjacent edge to the tree, and change vertex layers to
-- tighten that edge
--------------------------
-- Add_Edge_And_Recurse --
--------------------------
function Add_Edge_And_Recurse
(E : Edge_Access; V : Vertex_Access) return Boolean
is
begin
if not In_Tree (Spanning, V) and then Slack (Info, E) = 0 then
Add_Edge (Spanning, E);
if Is_Spanning (Spanning) or else Search (V) then
return True;
end if;
end if;
return False;
end Add_Edge_And_Recurse;
------------
-- Search --
------------
function Search (V : Vertex_Access) return Boolean is
Eit : Edge_Iterator;
E : Edge_Access;
begin
Eit := First (G, Src => V);
while not At_End (Eit) loop
E := Get (Eit);
if Add_Edge_And_Recurse (E, Get_Dest (E)) then
return True;
end if;
Next (Eit);
end loop;
Eit := First (G, Dest => V);
while not At_End (Eit) loop
E := Get (Eit);
if Add_Edge_And_Recurse (E, Get_Src (E)) then
return True;
end if;
Next (Eit);
end loop;
-- We force the edge into the tree (it might have been an edge
-- with no in or out edges).
Add_Vertex (Spanning, V);
return Is_Spanning (Spanning);
end Search;
-----------------------
-- Add_Adjacent_Edge --
-----------------------
procedure Add_Adjacent_Edge is
Vit : Vertex_Iterator := First (G);
V : Vertex_Access;
Eit : Edge_Iterator;
E : Edge_Access;
Last_Vertex_Not_In_Tree : Vertex_Access;
Layer_Delta : Integer;
Min_Slack : Integer := Integer'Last;
Vertex_To_Add : Vertex_Access;
Edge_To_Add : Edge_Access;
Sl : Integer;
Dummy : Boolean;
pragma Unreferenced (Dummy);
begin
For_Each_Vertex_Not_In_Tree :
while not At_End (Vit) loop
V := Get (Vit);
if not In_Tree (Spanning, V) then
Last_Vertex_Not_In_Tree := V;
Eit := First (G, Src => V);
while not At_End (Eit) loop
E := Get (Eit);
if In_Tree (Spanning, Get_Dest (E)) then
Sl := Slack (Info, E);
if Sl < Min_Slack then
Min_Slack := Sl;
Vertex_To_Add := V;
Edge_To_Add := E;
Layer_Delta := -Sl;
-- that will be the minimum anyway
exit For_Each_Vertex_Not_In_Tree when Sl = 1;
end if;
end if;
Next (Eit);
end loop;
Eit := First (G, Dest => V);
while not At_End (Eit) loop
E := Get (Eit);
if In_Tree (Spanning, Get_Src (E)) then
Sl := Slack (Info, E);
if Sl < Min_Slack then
Min_Slack := Sl;
Vertex_To_Add := V;
Edge_To_Add := E;
Layer_Delta := Sl;
-- that will be the minimum anyway
exit For_Each_Vertex_Not_In_Tree when Sl = 1;
end if;
end if;
Next (Eit);
end loop;
end if;
Next (Vit);
end loop For_Each_Vertex_Not_In_Tree;
-- Have we found an edge to tighten ?
if Vertex_To_Add /= null then
Vit := First (G);
while not At_End (Vit) loop
V := Get (Vit);
-- If the node is in the current component
if Spanning.Node_In_Tree (Get_Index (V)) =
Spanning.Disjoint_Components
then
Info.Layers (Get_Index (V)) :=
Info.Layers (Get_Index (V)) + Layer_Delta;
end if;
Next (Vit);
end loop;
-- Add the edge only after we had adjusted layers
Add_Edge (Spanning, Edge_To_Add);
Info.Min_Layer :=
Integer'Min (Info.Min_Layer, Info.Min_Layer + Layer_Delta);
Info.Max_Layer :=
Integer'Max (Info.Max_Layer, Info.Max_Layer + Layer_Delta);
elsif Last_Vertex_Not_In_Tree /= null then
-- No adjacent vertex, and yet the tree is not spanning. We
-- start from a new node.
Spanning.Disjoint_Components :=
Spanning.Disjoint_Components + 1;
Dummy := Search (Last_Vertex_Not_In_Tree);
end if;
end Add_Adjacent_Edge;
Vit : constant Vertex_Iterator := First (G);
Dummy : Boolean;
pragma Unreferenced (Dummy);
begin
if At_End (Vit) then
-- No nodes in graph
return;
end if;
Spanning.Disjoint_Components := 1;
Dummy := Search (Get (Vit)); -- initial tree (non-spanning)
while not Is_Spanning (Spanning) loop
Add_Adjacent_Edge;
end loop;
end Feasible_Tree;
----------------
-- Rank_Items --
----------------
procedure Rank_Items (G : in out Graph; Info : in out Layout_Info) is
Max_I : constant Integer := Max_Index (G);
Spanning : Tree (Max_I);
begin
Init_Rank (G, Info);
Feasible_Tree (G, Info, Spanning);
-- ??? Should now compute cut values, and adjust layers for edges
-- with negative cut values. The idea is that a node with for
-- instance more incoming edges than outgoing edges, should
-- preferably shorten the incoming edges
Normalize_Layers (Spanning, Info);
-- ??? Could balance the layers: when a node can be in multiple
-- layers (same number of incomding and outgoing edges), it should be
-- moved to the layer which has the fewest nodes to reduce crowding.
end Rank_Items;
---------------------
-- Layered_Layouts --
---------------------
package body Layered_Layouts is
procedure Insert_Dummy_Nodes
(G : in out Graph; Info : in out Layout_Info);
-- When an edge spans multiple layers, replace it with a chain of
-- edges, each of which only connects adjacent layers
------------------------
-- Insert_Dummy_Nodes --
------------------------
procedure Insert_Dummy_Nodes
(G : in out Graph; Info : in out Layout_Info)
is
Eit : Edge_Iterator := First (G);
E : Edge_Access;
V1 : Vertex_Access;
Start_Layer, End_Layer : Integer;
begin
while not At_End (Eit) loop
E := Get (Eit);
Next (Eit);
Start_Layer := Info.Layers (Get_Index (Get_Src (E)));
End_Layer := Info.Layers (Get_Index (Get_Dest (E)));
if Start_Layer < End_Layer - 1 then
declare
Dummies : Vertices_Array
(Start_Layer + 1 .. End_Layer - 1);
begin
V1 := Get_Src (E);
for Layer in Start_Layer + 1 .. End_Layer - 1 loop
-- We can't add the new layer to Layers, since there
-- is not enough space there.
Dummies (Layer) := new Dummy_Vertex;
Base_Dummy_Vertex (Dummies (Layer).all).Layer := Layer;
Add_Vertex (G, Dummies (Layer));
Add_Edge (G, V1, Dummies (Layer));
V1 := Dummies (Layer);
end loop;
Add_Edge (G, V1, Get_Dest (E));
Replaced_With_Dummy_Vertices
(Replaced_Edge => E,
Dummies => Dummies);
Remove (G, E);
end;
end if;
end loop;
end Insert_Dummy_Nodes;
------------
-- Layout --
------------
procedure Layout
(G : in out Graph;
Horizontal : Boolean := True;
Space_Between_Layers : Gdouble := 20.0;
Space_Between_Items : Gdouble := 10.0)
is
Info : Layout_Info;
begin
-- If the graph is empty, nothing to do
if Max_Index (G) = -1 then
return;
end if;
Info.Horizontal := Horizontal;
Info.Space_Between_Items := Space_Between_Items;
Info.Space_Between_Layers := Space_Between_Layers;
Info.Layers :=
new Integer_Array'(Min_Vertex_Index .. Max_Index (G) => 0);
if not Is_Directed (G) then
raise Program_Error
with "Layer layout only applies to directed graphs";
end if;
Make_Acyclic (G);
Rank_Items (G, Info);
if Add_Dummy_Nodes then
Insert_Dummy_Nodes (G, Info);
end if;
Organize_Nodes (G, Info);
Free (Info);
end Layout;
end Layered_Layouts;
end Glib.Graphs.Layouts;
|