# HG changeset patch
# User Chris Cannam
# Date 1295264657 0
# Node ID b8ded5213d16e095cc3582489d8a601b485db551
# Parent  45f69889d28d57d7574a6d480ad5ea7cf9ac85c5
 * Revert the grapher change from revision ec2baee80833 on Dec 19th 2010.  The change definitely performed worse than the original (now reinstated) logic in the real-world soundsoftware-site case, with far more connection overlaps and ambiguous placements.

diff -r 45f69889d28d -r b8ded5213d16 grapher.cpp
--- a/grapher.cpp	Wed Jan 12 16:38:13 2011 +0000
+++ b/grapher.cpp	Mon Jan 17 11:44:17 2011 +0000
@@ -23,10 +23,7 @@
 
 #include <iostream>
 
-#include <QMultiMap>
-
-int Grapher::findAvailableColumn(int row, int parent, int sign,
-                                 bool preferParentCol)
+int Grapher::findAvailableColumn(int row, int parent, bool preferParentCol)
 {
     int col = parent;
     if (preferParentCol) {
@@ -39,9 +36,7 @@
         if (isAvailable(row, ++col)) return col;
     }
     col = parent;
-    if (sign == 0) {
-        sign = (col < 0 ? -1 : 1);
-    }
+    int sign = (col < 0 ? -1 : 1);
     while (1) {
         col += sign;
         if (isAvailable(row, col)) return col;
@@ -147,7 +142,6 @@
     int col = 0;
     int row = item->row();
     QString branch = cs->branch();
-    int branchHome = m_branchHomes[branch];
 
     int nparents = cs->parents().size();
     QString parentId;
@@ -156,7 +150,8 @@
     switch (nparents) {
 
     case 0:
-        col = findAvailableColumn(row, branchHome, 0, true);
+        col = m_branchHomes[cs->branch()];
+        col = findAvailableColumn(row, col, true);
         break;
 
     case 1:
@@ -170,7 +165,7 @@
             col = m_items[parentId]->column();
         }
 
-        col = findAvailableColumn(row, col, branchHome - col, true);
+        col = findAvailableColumn(row, col, true);
         break;
 
     case 2:
@@ -190,9 +185,9 @@
 
         if (parentsOnSameBranch > 0) {
             col /= parentsOnSameBranch;
-            col = findAvailableColumn(item->row(), col, 0, true);
+            col = findAvailableColumn(item->row(), col, true);
         } else {
-            col = findAvailableColumn(item->row(), col, 0, false);
+            col = findAvailableColumn(item->row(), col, false);
         }
         break;
     }
@@ -209,7 +204,7 @@
 
     if (m_uncommittedParents.contains(id)) {
         if (m_uncommittedParents[0] == id) {
-            int ucol = findAvailableColumn(row-1, col, branchHome - col, true);
+            int ucol = findAvailableColumn(row-1, col, true);
             m_uncommitted->setColumn(ucol);
             m_haveAllocatedUncommittedColumn = true;
         }
@@ -263,7 +258,7 @@
             for (int i = 0; i < 2; ++i) {
                 int off = i * 2 - 1; // 0 -> -1, 1 -> 1
                 ChangesetItem *it = m_items[special[i]];
-                it->setColumn(findAvailableColumn(it->row(), col + off, 0, true));
+                it->setColumn(findAvailableColumn(it->row(), col + off, true));
                 for (int r = row-1; r >= it->row(); --r) {
                     m_alloc[r].insert(it->column());
                 }
@@ -287,34 +282,10 @@
 
 void Grapher::allocateBranchHomes(Changesets csets)
 {
-    QMap<QString, int> branchCounts;
-    QMap<QString, QString> branchParents;
-
-    QStringList branches;
-
     foreach (Changeset *cs, csets) {
-
         QString branch = cs->branch();
-
-        if (!branchCounts.contains(branch)) {
-            // Guess at the parent branch for this one which we
-            // haven't seen before. This is not entirely reliable, but
-            // it doesn't need to be
-            if (!cs->parents().empty()) {
-                QString firstParentId = cs->parents()[0];
-                if (m_changesets.contains(firstParentId)) {
-                    Changeset *firstParent = m_changesets[firstParentId];
-                    branchParents[branch] = firstParent->branch();
-                }
-            }
-            branches.push_back(branch);
-        }
-
-        branchCounts[branch]++;
-        
         ChangesetItem *item = m_items[cs->id()];
         if (!item) continue;
-
         int row = item->row();
         if (!m_branchRanges.contains(branch)) {
             m_branchRanges[branch] = Range(row, row);
@@ -328,20 +299,8 @@
 
     m_branchHomes[""] = 0;
     m_branchHomes["default"] = 0;
-/*
-    QStringList orderedBranches; // will be ordered by "popularity"
 
-    QMultiMap<int, QString> branchesByCount;
-    foreach (QString branch, branchCounts.keys()) {
-        branchesByCount.insert(branchCounts[branch], branch);
-    }
-    foreach (QString branch, branchesByCount) {
-        orderedBranches.push_front(branch);
-    }
-*/
-    int sign = -1;
-    
-    foreach (QString branch, branches) {
+    foreach (QString branch, m_branchRanges.keys()) {
         if (branch == "") continue;
         QSet<int> taken;
         taken.insert(0);
@@ -356,23 +315,26 @@
             }
         }
         int home = 2;
-        QString parent = branchParents[branch];
-        if (parent != "" && parent != "default" &&
-            m_branchHomes.contains(parent)) {
-            home = m_branchHomes[parent];
-            if (home > 0) sign = 1;
-            else sign = -1;
-        } else {
-            sign = -sign;
-        }
         while (taken.contains(home)) {
-            home = home + 2 * sign;
+            if (home > 0) {
+                if (home % 2 == 1) {
+                    home = -home;
+                } else {
+                    home = home + 1;
+                }
+            } else {
+                if ((-home) % 2 == 1) {
+                    home = home + 1;
+                } else {
+                    home = -(home-2);
+                }
+            }
         }
         m_branchHomes[branch] = home;
     }
 
-    foreach (QString branch, branches) {
-        DEBUG << branch << ": pop " << branchCounts[branch] << ", parent " << branchParents[branch] << ", range " << m_branchRanges[branch].first << " - " << m_branchRanges[branch].second << ", home " << m_branchHomes[branch] << endl;
+    foreach (QString branch, m_branchRanges.keys()) {
+        DEBUG << branch.toStdString() << ": " << m_branchRanges[branch].first << " - " << m_branchRanges[branch].second << ", home " << m_branchHomes[branch] << endl;
     }
 }
 
diff -r 45f69889d28d -r b8ded5213d16 grapher.h
--- a/grapher.h	Wed Jan 12 16:38:13 2011 +0000
+++ b/grapher.h	Mon Jan 17 11:44:17 2011 +0000
@@ -88,7 +88,7 @@
     void layoutCol(QString id);
     void allocateBranchHomes(Changesets csets);
     bool rangesConflict(const Range &r1, const Range &r2);
-    int findAvailableColumn(int row, int parent, int sign, bool preferParentCol);
+    int findAvailableColumn(int row, int parent, bool preferParentCol);
     bool isAvailable(int row, int col);
 };