From 7a0f255ecf23391f09488ac54fb9b1124827dfa7 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 12 Jun 2013 15:49:45 +0300
Subject: [PATCH] Add constraint types that allow flexible spacing between
 widgets

---
 source/layout.cpp    | 26 ++++++++++++++++++++------
 source/layout.h      |  8 +++++++-
 source/mixedrows.cpp |  6 ++----
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/source/layout.cpp b/source/layout.cpp
index 66eb66b..993c82f 100644
--- a/source/layout.cpp
+++ b/source/layout.cpp
@@ -88,7 +88,10 @@ Layout::Layout():
 	margin(8),
 	row_spacing(5),
 	col_spacing(4)
-{ }
+{
+	n_slack_constraints[0] = 0;
+	n_slack_constraints[1] = 0;
+}
 
 Layout::~Layout()
 {
@@ -167,10 +170,7 @@ void Layout::remove_widget(Widget &wdg)
 			delete *i;
 			slots.erase(i);
 
-			unsigned n = 0;
-			for(i=slots.begin(); i!=slots.end(); ++i, ++n)
-				(*i)->index = n;
-
+			update_slot_indices();
 			update();
 			return;
 		}
@@ -191,6 +191,16 @@ void Layout::update_slot_indices()
 		else
 			(*i)->index = -1;
 	}
+
+	n_slack_constraints[0] = 0;
+	n_slack_constraints[1] = 0;
+	for(list<Slot *>::iterator i=slots.begin(); i!=slots.end(); ++i)
+		if((*i)->index>=0)
+		{
+			for(list<Constraint>::iterator j=(*i)->constraints.begin(); j!=(*i)->constraints.end(); ++j)
+				if(j->target.index>(*i)->index && (j->type&SLACK))
+					++n_slack_constraints[j->type&1];
+		}
 }
 
 Layout::Slot &Layout::get_slot_for_widget(Widget &wdg)
@@ -224,6 +234,7 @@ void Layout::create_constraint(Widget &src, ConstraintType type, Widget &tgt, in
 	tgt_slot.constraints.push_back(Constraint(complement(type), src_slot));
 	tgt_slot.constraints.back().spacing = sp;
 
+	update_slot_indices();
 	update();
 }
 
@@ -286,7 +297,7 @@ void Layout::solve_constraints(int dir, SolveMode mode)
 	five columns for each widget, and one constant column.  The first and second
 	columns of a widget are its position and dimension, respectively.  The
 	remaining three are slack columns; see below for their purposes. */
-	LinearProgram linprog(n_active_slots*5+1);
+	LinearProgram linprog(n_active_slots*5+n_slack_constraints[dir]+1);
 	float weight = slots.size();
 	for(list<Slot *>::iterator i=slots.begin(); i!=slots.end(); ++i)
 	{
@@ -344,6 +355,7 @@ void Layout::solve_constraints(int dir, SolveMode mode)
 
 		/* Add rows for user-defined constraints.  Constraints are always added
 		in pairs, so it's only necessary to create a row for one half. */
+		unsigned k = n_active_slots*5;
 		for(list<Constraint>::iterator j=(*i)->constraints.begin(); j!=(*i)->constraints.end(); ++j)
 			if(j->target.index>(*i)->index && (j->type&1)==dir)
 			{
@@ -359,6 +371,8 @@ void Layout::solve_constraints(int dir, SolveMode mode)
 					row[j->target.index*5+1] = -polarity;
 				if(j->type&SPACING)
 					row.back() = (j->spacing>=0 ? j->spacing : this->*(ptrs.spacing));
+				if(j->type&SLACK)
+					row[k++] = -1;
 			}
 	}
 
diff --git a/source/layout.h b/source/layout.h
index 43d1ca8..2bddb77 100644
--- a/source/layout.h
+++ b/source/layout.h
@@ -61,7 +61,8 @@ private:
 		TARGET_POS = 8,
 		TARGET_DIM = 16,
 		TARGET_MASK = 24,
-		SPACING = 32
+		SPACING = 32,
+		SLACK = 64
 	};
 
 public:
@@ -71,6 +72,10 @@ public:
 		BELOW = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
 		RIGHT_OF = HORIZONTAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING,
 		LEFT_OF = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
+		FAR_ABOVE = VERTICAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING|SLACK,
+		FAR_BELOW = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING|SLACK,
+		FAR_RIGHT_OF = HORIZONTAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING|SLACK,
+		FAR_LEFT_OF = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING|SLACK,
 		ALIGN_TOP = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
 		ALIGN_BOTTOM = VERTICAL|SELF_POS|TARGET_POS,
 		ALIGN_RIGHT = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
@@ -129,6 +134,7 @@ protected:
 	Container *container;
 	std::list<Slot *> slots;
 	unsigned n_active_slots;
+	unsigned n_slack_constraints[2];
 	Sides margin;
 	unsigned row_spacing;
 	unsigned col_spacing;
diff --git a/source/mixedrows.cpp b/source/mixedrows.cpp
index bfcf621..7637020 100644
--- a/source/mixedrows.cpp
+++ b/source/mixedrows.cpp
@@ -43,8 +43,7 @@ Layout::Slot *MixedRows::create_slot(Widget &wdg)
 	if(!first)
 	{
 		Slot *prev = slots.back();
-		if(!hsplit)
-			slot->constraints.push_back(Constraint(RIGHT_OF, *prev));
+		slot->constraints.push_back(Constraint((hsplit ? FAR_RIGHT_OF : RIGHT_OF), *prev));
 		slot->constraints.push_back(Constraint(ALIGN_TOP, *prev));
 		slot->constraints.push_back(Constraint(ALIGN_BOTTOM, *prev));
 		if(uniform_cols)
@@ -53,8 +52,7 @@ Layout::Slot *MixedRows::create_slot(Widget &wdg)
 	else if(!slots.empty())
 	{
 		Slot *prev = slots.back();
-		if(!vsplit)
-			slot->constraints.push_back(Constraint(BELOW, *prev));
+		slot->constraints.push_back(Constraint((vsplit ? FAR_BELOW : BELOW), *prev));
 		if(uniform_rows)
 			slot->constraints.push_back(Constraint(COPY_HEIGHT, *prev));
 	}
-- 
2.43.0