From 3bd1ec9334856e4071cc4f1b3106efc1f44db30d Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Wed, 3 Sep 2014 18:30:38 -0400
Subject: [PATCH] Exported xspan/yspan in Grid to the Add() function parameter
 list.

---
 grid.go            | 15 ++++++++++-----
 yz_repaint_test.go | 16 ++++++++--------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/grid.go b/grid.go
index 4de9304..a6bb02c 100644
--- a/grid.go
+++ b/grid.go
@@ -8,7 +8,7 @@ import (
 
 // Grid is a Control that arranges other Controls in a grid.
 // Grid is a very powerful container: it can position and size each Control in several ways and can (and must) have Controls added to it at any time, in any direction.
-// [TODO it can also have Controls spanning multiple rows and columns.]
+// it can also have Controls spanning multiple rows and columns.
 // 
 // Each Control in a Grid has associated "expansion" and "alignment" values in both the X and Y direction.
 // Expansion determines whether all cells in the same row/column are given whatever space is left over after figuring out how big the rest of the Grid should be.
@@ -24,7 +24,9 @@ type Grid interface {
 	// Otherwise, it is placed relative to nextTo.
 	// If nextTo is nil, it is placed next to the previously added Control.
 	// The effect of adding the same Control multiple times is undefined, as is the effect of adding a Control next to one not present in the Grid.
-	Add(control Control, nextTo Control, side Side, xexpand bool, xalign Align, yexpand bool, yalign Align)
+	// The effect of overlapping spanning Controls is also undefined.
+	// Add panics if either xspan or yspan are zero or negative.
+	Add(control Control, nextTo Control, side Side, xexpand bool, xalign Align, yexpand bool, yalign Align, xspan int, yspan int)
 }
 
 // Align represents the alignment of a Control in its cell of a Grid.
@@ -112,15 +114,18 @@ func (g *grid) reorigin() {
 	}
 }
 
-func (g *grid) Add(control Control, nextTo Control, side Side, xexpand bool, xalign Align, yexpand bool, yalign Align) {
+func (g *grid) Add(control Control, nextTo Control, side Side, xexpand bool, xalign Align, yexpand bool, yalign Align, xspan int, yspan int) {
+	if xspan <= 0 || yspan <= 0 {
+		panic(fmt.Errorf("invalid span %dx%d given to Grid.Add()", xspan, yspan))
+	}
 	cell := gridCell{
 		control:		control,
 		xexpand:		xexpand,
 		xalign:		xalign,
 		yexpand:		yexpand,
 		yalign:		yalign,
-		xspan:		1,
-		yspan:		1,
+		xspan:		xspan,
+		yspan:		yspan,
 	}
 	if g.parent != nil {
 		control.setParent(g.parent)
diff --git a/yz_repaint_test.go b/yz_repaint_test.go
index 5623b6b..5c4f0fb 100644
--- a/yz_repaint_test.go
+++ b/yz_repaint_test.go
@@ -32,8 +32,8 @@ func newRepainter(times int) *repainter {
 	r.area = NewArea(r.img.Rect.Dx(), r.img.Rect.Dy(), r)
 	r.area.OnTextFieldDismissed(r.tfdone)
 	grid2 := NewGrid()
-	grid2.Add(r.area, nil, South, true, Fill, true, Fill)
-	grid2.Add(NewButton("X"), nil, East, false, LeftTop, true, Center)
+	grid2.Add(r.area, nil, South, true, Fill, true, Fill, 1, 1)
+	grid2.Add(NewButton("X"), nil, East, false, LeftTop, true, Center, 1, 1)
 	r.x = NewTextField()
 	r.x.OnChanged(r.setx)
 	r.y = NewTextField()
@@ -47,12 +47,12 @@ func newRepainter(times int) *repainter {
 	r.all = NewButton("All")
 	r.all.OnClicked(r.doall)
 	grid := NewGrid()
-	grid.Add(r.x, nil, North, true, Fill, false, LeftTop)
-	grid.Add(r.y, r.x, East, true, Fill, false, LeftTop)
-	grid.Add(r.repaint, nil, East, false, 0, false, LeftTop)
-	grid.Add(r.width, r.x, South, true, Fill, false, LeftTop)
-	grid.Add(r.height, nil, East, true, Fill, false, LeftTop)
-	grid.Add(r.all, nil, East, false, Center, false, LeftTop)
+	grid.Add(r.x, nil, North, true, Fill, false, LeftTop, 1, 1)
+	grid.Add(r.y, r.x, East, true, Fill, false, LeftTop, 1, 1)
+	grid.Add(r.repaint, nil, East, false, 0, false, LeftTop, 1, 1)
+	grid.Add(r.width, r.x, South, true, Fill, false, LeftTop, 1, 1)
+	grid.Add(r.height, nil, East, true, Fill, false, LeftTop, 1, 1)
+	grid.Add(r.all, nil, East, false, Center, false, LeftTop, 1, 1)
 	r.stack = NewVerticalStack(grid2, grid)
 	r.stack.SetStretchy(0)
 	return r