Add main axis alignment for BoxLayout.

ui/views/layout/box_layout.cc

Index: ui/views/layout/box_layout.cc
diff --git a/ui/views/layout/box_layout.cc b/ui/views/layout/box_layout.cc
index c11479678a998fe492103648b145b3e4911d81d2..3e6d3bea81e7f33c833feae31de8197d30c042a2 100644
--- a/ui/views/layout/box_layout.cc
+++ b/ui/views/layout/box_layout.cc
@@ -19,7 +19,8 @@ BoxLayout::BoxLayout(BoxLayout::Orientation orientation,
                             inside_border_vertical_spacing,
                             inside_border_horizontal_spacing),
       between_child_spacing_(between_child_spacing),
-      spread_blank_space_(false) {
+      spread_blank_space_(false),
+      box_pack_(BOX_PACK_START) {
 }
 
 BoxLayout::~BoxLayout() {
@@ -29,11 +30,9 @@ void BoxLayout::Layout(View* host) {
   gfx::Rect child_area(host->GetLocalBounds());
   child_area.Inset(host->GetInsets());
   child_area.Inset(inside_border_insets_);
-  int x = child_area.x();
-  int y = child_area.y();
 
   int padding = 0;
-  if (spread_blank_space_) {
+  if (box_pack_ != BOX_PACK_START || spread_blank_space_) {
     int total = 0;
     int visible = 0;
     for (int i = 0; i < host->child_count(); ++i) {
@@ -51,16 +50,39 @@ void BoxLayout::Layout(View* host) {
 
     if (visible) {
       total -= between_child_spacing_;
-      if (orientation_ == kHorizontal)
-        padding = (child_area.width() - total) / visible;
-      else
-        padding = (child_area.height() - total) / visible;
-
-      if (padding < 0)
-        padding = 0;
+      if (spread_blank_space_) {
+        if (orientation_ == kHorizontal)
+          padding = (child_area.width() - total) / visible;

[benwells, 2014/05/13 02:48:05]

I think this code would be easier to follow at a glance if you added three a few
private functions:

int BoxLayout::MainAxisSize(child)
int BoxLayout::MainAxisPosition(child)
void BoxLayout::SetMainAxisSize(child, size)
void BoxLayout::SetMainAxisPosition(child, position)

[calamity, 2014/05/13 04:29:29]

Done.

+        else
+          padding = (child_area.height() - total) / visible;
+
+        if (padding < 0)
+          padding = 0;
+      } else {
+        if (box_pack_ == BOX_PACK_CENTER) {
+          if (orientation_ == kHorizontal) {
+            child_area.set_x(child_area.x() + (child_area.width() - total) / 2);
+            child_area.set_width(total);
+          } else {
+            child_area.set_y(child_area.y() +
+                             (child_area.height() - total) / 2);
+            child_area.set_height(total);
+          }
+        } else if (box_pack_ == BOX_PACK_END) {
+          if (orientation_ == kHorizontal) {
+            child_area.set_x(child_area.x() + child_area.width() - total);
+            child_area.set_width(total);
+          } else {
+            child_area.set_y(child_area.y() + child_area.height() - total);
+            child_area.set_height(total);
+          }
+        }
+      }
     }
   }
 
+  int x = child_area.x();
+  int y = child_area.y();
   for (int i = 0; i < host->child_count(); ++i) {
     View* child = host->child_at(i);
     if (child->visible()) {