From d40305001bfd61bef7e118c8580895f68d36b163 Mon Sep 17 00:00:00 2001
From: "danakj@chromium.org"
 <danakj@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Tue, 23 Oct 2012 16:51:47 +0000
Subject: Make gfx::Rect class operations consistently mutate the class they
 are called on.

Currently some methods mutate the class, and some return a new value, requiring
API users to know what kind of method they are calling each time, and making
inconsistent code. For example:

gfx::Rect rect;
rect.Inset(1, 1, 1, 1);
rect = rect.Intersect(other_rect);
rect.Offset(1, 1);

Instead of:

gfx::Rect rect;
rect.Inset(1, 1, 1, 1);
rect.Intersect(other_rect);
rect.Offset(1, 1);

We could go either way - making the class immutable or all methods return a new
instance - but I believe it is better to instead make all methods mutate the
class. This allows for shorter lines of code by avoiding having to repeat the
object's name twice in order to change it.

This patch changes gfx::Rect classes and all the callsites that uses these
methods. It should make no change in behaviour, so no new tests added.

R=sky
BUG=147395

Review URL: https://codereview.chromium.org/11110004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@163579 0039d316-1c4b-4281-b951-d872f2087c98
---
 ui/gfx/rect_base_impl.h | 53 ++++++++++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 23 deletions(-)

(limited to 'ui/gfx/rect_base_impl.h')

diff --git a/ui/gfx/rect_base_impl.h b/ui/gfx/rect_base_impl.h
index ab71f42..291929d 100644
--- a/ui/gfx/rect_base_impl.h
+++ b/ui/gfx/rect_base_impl.h
@@ -165,8 +165,13 @@ template<typename Class,
          typename SizeClass,
          typename InsetsClass,
          typename Type>
-Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Intersect(
-    const Class& rect) const {
+void RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Intersect(
+    const Class& rect) {
+  if (IsEmpty() || rect.IsEmpty()) {
+    SetRect(0, 0, 0, 0);
+    return;
+  }
+
   Type rx = std::max(x(), rect.x());
   Type ry = std::max(y(), rect.y());
   Type rr = std::min(right(), rect.right());
@@ -175,7 +180,7 @@ Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Intersect(
   if (rx >= rr || ry >= rb)
     rx = ry = rr = rb = 0;  // non-intersecting
 
-  return Class(rx, ry, rr - rx, rb - ry);
+  SetRect(rx, ry, rr - rx, rb - ry);
 }
 
 template<typename Class,
@@ -183,20 +188,21 @@ template<typename Class,
          typename SizeClass,
          typename InsetsClass,
          typename Type>
-Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Union(
-    const Class& rect) const {
-  // special case empty rects...
-  if (IsEmpty())
-    return rect;
+void RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Union(
+    const Class& rect) {
+  if (IsEmpty()) {
+    *this = rect;
+    return;
+  }
   if (rect.IsEmpty())
-    return *static_cast<const Class*>(this);
+    return;
 
   Type rx = std::min(x(), rect.x());
   Type ry = std::min(y(), rect.y());
   Type rr = std::max(right(), rect.right());
   Type rb = std::max(bottom(), rect.bottom());
 
-  return Class(rx, ry, rr - rx, rb - ry);
+  SetRect(rx, ry, rr - rx, rb - ry);
 }
 
 template<typename Class,
@@ -204,13 +210,14 @@ template<typename Class,
          typename SizeClass,
          typename InsetsClass,
          typename Type>
-Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Subtract(
-    const Class& rect) const {
-  // boundary cases:
+void RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Subtract(
+    const Class& rect) {
   if (!Intersects(rect))
-    return *static_cast<const Class*>(this);
-  if (rect.Contains(*static_cast<const Class*>(this)))
-    return Class();
+    return;
+  if (rect.Contains(*static_cast<const Class*>(this))) {
+    SetRect(0, 0, 0, 0);
+    return;
+  }
 
   Type rx = x();
   Type ry = y();
@@ -232,7 +239,7 @@ Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Subtract(
       rb = rect.y();
     }
   }
-  return Class(rx, ry, rr - rx, rb - ry);
+  SetRect(rx, ry, rr - rx, rb - ry);
 }
 
 template<typename Class,
@@ -240,15 +247,15 @@ template<typename Class,
          typename SizeClass,
          typename InsetsClass,
          typename Type>
-Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::AdjustToFit(
-    const Class& rect) const {
+void RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::AdjustToFit(
+    const Class& rect) {
   Type new_x = x();
   Type new_y = y();
   Type new_width = width();
   Type new_height = height();
   AdjustAlongAxis(rect.x(), rect.width(), &new_x, &new_width);
   AdjustAlongAxis(rect.y(), rect.height(), &new_y, &new_height);
-  return Class(new_x, new_y, new_width, new_height);
+  SetRect(new_x, new_y, new_width, new_height);
 }
 
 template<typename Class,
@@ -266,13 +273,13 @@ template<typename Class,
          typename SizeClass,
          typename InsetsClass,
          typename Type>
-Class RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::Center(
-    const SizeClass& size) const {
+void RectBase<Class, PointClass, SizeClass, InsetsClass, Type>::
+    ClampToCenteredSize(const SizeClass& size) {
   Type new_width = std::min(width(), size.width());
   Type new_height = std::min(height(), size.height());
   Type new_x = x() + (width() - new_width) / 2;
   Type new_y = y() + (height() - new_height) / 2;
-  return Class(new_x, new_y, new_width, new_height);
+  SetRect(new_x, new_y, new_width, new_height);
 }
 
 template<typename Class,
-- 
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