Handle large rects better.

ui/gfx/geometry/rect_conversions.cc

Index: ui/gfx/geometry/rect_conversions.cc
diff --git a/ui/gfx/geometry/rect_conversions.cc b/ui/gfx/geometry/rect_conversions.cc
index b4ef3d44ec9c4e434b93ae64531cde2f6197014e..5bba79ea4f139e6507d0c44f7e197c210a0beb4f 100644
--- a/ui/gfx/geometry/rect_conversions.cc
+++ b/ui/gfx/geometry/rect_conversions.cc
@@ -15,32 +15,60 @@ namespace gfx {
 Rect ToEnclosingRect(const RectF& rect) {
   int min_x = ToFlooredInt(rect.x());
   int min_y = ToFlooredInt(rect.y());
-  float max_x = rect.right();
-  float max_y = rect.bottom();
-  int width =
-      rect.width() == 0
-          ? 0
-          : std::max(
-                ToCeiledInt(static_cast<double>(ToCeiledInt(max_x)) - min_x),
-                0);
-  int height =
-      rect.height() == 0
-          ? 0
-          : std::max(
-                ToCeiledInt(static_cast<double>(ToCeiledInt(max_y)) - min_y),
-                0);
+  int max_x = ToCeiledInt(rect.right());
+  int max_y = ToCeiledInt(rect.bottom());
+  int width = base::SaturatedSubtraction(max_x, min_x);
+  int height = base::SaturatedSubtraction(max_y, min_y);

[Peter Mayo, 2017/03/14 18:35:59]

move into set from range in header

+
+  // clamping may move one side, choose to move the bigger by recomputing it.
+  // The computation of right is implicit, so this happens vacuosly.
+  //  If Right is small, move left to width away.
+  //  If Left is big(negative), move them both to keep the center.
+  if (width >= std::numeric_limits<int>::max() / 2) {
+    if (base::SaturatedAbsolute(max_x) < width / 2)
+      min_x = max_x - width;
+    else if (base::SaturatedAbsolute(min_x) > width / 2)
+      min_x = min_x + width / 4;
+  }
+
+  // Same computation, other axis.
+  if (height >= std::numeric_limits<int>::max() / 2) {
+    if (base::SaturatedAbsolute(max_y) < height / 2)
+      min_y = max_y - height;
+    else if (base::SaturatedAbsolute(min_y) > height / 2)
+      min_y = min_y + height / 4;
+  }
+
   return Rect(min_x, min_y, width, height);
 }
 
 Rect ToEnclosedRect(const RectF& rect) {
   int min_x = ToCeiledInt(rect.x());
   int min_y = ToCeiledInt(rect.y());
-  float max_x = rect.right();
-  float max_y = rect.bottom();
-  int width = std::max(
-      ToFlooredInt(static_cast<float>(ToFlooredInt(max_x)) - min_x), 0);
-  int height = std::max(
-      ToFlooredInt(static_cast<float>(ToFlooredInt(max_y)) - min_y), 0);
+  int max_x = ToFlooredInt(rect.right());
+  int max_y = ToFlooredInt(rect.bottom());
+  int width = base::SaturatedSubtraction(max_x, min_x);
+  int height = base::SaturatedSubtraction(max_y, min_y);
+
+  // clamping may move one side, choose to move the bigger by recomputing it.
+  // The computation of right is implicit, so this happens vacuosly.
+  //  If Right is small, move left to width away.
+  //  If Left is big(negative), move them both to keep the center.
+  if (width >= std::numeric_limits<int>::max() / 2) {
+    if (base::SaturatedAbsolute(max_x) < width / 2)
+      min_x = max_x - width;
+    else if (base::SaturatedAbsolute(min_x) > width / 2)
+      min_x = min_x + width / 4;
+  }
+
+  // Same computation, other axis.
+  if (height >= std::numeric_limits<int>::max() / 2) {
+    if (base::SaturatedAbsolute(max_y) < height / 2)
+      min_y = max_y - height;
+    else if (base::SaturatedAbsolute(min_y) > height / 2)
+      min_y = min_y + height / 4;
+  }
+
   return Rect(min_x, min_y, width, height);
 }