Simplify some CFX_FloatRect methods.chromium/3285

Also add a comment about the various CFX_FloatRect to FX_RECT conversion
methods.

Change-Id: Ia9984797dc513cdc487fe9972b32c216c9f99ec1
Reviewed-on: https://pdfium-review.googlesource.com/20217
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/core/fxcrt/fx_coordinates.h b/core/fxcrt/fx_coordinates.h
index 1767e33f0c..55d28cd66f 100644
--- a/core/fxcrt/fx_coordinates.h
+++ b/core/fxcrt/fx_coordinates.h
@@ -247,9 +247,20 @@ class CFX_FloatRect {
   void Intersect(const CFX_FloatRect& other_rect);
   void Union(const CFX_FloatRect& other_rect);
 
+  // These may be better at rounding than ToFxRect() and friends.
+  //
+  // Returned rect has bounds rounded up/down such that it is contained in the
+  // original.
   FX_RECT GetInnerRect() const;
+
+  // Returned rect has bounds rounded up/down such that the original is
+  // contained in it.
   FX_RECT GetOuterRect() const;
+
+  // Returned rect has bounds rounded up/down such that the dimensions are
+  // rounded up and the sum of the error in the bounds is minimized.
   FX_RECT GetClosestRect() const;
+
   CFX_FloatRect GetCenterSquare() const;
 
   void InitRect(const CFX_PointF& point) {
@@ -329,7 +340,15 @@ class CFX_FloatRect {
   void Scale(float fScale);
   void ScaleFromCenterPoint(float fScale);
 
+  // GetInnerRect() and friends may be better at rounding than these methods.
+  // Unlike the methods above, these two blindly floor / round the LBRT values.
+  // Doing so may introduce rounding errors that are visible to users as
+  // off-by-one pixels/lines.
+  //
+  // Floors LBRT values.
   FX_RECT ToFxRect() const;
+
+  // Rounds LBRT values.
   FX_RECT ToRoundedFxRect() const;
 
   float left;