gfx/layers/DirectionUtils.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef GFX_DIRECTIONUTILS_H
   8 #define GFX_DIRECTIONUTILS_H
   9
  10 #include "LayersTypes.h"  // for ScrollDirection
  11 #include "Units.h"        // for Coord, Point, and Rect types
  12
  13 namespace mozilla {
  14 namespace layers {
  15
  16 template <typename PointOrRect>
  17 CoordOf<PointOrRect> GetAxisStart(ScrollDirection aDir,
  18                                   const PointOrRect& aValue) {
  19   if (aDir == ScrollDirection::eHorizontal) {
  20     return aValue.X();
  21   } else {
  22     return aValue.Y();
  23   }
  24 }
  25
  26 template <typename Rect>
  27 CoordOf<Rect> GetAxisEnd(ScrollDirection aDir, const Rect& aValue) {
  28   if (aDir == ScrollDirection::eHorizontal) {
  29     return aValue.XMost();
  30   } else {
  31     return aValue.YMost();
  32   }
  33 }
  34
  35 template <typename Rect>
  36 CoordOf<Rect> GetAxisLength(ScrollDirection aDir, const Rect& aValue) {
  37   if (aDir == ScrollDirection::eHorizontal) {
  38     return aValue.Width();
  39   } else {
  40     return aValue.Height();
  41   }
  42 }
  43
  44 template <typename FromUnits, typename ToUnits>
  45 float GetAxisScale(ScrollDirection aDir,
  46                    const gfx::ScaleFactors2D<FromUnits, ToUnits>& aValue) {
  47   if (aDir == ScrollDirection::eHorizontal) {
  48     return aValue.xScale;
  49   } else {
  50     return aValue.yScale;
  51   }
  52 }
  53
  54 inline ScrollDirection GetPerpendicularDirection(ScrollDirection aDir) {
  55   return aDir == ScrollDirection::eHorizontal ? ScrollDirection::eVertical
  56                                               : ScrollDirection::eHorizontal;
  57 }
  58
  59 }  // namespace layers
  60 }  // namespace mozilla
  61
  62 #endif /* GFX_DIRECTIONUTILS_H */