gfx/2d/ScaleFactor.h@97036ab72558
gfx/2d/ScaleFactor.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 * This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 #ifndef MOZILLA_GFX_SCALEFACTOR_H_
7 #define MOZILLA_GFX_SCALEFACTOR_H_
9 #include "mozilla/Attributes.h"
11 #include "gfxPoint.h"
13 namespace mozilla {
14 namespace gfx {
16 /*
17 * This class represents a scaling factor between two different pixel unit
18 * systems. This is effectively a type-safe float, intended to be used in
19 * combination with the known-type instances of gfx::Point, gfx::Rect, etc.
20 *
21 * Note that some parts of the code that pre-date this class used separate
22 * scaling factors for the x and y axes. However, at runtime these values
23 * were always expected to be the same, so this class uses only one scale
24 * factor for both axes. The two constructors that take two-axis scaling
25 * factors check to ensure that this assertion holds.
26 */
27 template<class src, class dst>
28 struct ScaleFactor {
29 float scale;
31 MOZ_CONSTEXPR ScaleFactor() : scale(1.0) {}
32 MOZ_CONSTEXPR ScaleFactor(const ScaleFactor<src, dst>& aCopy) : scale(aCopy.scale) {}
33 explicit MOZ_CONSTEXPR ScaleFactor(float aScale) : scale(aScale) {}
35 explicit ScaleFactor(float aX, float aY) : scale(aX) {
36 MOZ_ASSERT(fabs(aX - aY) < 1e-6);
37 }
39 ScaleFactor<dst, src> Inverse() {
40 return ScaleFactor<dst, src>(1 / scale);
41 }
43 bool operator==(const ScaleFactor<src, dst>& aOther) const {
44 return scale == aOther.scale;
45 }
47 bool operator!=(const ScaleFactor<src, dst>& aOther) const {
48 return !(*this == aOther);
49 }
51 bool operator<(const ScaleFactor<src, dst>& aOther) const {
52 return scale < aOther.scale;
53 }
55 bool operator<=(const ScaleFactor<src, dst>& aOther) const {
56 return scale <= aOther.scale;
57 }
59 bool operator>(const ScaleFactor<src, dst>& aOther) const {
60 return scale > aOther.scale;
61 }
63 bool operator>=(const ScaleFactor<src, dst>& aOther) const {
64 return scale >= aOther.scale;
65 }
67 template<class other>
68 ScaleFactor<other, dst> operator/(const ScaleFactor<src, other>& aOther) const {
69 return ScaleFactor<other, dst>(scale / aOther.scale);
70 }
72 template<class other>
73 ScaleFactor<src, other> operator/(const ScaleFactor<other, dst>& aOther) const {
74 return ScaleFactor<src, other>(scale / aOther.scale);
75 }
77 template<class other>
78 ScaleFactor<src, other> operator*(const ScaleFactor<dst, other>& aOther) const {
79 return ScaleFactor<src, other>(scale * aOther.scale);
80 }
82 template<class other>
83 ScaleFactor<other, dst> operator*(const ScaleFactor<other, src>& aOther) const {
84 return ScaleFactor<other, dst>(scale * aOther.scale);
85 }
86 };
88 }
89 }
91 #endif /* MOZILLA_GFX_SCALEFACTOR_H_ */
