gfx/src/nsBoundingMetrics.h@97036ab72558 (annotated)
gfx/src/nsBoundingMetrics.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.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef __nsBoundingMetrics_h |
| michael@0 | 7 | #define __nsBoundingMetrics_h |
| michael@0 | 8 | |
| michael@0 | 9 | #include "nsCoord.h" |
| michael@0 | 10 | #include <algorithm> |
| michael@0 | 11 | |
| michael@0 | 12 | /* Struct used for accurate measurements of a string, in order to |
| michael@0 | 13 | * allow precise positioning when processing MathML. This is in its |
| michael@0 | 14 | * own header file because some very-widely-included headers need it |
| michael@0 | 15 | * but not the rest of nsFontMetrics, or vice versa. |
| michael@0 | 16 | */ |
| michael@0 | 17 | |
| michael@0 | 18 | struct nsBoundingMetrics { |
| michael@0 | 19 | |
| michael@0 | 20 | /////////// |
| michael@0 | 21 | // Metrics that _exactly_ enclose the text: |
| michael@0 | 22 | |
| michael@0 | 23 | // The character coordinate system is the one used on X Windows: |
| michael@0 | 24 | // 1. The origin is located at the intersection of the baseline |
| michael@0 | 25 | // with the left of the character's cell. |
| michael@0 | 26 | // 2. All horizontal bearings are oriented from left to right. |
| michael@0 | 27 | // 2. All horizontal bearings are oriented from left to right. |
| michael@0 | 28 | // 3. The ascent is oriented from bottom to top (being 0 at the orgin). |
| michael@0 | 29 | // 4. The descent is oriented from top to bottom (being 0 at the origin). |
| michael@0 | 30 | |
| michael@0 | 31 | // Note that Win32/Mac/PostScript use a different convention for |
| michael@0 | 32 | // the descent (all vertical measurements are oriented from bottom |
| michael@0 | 33 | // to top on these palatforms). Make sure to flip the sign of the |
| michael@0 | 34 | // descent on these platforms for cross-platform compatibility. |
| michael@0 | 35 | |
| michael@0 | 36 | // Any of the following member variables listed here can have |
| michael@0 | 37 | // positive or negative value. |
| michael@0 | 38 | |
| michael@0 | 39 | nscoord leftBearing; |
| michael@0 | 40 | /* The horizontal distance from the origin of the drawing |
| michael@0 | 41 | operation to the left-most part of the drawn string. */ |
| michael@0 | 42 | |
| michael@0 | 43 | nscoord rightBearing; |
| michael@0 | 44 | /* The horizontal distance from the origin of the drawing |
| michael@0 | 45 | operation to the right-most part of the drawn string. |
| michael@0 | 46 | The _exact_ width of the string is therefore: |
| michael@0 | 47 | rightBearing - leftBearing */ |
| michael@0 | 48 | |
| michael@0 | 49 | nscoord ascent; |
| michael@0 | 50 | /* The vertical distance from the origin of the drawing |
| michael@0 | 51 | operation to the top-most part of the drawn string. */ |
| michael@0 | 52 | |
| michael@0 | 53 | nscoord descent; |
| michael@0 | 54 | /* The vertical distance from the origin of the drawing |
| michael@0 | 55 | operation to the bottom-most part of the drawn string. |
| michael@0 | 56 | The _exact_ height of the string is therefore: |
| michael@0 | 57 | ascent + descent */ |
| michael@0 | 58 | |
| michael@0 | 59 | nscoord width; |
| michael@0 | 60 | /* The horizontal distance from the origin of the drawing |
| michael@0 | 61 | operation to the correct origin for drawing another string |
| michael@0 | 62 | to follow the current one. Depending on the font, this |
| michael@0 | 63 | could be greater than or less than the right bearing. */ |
| michael@0 | 64 | |
| michael@0 | 65 | nsBoundingMetrics() : leftBearing(0), rightBearing(0), |
| michael@0 | 66 | ascent(0), descent(0), width(0) |
| michael@0 | 67 | {} |
| michael@0 | 68 | |
| michael@0 | 69 | void |
| michael@0 | 70 | operator += (const nsBoundingMetrics& bm) { |
| michael@0 | 71 | if (ascent + descent == 0 && rightBearing - leftBearing == 0) { |
| michael@0 | 72 | ascent = bm.ascent; |
| michael@0 | 73 | descent = bm.descent; |
| michael@0 | 74 | leftBearing = width + bm.leftBearing; |
| michael@0 | 75 | rightBearing = width + bm.rightBearing; |
| michael@0 | 76 | } |
| michael@0 | 77 | else { |
| michael@0 | 78 | if (ascent < bm.ascent) ascent = bm.ascent; |
| michael@0 | 79 | if (descent < bm.descent) descent = bm.descent; |
| michael@0 | 80 | leftBearing = std::min(leftBearing, width + bm.leftBearing); |
| michael@0 | 81 | rightBearing = std::max(rightBearing, width + bm.rightBearing); |
| michael@0 | 82 | } |
| michael@0 | 83 | width += bm.width; |
| michael@0 | 84 | } |
| michael@0 | 85 | }; |
| michael@0 | 86 | |
| michael@0 | 87 | #endif // __nsBoundingMetrics_h |
