LCOV - app.info - gfx/src/nsBoundingMetrics.h

LCOV - code coverage report
| Current view: | directory - gfx/src - nsBoundingMetrics.h (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 15 | 0 | 0.0 %
| Date: | 2012-06-02 | Functions: | 2 | 0 | 0.0 %

           1                 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
           2                 : /* ***** BEGIN LICENSE BLOCK *****
           3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
           4                 :  *
           5                 :  * The contents of this file are subject to the Mozilla Public License Version
           6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
           7                 :  * the License. You may obtain a copy of the License at
           8                 :  * http://www.mozilla.org/MPL/
           9                 :  *
          10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
          11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
          12                 :  * for the specific language governing rights and limitations under the
          13                 :  * License.
          14                 :  *
          15                 :  * The Original Code is mozilla.org code.
          16                 :  *
          17                 :  * The Initial Developer of the Original Code is
          18                 :  * Christopher Blizzard <blizzard@mozilla.org>.
          19                 :  * Portions created by the Initial Developer are Copyright (C) 2002
          20                 :  * the Initial Developer. All Rights Reserved.
          21                 :  *
          22                 :  * Contributor(s):
          23                 :  *
          24                 :  * Alternatively, the contents of this file may be used under the terms of
          25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
          26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
          27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
          28                 :  * of those above. If you wish to allow use of your version of this file only
          29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
          30                 :  * use your version of this file under the terms of the MPL, indicate your
          31                 :  * decision by deleting the provisions above and replace them with the notice
          32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
          33                 :  * the provisions above, a recipient may use your version of this file under
          34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
          35                 :  *
          36                 :  * ***** END LICENSE BLOCK ***** */
          37                 :
          38                 : #ifndef __nsBoundingMetrics_h
          39                 : #define __nsBoundingMetrics_h
          40                 :
          41                 : #include "nsCoord.h"
          42                 :
          43                 : /* Struct used for accurate measurements of a string, in order to
          44                 :  * allow precise positioning when processing MathML.  This is in its
          45                 :  * own header file because some very-widely-included headers need it
          46                 :  * but not the rest of nsFontMetrics, or vice versa.
          47                 :  */
          48                 :
          49                 : struct nsBoundingMetrics {
          50                 :
          51                 :     ///////////
          52                 :     // Metrics that _exactly_ enclose the text:
          53                 :
          54                 :     // The character coordinate system is the one used on X Windows:
          55                 :     // 1. The origin is located at the intersection of the baseline
          56                 :     //    with the left of the character's cell.
          57                 :     // 2. All horizontal bearings are oriented from left to right.
          58                 :     // 2. All horizontal bearings are oriented from left to right.
          59                 :     // 3. The ascent is oriented from bottom to top (being 0 at the orgin).
          60                 :     // 4. The descent is oriented from top to bottom (being 0 at the origin).
          61                 :
          62                 :     // Note that Win32/Mac/PostScript use a different convention for
          63                 :     // the descent (all vertical measurements are oriented from bottom
          64                 :     // to top on these palatforms). Make sure to flip the sign of the
          65                 :     // descent on these platforms for cross-platform compatibility.
          66                 :
          67                 :     // Any of the following member variables listed here can have
          68                 :     // positive or negative value.
          69                 :
          70                 :     nscoord leftBearing;
          71                 :     /* The horizontal distance from the origin of the drawing
          72                 :        operation to the left-most part of the drawn string. */
          73                 :
          74                 :     nscoord rightBearing;
          75                 :     /* The horizontal distance from the origin of the drawing
          76                 :        operation to the right-most part of the drawn string.
          77                 :        The _exact_ width of the string is therefore:
          78                 :        rightBearing - leftBearing */
          79                 :
          80                 :     nscoord ascent;
          81                 :     /* The vertical distance from the origin of the drawing
          82                 :        operation to the top-most part of the drawn string. */
          83                 :
          84                 :     nscoord descent;
          85                 :     /* The vertical distance from the origin of the drawing
          86                 :        operation to the bottom-most part of the drawn string.
          87                 :        The _exact_ height of the string is therefore:
          88                 :        ascent + descent */
          89                 :
          90                 :     nscoord width;
          91                 :     /* The horizontal distance from the origin of the drawing
          92                 :        operation to the correct origin for drawing another string
          93                 :        to follow the current one. Depending on the font, this
          94                 :        could be greater than or less than the right bearing. */
          95                 :
          96               0 :     nsBoundingMetrics() : leftBearing(0), rightBearing(0),
          97               0 :                           ascent(0), descent(0), width(0)
          98               0 :     {}
          99                 :
         100                 :     void
         101               0 :     operator += (const nsBoundingMetrics& bm) {
         102               0 :         if (ascent + descent == 0 && rightBearing - leftBearing == 0) {
         103               0 :             ascent = bm.ascent;
         104               0 :             descent = bm.descent;
         105               0 :             leftBearing = width + bm.leftBearing;
         106               0 :             rightBearing = width + bm.rightBearing;
         107                 :         }
         108                 :         else {
         109               0 :             if (ascent < bm.ascent) ascent = bm.ascent;
         110               0 :             if (descent < bm.descent) descent = bm.descent;
         111               0 :             leftBearing = NS_MIN(leftBearing, width + bm.leftBearing);
         112               0 :             rightBearing = NS_MAX(rightBearing, width + bm.rightBearing);
         113                 :         }
         114               0 :         width += bm.width;
         115               0 :     }
         116                 : };
         117                 :
         118                 : #endif // __nsBoundingMetrics_h

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