LCOV - code coverage report
Current view: directory - content/svg/content/src - SVGLength.h (source / functions) Found Hit Coverage
Test: app.info Lines: 54 0 0.0 %
Date: 2012-06-02 Functions: 16 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       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 SVG Project code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is the Mozilla Foundation.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2010
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *
      23                 :  * Alternatively, the contents of this file may be used under the terms of
      24                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      25                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      26                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      27                 :  * of those above. If you wish to allow use of your version of this file only
      28                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      29                 :  * use your version of this file under the terms of the MPL, indicate your
      30                 :  * decision by deleting the provisions above and replace them with the notice
      31                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      32                 :  * the provisions above, a recipient may use your version of this file under
      33                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      34                 :  *
      35                 :  * ***** END LICENSE BLOCK ***** */
      36                 : 
      37                 : #ifndef MOZILLA_SVGLENGTH_H__
      38                 : #define MOZILLA_SVGLENGTH_H__
      39                 : 
      40                 : #include "nsDebug.h"
      41                 : #include "nsIDOMSVGLength.h"
      42                 : #include "nsMathUtils.h"
      43                 : 
      44                 : class nsSVGElement;
      45                 : 
      46                 : namespace mozilla {
      47                 : 
      48                 : /**
      49                 :  * This SVGLength class is currently used for SVGLength *list* attributes only.
      50                 :  * The class that is currently used for <length> attributes is nsSVGLength2.
      51                 :  *
      52                 :  * The member mUnit should always be valid, but the member mValue may be
      53                 :  * numeric_limits<float>::quiet_NaN() under one circumstances (see the comment
      54                 :  * in SetValueAndUnit below). Even if mValue is valid, some methods may return
      55                 :  * numeric_limits<float>::quiet_NaN() if they involve a unit conversion that
      56                 :  * fails - see comments below.
      57                 :  *
      58                 :  * The DOM wrapper class for this class is DOMSVGLength.
      59                 :  */
      60                 : class SVGLength
      61               0 : {
      62                 : public:
      63                 : 
      64               0 :   SVGLength()
      65                 : #ifdef DEBUG
      66                 :     : mValue(0.0f)
      67               0 :     , mUnit(nsIDOMSVGLength::SVG_LENGTHTYPE_UNKNOWN) // caught by IsValid()
      68                 : #endif
      69               0 :   {}
      70                 : 
      71               0 :   SVGLength(float aValue, PRUint8 aUnit)
      72                 :     : mValue(aValue)
      73               0 :     , mUnit(aUnit)
      74                 :   {
      75               0 :     NS_ASSERTION(IsValid(), "Constructed an invalid length");
      76               0 :   }
      77                 : 
      78               0 :   SVGLength(const SVGLength &aOther)
      79                 :     : mValue(aOther.mValue)
      80               0 :     , mUnit(aOther.mUnit)
      81               0 :   {}
      82                 : 
      83               0 :   SVGLength& operator=(const SVGLength &rhs) {
      84               0 :     mValue = rhs.mValue;
      85               0 :     mUnit = rhs.mUnit;
      86               0 :     return *this;
      87                 :   }
      88                 : 
      89               0 :   bool operator==(const SVGLength &rhs) const {
      90               0 :     return mValue == rhs.mValue && mUnit == rhs.mUnit;
      91                 :   }
      92                 : 
      93                 :   void GetValueAsString(nsAString& aValue) const;
      94                 : 
      95                 :   /**
      96                 :    * This method returns true, unless there was a parse failure, in which
      97                 :    * case it returns false (and the length is left unchanged).
      98                 :    */
      99                 :   bool SetValueFromString(const nsAString& aValue);
     100                 : 
     101                 :   /**
     102                 :    * This will usually return a valid, finite number. There is one exception
     103                 :    * though - see the comment in SetValueAndUnit().
     104                 :    */
     105               0 :   float GetValueInCurrentUnits() const {
     106               0 :     return mValue;
     107                 :   }
     108                 : 
     109               0 :   PRUint8 GetUnit() const {
     110               0 :     return mUnit;
     111                 :   }
     112                 : 
     113               0 :   void SetValueInCurrentUnits(float aValue) {
     114               0 :     mValue = aValue;
     115               0 :     NS_ASSERTION(IsValid(), "Set invalid SVGLength");
     116               0 :   }
     117                 : 
     118               0 :   void SetValueAndUnit(float aValue, PRUint8 aUnit) {
     119               0 :     mValue = aValue;
     120               0 :     mUnit = aUnit;
     121                 : 
     122                 :     // IsValid() should always be true, with one exception: if
     123                 :     // SVGLengthListSMILType has to convert between unit types and the unit
     124                 :     // conversion is undefined, it will end up passing in and setting
     125                 :     // numeric_limits<float>::quiet_NaN(). Because of that we only check the
     126                 :     // unit here, and allow mValue to be invalid. The painting code has to be
     127                 :     // able to handle NaN anyway, since conversion to user units may fail in
     128                 :     // general.
     129                 : 
     130               0 :     NS_ASSERTION(IsValidUnitType(mUnit), "Set invalid SVGLength");
     131               0 :   }
     132                 : 
     133                 :   /**
     134                 :    * If it's not possible to convert this length's value to user units, then
     135                 :    * this method will return numeric_limits<float>::quiet_NaN().
     136                 :    */
     137               0 :   float GetValueInUserUnits(const nsSVGElement *aElement, PRUint8 aAxis) const {
     138               0 :     return mValue * GetUserUnitsPerUnit(aElement, aAxis);
     139                 :   }
     140                 : 
     141                 :   /**
     142                 :    * Sets this length's value, converting the supplied user unit value to this
     143                 :    * lengths *current* unit (i.e. leaving the length's unit unchanged).
     144                 :    *
     145                 :    * This method returns true, unless the user unit value couldn't be
     146                 :    * converted to this length's current unit, in which case it returns false
     147                 :    * (and the length is left unchanged).
     148                 :    */
     149               0 :   bool SetFromUserUnitValue(float aUserUnitValue,
     150                 :                               nsSVGElement *aElement,
     151                 :                               PRUint8 aAxis) {
     152               0 :     float uuPerUnit = GetUserUnitsPerUnit(aElement, aAxis);
     153               0 :     float value = aUserUnitValue / uuPerUnit;
     154               0 :     if (uuPerUnit > 0 && NS_finite(value)) {
     155               0 :       mValue = value;
     156               0 :       NS_ASSERTION(IsValid(), "Set invalid SVGLength");
     157               0 :       return true;
     158                 :     }
     159               0 :     return false;
     160                 :   }
     161                 : 
     162                 :   /**
     163                 :    * Get this length's value in the units specified.
     164                 :    *
     165                 :    * This method returns numeric_limits<float>::quiet_NaN() if it is not
     166                 :    * possible to convert the value to the specified unit.
     167                 :    */
     168                 :   float GetValueInSpecifiedUnit(PRUint8 aUnit,
     169                 :                                 const nsSVGElement *aElement,
     170                 :                                 PRUint8 aAxis) const;
     171                 : 
     172                 :   /**
     173                 :    * Convert this length's value to the unit specified.
     174                 :    *
     175                 :    * This method returns true, unless it isn't possible to convert the
     176                 :    * length to the specified unit. In that case the length is left unchanged
     177                 :    * and this method returns false.
     178                 :    */
     179               0 :   bool ConvertToUnit(PRUint32 aUnit, nsSVGElement *aElement, PRUint8 aAxis) {
     180               0 :     float val = GetValueInSpecifiedUnit(aUnit, aElement, aAxis);
     181               0 :     if (NS_finite(val)) {
     182               0 :       mValue = val;
     183               0 :       mUnit = aUnit;
     184               0 :       NS_ASSERTION(IsValid(), "Set invalid SVGLength");
     185               0 :       return true;
     186                 :     }
     187               0 :     return false;
     188                 :   }
     189                 : 
     190                 :   bool IsPercentage() const {
     191                 :     return mUnit == nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE;
     192                 :   }
     193                 : 
     194               0 :   static bool IsValidUnitType(PRUint16 unit) {
     195                 :     return unit > nsIDOMSVGLength::SVG_LENGTHTYPE_UNKNOWN &&
     196               0 :            unit <= nsIDOMSVGLength::SVG_LENGTHTYPE_PC;
     197                 :   }
     198                 : 
     199                 : private:
     200                 : 
     201                 : #ifdef DEBUG
     202               0 :   bool IsValid() const {
     203               0 :     return NS_finite(mValue) && IsValidUnitType(mUnit);
     204                 :   }
     205                 : #endif
     206                 : 
     207                 :   /**
     208                 :    * Returns the number of user units per current unit.
     209                 :    *
     210                 :    * This method returns numeric_limits<float>::quiet_NaN() if the conversion
     211                 :    * factor between the length's current unit and user units is undefined (see
     212                 :    * the comments for GetUserUnitsPerInch and GetUserUnitsPerPercent).
     213                 :    */
     214                 :   float GetUserUnitsPerUnit(const nsSVGElement *aElement, PRUint8 aAxis) const;
     215                 : 
     216                 :   /**
     217                 :    * The conversion factor between user units (CSS px) and CSS inches is
     218                 :    * constant: 96 px per inch.
     219                 :    */
     220               0 :   static float GetUserUnitsPerInch()
     221                 :   {
     222               0 :     return 96.0;
     223                 :   }
     224                 : 
     225                 :   /**
     226                 :    * The conversion factor between user units and percentage units depends on
     227                 :    * aElement being non-null, and on aElement having a viewport element
     228                 :    * ancestor with only appropriate SVG elements between aElement and that
     229                 :    * ancestor. If that's not the case, then the conversion factor is undefined.
     230                 :    *
     231                 :    * This function returns a non-negative value if the conversion factor is
     232                 :    * defined, otherwise it returns numeric_limits<float>::quiet_NaN().
     233                 :    */
     234                 :   static float GetUserUnitsPerPercent(const nsSVGElement *aElement, PRUint8 aAxis);
     235                 : 
     236                 :   float mValue;
     237                 :   PRUint8 mUnit;
     238                 : };
     239                 : 
     240                 : } // namespace mozilla
     241                 : 
     242                 : #endif // MOZILLA_SVGLENGTH_H__

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