The Tor Browser: gfx/src/nsFontMetrics.h@97036ab72558 (annotated)

gfx/src/nsFontMetrics.h@97036ab72558 (annotated)

gfx/src/nsFontMetrics.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.

 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef NSFONTMETRICS__H__
 #define NSFONTMETRICS__H__
 #include <stdint.h>                     // for uint32_t
 #include <sys/types.h>                  // for int32_t
 #include "gfxFont.h"                    // for gfxFont, gfxFontGroup
 #include "mozilla/Assertions.h"         // for MOZ_ASSERT_HELPER2
 #include "nsAutoPtr.h"                  // for nsRefPtr
 #include "nsCOMPtr.h"                   // for nsCOMPtr
 #include "nsCoord.h"                    // for nscoord
 #include "nsError.h"                    // for nsresult
 #include "nsFont.h"                     // for nsFont
 #include "nsISupports.h"                // for NS_INLINE_DECL_REFCOUNTING
 #include "nscore.h"                     // for char16_t
 class gfxUserFontSet;
 class gfxTextPerfMetrics;
 class nsDeviceContext;
 class nsIAtom;
 class nsRenderingContext;
 struct nsBoundingMetrics;
 /**
  * Font metrics
  *
  * This class may be somewhat misnamed. A better name might be
  * nsFontList. The style system uses the nsFont struct for various
  * font properties, one of which is font-family, which can contain a
  * *list* of font names. The nsFont struct is "realized" by asking the
  * device context to cough up an nsFontMetrics object, which contains
  * a list of real font handles, one for each font mentioned in
  * font-family (and for each fallback when we fall off the end of that
  * list).
  *
  * The style system needs to have access to certain metrics, such as
  * the em height (for the CSS "em" unit), and we use the first Western
  * font's metrics for that purpose. The platform-specific
  * implementations are expected to select non-Western fonts that "fit"
  * reasonably well with the Western font that is loaded at Init time.
  */
 class nsFontMetrics MOZ_FINAL
 {
 public:
     nsFontMetrics();
     NS_INLINE_DECL_REFCOUNTING(nsFontMetrics)
     /**
      * Initialize the font metrics. Call this after creating the font metrics.
      * Font metrics you get from the font cache do NOT need to be initialized
      *
      * @see nsDeviceContext#GetMetricsFor()
      */
     nsresult Init(const nsFont& aFont, nsIAtom* aLanguage,
                   nsDeviceContext *aContext,
                   gfxUserFontSet *aUserFontSet,
                   gfxTextPerfMetrics *aTextPerf);
     /**
      * Destroy this font metrics. This breaks the association between
      * the font metrics and the device context.
      */
     void Destroy();
     /**
      * Return the font's x-height.
      */
     nscoord XHeight();
     /**
      * Return the font's superscript offset (the distance from the
      * baseline to where a superscript's baseline should be placed).
      * The value returned will be positive.
      */
     nscoord SuperscriptOffset();
     /**
      * Return the font's subscript offset (the distance from the
      * baseline to where a subscript's baseline should be placed).
      * The value returned will be positive.
      */
     nscoord SubscriptOffset();
     /**
      * Return the font's strikeout offset (the distance from the
      * baseline to where a strikeout should be placed) and size.
      * Positive values are above the baseline, negative below.
      */
     void GetStrikeout(nscoord& aOffset, nscoord& aSize);
     /**
      * Return the font's underline offset (the distance from the
      * baseline to where a underline should be placed) and size.
      * Positive values are above the baseline, negative below.
      */
     void GetUnderline(nscoord& aOffset, nscoord& aSize);
     /**
      * Returns the amount of internal leading for the font.
      * This is normally the difference between the max ascent
      * and the em ascent.
      */
     nscoord InternalLeading();
     /**
      * Returns the amount of external leading for the font.
      * em ascent(?) plus external leading is the font designer's
      * recommended line-height for this font.
      */
     nscoord ExternalLeading();
     /**
      * Returns the height of the em square.
      * This is em ascent plus em descent.
      */
     nscoord EmHeight();
     /**
      * Returns the ascent part of the em square.
      */
     nscoord EmAscent();
     /**
      * Returns the descent part of the em square.
      */
     nscoord EmDescent();
     /**
      * Returns the height of the bounding box.
      * This is max ascent plus max descent.
      */
     nscoord MaxHeight();
     /**
      * Returns the maximum distance characters in this font extend
      * above the base line.
      */
     nscoord MaxAscent();
     /**
      * Returns the maximum distance characters in this font extend
      * below the base line.
      */
     nscoord MaxDescent();
     /**
      * Returns the maximum character advance for the font.
      */
     nscoord MaxAdvance();
     /**
      * Returns the average character width
      */
     nscoord AveCharWidth();
     /**
      * Returns the often needed width of the space character
      */
     nscoord SpaceWidth();
     /**
      * Returns the font associated with these metrics. The return value
      * is only defined after Init() has been called.
      */
     const nsFont &Font() { return mFont; }
     /**
      * Returns the language associated with these metrics
      */
     nsIAtom* Language() { return mLanguage; }
     int32_t GetMaxStringLength();
     // Get the width for this string.  aWidth will be updated with the
     // width in points, not twips.  Callers must convert it if they
     // want it in another format.
     nscoord GetWidth(const char* aString, uint32_t aLength,
                      nsRenderingContext *aContext);
     nscoord GetWidth(const char16_t* aString, uint32_t aLength,
                      nsRenderingContext *aContext);
     // Draw a string using this font handle on the surface passed in.
     void DrawString(const char *aString, uint32_t aLength,
                     nscoord aX, nscoord aY,
                     nsRenderingContext *aContext);
     void DrawString(const char16_t* aString, uint32_t aLength,
                     nscoord aX, nscoord aY,
                     nsRenderingContext *aContext,
                     nsRenderingContext *aTextRunConstructionContext);
     nsBoundingMetrics GetBoundingMetrics(const char16_t *aString,
                                          uint32_t aLength,
                                          nsRenderingContext *aContext);
     // Returns the LOOSE_INK_EXTENTS bounds of the text for determing the
     // overflow area of the string.
     nsBoundingMetrics GetInkBoundsForVisualOverflow(const char16_t *aString,
                                                     uint32_t aLength,
                                                     nsRenderingContext *aContext);
     void SetTextRunRTL(bool aIsRTL) { mTextRunRTL = aIsRTL; }
     bool GetTextRunRTL() { return mTextRunRTL; }
     gfxFontGroup* GetThebesFontGroup() { return mFontGroup; }
     gfxUserFontSet* GetUserFontSet() { return mFontGroup->GetUserFontSet(); }
     int32_t AppUnitsPerDevPixel() { return mP2A; }
 private:
     // Private destructor, to discourage deletion outside of Release():
     ~nsFontMetrics();
     const gfxFont::Metrics& GetMetrics() const;
     nsFont mFont;
     nsRefPtr<gfxFontGroup> mFontGroup;
     nsCOMPtr<nsIAtom> mLanguage;
     nsDeviceContext *mDeviceContext;
     int32_t mP2A;
     bool mTextRunRTL;
 };
 #endif /* NSFONTMETRICS__H__ */

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gfx/src/nsFontMetrics.h@97036ab72558 (annotated)

gfx/src/nsFontMetrics.h