LCOV - code coverage report
Current view: directory - gfx/thebes - gfxFT2FontBase.cpp (source / functions) Found Hit Coverage
Test: app.info Lines: 70 0 0.0 %
Date: 2012-06-02 Functions: 11 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 Foundation code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is Mozilla Foundation.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2009
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *   Vladimir Vukicevic <vladimir@mozilla.com>
      23                 :  *   Masayuki Nakano <masayuki@d-toybox.com>
      24                 :  *   Behdad Esfahbod <behdad@gnome.org>
      25                 :  *   Mats Palmgren <mats.palmgren@bredband.net>
      26                 :  *   Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
      27                 :  *   Takuro Ashie <ashie@clear-code.com>
      28                 :  *
      29                 :  * Alternatively, the contents of this file may be used under the terms of
      30                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      31                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      32                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      33                 :  * of those above. If you wish to allow use of your version of this file only
      34                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      35                 :  * use your version of this file under the terms of the MPL, indicate your
      36                 :  * decision by deleting the provisions above and replace them with the notice
      37                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      38                 :  * the provisions above, a recipient may use your version of this file under
      39                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      40                 :  *
      41                 :  * ***** END LICENSE BLOCK ***** */
      42                 : 
      43                 : #include "gfxFT2FontBase.h"
      44                 : #include "gfxFT2Utils.h"
      45                 : #include "harfbuzz/hb-blob.h"
      46                 : 
      47               0 : gfxFT2FontBase::gfxFT2FontBase(cairo_scaled_font_t *aScaledFont,
      48                 :                                gfxFontEntry *aFontEntry,
      49                 :                                const gfxFontStyle *aFontStyle)
      50                 :     : gfxFont(aFontEntry, aFontStyle, kAntialiasDefault, aScaledFont),
      51                 :       mSpaceGlyph(0),
      52               0 :       mHasMetrics(false)
      53                 : {
      54               0 :     cairo_scaled_font_reference(mScaledFont);
      55               0 : }
      56                 : 
      57               0 : gfxFT2FontBase::~gfxFT2FontBase()
      58                 : {
      59               0 :     cairo_scaled_font_destroy(mScaledFont);
      60               0 : }
      61                 : 
      62                 : PRUint32
      63               0 : gfxFT2FontBase::GetGlyph(PRUint32 aCharCode)
      64                 : {
      65                 :     // FcFreeTypeCharIndex needs to lock the FT_Face and can end up searching
      66                 :     // through all the postscript glyph names in the font.  Therefore use a
      67                 :     // lightweight cache, which is stored on the cairo_font_face_t.
      68                 : 
      69                 :     cairo_font_face_t *face =
      70               0 :         cairo_scaled_font_get_font_face(CairoScaledFont());
      71                 : 
      72               0 :     if (cairo_font_face_status(face) != CAIRO_STATUS_SUCCESS)
      73               0 :         return 0;
      74                 : 
      75                 :     // This cache algorithm and size is based on what is done in
      76                 :     // cairo_scaled_font_text_to_glyphs and pango_fc_font_real_get_glyph.  I
      77                 :     // think the concept is that adjacent characters probably come mostly from
      78                 :     // one Unicode block.  This assumption is probably not so valid with
      79                 :     // scripts with large character sets as used for East Asian languages.
      80                 : 
      81                 :     struct CmapCacheSlot {
      82                 :         PRUint32 mCharCode;
      83                 :         PRUint32 mGlyphIndex;
      84                 :     };
      85               0 :     const PRUint32 kNumSlots = 256;
      86                 :     static cairo_user_data_key_t sCmapCacheKey;
      87                 : 
      88                 :     CmapCacheSlot *slots = static_cast<CmapCacheSlot*>
      89               0 :         (cairo_font_face_get_user_data(face, &sCmapCacheKey));
      90                 : 
      91               0 :     if (!slots) {
      92                 :         // cairo's caches can keep some cairo_font_faces alive past our last
      93                 :         // destroy, so the destroy function (free) for the cache must be
      94                 :         // callable from cairo without any assumptions about what other
      95                 :         // modules have not been shutdown.
      96                 :         slots = static_cast<CmapCacheSlot*>
      97               0 :             (calloc(kNumSlots, sizeof(CmapCacheSlot)));
      98               0 :         if (!slots)
      99               0 :             return 0;
     100                 : 
     101                 :         cairo_status_t status =
     102               0 :             cairo_font_face_set_user_data(face, &sCmapCacheKey, slots, free);
     103               0 :         if (status != CAIRO_STATUS_SUCCESS) { // OOM
     104               0 :             free(slots);
     105               0 :             return 0;
     106                 :         }
     107                 : 
     108                 :         // Invalidate slot 0 by setting its char code to something that would
     109                 :         // never end up in slot 0.  All other slots are already invalid
     110                 :         // because they have mCharCode = 0 and a glyph for char code 0 will
     111                 :         // always be in the slot 0.
     112               0 :         slots[0].mCharCode = 1;
     113                 :     }
     114                 : 
     115               0 :     CmapCacheSlot *slot = &slots[aCharCode % kNumSlots];
     116               0 :     if (slot->mCharCode != aCharCode) {
     117               0 :         slot->mCharCode = aCharCode;
     118               0 :         slot->mGlyphIndex = gfxFT2LockedFace(this).GetGlyph(aCharCode);
     119                 :     }
     120                 : 
     121               0 :     return slot->mGlyphIndex;
     122                 : }
     123                 : 
     124                 : void
     125               0 : gfxFT2FontBase::GetGlyphExtents(PRUint32 aGlyph, cairo_text_extents_t* aExtents)
     126                 : {
     127               0 :     NS_PRECONDITION(aExtents != NULL, "aExtents must not be NULL");
     128                 : 
     129                 :     cairo_glyph_t glyphs[1];
     130               0 :     glyphs[0].index = aGlyph;
     131               0 :     glyphs[0].x = 0.0;
     132               0 :     glyphs[0].y = 0.0;
     133                 :     // cairo does some caching for us here but perhaps a small gain could be
     134                 :     // made by caching more.  It is usually only the advance that is needed,
     135                 :     // so caching only the advance could allow many requests to be cached with
     136                 :     // little memory use.  Ideally this cache would be merged with
     137                 :     // gfxGlyphExtents.
     138               0 :     cairo_scaled_font_glyph_extents(CairoScaledFont(), glyphs, 1, aExtents);
     139               0 : }
     140                 : 
     141                 : const gfxFont::Metrics&
     142               0 : gfxFT2FontBase::GetMetrics()
     143                 : {
     144               0 :     if (mHasMetrics)
     145               0 :         return mMetrics;
     146                 : 
     147               0 :     if (NS_UNLIKELY(GetStyle()->size <= 0.0)) {
     148               0 :         new(&mMetrics) gfxFont::Metrics(); // zero initialize
     149               0 :         mSpaceGlyph = 0;
     150                 :     } else {
     151               0 :         gfxFT2LockedFace(this).GetMetrics(&mMetrics, &mSpaceGlyph);
     152                 :     }
     153                 : 
     154               0 :     SanitizeMetrics(&mMetrics, false);
     155                 : 
     156                 : #if 0
     157                 :     //    printf("font name: %s %f\n", NS_ConvertUTF16toUTF8(GetName()).get(), GetStyle()->size);
     158                 :     //    printf ("pango font %s\n", pango_font_description_to_string (pango_font_describe (font)));
     159                 : 
     160                 :     fprintf (stderr, "Font: %s\n", NS_ConvertUTF16toUTF8(GetName()).get());
     161                 :     fprintf (stderr, "    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
     162                 :     fprintf (stderr, "    maxAscent: %f maxDescent: %f\n", mMetrics.maxAscent, mMetrics.maxDescent);
     163                 :     fprintf (stderr, "    internalLeading: %f externalLeading: %f\n", mMetrics.externalLeading, mMetrics.internalLeading);
     164                 :     fprintf (stderr, "    spaceWidth: %f aveCharWidth: %f xHeight: %f\n", mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.xHeight);
     165                 :     fprintf (stderr, "    uOff: %f uSize: %f stOff: %f stSize: %f suOff: %f suSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize, mMetrics.superscriptOffset, mMetrics.subscriptOffset);
     166                 : #endif
     167                 : 
     168               0 :     mHasMetrics = true;
     169               0 :     return mMetrics;
     170                 : }
     171                 : 
     172                 : // Get the glyphID of a space
     173                 : PRUint32
     174               0 : gfxFT2FontBase::GetSpaceGlyph()
     175                 : {
     176               0 :     NS_ASSERTION(GetStyle()->size != 0,
     177                 :                  "forgot to short-circuit a text run with zero-sized font?");
     178               0 :     GetMetrics();
     179               0 :     return mSpaceGlyph;
     180                 : }
     181                 : 
     182                 : hb_blob_t *
     183               0 : gfxFT2FontBase::GetFontTable(PRUint32 aTag)
     184                 : {
     185                 :     hb_blob_t *blob;
     186               0 :     if (mFontEntry->GetExistingFontTable(aTag, &blob))
     187               0 :         return blob;
     188                 : 
     189               0 :     FallibleTArray<PRUint8> buffer;
     190               0 :     bool haveTable = gfxFT2LockedFace(this).GetFontTable(aTag, buffer);
     191                 : 
     192                 :     // Cache even when there is no table to save having to open the FT_Face
     193                 :     // again.
     194                 :     return mFontEntry->ShareFontTableAndGetBlob(aTag,
     195               0 :                                                 haveTable ? &buffer : nsnull);
     196                 : }
     197                 : 
     198                 : PRUint32
     199               0 : gfxFT2FontBase::GetGlyph(PRUint32 unicode, PRUint32 variation_selector)
     200                 : {
     201               0 :     if (variation_selector) {
     202                 :         PRUint32 id =
     203               0 :             gfxFT2LockedFace(this).GetUVSGlyph(unicode, variation_selector);
     204               0 :         if (id)
     205               0 :             return id;
     206                 :     }
     207                 : 
     208               0 :     return GetGlyph(unicode);
     209                 : }
     210                 : 
     211                 : PRInt32
     212               0 : gfxFT2FontBase::GetGlyphWidth(gfxContext *aCtx, PRUint16 aGID)
     213                 : {
     214                 :     cairo_text_extents_t extents;
     215               0 :     GetGlyphExtents(aGID, &extents);
     216                 :     // convert to 16.16 fixed point
     217               0 :     return NS_lround(0x10000 * extents.x_advance);
     218                 : }
     219                 : 
     220                 : bool
     221               0 : gfxFT2FontBase::SetupCairoFont(gfxContext *aContext)
     222                 : {
     223               0 :     cairo_t *cr = aContext->GetCairo();
     224                 : 
     225                 :     // The scaled font ctm is not relevant right here because
     226                 :     // cairo_set_scaled_font does not record the scaled font itself, but
     227                 :     // merely the font_face, font_matrix, font_options.  The scaled_font used
     228                 :     // for the target can be different from the scaled_font passed to
     229                 :     // cairo_set_scaled_font.  (Unfortunately we have measured only for an
     230                 :     // identity ctm.)
     231               0 :     cairo_scaled_font_t *cairoFont = CairoScaledFont();
     232                 : 
     233               0 :     if (cairo_scaled_font_status(cairoFont) != CAIRO_STATUS_SUCCESS) {
     234                 :         // Don't cairo_set_scaled_font as that would propagate the error to
     235                 :         // the cairo_t, precluding any further drawing.
     236               0 :         return false;
     237                 :     }
     238                 :     // Thoughts on which font_options to set on the context:
     239                 :     //
     240                 :     // cairoFont has been created for screen rendering.
     241                 :     //
     242                 :     // When the context is being used for screen rendering, we should set
     243                 :     // font_options such that the same scaled_font gets used (when the ctm is
     244                 :     // the same).  The use of explicit font_options recorded in
     245                 :     // CreateScaledFont ensures that this will happen.
     246                 :     //
     247                 :     // XXXkt: For pdf and ps surfaces, I don't know whether it's better to
     248                 :     // remove surface-specific options, or try to draw with the same
     249                 :     // scaled_font that was used to measure.  As the same font_face is being
     250                 :     // used, its font_options will often override some values anyway (unless
     251                 :     // perhaps we remove those from the FcPattern at face creation).
     252                 :     //
     253                 :     // I can't see any significant difference in printing, irrespective of
     254                 :     // what is set here.  It's too late to change things here as measuring has
     255                 :     // already taken place.  We should really be measuring with a different
     256                 :     // font for pdf and ps surfaces (bug 403513).
     257               0 :     cairo_set_scaled_font(cr, cairoFont);
     258               0 :     return true;
     259                 : }

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