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      1 /*
      2  * Copyright (C) 2006, 2007 Apple Inc. All Rights Reserved.
      3  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are
      7  * met:
      8  *
      9  *     * Redistributions of source code must retain the above copyright
     10  * notice, this list of conditions and the following disclaimer.
     11  *     * Redistributions in binary form must reproduce the above
     12  * copyright notice, this list of conditions and the following disclaimer
     13  * in the documentation and/or other materials provided with the
     14  * distribution.
     15  *     * Neither the name of Google Inc. nor the names of its
     16  * contributors may be used to endorse or promote products derived from
     17  * this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "config.h"
     33 #include "SimpleFontData.h"
     34 
     35 #include "FloatRect.h"
     36 #include "Font.h"
     37 #include "FontCache.h"
     38 #include "FontDescription.h"
     39 #include "PlatformBridge.h"
     40 #include <wtf/MathExtras.h>
     41 
     42 #include <unicode/uchar.h>
     43 #include <unicode/unorm.h>
     44 #include <objidl.h>
     45 #include <mlang.h>
     46 
     47 namespace WebCore {
     48 
     49 static inline float scaleEmToUnits(float x, int unitsPerEm)
     50 {
     51     return unitsPerEm ? x / static_cast<float>(unitsPerEm) : x;
     52 }
     53 
     54 void SimpleFontData::platformInit()
     55 {
     56     if (!m_platformData.size()) {
     57         m_fontMetrics.reset();
     58         m_avgCharWidth = 0;
     59         m_maxCharWidth = 0;
     60         return;
     61     }
     62 
     63     HDC dc = GetDC(0);
     64     HGDIOBJ oldFont = SelectObject(dc, m_platformData.hfont());
     65 
     66     TEXTMETRIC textMetric = {0};
     67     if (!GetTextMetrics(dc, &textMetric)) {
     68         if (PlatformBridge::ensureFontLoaded(m_platformData.hfont())) {
     69             // Retry GetTextMetrics.
     70             // FIXME: Handle gracefully the error if this call also fails.
     71             // See http://crbug.com/6401.
     72             if (!GetTextMetrics(dc, &textMetric))
     73                 LOG_ERROR("Unable to get the text metrics after second attempt");
     74         }
     75     }
     76 
     77     m_avgCharWidth = textMetric.tmAveCharWidth;
     78     m_maxCharWidth = textMetric.tmMaxCharWidth;
     79 
     80     // FIXME: Access ascent/descent/lineGap with floating point precision.
     81     float ascent = textMetric.tmAscent;
     82     float descent = textMetric.tmDescent;
     83     float lineGap = textMetric.tmExternalLeading;
     84     float xHeight = ascent * 0.56f; // Best guess for xHeight for non-Truetype fonts.
     85 
     86     OUTLINETEXTMETRIC outlineTextMetric;
     87     if (GetOutlineTextMetrics(dc, sizeof(outlineTextMetric), &outlineTextMetric) > 0) {
     88         // This is a TrueType font.  We might be able to get an accurate xHeight.
     89         GLYPHMETRICS glyphMetrics = {0};
     90         MAT2 identityMatrix = {{0, 1}, {0, 0}, {0, 0}, {0, 1}};
     91         DWORD len = GetGlyphOutlineW(dc, 'x', GGO_METRICS, &glyphMetrics, 0, 0, &identityMatrix);
     92         if (len != GDI_ERROR && glyphMetrics.gmBlackBoxY > 0)
     93             xHeight = static_cast<float>(glyphMetrics.gmBlackBoxY);
     94     }
     95 
     96     m_fontMetrics.setAscent(ascent);
     97     m_fontMetrics.setDescent(descent);
     98     m_fontMetrics.setLineGap(lineGap);
     99     m_fontMetrics.setXHeight(xHeight);
    100     m_fontMetrics.setLineSpacing(ascent + descent + lineGap);
    101 
    102     SelectObject(dc, oldFont);
    103     ReleaseDC(0, dc);
    104 }
    105 
    106 void SimpleFontData::platformCharWidthInit()
    107 {
    108     // charwidths are set in platformInit.
    109 }
    110 
    111 void SimpleFontData::platformDestroy()
    112 {
    113 }
    114 
    115 SimpleFontData* SimpleFontData::scaledFontData(const FontDescription& fontDescription, float scaleFactor) const
    116 {
    117     LOGFONT winFont;
    118     GetObject(m_platformData.hfont(), sizeof(LOGFONT), &winFont);
    119     float scaledSize = scaleFactor * fontDescription.computedSize();
    120     winFont.lfHeight = -lroundf(scaledSize);
    121     HFONT hfont = CreateFontIndirect(&winFont);
    122     return new SimpleFontData(FontPlatformData(hfont, scaledSize), isCustomFont(), false);
    123 }
    124 
    125 SimpleFontData* SimpleFontData::smallCapsFontData(const FontDescription& fontDescription) const
    126 {
    127     if (!m_derivedFontData)
    128         m_derivedFontData = DerivedFontData::create(isCustomFont());
    129     if (!m_derivedFontData->smallCaps)
    130         m_derivedFontData->smallCaps = scaledFontData(fontDescription, .7);
    131 
    132     return m_derivedFontData->smallCaps.get();
    133 }
    134 
    135 SimpleFontData* SimpleFontData::emphasisMarkFontData(const FontDescription& fontDescription) const
    136 {
    137     if (!m_derivedFontData)
    138         m_derivedFontData = DerivedFontData::create(isCustomFont());
    139     if (!m_derivedFontData->emphasisMark)
    140         m_derivedFontData->emphasisMark = scaledFontData(fontDescription, .5);
    141 
    142     return m_derivedFontData->emphasisMark.get();
    143 }
    144 
    145 bool SimpleFontData::containsCharacters(const UChar* characters, int length) const
    146 {
    147   // This used to be implemented with IMLangFontLink2, but since that code has
    148   // been disabled, this would always return false anyway.
    149   return false;
    150 }
    151 
    152 void SimpleFontData::determinePitch()
    153 {
    154     // TEXTMETRICS have this.  Set m_treatAsFixedPitch based off that.
    155     HDC dc = GetDC(0);
    156     HGDIOBJ oldFont = SelectObject(dc, m_platformData.hfont());
    157 
    158     // Yes, this looks backwards, but the fixed pitch bit is actually set if the font
    159     // is *not* fixed pitch.  Unbelievable but true.
    160     TEXTMETRIC textMetric = {0};
    161     if (!GetTextMetrics(dc, &textMetric)) {
    162         if (PlatformBridge::ensureFontLoaded(m_platformData.hfont())) {
    163             // Retry GetTextMetrics.
    164             // FIXME: Handle gracefully the error if this call also fails.
    165             // See http://crbug.com/6401.
    166             if (!GetTextMetrics(dc, &textMetric))
    167                 LOG_ERROR("Unable to get the text metrics after second attempt");
    168         }
    169     }
    170 
    171     m_treatAsFixedPitch = ((textMetric.tmPitchAndFamily & TMPF_FIXED_PITCH) == 0);
    172 
    173     SelectObject(dc, oldFont);
    174     ReleaseDC(0, dc);
    175 }
    176 
    177 FloatRect SimpleFontData::platformBoundsForGlyph(Glyph) const
    178 {
    179     return FloatRect();
    180 }
    181 
    182 float SimpleFontData::platformWidthForGlyph(Glyph glyph) const
    183 {
    184     if (!m_platformData.size())
    185         return 0;
    186 
    187     HDC dc = GetDC(0);
    188     HGDIOBJ oldFont = SelectObject(dc, m_platformData.hfont());
    189 
    190     int width = 0;
    191     if (!GetCharWidthI(dc, glyph, 1, 0, &width)) {
    192         // Ask the browser to preload the font and retry.
    193         if (PlatformBridge::ensureFontLoaded(m_platformData.hfont())) {
    194             // FIXME: Handle gracefully the error if this call also fails.
    195             // See http://crbug.com/6401.
    196             if (!GetCharWidthI(dc, glyph, 1, 0, &width))
    197                 LOG_ERROR("Unable to get the char width after second attempt");
    198         }
    199     }
    200 
    201     SelectObject(dc, oldFont);
    202     ReleaseDC(0, dc);
    203 
    204     return static_cast<float>(width);
    205 }
    206 
    207 }  // namespace WebCore
    208