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
47namespace WebCore {
48
49static inline float scaleEmToUnits(float x, int unitsPerEm)
50{
51    return unitsPerEm ? x / static_cast<float>(unitsPerEm) : x;
52}
53
54void 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
106void SimpleFontData::platformCharWidthInit()
107{
108    // charwidths are set in platformInit.
109}
110
111void SimpleFontData::platformDestroy()
112{
113}
114
115SimpleFontData* 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
125SimpleFontData* 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
135SimpleFontData* 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
145bool 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
152void 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
177FloatRect SimpleFontData::platformBoundsForGlyph(Glyph) const
178{
179    return FloatRect();
180}
181
182float 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