1/*
2 * Copyright (C) 2006 Apple Inc.  All rights reserved.
3 * Copyright (C) 2006 Michael Emmel mike.emmel@gmail.com
4 * Copyright (C) 2007, 2008 Alp Toker <alp@atoker.com>
5 * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
6 * Copyright (C) 2010 Holger Hans Peter Freyther
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
21 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
24 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
25 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include "config.h"
31#include "Font.h"
32
33#include "AffineTransform.h"
34#include "CairoUtilities.h"
35#include "GlyphBuffer.h"
36#include "Gradient.h"
37#include "GraphicsContext.h"
38#include "ImageBuffer.h"
39#include "Pattern.h"
40#include "PlatformContextCairo.h"
41#include "ShadowBlur.h"
42#include "SimpleFontData.h"
43
44namespace WebCore {
45
46static void drawGlyphsToContext(cairo_t* context, const SimpleFontData* font, GlyphBufferGlyph* glyphs, int numGlyphs)
47{
48    cairo_matrix_t originalTransform;
49    float syntheticBoldOffset = font->syntheticBoldOffset();
50    if (syntheticBoldOffset)
51        cairo_get_matrix(context, &originalTransform);
52
53    cairo_set_scaled_font(context, font->platformData().scaledFont());
54    cairo_show_glyphs(context, glyphs, numGlyphs);
55
56    if (syntheticBoldOffset) {
57        cairo_translate(context, syntheticBoldOffset, 0);
58        cairo_show_glyphs(context, glyphs, numGlyphs);
59    }
60
61    if (syntheticBoldOffset)
62        cairo_set_matrix(context, &originalTransform);
63}
64
65static void drawGlyphsShadow(GraphicsContext* graphicsContext, const FloatPoint& point, const SimpleFontData* font, GlyphBufferGlyph* glyphs, int numGlyphs)
66{
67    ShadowBlur& shadow = graphicsContext->platformContext()->shadowBlur();
68
69    if (!(graphicsContext->textDrawingMode() & TextModeFill) || shadow.type() == ShadowBlur::NoShadow)
70        return;
71
72    if (!graphicsContext->mustUseShadowBlur()) {
73        // Optimize non-blurry shadows, by just drawing text without the ShadowBlur.
74        cairo_t* context = graphicsContext->platformContext()->cr();
75        cairo_save(context);
76
77        FloatSize shadowOffset(graphicsContext->state().shadowOffset);
78        cairo_translate(context, shadowOffset.width(), shadowOffset.height());
79        setSourceRGBAFromColor(context, graphicsContext->state().shadowColor);
80        drawGlyphsToContext(context, font, glyphs, numGlyphs);
81
82        cairo_restore(context);
83        return;
84    }
85
86    cairo_text_extents_t extents;
87    cairo_scaled_font_glyph_extents(font->platformData().scaledFont(), glyphs, numGlyphs, &extents);
88    FloatRect fontExtentsRect(point.x() + extents.x_bearing, point.y() + extents.y_bearing, extents.width, extents.height);
89
90    if (GraphicsContext* shadowContext = shadow.beginShadowLayer(graphicsContext, fontExtentsRect)) {
91        drawGlyphsToContext(shadowContext->platformContext()->cr(), font, glyphs, numGlyphs);
92        shadow.endShadowLayer(graphicsContext);
93    }
94}
95
96void Font::drawGlyphs(GraphicsContext* context, const SimpleFontData* font, const GlyphBuffer& glyphBuffer,
97    int from, int numGlyphs, const FloatPoint& point) const
98{
99    if (!font->platformData().size())
100        return;
101
102    GlyphBufferGlyph* glyphs = const_cast<GlyphBufferGlyph*>(glyphBuffer.glyphs(from));
103
104    float offset = point.x();
105    for (int i = 0; i < numGlyphs; i++) {
106        glyphs[i].x = offset;
107        glyphs[i].y = point.y();
108        offset += glyphBuffer.advanceAt(from + i).width();
109    }
110
111    PlatformContextCairo* platformContext = context->platformContext();
112    drawGlyphsShadow(context, point, font, glyphs, numGlyphs);
113
114    cairo_t* cr = platformContext->cr();
115    cairo_save(cr);
116
117    if (context->textDrawingMode() & TextModeFill) {
118        platformContext->prepareForFilling(context->state(), PlatformContextCairo::AdjustPatternForGlobalAlpha);
119        drawGlyphsToContext(cr, font, glyphs, numGlyphs);
120    }
121
122    // Prevent running into a long computation within cairo. If the stroke width is
123    // twice the size of the width of the text we will not ask cairo to stroke
124    // the text as even one single stroke would cover the full wdth of the text.
125    //  See https://bugs.webkit.org/show_bug.cgi?id=33759.
126    if (context->textDrawingMode() & TextModeStroke && context->strokeThickness() < 2 * offset) {
127        platformContext->prepareForStroking(context->state());
128        cairo_set_line_width(cr, context->strokeThickness());
129
130        // This may disturb the CTM, but we are going to call cairo_restore soon after.
131        cairo_set_scaled_font(cr, font->platformData().scaledFont());
132        cairo_glyph_path(cr, glyphs, numGlyphs);
133        cairo_stroke(cr);
134    }
135
136    cairo_restore(cr);
137}
138
139}
140