1/*
2 * Copyright (C) 2013 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "TextPaintStyle.h"
28
29#include "FocusController.h"
30#include "Frame.h"
31#include "GraphicsContext.h"
32#include "Page.h"
33#include "PaintInfo.h"
34#include "RenderStyle.h"
35#include "RenderText.h"
36#include "RenderTheme.h"
37#include "RenderView.h"
38#include "Settings.h"
39
40namespace WebCore {
41
42TextPaintStyle::TextPaintStyle(const Color& color)
43 : fillColor(color)
44 , strokeColor(color)
45{
46}
47
48bool TextPaintStyle::operator==(const TextPaintStyle& other) const
49{
50 return fillColor == other.fillColor && strokeColor == other.strokeColor && emphasisMarkColor == other.emphasisMarkColor
51 && strokeWidth == other.strokeWidth && paintOrder == other.paintOrder && lineJoin == other.lineJoin
52#if ENABLE(LETTERPRESS)
53 && useLetterpressEffect == other.useLetterpressEffect
54#endif
55 && lineCap == other.lineCap && miterLimit == other.miterLimit;
56}
57
58bool textColorIsLegibleAgainstBackgroundColor(const Color& textColor, const Color& backgroundColor)
59{
60 // Semi-arbitrarily chose 65025 (255^2) value here after a few tests.
61 return differenceSquared(textColor, backgroundColor) > 65025;
62}
63
64static Color adjustColorForVisibilityOnBackground(const Color& textColor, const Color& backgroundColor)
65{
66 if (textColorIsLegibleAgainstBackgroundColor(textColor, backgroundColor))
67 return textColor;
68
69 int distanceFromWhite = differenceSquared(textColor, Color::white);
70 int distanceFromBlack = differenceSquared(textColor, Color::black);
71 if (distanceFromWhite < distanceFromBlack)
72 return textColor.dark();
73
74 return textColor.light();
75}
76
77TextPaintStyle computeTextPaintStyle(const Frame& frame, const RenderStyle& lineStyle, const PaintInfo& paintInfo)
78{
79 TextPaintStyle paintStyle;
80
81#if ENABLE(LETTERPRESS)
82 paintStyle.useLetterpressEffect = lineStyle.textDecorationsInEffect().contains(TextDecoration::Letterpress);
83#endif
84 auto viewportSize = frame.view() ? frame.view()->size() : IntSize();
85 paintStyle.strokeWidth = lineStyle.computedStrokeWidth(viewportSize);
86 paintStyle.paintOrder = lineStyle.paintOrder();
87 paintStyle.lineJoin = lineStyle.joinStyle();
88 paintStyle.lineCap = lineStyle.capStyle();
89 paintStyle.miterLimit = lineStyle.strokeMiterLimit();
90
91 if (paintInfo.forceTextColor()) {
92 paintStyle.fillColor = paintInfo.forcedTextColor();
93 paintStyle.strokeColor = paintInfo.forcedTextColor();
94 paintStyle.emphasisMarkColor = paintInfo.forcedTextColor();
95 return paintStyle;
96 }
97
98 if (lineStyle.insideDefaultButton()) {
99 Page* page = frame.page();
100 if (page && page->focusController().isActive()) {
101 OptionSet<StyleColor::Options> options;
102 if (page->useSystemAppearance())
103 options.add(StyleColor::Options::UseSystemAppearance);
104 paintStyle.fillColor = RenderTheme::singleton().systemColor(CSSValueActivebuttontext, options);
105 return paintStyle;
106 }
107 }
108
109 paintStyle.fillColor = lineStyle.visitedDependentColorWithColorFilter(CSSPropertyWebkitTextFillColor);
110
111 bool forceBackgroundToWhite = false;
112 if (frame.document() && frame.document()->printing()) {
113 if (lineStyle.printColorAdjust() == PrintColorAdjust::Economy)
114 forceBackgroundToWhite = true;
115 if (frame.settings().shouldPrintBackgrounds())
116 forceBackgroundToWhite = false;
117 }
118
119 // Make the text fill color legible against a white background
120 if (forceBackgroundToWhite)
121 paintStyle.fillColor = adjustColorForVisibilityOnBackground(paintStyle.fillColor, Color::white);
122
123 paintStyle.strokeColor = lineStyle.colorByApplyingColorFilter(lineStyle.computedStrokeColor());
124
125 // Make the text stroke color legible against a white background
126 if (forceBackgroundToWhite)
127 paintStyle.strokeColor = adjustColorForVisibilityOnBackground(paintStyle.strokeColor, Color::white);
128
129 paintStyle.emphasisMarkColor = lineStyle.visitedDependentColorWithColorFilter(CSSPropertyWebkitTextEmphasisColor);
130
131 // Make the text stroke color legible against a white background
132 if (forceBackgroundToWhite)
133 paintStyle.emphasisMarkColor = adjustColorForVisibilityOnBackground(paintStyle.emphasisMarkColor, Color::white);
134
135 return paintStyle;
136}
137
138TextPaintStyle computeTextSelectionPaintStyle(const TextPaintStyle& textPaintStyle, const RenderText& renderer, const RenderStyle& lineStyle, const PaintInfo& paintInfo, Optional<ShadowData>& selectionShadow)
139{
140 TextPaintStyle selectionPaintStyle = textPaintStyle;
141
142#if ENABLE(TEXT_SELECTION)
143 Color foreground = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : renderer.selectionForegroundColor();
144 if (foreground.isValid() && foreground != selectionPaintStyle.fillColor)
145 selectionPaintStyle.fillColor = foreground;
146
147 Color emphasisMarkForeground = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : renderer.selectionEmphasisMarkColor();
148 if (emphasisMarkForeground.isValid() && emphasisMarkForeground != selectionPaintStyle.emphasisMarkColor)
149 selectionPaintStyle.emphasisMarkColor = emphasisMarkForeground;
150
151 if (auto pseudoStyle = renderer.selectionPseudoStyle()) {
152 selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : pseudoStyle->textShadow());
153 auto viewportSize = renderer.frame().view() ? renderer.frame().view()->size() : IntSize();
154 float strokeWidth = pseudoStyle->computedStrokeWidth(viewportSize);
155 if (strokeWidth != selectionPaintStyle.strokeWidth)
156 selectionPaintStyle.strokeWidth = strokeWidth;
157
158 Color stroke = paintInfo.forceTextColor() ? paintInfo.forcedTextColor() : pseudoStyle->computedStrokeColor();
159 if (stroke != selectionPaintStyle.strokeColor)
160 selectionPaintStyle.strokeColor = stroke;
161 } else
162 selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : lineStyle.textShadow());
163#else
164 UNUSED_PARAM(renderer);
165 UNUSED_PARAM(lineStyle);
166 UNUSED_PARAM(paintInfo);
167 selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : lineStyle.textShadow());
168#endif
169 return selectionPaintStyle;
170}
171
172void updateGraphicsContext(GraphicsContext& context, const TextPaintStyle& paintStyle, FillColorType fillColorType)
173{
174 TextDrawingModeFlags mode = context.textDrawingMode();
175 TextDrawingModeFlags newMode = mode;
176#if ENABLE(LETTERPRESS)
177 if (paintStyle.useLetterpressEffect)
178 newMode |= TextModeLetterpress;
179 else
180 newMode &= ~TextModeLetterpress;
181#endif
182 if (paintStyle.strokeWidth > 0 && paintStyle.strokeColor.isVisible())
183 newMode |= TextModeStroke;
184 if (mode != newMode) {
185 context.setTextDrawingMode(newMode);
186 mode = newMode;
187 }
188
189 Color fillColor = fillColorType == UseEmphasisMarkColor ? paintStyle.emphasisMarkColor : paintStyle.fillColor;
190 if (mode & TextModeFill && (fillColor != context.fillColor()))
191 context.setFillColor(fillColor);
192
193 if (mode & TextModeStroke) {
194 if (paintStyle.strokeColor != context.strokeColor())
195 context.setStrokeColor(paintStyle.strokeColor);
196 if (paintStyle.strokeWidth != context.strokeThickness())
197 context.setStrokeThickness(paintStyle.strokeWidth);
198 context.setLineJoin(paintStyle.lineJoin);
199 context.setLineCap(paintStyle.lineCap);
200 if (paintStyle.lineJoin == MiterJoin)
201 context.setMiterLimit(paintStyle.miterLimit);
202 }
203}
204
205}
206