1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "config.h"
#include "core/html/HTMLImageFallbackHelper.h"
#include "core/HTMLNames.h"
#include "core/InputTypeNames.h"
#include "core/dom/ElementRareData.h"
#include "core/dom/Text.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/fetch/ImageResource.h"
#include "core/html/FormDataList.h"
#include "core/html/HTMLDivElement.h"
#include "core/html/HTMLElement.h"
#include "core/html/HTMLImageElement.h"
#include "core/html/HTMLImageLoader.h"
#include "core/html/HTMLInputElement.h"
#include "core/html/HTMLStyleElement.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/text/StringBuilder.h"
namespace blink {
using namespace HTMLNames;
static bool noImageSourceSpecified(const Element& element)
{
bool noSrcSpecified = !element.hasAttribute(srcAttr) || element.getAttribute(srcAttr).isNull() || element.getAttribute(srcAttr).isEmpty();
bool noSrcsetSpecified = !element.hasAttribute(srcsetAttr) || element.getAttribute(srcsetAttr).isNull() || element.getAttribute(srcsetAttr).isEmpty();
return noSrcSpecified && noSrcsetSpecified;
}
void HTMLImageFallbackHelper::createAltTextShadowTree(Element& element)
{
ShadowRoot& root = element.ensureUserAgentShadowRoot();
RefPtrWillBeRawPtr<HTMLDivElement> container = HTMLDivElement::create(element.document());
root.appendChild(container);
container->setAttribute(idAttr, AtomicString("alttext-container", AtomicString::ConstructFromLiteral));
container->setInlineStyleProperty(CSSPropertyOverflow, CSSValueHidden);
container->setInlineStyleProperty(CSSPropertyBorderWidth, 1, CSSPrimitiveValue::CSS_PX);
container->setInlineStyleProperty(CSSPropertyBorderStyle, CSSValueSolid);
container->setInlineStyleProperty(CSSPropertyBorderColor, CSSValueSilver);
container->setInlineStyleProperty(CSSPropertyDisplay, CSSValueInlineBlock);
container->setInlineStyleProperty(CSSPropertyBoxSizing, CSSValueBorderBox);
container->setInlineStyleProperty(CSSPropertyPadding, 1, CSSPrimitiveValue::CSS_PX);
RefPtrWillBeRawPtr<HTMLImageElement> brokenImage = HTMLImageElement::create(element.document());
container->appendChild(brokenImage);
brokenImage->setIsFallbackImage();
brokenImage->setAttribute(idAttr, AtomicString("alttext-image", AtomicString::ConstructFromLiteral));
brokenImage->setAttribute(widthAttr, AtomicString("16", AtomicString::ConstructFromLiteral));
brokenImage->setAttribute(heightAttr, AtomicString("16", AtomicString::ConstructFromLiteral));
brokenImage->setAttribute(alignAttr, AtomicString("left", AtomicString::ConstructFromLiteral));
brokenImage->setInlineStyleProperty(CSSPropertyMargin, 0, CSSPrimitiveValue::CSS_PX);
RefPtrWillBeRawPtr<HTMLDivElement> altText = HTMLDivElement::create(element.document());
container->appendChild(altText);
altText->setAttribute(idAttr, AtomicString("alttext", AtomicString::ConstructFromLiteral));
altText->setInlineStyleProperty(CSSPropertyOverflow, CSSValueHidden);
altText->setInlineStyleProperty(CSSPropertyDisplay, CSSValueBlock);
RefPtrWillBeRawPtr<Text> text = Text::create(element.document(), toHTMLElement(element).altText());
altText->appendChild(text);
}
PassRefPtr<RenderStyle> HTMLImageFallbackHelper::customStyleForAltText(Element& element, PassRefPtr<RenderStyle> newStyle)
{
// If we have an author shadow root or have not created the UA shadow root yet, bail early. We can't
// use ensureUserAgentShadowRoot() here because that would alter the DOM tree during style recalc.
if (element.shadowRoot() || !element.userAgentShadowRoot())
return newStyle;
Element* placeHolder = element.userAgentShadowRoot()->getElementById("alttext-container");
// Input elements have a UA shadow root of their own. We may not have replaced it with fallback content yet.
if (!placeHolder)
return newStyle;
Element* brokenImage = element.userAgentShadowRoot()->getElementById("alttext-image");
if (element.document().inQuirksMode()) {
// Mimic the behaviour of the image host by setting symmetric dimensions if only one dimension is specified.
if (newStyle->width().isSpecifiedOrIntrinsic() && newStyle->height().isAuto())
newStyle->setHeight(newStyle->width());
else if (newStyle->height().isSpecifiedOrIntrinsic() && newStyle->width().isAuto())
newStyle->setWidth(newStyle->height());
if (newStyle->width().isSpecifiedOrIntrinsic() && newStyle->height().isSpecifiedOrIntrinsic()) {
placeHolder->setInlineStyleProperty(CSSPropertyVerticalAlign, CSSValueBaseline);
}
}
// If the image has specified dimensions allow the alt-text container expand to fill them.
if (newStyle->width().isSpecifiedOrIntrinsic() && newStyle->height().isSpecifiedOrIntrinsic()) {
placeHolder->setInlineStyleProperty(CSSPropertyWidth, 100, CSSPrimitiveValue::CSS_PERCENTAGE);
placeHolder->setInlineStyleProperty(CSSPropertyHeight, 100, CSSPrimitiveValue::CSS_PERCENTAGE);
}
// Make sure the broken image icon appears on the appropriate side of the image for the element's writing direction.
brokenImage->setInlineStyleProperty(CSSPropertyFloat, AtomicString(newStyle->direction() == LTR ? "left" : "right"));
// This is an <img> with no attributes, so don't display anything.
if (noImageSourceSpecified(element) && !newStyle->width().isSpecifiedOrIntrinsic() && !newStyle->height().isSpecifiedOrIntrinsic() && toHTMLElement(element).altText().isEmpty())
newStyle->setDisplay(NONE);
// This preserves legacy behaviour originally defined when alt-text was managed by RenderImage.
if (noImageSourceSpecified(element))
brokenImage->setInlineStyleProperty(CSSPropertyDisplay, CSSValueNone);
else
brokenImage->setInlineStyleProperty(CSSPropertyDisplay, CSSValueInline);
return newStyle;
}
} // namespace blink
|
