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
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/*
* Copyright (C) 2017-2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "LayoutIntegrationPagination.h"
#if ENABLE(LAYOUT_FORMATTING_CONTEXT)
#include "FontCascade.h"
#include "RenderBlockFlow.h"
namespace WebCore {
namespace LayoutIntegration {
struct Strut {
unsigned lineBreak;
float offset;
};
struct PaginatedLine {
LayoutUnit top;
LayoutUnit height;
};
using PaginatedLines = Vector<PaginatedLine, 20>;
static PaginatedLine computeLineTopAndBottomWithOverflow(const RenderBlockFlow&, InlineContent::Lines& lines, unsigned lineIndex, Vector<Strut>& struts)
{
LayoutUnit offset = 0;
for (auto& strut : struts) {
if (strut.lineBreak > lineIndex)
break;
offset += strut.offset;
}
auto overflowRect = LayoutRect(lines[lineIndex].inkOverflow());
return { overflowRect.y() + offset, overflowRect.height() };
}
static unsigned computeLineBreakIndex(unsigned breakCandidate, unsigned lineCount, int orphansNeeded, int widowsNeeded,
const Vector<Strut>& struts)
{
// First line does not fit the current page.
if (!breakCandidate)
return breakCandidate;
int widowsOnTheNextPage = lineCount - breakCandidate;
if (widowsNeeded <= widowsOnTheNextPage)
return breakCandidate;
// Only break after the first line with widows.
auto lineBreak = std::max<int>(lineCount - widowsNeeded, 1);
if (orphansNeeded > lineBreak)
return breakCandidate;
// Break on current page only.
if (struts.isEmpty())
return lineBreak;
ASSERT(struts.last().lineBreak + 1 < lineCount);
return std::max<unsigned>(struts.last().lineBreak + 1, lineBreak);
}
static LayoutUnit computeOffsetAfterLineBreak(LayoutUnit lineBreakPosition, bool isFirstLine, bool atTheTopOfColumnOrPage, const RenderBlockFlow& flow)
{
// No offset for top of the page lines unless widows pushed the line break.
LayoutUnit offset = isFirstLine ? flow.borderAndPaddingBefore() : 0_lu;
if (atTheTopOfColumnOrPage)
return offset;
return offset + flow.pageRemainingLogicalHeightForOffset(lineBreakPosition, RenderBlockFlow::ExcludePageBoundary);
}
static void setPageBreakForLine(unsigned lineBreakIndex, PaginatedLines& lines, RenderBlockFlow& flow, Vector<Strut>& struts,
bool atTheTopOfColumnOrPage, bool lineDoesNotFit)
{
auto line = lines.at(lineBreakIndex);
auto remainingLogicalHeight = flow.pageRemainingLogicalHeightForOffset(line.top, RenderBlockFlow::ExcludePageBoundary);
auto& style = flow.style();
auto firstLineDoesNotFit = !lineBreakIndex && line.height < flow.pageLogicalHeightForOffset(line.top);
auto moveOrphanToNextColumn = lineDoesNotFit && !style.hasAutoOrphans() && style.orphans() > (short)lineBreakIndex;
if (firstLineDoesNotFit || moveOrphanToNextColumn) {
auto firstLine = lines.first();
auto firstLineUpperOverhang = std::max(LayoutUnit(-firstLine.top), 0_lu);
flow.setPaginationStrut(line.top + remainingLogicalHeight + firstLineUpperOverhang);
return;
}
if (atTheTopOfColumnOrPage)
flow.setPageBreak(line.top, line.height);
else
flow.setPageBreak(line.top, line.height - remainingLogicalHeight);
struts.append({ lineBreakIndex, computeOffsetAfterLineBreak(lines[lineBreakIndex].top, !lineBreakIndex, atTheTopOfColumnOrPage, flow) });
}
static void updateMinimumPageHeight(RenderBlockFlow& flow, const InlineContent& inlineContent, unsigned lineCount)
{
auto& style = flow.style();
auto widows = style.hasAutoWidows() ? 1 : std::max<int>(style.widows(), 1);
auto orphans = style.hasAutoOrphans() ? 1 : std::max<int>(style.orphans(), 1);
auto minimumLineCount = std::min<unsigned>(std::max(widows, orphans), lineCount);
flow.updateMinimumPageHeight(0, LayoutUnit(inlineContent.lines[minimumLineCount - 1].lineBoxBottom()));
}
static Ref<InlineContent> makeAdjustedContent(const InlineContent& inlineContent, Vector<float> adjustments)
{
auto moveVertically = [](FloatRect rect, float offset) {
rect.move(FloatSize(0, offset));
return rect;
};
auto adjustedLine = [&](const Line& line, float offset)
{
return Line {
line.firstBoxIndex(),
line.boxCount(),
moveVertically({ FloatPoint { line.lineBoxLeft(), line.lineBoxTop() }, FloatPoint { line.lineBoxRight(), line.lineBoxBottom() } }, offset),
line.enclosingContentTop() + offset,
line.enclosingContentBottom() + offset,
moveVertically(line.scrollableOverflow(), offset),
moveVertically(line.inkOverflow(), offset),
line.baseline(),
line.baselineType(),
line.contentLogicalOffset(),
line.contentLogicalWidth(),
line.isHorizontal()
};
};
auto adjustedBox = [&](const InlineDisplay::Box& box, float offset)
{
auto adjustedBox = box;
adjustedBox.moveVertically(offset);
return adjustedBox;
};
auto adjustedContent = InlineContent::create(inlineContent.lineLayout());
for (size_t lineIndex = 0; lineIndex < inlineContent.lines.size(); ++lineIndex)
adjustedContent->lines.append(adjustedLine(inlineContent.lines[lineIndex], adjustments[lineIndex]));
for (auto& box : inlineContent.boxes)
adjustedContent->boxes.append(adjustedBox(box, adjustments[box.lineIndex()]));
return adjustedContent;
}
Ref<InlineContent> adjustLinePositionsForPagination(InlineContent& inlineContent, RenderBlockFlow& flow)
{
Vector<Strut> struts;
auto lineCount = inlineContent.lines.size();
updateMinimumPageHeight(flow, inlineContent, lineCount);
// First pass with no pagination offset?
if (!flow.pageLogicalHeightForOffset(0))
return inlineContent;
auto widows = flow.style().hasAutoWidows() ? 1 : std::max<int>(flow.style().widows(), 1);
auto orphans = flow.style().hasAutoOrphans() ? 1 : std::max<int>(flow.style().orphans(), 1);
PaginatedLines lines;
for (unsigned lineIndex = 0; lineIndex < lineCount; ++lineIndex) {
auto line = computeLineTopAndBottomWithOverflow(flow, inlineContent.lines, lineIndex, struts);
lines.append(line);
auto remainingHeight = flow.pageRemainingLogicalHeightForOffset(line.top, RenderBlockFlow::ExcludePageBoundary);
auto atTheTopOfColumnOrPage = flow.pageLogicalHeightForOffset(line.top) == remainingHeight;
auto lineDoesNotFit = line.height > remainingHeight;
if (lineDoesNotFit || (atTheTopOfColumnOrPage && lineIndex)) {
auto lineBreakIndex = computeLineBreakIndex(lineIndex, lineCount, orphans, widows, struts);
// Are we still at the top of the column/page?
atTheTopOfColumnOrPage = atTheTopOfColumnOrPage ? lineIndex == lineBreakIndex : false;
setPageBreakForLine(lineBreakIndex, lines, flow, struts, atTheTopOfColumnOrPage, lineDoesNotFit);
// Recompute line positions that we already visited but widow break pushed them to a new page.
for (auto i = lineBreakIndex; i < lines.size(); ++i)
lines.at(i) = computeLineTopAndBottomWithOverflow(flow, inlineContent.lines, i, struts);
}
}
if (struts.isEmpty())
return inlineContent;
auto adjustments = Vector<float>(lineCount, 0);
for (auto& strut : struts) {
for (auto lineIndex = strut.lineBreak; lineIndex < lineCount; ++lineIndex)
adjustments[lineIndex] += strut.offset;
}
return makeAdjustedContent(inlineContent, adjustments);
}
}
}
#endif
|
