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1 // Copyright 2016 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "core/layout/FragmentainerIterator.h" | |
6 | |
7 #include "core/layout/LayoutMultiColumnSet.h" | |
8 | |
9 namespace blink { | |
10 | |
11 FragmentainerIterator::FragmentainerIterator(const LayoutFlowThread& flowThread, const LayoutRect& physicalBoundingBoxInFlowThread, const LayoutRect& clipRectIn MulticolContainer) | |
12 : m_flowThread(flowThread) | |
13 , m_clipRectInMulticolContainer(clipRectInMulticolContainer) | |
14 , m_currentFragmentainerGroupIndex(0) | |
15 { | |
16 // Put the bounds into flow thread-local coordinates by flipping it first. T his is how | |
17 // rectangles typically are represented in layout, i.e. with the block direc tion coordinate | |
18 // flipped, if writing mode is vertical-rl. | |
19 LayoutRect boundsInFlowThread = physicalBoundingBoxInFlowThread; | |
20 m_flowThread.flipForWritingMode(boundsInFlowThread); | |
21 | |
22 if (m_flowThread.isHorizontalWritingMode()) { | |
23 m_logicalTopInFlowThread = boundsInFlowThread.y(); | |
24 m_logicalBottomInFlowThread = boundsInFlowThread.maxY(); | |
25 } else { | |
26 m_logicalTopInFlowThread = boundsInFlowThread.x(); | |
27 m_logicalBottomInFlowThread = boundsInFlowThread.maxX(); | |
28 } | |
29 | |
30 // Jump to the first interesting column set. | |
31 m_currentColumnSet = flowThread.columnSetAtBlockOffset(m_logicalTopInFlowThr ead); | |
32 if (!m_currentColumnSet || m_currentColumnSet->logicalTopInFlowThread() >= m _logicalBottomInFlowThread) { | |
33 setAtEnd(); | |
34 return; | |
35 } | |
36 // Then find the first interesting fragmentainer group. | |
37 m_currentFragmentainerGroupIndex = m_currentColumnSet->fragmentainerGroupInd exAtFlowThreadOffset(m_logicalTopInFlowThread); | |
38 | |
39 // Now find the first and last fragmentainer we're interested in. We'll also clip against | |
40 // the clip rect here. In case the clip rect doesn't intersect with any of t he | |
41 // fragmentainers, we have to move on to the next fragmentainer group, and s ee if we find | |
42 // something there. | |
43 if (!setFragmentainersOfInterest()) { | |
44 moveToNextFragmentainerGroup(); | |
45 if (atEnd()) | |
46 return; | |
47 } | |
48 | |
49 updateOutput(); | |
50 } | |
51 | |
52 void FragmentainerIterator::advance() | |
53 { | |
54 DCHECK(!atEnd()); | |
55 m_currentFragmentainerIndex++; | |
56 | |
57 if (m_currentFragmentainerIndex > m_endFragmentainerIndex) { | |
eae
2016/09/08 08:15:03
How about reversing this logic instead of increasi
mstensho (USE GERRIT)
2016/09/08 08:59:51
Done. Very nice! I like!
| |
58 // That was the last fragmentainer to visit in this fragmentainer group. Advance to the | |
59 // next group. | |
60 moveToNextFragmentainerGroup(); | |
61 if (atEnd()) | |
62 return; | |
63 } | |
64 updateOutput(); | |
65 } | |
66 | |
67 const MultiColumnFragmentainerGroup& FragmentainerIterator::currentGroup() const | |
68 { | |
69 DCHECK(!atEnd()); | |
70 return m_currentColumnSet->fragmentainerGroups()[m_currentFragmentainerGroup Index]; | |
71 } | |
72 | |
73 void FragmentainerIterator::moveToNextFragmentainerGroup() | |
74 { | |
75 do { | |
76 m_currentFragmentainerGroupIndex++; | |
77 if (m_currentFragmentainerGroupIndex >= m_currentColumnSet->fragmentaine rGroups().size()) { | |
78 // That was the last fragmentainer group in this set. Advance to the next set. | |
79 m_currentColumnSet = m_currentColumnSet->nextSiblingMultiColumnSet() ; | |
80 m_currentFragmentainerGroupIndex = 0; | |
81 if (!m_currentColumnSet || m_currentColumnSet->logicalTopInFlowThrea d() >= m_logicalBottomInFlowThread) { | |
82 setAtEnd(); | |
83 return; // No more sets or next set out of range. We're done. | |
84 } | |
85 } | |
86 if (currentGroup().logicalTopInFlowThread() >= m_logicalBottomInFlowThre ad) { | |
87 setAtEnd(); // This fragmentainer group doesn't intersect with the r ange we're interested in. We're done. | |
88 return; | |
89 } | |
90 } while (!setFragmentainersOfInterest()); | |
91 } | |
92 | |
93 bool FragmentainerIterator::setFragmentainersOfInterest() | |
94 { | |
95 const MultiColumnFragmentainerGroup& group = currentGroup(); | |
96 | |
97 // Figure out the start and end fragmentainers for the block range we're int erested in. We | |
98 // might not have to walk the entire fragmentainer group. | |
99 group.columnIntervalForBlockRangeInFlowThread(m_logicalTopInFlowThread, m_lo gicalBottomInFlowThread, m_currentFragmentainerIndex, m_endFragmentainerIndex); | |
100 | |
101 // Now intersect with the fragmentainers that actually intersect with the cl ip rect, to narrow | |
102 // it down even further. | |
103 unsigned firstFragmentainerInClipRect, lastFragmentainerInClipRect; | |
104 group.columnIntervalForVisualRect(m_clipRectInMulticolContainer, firstFragme ntainerInClipRect, lastFragmentainerInClipRect); | |
105 // If the two fragmentainer intervals are disjoint, there's nothing of inter est in this | |
106 // fragmentainer group. | |
107 if (firstFragmentainerInClipRect > m_endFragmentainerIndex || lastFragmentai nerInClipRect < m_currentFragmentainerIndex) | |
108 return false; | |
109 if (m_currentFragmentainerIndex < firstFragmentainerInClipRect) | |
110 m_currentFragmentainerIndex = firstFragmentainerInClipRect; | |
111 if (m_endFragmentainerIndex > lastFragmentainerInClipRect) | |
112 m_endFragmentainerIndex = lastFragmentainerInClipRect; | |
113 DCHECK(m_endFragmentainerIndex >= m_currentFragmentainerIndex); | |
114 return true; | |
115 } | |
116 | |
117 void FragmentainerIterator::updateOutput() | |
118 { | |
119 const MultiColumnFragmentainerGroup& group = currentGroup(); | |
120 | |
121 // Set the physical translation offset. | |
122 LayoutUnit fragmentainerLogicalTopInFlowThread = group.logicalTopInFlowThrea d() + m_currentFragmentainerIndex * group.logicalHeight(); | |
123 m_paginationOffset = group.flowThreadTranslationAtOffset(fragmentainerLogica lTopInFlowThread, CoordinateSpaceConversion::Visual); | |
124 | |
125 // Set the overflow clip rect that corresponds to the fragmentainer. | |
126 m_clipRectInFlowThread = group.flowThreadPortionOverflowRectAt(m_currentFrag mentainerIndex); | |
127 | |
128 // Flip it into a physical rectangle. | |
129 m_flowThread.flipForWritingMode(m_clipRectInFlowThread); | |
130 } | |
131 | |
132 } // namespace blink | |
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