Implement CSS `display: flow-root` (modern clearfix)
[WebKit-https.git] / Source / WebCore / rendering / style / NinePieceImage.cpp
1 /*
2  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
3  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
4  *           (C) 2000 Dirk Mueller (mueller@kde.org)
5  * Copyright (C) 2003-2017 Apple Inc. All rights reserved.
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Library General Public
9  * License as published by the Free Software Foundation; either
10  * version 2 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Library General Public License for more details.
16  *
17  * You should have received a copy of the GNU Library General Public License
18  * along with this library; see the file COPYING.LIB.  If not, write to
19  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20  * Boston, MA 02110-1301, USA.
21  *
22  */
23
24 #include "config.h"
25 #include "NinePieceImage.h"
26
27 #include "GraphicsContext.h"
28 #include "ImageQualityController.h"
29 #include "LengthFunctions.h"
30 #include "RenderStyle.h"
31 #include <wtf/NeverDestroyed.h>
32 #include <wtf/PointerComparison.h>
33 #include <wtf/text/TextStream.h>
34
35 namespace WebCore {
36
37 inline DataRef<NinePieceImage::Data>& NinePieceImage::defaultData()
38 {
39     static NeverDestroyed<DataRef<Data>> data { Data::create() };
40     return data.get();
41 }
42
43 NinePieceImage::NinePieceImage()
44     : m_data(defaultData())
45 {
46 }
47
48 NinePieceImage::NinePieceImage(RefPtr<StyleImage>&& image, LengthBox imageSlices, bool fill, LengthBox borderSlices, LengthBox outset, ENinePieceImageRule horizontalRule, ENinePieceImageRule verticalRule)
49     : m_data(Data::create(WTFMove(image), imageSlices, fill, borderSlices, outset, horizontalRule, verticalRule))
50 {
51 }
52
53 LayoutUnit NinePieceImage::computeSlice(Length length, LayoutUnit width, LayoutUnit slice, LayoutUnit extent)
54 {
55     if (length.isRelative())
56         return length.value() * width;
57     if (length.isAuto())
58         return slice;
59     return valueForLength(length, extent);
60 }
61
62 LayoutBoxExtent NinePieceImage::computeSlices(const LayoutSize& size, const LengthBox& lengths, int scaleFactor)
63 {
64     return {
65         std::min(size.height(), valueForLength(lengths.top(), size.height())) * scaleFactor,
66         std::min(size.width(), valueForLength(lengths.right(), size.width()))  * scaleFactor,
67         std::min(size.height(), valueForLength(lengths.bottom(), size.height())) * scaleFactor,
68         std::min(size.width(), valueForLength(lengths.left(), size.width()))  * scaleFactor
69     };
70 }
71
72 LayoutBoxExtent NinePieceImage::computeSlices(const LayoutSize& size, const LengthBox& lengths, const FloatBoxExtent& widths, const LayoutBoxExtent& slices)
73 {
74     return {
75         computeSlice(lengths.top(), widths.top(), slices.top(), size.height()),
76         computeSlice(lengths.right(), widths.right(), slices.right(), size.width()),
77         computeSlice(lengths.bottom(), widths.bottom(), slices.bottom(), size.height()),
78         computeSlice(lengths.left(), widths.left(), slices.left(), size.width())
79     };
80 }
81
82 void NinePieceImage::scaleSlicesIfNeeded(const LayoutSize& size, LayoutBoxExtent& slices, float deviceScaleFactor)
83 {
84     LayoutUnit width  = std::max<LayoutUnit>(1 / deviceScaleFactor, slices.left() + slices.right());
85     LayoutUnit height = std::max<LayoutUnit>(1 / deviceScaleFactor, slices.top() + slices.bottom());
86
87     float sliceScaleFactor = std::min((float)size.width() / width, (float)size.height() / height);
88
89     if (sliceScaleFactor >= 1)
90         return;
91
92     // All slices are reduced by multiplying them by sliceScaleFactor.
93     slices.top()    *= sliceScaleFactor;
94     slices.right()  *= sliceScaleFactor;
95     slices.bottom() *= sliceScaleFactor;
96     slices.left()   *= sliceScaleFactor;
97 }
98
99 bool NinePieceImage::isEmptyPieceRect(ImagePiece piece, const LayoutBoxExtent& slices)
100 {
101     if (piece == MiddlePiece)
102         return false;
103
104     auto horizontalSide = imagePieceHorizontalSide(piece);
105     auto verticalSide = imagePieceVerticalSide(piece);
106     return !((!horizontalSide || slices.at(*horizontalSide)) && (!verticalSide || slices.at(*verticalSide)));
107 }
108
109 bool NinePieceImage::isEmptyPieceRect(ImagePiece piece, const Vector<FloatRect>& destinationRects, const Vector<FloatRect>& sourceRects)
110 {
111     return destinationRects[piece].isEmpty() || sourceRects[piece].isEmpty();
112 }
113
114 Vector<FloatRect> NinePieceImage::computeNineRects(const FloatRect& outer, const LayoutBoxExtent& slices, float deviceScaleFactor)
115 {
116     FloatRect inner = outer;
117     inner.move(slices.left(), slices.top());
118     inner.contract(slices.left() + slices.right(), slices.top() + slices.bottom());
119     ASSERT(outer.contains(inner));
120
121     Vector<FloatRect> rects(MaxPiece);
122
123     rects[TopLeftPiece]     = snapRectToDevicePixels(outer.x(),    outer.y(),    slices.left(),  slices.top(),    deviceScaleFactor);
124     rects[BottomLeftPiece]  = snapRectToDevicePixels(outer.x(),    inner.maxY(), slices.left(),  slices.bottom(), deviceScaleFactor);
125     rects[LeftPiece]        = snapRectToDevicePixels(outer.x(),    inner.y(),    slices.left(),  inner.height(),  deviceScaleFactor);
126
127     rects[TopRightPiece]    = snapRectToDevicePixels(inner.maxX(), outer.y(),    slices.right(), slices.top(),    deviceScaleFactor);
128     rects[BottomRightPiece] = snapRectToDevicePixels(inner.maxX(), inner.maxY(), slices.right(), slices.bottom(), deviceScaleFactor);
129     rects[RightPiece]       = snapRectToDevicePixels(inner.maxX(), inner.y(),    slices.right(), inner.height(),  deviceScaleFactor);
130
131     rects[TopPiece]         = snapRectToDevicePixels(inner.x(),    outer.y(),    inner.width(),  slices.top(),    deviceScaleFactor);
132     rects[BottomPiece]      = snapRectToDevicePixels(inner.x(),    inner.maxY(), inner.width(),  slices.bottom(), deviceScaleFactor);
133
134     rects[MiddlePiece]      = snapRectToDevicePixels(inner.x(),    inner.y(),    inner.width(),  inner.height(),  deviceScaleFactor);
135     return rects;
136 }
137
138 FloatSize NinePieceImage::computeSideTileScale(ImagePiece piece, const Vector<FloatRect>& destinationRects, const Vector<FloatRect>& sourceRects)
139 {
140     ASSERT(!isCornerPiece(piece) && !isMiddlePiece(piece));
141     if (isEmptyPieceRect(piece, destinationRects, sourceRects))
142         return FloatSize(1, 1);
143
144     float scale;
145     if (isHorizontalPiece(piece))
146         scale = destinationRects[piece].height() / sourceRects[piece].height();
147     else
148         scale = destinationRects[piece].width() / sourceRects[piece].width();
149
150     return FloatSize(scale, scale);
151 }
152
153 FloatSize NinePieceImage::computeMiddleTileScale(const Vector<FloatSize>& scales, const Vector<FloatRect>& destinationRects, const Vector<FloatRect>& sourceRects, ENinePieceImageRule hRule, ENinePieceImageRule vRule)
154 {
155     FloatSize scale(1, 1);
156     if (isEmptyPieceRect(MiddlePiece, destinationRects, sourceRects))
157         return scale;
158
159     // Unlike the side pieces, the middle piece can have "stretch" specified in one axis but not the other.
160     // In fact the side pieces don't even use the scale factor unless they have a rule other than "stretch".
161     if (hRule == StretchImageRule)
162         scale.setWidth(destinationRects[MiddlePiece].width() / sourceRects[MiddlePiece].width());
163     else if (!isEmptyPieceRect(TopPiece, destinationRects, sourceRects))
164         scale.setWidth(scales[TopPiece].width());
165     else if (!isEmptyPieceRect(BottomPiece, destinationRects, sourceRects))
166         scale.setWidth(scales[BottomPiece].width());
167
168     if (vRule == StretchImageRule)
169         scale.setHeight(destinationRects[MiddlePiece].height() / sourceRects[MiddlePiece].height());
170     else if (!isEmptyPieceRect(LeftPiece, destinationRects, sourceRects))
171         scale.setHeight(scales[LeftPiece].height());
172     else if (!isEmptyPieceRect(RightPiece, destinationRects, sourceRects))
173         scale.setHeight(scales[RightPiece].height());
174
175     return scale;
176 }
177
178 Vector<FloatSize> NinePieceImage::computeTileScales(const Vector<FloatRect>& destinationRects, const Vector<FloatRect>& sourceRects, ENinePieceImageRule hRule, ENinePieceImageRule vRule)
179 {
180     Vector<FloatSize> scales(MaxPiece, FloatSize(1, 1));
181
182     scales[TopPiece]    = computeSideTileScale(TopPiece,    destinationRects, sourceRects);
183     scales[RightPiece]  = computeSideTileScale(RightPiece,  destinationRects, sourceRects);
184     scales[BottomPiece] = computeSideTileScale(BottomPiece, destinationRects, sourceRects);
185     scales[LeftPiece]   = computeSideTileScale(LeftPiece,   destinationRects, sourceRects);
186
187     scales[MiddlePiece] = computeMiddleTileScale(scales, destinationRects, sourceRects, hRule, vRule);
188     return scales;
189 }
190
191 void NinePieceImage::paint(GraphicsContext& graphicsContext, RenderElement* renderer, const RenderStyle& style, const LayoutRect& destination, const LayoutSize& source, float deviceScaleFactor, CompositeOperator op) const
192 {
193     StyleImage* styleImage = image();
194     ASSERT(styleImage);
195     ASSERT(styleImage->isLoaded());
196
197     LayoutBoxExtent sourceSlices = computeSlices(source, imageSlices(), styleImage->imageScaleFactor());
198     LayoutBoxExtent destinationSlices = computeSlices(destination.size(), borderSlices(), style.borderWidth(), sourceSlices);
199
200     scaleSlicesIfNeeded(destination.size(), destinationSlices, deviceScaleFactor);
201
202     Vector<FloatRect> destinationRects = computeNineRects(destination, destinationSlices, deviceScaleFactor);
203     Vector<FloatRect> sourceRects = computeNineRects(FloatRect(FloatPoint(), source), sourceSlices, deviceScaleFactor);
204     Vector<FloatSize> tileScales = computeTileScales(destinationRects, sourceRects, horizontalRule(), verticalRule());
205
206     RefPtr<Image> image = styleImage->image(renderer, source);
207     if (!image)
208         return;
209
210     InterpolationQualityMaintainer interpolationMaintainer(graphicsContext, ImageQualityController::interpolationQualityFromStyle(style));
211     for (ImagePiece piece = MinPiece; piece < MaxPiece; ++piece) {
212         if ((piece == MiddlePiece && !fill()) || isEmptyPieceRect(piece, destinationRects, sourceRects))
213             continue;
214
215         if (isCornerPiece(piece)) {
216             graphicsContext.drawImage(*image, destinationRects[piece], sourceRects[piece], op);
217             continue;
218         }
219
220         Image::TileRule hRule = isHorizontalPiece(piece) ? static_cast<Image::TileRule>(horizontalRule()) : Image::StretchTile;
221         Image::TileRule vRule = isVerticalPiece(piece) ? static_cast<Image::TileRule>(verticalRule()) : Image::StretchTile;
222         graphicsContext.drawTiledImage(*image, destinationRects[piece], sourceRects[piece], tileScales[piece], hRule, vRule, op);
223     }
224 }
225
226 inline NinePieceImage::Data::Data()
227     : fill(false)
228     , horizontalRule(StretchImageRule)
229     , verticalRule(StretchImageRule)
230 {
231 }
232
233 inline NinePieceImage::Data::Data(RefPtr<StyleImage>&& image, LengthBox imageSlices, bool fill, LengthBox borderSlices, LengthBox outset, ENinePieceImageRule horizontalRule, ENinePieceImageRule verticalRule)
234     : fill(fill)
235     , horizontalRule(horizontalRule)
236     , verticalRule(verticalRule)
237     , image(WTFMove(image))
238     , imageSlices(imageSlices)
239     , borderSlices(borderSlices)
240     , outset(outset)
241 {
242 }
243
244 inline NinePieceImage::Data::Data(const Data& other)
245     : RefCounted<Data>()
246     , fill(other.fill)
247     , horizontalRule(other.horizontalRule)
248     , verticalRule(other.verticalRule)
249     , image(other.image)
250     , imageSlices(other.imageSlices)
251     , borderSlices(other.borderSlices)
252     , outset(other.outset)
253 {
254 }
255
256 inline Ref<NinePieceImage::Data> NinePieceImage::Data::create()
257 {
258     return adoptRef(*new Data);
259 }
260
261 inline Ref<NinePieceImage::Data> NinePieceImage::Data::create(RefPtr<StyleImage>&& image, LengthBox imageSlices, bool fill, LengthBox borderSlices, LengthBox outset, ENinePieceImageRule horizontalRule, ENinePieceImageRule verticalRule)
262 {
263     return adoptRef(*new Data(WTFMove(image), imageSlices, fill, borderSlices, outset, horizontalRule, verticalRule));
264 }
265
266 Ref<NinePieceImage::Data> NinePieceImage::Data::copy() const
267 {
268     return adoptRef(*new Data(*this));
269 }
270
271 bool NinePieceImage::Data::operator==(const Data& other) const
272 {
273     return arePointingToEqualData(image, other.image)
274         && imageSlices == other.imageSlices
275         && fill == other.fill
276         && borderSlices == other.borderSlices
277         && outset == other.outset
278         && horizontalRule == other.horizontalRule
279         && verticalRule == other.verticalRule;
280 }
281
282 TextStream& operator<<(TextStream& ts, const NinePieceImage& image)
283 {
284     ts << "style-image " << image.image() << " slices " << image.imageSlices();
285     return ts;
286 }
287
288 }