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      1 /*
      2  * Copyright (C) 2006 Oliver Hunt <ojh16 (at) student.canterbury.ac.nz>
      3  * Copyright (C) 2006 Apple Computer Inc.
      4  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann (at) kde.org>
      5  * Copyright (C) 2008 Rob Buis <buis (at) kde.org>
      6  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
      7  *
      8  * This library is free software; you can redistribute it and/or
      9  * modify it under the terms of the GNU Library General Public
     10  * License as published by the Free Software Foundation; either
     11  * version 2 of the License, or (at your option) any later version.
     12  *
     13  * This library is distributed in the hope that it will be useful,
     14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     16  * Library General Public License for more details.
     17  *
     18  * You should have received a copy of the GNU Library General Public License
     19  * along with this library; see the file COPYING.LIB.  If not, write to
     20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     21  * Boston, MA 02110-1301, USA.
     22  */
     23 
     24 #include "config.h"
     25 
     26 #include "core/rendering/svg/RenderSVGInlineText.h"
     27 
     28 #include "core/css/CSSFontSelector.h"
     29 #include "core/css/FontSize.h"
     30 #include "core/editing/VisiblePosition.h"
     31 #include "core/rendering/svg/RenderSVGText.h"
     32 #include "core/rendering/svg/SVGInlineTextBox.h"
     33 #include "core/rendering/svg/SVGRenderingContext.h"
     34 
     35 namespace WebCore {
     36 
     37 static PassRefPtr<StringImpl> applySVGWhitespaceRules(PassRefPtr<StringImpl> string, bool preserveWhiteSpace)
     38 {
     39     if (preserveWhiteSpace) {
     40         // Spec: When xml:space="preserve", the SVG user agent will do the following using a
     41         // copy of the original character data content. It will convert all newline and tab
     42         // characters into space characters. Then, it will draw all space characters, including
     43         // leading, trailing and multiple contiguous space characters.
     44         RefPtr<StringImpl> newString = string->replace('\t', ' ');
     45         newString = newString->replace('\n', ' ');
     46         newString = newString->replace('\r', ' ');
     47         return newString.release();
     48     }
     49 
     50     // Spec: When xml:space="default", the SVG user agent will do the following using a
     51     // copy of the original character data content. First, it will remove all newline
     52     // characters. Then it will convert all tab characters into space characters.
     53     // Then, it will strip off all leading and trailing space characters.
     54     // Then, all contiguous space characters will be consolidated.
     55     RefPtr<StringImpl> newString = string->replace('\n', StringImpl::empty());
     56     newString = newString->replace('\r', StringImpl::empty());
     57     newString = newString->replace('\t', ' ');
     58     return newString.release();
     59 }
     60 
     61 RenderSVGInlineText::RenderSVGInlineText(Node* n, PassRefPtr<StringImpl> string)
     62     : RenderText(n, applySVGWhitespaceRules(string, false))
     63     , m_scalingFactor(1)
     64     , m_layoutAttributes(this)
     65 {
     66 }
     67 
     68 void RenderSVGInlineText::setTextInternal(PassRefPtr<StringImpl> text)
     69 {
     70     RenderText::setTextInternal(text);
     71     if (RenderSVGText* textRenderer = RenderSVGText::locateRenderSVGTextAncestor(this))
     72         textRenderer->subtreeTextDidChange(this);
     73 }
     74 
     75 void RenderSVGInlineText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
     76 {
     77     RenderText::styleDidChange(diff, oldStyle);
     78     updateScaledFont();
     79 
     80     bool newPreserves = style() ? style()->whiteSpace() == PRE : false;
     81     bool oldPreserves = oldStyle ? oldStyle->whiteSpace() == PRE : false;
     82     if (oldPreserves && !newPreserves) {
     83         setText(applySVGWhitespaceRules(originalText(), false), true);
     84         return;
     85     }
     86 
     87     if (!oldPreserves && newPreserves) {
     88         setText(applySVGWhitespaceRules(originalText(), true), true);
     89         return;
     90     }
     91 
     92     if (diff != StyleDifferenceLayout)
     93         return;
     94 
     95     // The text metrics may be influenced by style changes.
     96     if (RenderSVGText* textRenderer = RenderSVGText::locateRenderSVGTextAncestor(this))
     97         textRenderer->subtreeStyleDidChange(this);
     98 }
     99 
    100 InlineTextBox* RenderSVGInlineText::createTextBox()
    101 {
    102     InlineTextBox* box = new SVGInlineTextBox(this);
    103     box->setHasVirtualLogicalHeight();
    104     return box;
    105 }
    106 
    107 LayoutRect RenderSVGInlineText::localCaretRect(InlineBox* box, int caretOffset, LayoutUnit*)
    108 {
    109     if (!box || !box->isInlineTextBox())
    110         return LayoutRect();
    111 
    112     InlineTextBox* textBox = toInlineTextBox(box);
    113     if (static_cast<unsigned>(caretOffset) < textBox->start() || static_cast<unsigned>(caretOffset) > textBox->start() + textBox->len())
    114         return LayoutRect();
    115 
    116     // Use the edge of the selection rect to determine the caret rect.
    117     if (static_cast<unsigned>(caretOffset) < textBox->start() + textBox->len()) {
    118         LayoutRect rect = textBox->localSelectionRect(caretOffset, caretOffset + 1);
    119         LayoutUnit x = box->isLeftToRightDirection() ? rect.x() : rect.maxX();
    120         return LayoutRect(x, rect.y(), caretWidth, rect.height());
    121     }
    122 
    123     LayoutRect rect = textBox->localSelectionRect(caretOffset - 1, caretOffset);
    124     LayoutUnit x = box->isLeftToRightDirection() ? rect.maxX() : rect.x();
    125     return LayoutRect(x, rect.y(), caretWidth, rect.height());
    126 }
    127 
    128 FloatRect RenderSVGInlineText::floatLinesBoundingBox() const
    129 {
    130     FloatRect boundingBox;
    131     for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
    132         boundingBox.unite(box->calculateBoundaries());
    133     return boundingBox;
    134 }
    135 
    136 IntRect RenderSVGInlineText::linesBoundingBox() const
    137 {
    138     return enclosingIntRect(floatLinesBoundingBox());
    139 }
    140 
    141 bool RenderSVGInlineText::characterStartsNewTextChunk(int position) const
    142 {
    143     ASSERT(position >= 0);
    144     ASSERT(position < static_cast<int>(textLength()));
    145 
    146     // Each <textPath> element starts a new text chunk, regardless of any x/y values.
    147     if (!position && parent()->isSVGTextPath() && !previousSibling())
    148         return true;
    149 
    150     const SVGCharacterDataMap::const_iterator it = m_layoutAttributes.characterDataMap().find(static_cast<unsigned>(position + 1));
    151     if (it == m_layoutAttributes.characterDataMap().end())
    152         return false;
    153 
    154     return it->value.x != SVGTextLayoutAttributes::emptyValue() || it->value.y != SVGTextLayoutAttributes::emptyValue();
    155 }
    156 
    157 PositionWithAffinity RenderSVGInlineText::positionForPoint(const LayoutPoint& point)
    158 {
    159     if (!firstTextBox() || !textLength())
    160         return createPositionWithAffinity(0, DOWNSTREAM);
    161 
    162     float baseline = m_scaledFont.fontMetrics().floatAscent();
    163 
    164     RenderBlock* containingBlock = this->containingBlock();
    165     ASSERT(containingBlock);
    166 
    167     // Map local point to absolute point, as the character origins stored in the text fragments use absolute coordinates.
    168     FloatPoint absolutePoint(point);
    169     absolutePoint.moveBy(containingBlock->location());
    170 
    171     float closestDistance = std::numeric_limits<float>::max();
    172     float closestDistancePosition = 0;
    173     const SVGTextFragment* closestDistanceFragment = 0;
    174     SVGInlineTextBox* closestDistanceBox = 0;
    175 
    176     AffineTransform fragmentTransform;
    177     for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
    178         if (!box->isSVGInlineTextBox())
    179             continue;
    180 
    181         SVGInlineTextBox* textBox = toSVGInlineTextBox(box);
    182         Vector<SVGTextFragment>& fragments = textBox->textFragments();
    183 
    184         unsigned textFragmentsSize = fragments.size();
    185         for (unsigned i = 0; i < textFragmentsSize; ++i) {
    186             const SVGTextFragment& fragment = fragments.at(i);
    187             FloatRect fragmentRect(fragment.x, fragment.y - baseline, fragment.width, fragment.height);
    188             fragment.buildFragmentTransform(fragmentTransform);
    189             if (!fragmentTransform.isIdentity())
    190                 fragmentRect = fragmentTransform.mapRect(fragmentRect);
    191 
    192             float distance = powf(fragmentRect.x() - absolutePoint.x(), 2) +
    193                              powf(fragmentRect.y() + fragmentRect.height() / 2 - absolutePoint.y(), 2);
    194 
    195             if (distance < closestDistance) {
    196                 closestDistance = distance;
    197                 closestDistanceBox = textBox;
    198                 closestDistanceFragment = &fragment;
    199                 closestDistancePosition = fragmentRect.x();
    200             }
    201         }
    202     }
    203 
    204     if (!closestDistanceFragment)
    205         return createPositionWithAffinity(0, DOWNSTREAM);
    206 
    207     int offset = closestDistanceBox->offsetForPositionInFragment(*closestDistanceFragment, absolutePoint.x() - closestDistancePosition, true);
    208     return createPositionWithAffinity(offset + closestDistanceBox->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM);
    209 }
    210 
    211 void RenderSVGInlineText::updateScaledFont()
    212 {
    213     computeNewScaledFontForStyle(this, style(), m_scalingFactor, m_scaledFont);
    214 }
    215 
    216 void RenderSVGInlineText::computeNewScaledFontForStyle(RenderObject* renderer, const RenderStyle* style, float& scalingFactor, Font& scaledFont)
    217 {
    218     ASSERT(style);
    219     ASSERT(renderer);
    220 
    221     // Alter font-size to the right on-screen value to avoid scaling the glyphs themselves, except when GeometricPrecision is specified.
    222     scalingFactor = SVGRenderingContext::calculateScreenFontSizeScalingFactor(renderer);
    223     if (scalingFactor == 1 || !scalingFactor) {
    224         scalingFactor = 1;
    225         scaledFont = style->font();
    226         return;
    227     }
    228 
    229     if (style->fontDescription().textRenderingMode() == GeometricPrecision)
    230         scalingFactor = 1;
    231 
    232     FontDescription fontDescription(style->fontDescription());
    233 
    234     Document& document = renderer->document();
    235     // FIXME: We need to better handle the case when we compute very small fonts below (below 1pt).
    236     fontDescription.setComputedSize(FontSize::getComputedSizeFromSpecifiedSize(&document, scalingFactor, fontDescription.isAbsoluteSize(), fontDescription.specifiedSize(), DoNotUseSmartMinimumForFontSize));
    237 
    238     scaledFont = Font(fontDescription, 0, 0);
    239     scaledFont.update(document.styleEngine()->fontSelector());
    240 }
    241 
    242 }
    243