Home | History | Annotate | Download | only in svg 
      1 /*
      2  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
      3  *
      4  * This library is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU Library General Public
      6  * License as published by the Free Software Foundation; either
      7  * version 2 of the License, or (at your option) any later version.
      8  *
      9  * This library is distributed in the hope that it will be useful,
     10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * Library General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU Library General Public License
     15  * along with this library; see the file COPYING.LIB.  If not, write to
     16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  * Boston, MA 02110-1301, USA.
     18  */
     19 
     20 #include "config.h"
     21 
     22 #if ENABLE(SVG)
     23 #include "SVGTextMetrics.h"
     24 
     25 #include "RenderSVGInlineText.h"
     26 #include "TextRun.h"
     27 
     28 namespace WebCore {
     29 
     30 SVGTextMetrics::SVGTextMetrics()
     31     : m_width(0)
     32     , m_height(0)
     33     , m_length(0)
     34 {
     35 }
     36 
     37 SVGTextMetrics::SVGTextMetrics(RenderSVGInlineText* textRenderer, const TextRun& run, unsigned position, unsigned textLength)
     38 {
     39     ASSERT(textRenderer);
     40 
     41     float scalingFactor = textRenderer->scalingFactor();
     42     ASSERT(scalingFactor);
     43 
     44     const Font& scaledFont = textRenderer->scaledFont();
     45 
     46     int extraCharsAvailable = textLength - (position + run.length());
     47     int length = 0;
     48 
     49     // Calculate width/height using the scaled font, divide this result by the scalingFactor afterwards.
     50     m_width = scaledFont.width(run, extraCharsAvailable, length, m_glyph.name) / scalingFactor;
     51     m_height = scaledFont.fontMetrics().floatHeight() / scalingFactor;
     52 
     53     m_glyph.unicodeString = String(run.characters(), length);
     54     m_glyph.isValid = true;
     55 
     56     ASSERT(length >= 0);
     57     m_length = static_cast<unsigned>(length);
     58 }
     59 
     60 bool SVGTextMetrics::operator==(const SVGTextMetrics& other)
     61 {
     62     return m_width == other.m_width
     63         && m_height == other.m_height
     64         && m_length == other.m_length
     65         && m_glyph == other.m_glyph;
     66 }
     67 
     68 SVGTextMetrics SVGTextMetrics::emptyMetrics()
     69 {
     70     DEFINE_STATIC_LOCAL(SVGTextMetrics, s_emptyMetrics, ());
     71     s_emptyMetrics.m_length = 1;
     72     return s_emptyMetrics;
     73 }
     74 
     75 static TextRun constructTextRun(RenderSVGInlineText* text, const UChar* characters, unsigned position, unsigned length)
     76 {
     77     RenderStyle* style = text->style();
     78     ASSERT(style);
     79 
     80     TextRun run(characters + position
     81                 , length
     82                 , false /* allowTabs */
     83                 , 0 /* xPos, only relevant with allowTabs=true */
     84                 , 0 /* padding, only relevant for justified text, not relevant for SVG */
     85                 , TextRun::AllowTrailingExpansion
     86                 , !style->isLeftToRightDirection()
     87                 , style->unicodeBidi() == Override /* directionalOverride */);
     88 
     89 #if ENABLE(SVG_FONTS)
     90     run.setReferencingRenderObject(text);
     91 #endif
     92 
     93     // We handle letter & word spacing ourselves.
     94     run.disableSpacing();
     95     return run;
     96 }
     97 
     98 SVGTextMetrics SVGTextMetrics::measureCharacterRange(RenderSVGInlineText* text, unsigned position, unsigned length)
     99 {
    100     ASSERT(text);
    101     TextRun run(constructTextRun(text, text->characters(), position, length));
    102     return SVGTextMetrics(text, run, position, text->textLength());
    103 }
    104 
    105 }
    106 
    107 #endif // ENABLE(SVG)
    108