render_text.cpp

konqueror3 embedded版本, KDE环境下的当家浏览器的嵌入式版本源码包.

/**
 * This file is part of the DOM implementation for KDE.
 *
 * Copyright (C) 1999-2003 Lars Knoll ([e-mail])
 *           (C) 2000-2003 Dirk Mueller ([e-mail])
 *           (C) 2003 Apple Computer, Inc.
 *           (C) 2004-2005 Allan Sandfeld Jensen ([e-mail])
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

//#define DEBUG_LAYOUT
//#define BIDI_DEBUG

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "rendering/render_text.h"
#include "rendering/render_canvas.h"
#include "rendering/break_lines.h"
#include "rendering/render_arena.h"
#include "xml/dom_nodeimpl.h"

#include "misc/loader.h"
#include "misc/helper.h"

#include <qbitmap.h>
#include <qimage.h>
#include <qpainter.h>
#include <kdebug.h>
#include <kglobal.h>
#include <assert.h>
#include <limits.h>
#include <math.h>

#ifdef HAVE_ALLOCA_H
// explicitly included for systems that don't provide it in stdlib.h
#include <alloca.h>
#else
#include <stdlib.h>
#endif

using namespace khtml;
using namespace DOM;

#ifndef NDEBUG
static bool inInlineTextBoxDetach;
#endif

void InlineTextBox::detach(RenderArena* renderArena)
{
    if (m_parent)
        m_parent->removeFromLine(this);

#ifndef NDEBUG
    inInlineTextBoxDetach = true;
#endif
    delete this;
#ifndef NDEBUG
    inInlineTextBoxDetach = false;
#endif

    // Recover the size left there for us by operator delete and free the memory.
    renderArena->free(*(size_t *)this, this);
}

void* InlineTextBox::operator new(size_t sz, RenderArena* renderArena) throw()
{
    return renderArena->allocate(sz);
}

void InlineTextBox::operator delete(void* ptr, size_t sz)
{
    assert(inInlineTextBoxDetach);

    // Stash size where detach can find it.
    *(size_t *)ptr = sz;
}

/** returns the proper ::selection pseudo style for the given element
 * @return the style or 0 if no ::selection pseudo applies.
 */
inline const RenderStyle *retrieveSelectionPseudoStyle(const RenderObject *obj)
{
  // http://www.w3.org/Style/CSS/Test/CSS3/Selectors/20021129/html/tests/css3-modsel-162.html
  // is of the opinion that ::selection of parent elements is also to be applied
  // to children, so let's do it.
  while (obj) {
    const RenderStyle *style = obj->style()->getPseudoStyle(RenderStyle::SELECTION);
    if (style) return style;

    obj = obj->parent();
  }/*wend*/
  return 0;
}

void InlineTextBox::paintSelection(const Font *f, RenderText *text, QPainter *p, RenderStyle* style, int tx, int ty, int startPos, int endPos, int deco)
{
    if(startPos > m_len) return;
    if(startPos < 0) startPos = 0;

    QColor hc;
    QColor hbg;
    const RenderStyle* pseudoStyle = retrieveSelectionPseudoStyle(text);
    if (pseudoStyle) {
        // ### support outline (mandated by CSS3)
	// ### support background-image? (optional by CSS3)
        if (pseudoStyle->backgroundColor().isValid())
            hbg = pseudoStyle->backgroundColor();
        hc = pseudoStyle->color();
    } else {
        const QColorGroup &grp = style->palette().active();
        hc = grp.highlightedText();
        hbg = grp.highlight();
	// ### should be at most retrieved once per render text
	QColor bg = khtml::retrieveBackgroundColor(text);
	// It may happen that the contrast is -- well -- virtually non existent.
	// In this case, simply invert the colors
	if (!khtml::hasSufficientContrast(hbg, bg)) {
	    hc = QColor(0xff-hc.red(),0xff-hc.green(),0xff-hc.blue());
	    hbg = QColor(0xff-hbg.red(),0xff-hbg.green(),0xff-hbg.blue());
	}/*end if*/
    }

    p->setPen(hc);

    //kdDebug( 6040 ) << "textRun::painting(" << QConstString(text->str->s + m_start, m_len).string().left(30) << ") at(" << m_x+tx << "/" << m_y+ty << ")" << endl;
    f->drawText(p, m_x + tx, m_y + ty + m_baseline, text->str->s, text->str->l,
    		m_start, m_len, m_toAdd,
		m_reversed ? QPainter::RTL : QPainter::LTR,
		startPos, endPos, hbg, m_y + ty, height(), deco);
}

void InlineTextBox::paintDecoration( QPainter *pt, const Font *f, int _tx, int _ty, int deco)
{
    _tx += m_x;
    _ty += m_y;

    int width = m_width - 1;

    RenderObject *p = object();

    QColor underline, overline, linethrough;
    p->getTextDecorationColors(deco, underline, overline, linethrough, p->style()->htmlHacks());

    if(deco & UNDERLINE){
        pt->setPen(underline);
        f->drawDecoration(pt, _tx, _ty, baseline(), width, height(), Font::UNDERLINE);
    }
    if (deco & OVERLINE) {
        pt->setPen(overline);
        f->drawDecoration(pt, _tx, _ty, baseline(), width, height(), Font::OVERLINE);
    }
    if(deco & LINE_THROUGH) {
        pt->setPen(linethrough);
        f->drawDecoration(pt, _tx, _ty, baseline(), width, height(), Font::LINE_THROUGH);
    }
    // NO! Do NOT add BLINK! It is the most annouing feature of Netscape, and IE has a reason not to
    // support it. Lars
}

void InlineTextBox::paintShadow(QPainter *pt, const Font *f, int _tx, int _ty, const ShadowData *shadow )
{
    int x = m_x + _tx + shadow->x;
    int y = m_y + _ty + shadow->y;
    const RenderText* text = renderText();

    if (shadow->blur <= 0) {
        QColor c = pt->pen().color();
        pt->setPen(shadow->color);
        f->drawText(pt, x, y+m_baseline, text->str->s, text->str->l,
                    m_start, m_len, m_toAdd,
                    m_reversed ? QPainter::RTL : QPainter::LTR);
        pt->setPen(c);

    }
    else {
        const int thickness = shadow->blur;
        const int w = m_width+2*thickness;
        const int h = m_height+2*thickness;
        const QRgb color = shadow->color.rgb();
        const int gray = qGray(color);
        const bool inverse = (gray < 100);
        const QRgb bgColor = (inverse) ? qRgb(255,255,255) : qRgb(0,0,0);
        QPixmap pixmap(w, h);
        pixmap.fill(bgColor);
        QPainter p;

        p.begin(&pixmap);
        p.setPen(shadow->color);
        p.setFont(pt->font());
        f->drawText(&p, thickness, thickness+m_baseline, text->str->s, text->str->l,
                    m_start, m_len, m_toAdd,
                    m_reversed ? QPainter::RTL : QPainter::LTR);

        p.end();
        QImage img = pixmap.convertToImage().convertDepth(32);

        int md = thickness*thickness; // max-dist^2

        // blur map (division cache)
        float *bmap = (float*)alloca(sizeof(float)*(md+1));
        for(int n=0; n<=md; n++) {
            float f;
            f = n/(float)(md+1);
            f = 1.0 - f*f;
            bmap[n] = f;
        }

        float factor = 0.0; // maximal opacity-sum
        for(int n=-thickness; n<=thickness; n++)
            for(int m=-thickness; m<=thickness; m++) {
                int d = n*n+m*m;
                if (d<=md)
                    factor += bmap[d];
            }

        factor = 1.0/factor;

        // alpha map
        float* amap = (float*)alloca(sizeof(float)*(h*w));
        memset(amap, 0, h*w*(sizeof(float)));
        for(int j=thickness; j<h-thickness; j++) {
            for(int i=thickness; i<w-thickness; i++) {
                QRgb col= img.pixel(i,j);
                if (col == bgColor) continue;
                float g = qGray(col);
                if (inverse)
                    g = (255-g)/(255-gray);
                else
                    g = g/gray;
                for(int n=-thickness; n<=thickness; n++) {
                    for(int m=-thickness; m<=thickness; m++) {
                        int d = n*n+m*m;
                        if (d>md) continue;
                        float f = bmap[d];
                        amap[(i+m)+(j+n)*w] += (g*f);
                    }
                }
            }
        }

        QImage res(w,h,32);
        res.setAlphaBuffer(true);
        int r = qRed(color);
        int g = qGreen(color);
        int b = qBlue(color);

        for(int j=0; j<h; j++) {
            for(int i=0; i<w; i++) {
                res.setPixel(i,j, qRgba(r,g,b,(int)(amap[i+j*w]*factor*255.0)));
            }
        }

        pt->drawImage(x-thickness, y-thickness, res, 0, 0, -1, -1, Qt::DiffuseAlphaDither | Qt::ColorOnly | Qt::PreferDither);
    }
    // Paint next shadow effect
    if (shadow->next) paintShadow(pt, f, _tx, _ty, shadow->next);
}

/**
 * Distributes pixels to justify text.
 * @param numSpaces spaces left, will be decremented by one
 * @param toAdd number of pixels left to be distributed, will have the
 *	amount of pixels distributed during this call subtracted.
 * @return number of pixels to distribute
 */
static inline int justifyWidth(int &numSpaces, int &toAdd) {
  int a = 0;
  if ( numSpaces ) {
    a = toAdd/numSpaces;
    toAdd -= a;
    numSpaces--;
  }/*end if*/
  return a;
}

FindSelectionResult InlineTextBox::checkSelectionPoint(int _x, int _y, int _tx, int _ty, const Font *f, RenderText *text, int & offset, short lineHeight)
{
//       kdDebug(6040) << "InlineTextBox::checkSelectionPoint " << this << " _x=" << _x << " _y=" << _y
//                     << " _tx+m_x=" << _tx+m_x << " _ty+m_y=" << _ty+m_y << endl;
    offset = 0;

    if ( _y < _ty + m_y )
        return SelectionPointBefore; // above -> before

    if ( _y > _ty + m_y + lineHeight ) {
        // below -> after
        // Set the offset to the max
        offset = m_len;
        return SelectionPointAfter;
    }
    if ( _x > _tx + m_x + m_width ) {
	// to the right
	return m_reversed ? SelectionPointBeforeInLine : SelectionPointAfterInLine;
    }

    // The Y matches, check if we're on the left
    if ( _x < _tx + m_x ) {
        return m_reversed ? SelectionPointAfterInLine : SelectionPointBeforeInLine;
    }

    // consider spacing for justified text
    int toAdd = m_toAdd;
    bool justified = text->style()->textAlign() == JUSTIFY && toAdd > 0;
    int numSpaces = 0;
    if (justified) {

        for( int i = 0; i < m_len; i++ )
            if ( text->str->s[m_start+i].category() == QChar::Separator_Space )
	        numSpaces++;

    }/*end if*/

    int delta = _x - (_tx + m_x);
    //kdDebug(6040) << "InlineTextBox::checkSelectionPoint delta=" << delta << endl;
    int pos = 0;
    if ( m_reversed ) {
	delta -= m_width;
	while(pos < m_len) {
	    int w = f->width( text->str->s, text->str->l, m_start + pos);
	    if (justified && text->str->s[m_start + pos].category() == QChar::Separator_Space)
	        w += justifyWidth(numSpaces, toAdd);
	    int w2 = w/2;
	    w -= w2;
	    delta += w2;
	    if(delta >= 0) break;
	    pos++;
	    delta += w;
	}
    } else {
	while(pos < m_len) {
	    int w = f->width( text->str->s, text->str->l, m_start + pos);
	    if (justified && text->str->s[m_start + pos].category() == QChar::Separator_Space)
	        w += justifyWidth(numSpaces, toAdd);
	    int w2 = w/2;
	    w -= w2;
	    delta -= w2;
	    if(delta <= 0) break;
	    pos++;
	    delta -= w;
	}
    }
//     kdDebug( 6040 ) << " Text  --> inside at position " << pos << endl;
    offset = pos;
    return SelectionPointInside;
}

int InlineTextBox::offsetForPoint(int _x, int &ax) const
{
  // Do binary search for finding out offset, saves some time for long
  // runs.
  int start = 0;
  int end = m_len;
  ax = m_x;
  int offset = (start + end) / 2;
  while (end - start > 0) {
    // always snap to the right column. This makes up for "jumpy" vertical
    // navigation.
    if (end - start == 1) start = end;

    offset = (start + end) / 2;
    ax = m_x + widthFromStart(offset);