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/*
* This file is part of the CSS implementation for KDE.
*
* Copyright (C) 1999-2003 Lars Knoll (knoll@kde.org)
* (C) David Carson <dacarson@gmail.com>
*
* 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.
*
*/
#include "helper.h"
#include "khtmllayout.h"
#include <qmap.h>
#include <qpainter.h>
#include <dom/dom_string.h>
#include <xml/dom_stringimpl.h>
#include <rendering/render_object.h>
#include <qptrlist.h>
#include <kstaticdeleter.h>
#include <kapplication.h>
#include <kconfig.h>
#include <qtooltip.h>
using namespace DOM;
using namespace khtml;
namespace khtml {
QPainter *printpainter;
}
void khtml::setPrintPainter( QPainter *printer )
{
printpainter = printer;
}
double calcHue(double temp1, double temp2, double hueVal)
{
if (hueVal < 0)
hueVal++;
else if (hueVal > 1)
hueVal--;
if (hueVal * 6 < 1)
return temp1 + (temp2 - temp1) * hueVal * 6;
if (hueVal * 2 < 1)
return temp2;
if (hueVal * 3 < 2)
return temp1 + (temp2 - temp1) * (2.0 / 3.0 - hueVal) * 6;
return temp1;
}
// Explanation of this algorithm can be found in the CSS3 Color Module
// specification at http://www.w3.org/TR/css3-color/#hsl-color with further
// explanation available at http://en.wikipedia.org/wiki/HSL_color_space
// all values are in the range of 0 to 1.0
QRgb khtml::qRgbaFromHsla(double h, double s, double l, double a)
{
double temp2 = l < 0.5 ? l * (1.0 + s) : l + s - l * s;
double temp1 = 2.0 * l - temp2;
return qRgba(calcHue(temp1, temp2, h + 1.0 / 3.0) * 255, calcHue(temp1, temp2, h) * 255, calcHue(temp1, temp2, h - 1.0 / 3.0) * 255, a * 255);
}
/** finds out the background color of an element
* @param obj render object
* @return the background color. It is guaranteed that a valid color is returned.
*/
QColor khtml::retrieveBackgroundColor(const RenderObject *obj)
{
QColor result;
while (!obj->isCanvas()) {
result = obj->style()->backgroundColor();
if (result.isValid()) return result;
obj = obj->container();
}/*wend*/
// everything transparent? Use base then.
return obj->style()->palette().active().base();
}
/** checks whether the given colors have enough contrast
* @returns @p true if contrast is ok.
*/
bool khtml::hasSufficientContrast(const QColor &c1, const QColor &c2)
{
// New version from Germain Garand, better suited for contrast measurement
#if 1
#define HUE_DISTANCE 40
#define CONTRAST_DISTANCE 10
int h1, s1, v1, h2, s2, v2;
int hdist = -CONTRAST_DISTANCE;
c1.hsv(&h1,&s1,&v1);
c2.hsv(&h2,&s2,&v2);
if(h1!=-1 && h2!=-1) { // grey values have no hue
hdist = kAbs(h1-h2);
if (hdist > 180) hdist = 360-hdist;
if (hdist < HUE_DISTANCE) {
hdist -= HUE_DISTANCE;
// see if they are high key or low key colours
bool hk1 = h1>=45 && h1<=225;
bool hk2 = h2>=45 && h2<=225;
if (hk1 && hk2)
hdist = (5*hdist)/3;
else if (!hk1 && !hk2)
hdist = (7*hdist)/4;
}
hdist = kMin(hdist, HUE_DISTANCE*2);
}
return hdist + (kAbs(s1-s2)*128)/(160+kMin(s1,s2)) + kAbs(v1-v2) > CONTRAST_DISTANCE;
#undef CONTRAST_DISTANCE
#undef HUE_DISTANCE
#else // orginal fast but primitive version by me (LS)
// ### arbitrary value, to be adapted if necessary (LS)
#define CONTRAST_DISTANCE 32
if (kAbs(c1.red() - c2.red()) > CONTRAST_DISTANCE) return true;
if (kAbs(c1.green() - c2.green()) > CONTRAST_DISTANCE) return true;
if (kAbs(c1.blue() - c2.blue()) > CONTRAST_DISTANCE) return true;
return false;
#undef CONTRAST_DISTANCE
#endif
}
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