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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 "tdehtmllayout.h"
+#include <tqmap.h>
+#include <tqpainter.h>
+#include <dom/dom_string.h>
+#include <xml/dom_stringimpl.h>
+#include <rendering/render_object.h>
+#include <tqptrlist.h>
+#include <kstaticdeleter.h>
+#include <kapplication.h>
+#include <kconfig.h>
+#include <tqtooltip.h>
+
+using namespace DOM;
+using namespace tdehtml;
+
+namespace tdehtml {
+ TQPainter *printpainter;
+}
+
+void tdehtml::setPrintPainter( TQPainter *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 tdehtml::tqRgbaFromHsla(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 tqRgba(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.
+ */
+TQColor tdehtml::retrieveBackgroundColor(const RenderObject *obj)
+{
+ TQColor 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 tdehtml::hasSufficientContrast(const TQColor &c1, const TQColor &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
+}