1 files changed, 144 insertions, 0 deletions
diff --git a/khtml/misc/helper.cpp b/khtml/misc/helper.cpp
new file mode 100644
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--- /dev/null
+++ b/khtml/misc/helper.cpp
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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
+}