1 files changed, 126 insertions, 0 deletions
diff --git a/src/shadow.cpp b/src/shadow.cpp
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+/* Copyright (C) 2005 Gerd Fleischer <gerdfleischer@web.de>
+ * Copyright (C) 2003 by Sandro Giessl
+ * based on the nice CVS KDesktop KShadowEngine class. thanks!
+ * looking forward to see KShadowEngine in kdefx somewhen btw.. :)
+ * ------------------------------------------------------------------------
+ * these are the original copyright notes:
+ * This file is proposed to be part of the KDE libraries.
+ * Copyright (C) 2003 Laur Ivan <laurivan@eircom.net>
+ *
+ * Many thanks to:
+ *  - Bernardo Hung <deciare@gta.igs.net> for the enhanced shadow
+ *    algorithm (currently used)
+ *  - Tim Jansen <tim@tjansen.de> for the API updates and fixes.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * 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 St, Fifth Floor,
+ * Boston, MA  02110-1301  USA.
+ */
+
+#include "shadow.h"
+#include <qcolor.h>
+
+ShadowEngine::ShadowEngine()
+{
+    thickness_ = 1;
+    multiplicationFactor_ = 10.0;
+}
+
+ShadowEngine::~ShadowEngine()
+{
+}
+
+QImage ShadowEngine::makeShadow(const QPixmap& textPixmap, const QColor &bgColor)
+{
+  QImage result;
+
+  // create a new image for for the shaddow
+  int w = textPixmap.width();
+  int h = textPixmap.height();
+
+  // avoid calling these methods for every pixel
+  int bgRed = bgColor.red();
+  int bgGreen = bgColor.green();
+  int bgBlue = bgColor.blue();
+
+  float alphaShadow;
+
+  /*
+   *	This is the source pixmap
+   */
+  QImage img = textPixmap.convertToImage().convertDepth(32);
+
+  /*
+   *	Resize the image if necessary
+   */
+  if ((result.width() != w) || (result.height() != h))
+  {
+    result.create(w, h, 32);
+  }
+
+  result.fill(0); // all black
+  result.setAlphaBuffer(true);
+
+  for (int i = thickness_; i < w - thickness_; i++)
+  {
+    for (int j = thickness_; j < h - thickness_; j++)
+    {
+        alphaShadow = decay(img, i, j);
+        alphaShadow = (alphaShadow > 180.0) ? 180.0 : alphaShadow;
+      // update the shadow's i,j pixel.
+      result.setPixel(i,j, qRgba(bgRed, bgGreen , bgBlue, (int) alphaShadow));
+    }
+  }
+
+  return result;
+}
+
+float ShadowEngine::decay(QImage& source, int i, int j)
+{
+  // create a new image for the shadow
+  int w = source.width();
+  int h = source.height();
+  int sx, sy;
+
+  float alphaShadow = 0;
+  float opacity = 0;
+  for (int k = 1; k <= thickness_; k++) {
+    /* Generate a shadow thickness_ pixels thicker
+     * on either side than the text image. Ensure
+     * that i +/- k and j +/- k are within the
+     * bounds of the text pixmap.
+     */
+    opacity = 0;
+    for (int l = -k; l <= k; l++) {
+      if (i < k)
+	sx = 0;
+      else if (i >= w - k)
+	sx = w - 1;
+      else
+	sx = i + l;
+
+      for (int m = -k; m <= k; m++) {
+	if (j < k)
+	  sy = 0;
+	else if (j >= h - k)
+	  sy = h - 1;
+	else
+	  sy = j + m;
+
+	opacity += qGray(source.pixel(sx, sy));
+      }
+    }
+    alphaShadow += opacity / multiplicationFactor_;
+  }
+  return alphaShadow;
+}