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+/* Copyright (C) 2005 Gerd Fleischer <[email protected]>
+ * 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 <[email protected]>
+ *
+ * Many thanks to:
+ * - Bernardo Hung <[email protected]> for the enhanced shadow
+ * algorithm (currently used)
+ * - Tim Jansen <[email protected]> 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;
+}