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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;
}
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