109 lines
3.3 KiB
C++
109 lines
3.3 KiB
C++
/* Copyright (C) 2003-2005 by Sandro Giessl
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*
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* based on the text shadow code from KHTML. Original copyright notes:
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*
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* This file is part of the DOM implementation for KDE.
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*
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* Copyright (C) 1999-2003 Lars Knoll (knoll@kde.org)
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* (C) 2000-2003 Dirk Mueller (mueller@kde.org)
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* (C) 2003 Apple Computer, Inc.
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* (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include "shadow.h"
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#include <qcolor.h>
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#include <qimage.h>
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#include <qpainter.h>
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#include <qpixmap.h>
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#ifdef HAVE_ALLOCA_H
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// explicitly included for systems that don't provide it in stdlib.h
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#include <alloca.h>
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#else
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#include <stdlib.h>
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#endif
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void paintShadow(QPainter *pt, const QPixmap& textPixmap, int x, int y, int thickness, const QColor &c)
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{
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const QRgb color = c.rgb();
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const int fgGray = qGray(qRgb(255,255,255) );
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const QRgb bgColor = qRgb(0,0,0);
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const int w = textPixmap.width();
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const int h = textPixmap.height();
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QImage img = textPixmap.convertToImage().convertDepth(32);
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int md = thickness*thickness; // max-dist²
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// blur map (division cache)
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float *bmap = (float*)alloca(sizeof(float)*(md+1));
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for(int n=0; n<=md; n++) {
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float f;
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f = n/(float)(md+1);
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f = 1.0 - f*f;
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bmap[n] = f;
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}
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float factor = 0.0; // maximal opacity-sum
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for(int n=-thickness; n<=thickness; n++) {
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for(int m=-thickness; m<=thickness; m++) {
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int d = n*n+m*m;
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if (d<=md) {
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factor += bmap[d];
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}
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}
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}
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factor = 1.0/factor;
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// alpha map
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float* amap = (float*)alloca(sizeof(float)*(h*w));
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memset(amap, 0, h*w*(sizeof(float)));
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for(int j=thickness; j<h-thickness; j++) {
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for(int i=thickness; i<w-thickness; i++) {
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QRgb col= img.pixel(i,j);
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if (col == bgColor) continue;
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float g = qGray(col);
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g = g/fgGray;
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for(int n=-thickness; n<=thickness; n++) {
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for(int m=-thickness; m<=thickness; m++) {
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int d = n*n+m*m;
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if (d>md) continue;
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float f = bmap[d];
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amap[(i+m)+(j+n)*w] += (g*f);
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}
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}
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}
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}
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QImage res(w,h,32);
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res.setAlphaBuffer(true);
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int r = qRed(color);
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int g = qGreen(color);
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int b = qBlue(color);
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for(int j=0; j<h; j++) {
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for(int i=0; i<w; i++) {
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res.setPixel(i,j, qRgba(r,g,b,(int)(amap[i+j*w]*factor*255.0)));
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}
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}
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pt->drawImage(x,y, res);
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}
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