109 lines
3.8 KiB
C++
109 lines
3.8 KiB
C++
/*
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* shadowengine.cpp - Emerald window decoration for KDE
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*
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* Copyright (c) 2010 Christoph Feck <christoph@maxiom.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include "shadowengine.h"
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#include <QImage>
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#include <cmath>
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namespace Smaragd
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{
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QImage createShadowImage(const ShadowSettings &settings)
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{
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const int radius = settings.radius + 32;
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const int size = 2 * radius + 1;
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QImage shadowImage(size, size, QImage::Format_ARGB32_Premultiplied);
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shadowImage.fill(0);
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QRadialGradient gradient(radius + 0.5, radius + 0.5, radius + 0.5);
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for (qreal v = 0.0; v <= 1.0; v += 1.0 / 64) {
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qreal k;
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QColor color = settings.color;
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if (v * radius < radius - (32.0 + settings.size)) {
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k = 0.0;
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} else {
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qreal x = (radius - 32.0) / radius;
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k = (v - x) / (1.0 - x);
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k = pow(1.0 - k, settings.linearDecay) * exp(-settings.exponentialDecay * k);
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}
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color.setAlpha(qBound(0, qRound(color.alpha() * k), 255));
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gradient.setColorAt(v, color);
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}
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QPainter p(&shadowImage);
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p.setCompositionMode(QPainter::CompositionMode_Source);
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p.setRenderHint(QPainter::Antialiasing, true);
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p.setBrush(gradient);
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p.setPen(Qt::NoPen);
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p.drawEllipse(0, 0, size, size);
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p.end();
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return shadowImage;
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}
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void paintShadow(QPainter *p, const QRect &r, const ShadowSettings &settings, const QImage &shadowImage)
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{
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const int s = -settings.size;
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QRect rect = r.adjusted(s - 32, s - 32, 32 - s, 32 - s);
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rect.adjust(settings.offsetX, settings.offsetY, settings.offsetX, settings.offsetY);
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int radius = shadowImage.width() / 2;
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// corners
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for (int i = 0; i < 4; ++i) {
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const int x = i & 1 ? rect.x() : rect.x() + rect.width() - radius;
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const int y = i & 2 ? rect.y() : rect.y() + rect.height() - radius;
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p->drawImage(x, y, shadowImage,
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i & 1 ? 0 : radius + 1, i & 2 ? 0 : radius + 1, radius, radius);
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}
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// sides
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for (int i = 0; i < 2; ++i) {
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const int x = rect.x() + radius;
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const int y = i & 1 ? rect.y() : rect.y() + rect.height() - radius;
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p->drawTiledPixmap(x, y, rect.width() - 2 * radius, radius,
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QPixmap::fromImage(shadowImage.copy(radius, i & 1 ? 0 : radius + 1, 1, radius)));
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}
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for (int i = 0; i < 2; ++i) {
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const int x = i & 1 ? rect.x() : rect.x() + rect.width() - radius;
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const int y = rect.y() + radius;
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p->drawTiledPixmap(x, y, radius, rect.height() - 2 * radius,
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QPixmap::fromImage(shadowImage.copy(i & 1 ? 0 : radius + 1, radius, radius, 1)));
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}
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// center
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QRgb pixel = shadowImage.pixel(radius, radius);
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if (shadowImage.format() == QImage::Format_ARGB32_Premultiplied) {
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const int alpha = qAlpha(pixel);
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if (alpha != 0 && alpha != 255) {
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pixel = qRgba(qBound(0, qRed(pixel) * 255 / alpha, 255),
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qBound(0, qGreen(pixel) * 255 / alpha, 255),
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qBound(0, qBlue(pixel) * 255 / alpha, 255),
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alpha);
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}
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}
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p->fillRect(rect.adjusted(radius, radius, -radius, -radius), QColor::fromRgba(pixel));
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}
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}; // namespace Smaragd
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