plasma-framework/paintutils.cpp

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/*
* Copyright 2005 by Aaron Seigo <aseigo@kde.org>
* Copyright 2008 by Andrew Lake <jamboarder@yahoo.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2, or
* (at your option) any later version.
*
* This program 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 General Public License for more details
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <paintutils.h>
#include <QImage>
#include <QPainter>
#include <QPaintEngine>
#include <QPixmap>
#include "private/effects/blur.cpp"
namespace Plasma
{
namespace PaintUtils
{
void shadowBlur(QImage &image, int radius, const QColor &color)
{
if (radius < 1) {
return;
}
if (image.isNull()) {
return;
}
expblur<16, 7>(image, radius);
QPainter p(&image);
p.setCompositionMode(QPainter::CompositionMode_SourceIn);
p.fillRect(image.rect(), color);
p.end();
}
//TODO: we should have shadowText methods that paint the results directly into a QPainter passed in
QPixmap shadowText(QString text, QColor textColor, QColor shadowColor, QPoint offset, int radius)
{
return shadowText(text, qApp->font(), textColor, shadowColor, offset, radius);
}
QPixmap shadowText(QString text, const QFont &font, QColor textColor, QColor shadowColor, QPoint offset, int radius)
{
//don't try to paint stuff on a future null pixmap because the text is empty
if (text.isEmpty()) {
return QPixmap();
}
// Draw text
QFontMetrics fm(font);
QRect textRect = fm.boundingRect(text);
QPixmap textPixmap(textRect.width(), fm.height());
textPixmap.fill(Qt::transparent);
QPainter p(&textPixmap);
p.setPen(textColor);
p.setFont(font);
// FIXME: the center alignment here is odd: the rect should be the size needed by
// the text, but for some fonts and configurations this is off by a pixel or so
// and "centering" the text painting 'fixes' that. Need to research why
// this is the case and determine if we should be painting it differently here,
// doing soething different with the boundingRect call or if it's a problem
// in Qt itself
p.drawText(textPixmap.rect(), Qt::AlignCenter, text);
p.end();
//Draw blurred shadow
QImage img(textRect.size() + QSize(radius * 2, radius * 2),
QImage::Format_ARGB32_Premultiplied);
img.fill(0);
p.begin(&img);
p.drawImage(QPoint(radius, radius), textPixmap.toImage());
p.end();
shadowBlur(img, radius, shadowColor);
//Compose text and shadow
int addSizeX;
int addSizeY;
if (offset.x() > radius) {
addSizeX = abs(offset.x()) - radius;
} else {
addSizeX = 0;
}
if (offset.y() > radius) {
addSizeY = abs(offset.y()) - radius;
} else {
addSizeY = 0;
}
QPixmap finalPixmap(img.size() + QSize(addSizeX, addSizeY));
finalPixmap.fill(Qt::transparent);
p.begin(&finalPixmap);
QPointF offsetF(offset);
QPointF textTopLeft(finalPixmap.rect().topLeft() +
QPointF ((finalPixmap.width() - textPixmap.width()) / 2.0, (finalPixmap.height() - textPixmap.height()) / 2.0) -
(offsetF / 2.0));
QPointF shadowTopLeft(finalPixmap.rect().topLeft() +
QPointF ((finalPixmap.width() - img.width()) / 2.0, (finalPixmap.height() - img.height()) / 2.0) +
(offsetF / 2.0));
p.drawImage(shadowTopLeft, img);
p.drawPixmap(textTopLeft, textPixmap);
p.end();
return finalPixmap;
}
QPainterPath roundedRectangle(const QRectF &rect, qreal radius)
{
QPainterPath path(QPointF(rect.left(), rect.top() + radius));
path.quadTo(rect.left(), rect.top(), rect.left() + radius, rect.top()); // Top left corner
path.lineTo(rect.right() - radius, rect.top()); // Top side
path.quadTo(rect.right(), rect.top(), rect.right(), rect.top() + radius); // Top right corner
path.lineTo(rect.right(), rect.bottom() - radius); // Right side
path.quadTo(rect.right(), rect.bottom(), rect.right() - radius, rect.bottom()); // Bottom right corner
path.lineTo(rect.left() + radius, rect.bottom()); // Bottom side
path.quadTo(rect.left(), rect.bottom(), rect.left(), rect.bottom() - radius); // Bottom left corner
path.closeSubpath();
return path;
}
QPixmap transition(const QPixmap &from, const QPixmap &to, qreal amount)
{
if (from.isNull() || to.isNull()) {
return from;
}
int value = int(0xff * amount);
if (value == 0) {
return from;
} else if (value == 1) {
return to;
}
QColor color;
color.setAlphaF(amount);
//paint to in the center of from
QRect toRect = to.rect();
toRect.moveCenter(from.rect().center());
// If the native paint engine supports Porter/Duff compositing and CompositionMode_Plus
if (from.paintEngine()->hasFeature(QPaintEngine::PorterDuff) &&
from.paintEngine()->hasFeature(QPaintEngine::BlendModes)) {
QPixmap under = from;
QPixmap over = to;
QPainter p;
p.begin(&over);
p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
p.fillRect(over.rect(), color);
p.end();
p.begin(&under);
p.setCompositionMode(QPainter::CompositionMode_DestinationOut);
p.fillRect(under.rect(), color);
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawPixmap(toRect.topLeft(), over);
p.end();
return under;
}
#if defined(Q_WS_X11) && defined(HAVE_XRENDER)
// We have Xrender support
else if (from.paintEngine()->hasFeature(QPaintEngine::PorterDuff)) {
// QX11PaintEngine doesn't implement CompositionMode_Plus in Qt 4.3,
// which we need to be able to do a transition from one pixmap to
// another.
//
// In order to avoid the overhead of converting the pixmaps to images
// and doing the operation entirely in software, this function has a
// specialized path for X11 that uses Xrender directly to do the
// transition. This operation can be fully accelerated in HW.
//
// This specialization can be removed when QX11PaintEngine supports
// CompositionMode_Plus.
QPixmap source(to), destination(from);
source.detach();
destination.detach();
Display *dpy = QX11Info::display();
XRenderPictFormat *format = XRenderFindStandardFormat(dpy, PictStandardA8);
XRenderPictureAttributes pa;
pa.repeat = 1; // RepeatNormal
// Create a 1x1 8 bit repeating alpha picture
Pixmap pixmap = XCreatePixmap(dpy, destination.handle(), 1, 1, 8);
Picture alpha = XRenderCreatePicture(dpy, pixmap, format, CPRepeat, &pa);
XFreePixmap(dpy, pixmap);
// Fill the alpha picture with the opacity value
XRenderColor xcolor;
xcolor.alpha = quint16(0xffff * amount);
XRenderFillRectangle(dpy, PictOpSrc, alpha, &xcolor, 0, 0, 1, 1);
// Reduce the alpha of the destination with 1 - opacity
XRenderComposite(dpy, PictOpOutReverse, alpha, None, destination.x11PictureHandle(),
0, 0, 0, 0, 0, 0, destination.width(), destination.height());
// Add source * opacity to the destination
XRenderComposite(dpy, PictOpAdd, source.x11PictureHandle(), alpha,
destination.x11PictureHandle(),
toRect.x(), toRect.y(), 0, 0, 0, 0, destination.width(), destination.height());
XRenderFreePicture(dpy, alpha);
return destination;
}
#endif
else {
// Fall back to using QRasterPaintEngine to do the transition.
QImage under = from.toImage();
QImage over = to.toImage();
QPainter p;
p.begin(&over);
p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
p.fillRect(over.rect(), color);
p.end();
p.begin(&under);
p.setCompositionMode(QPainter::CompositionMode_DestinationOut);
p.fillRect(under.rect(), color);
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawImage(toRect.topLeft(), over);
p.end();
return QPixmap::fromImage(under);
}
}
} // PaintUtils namespace
} // Plasma namespace