plasma-framework/widgets/flowlayout.cpp

205 lines
5.4 KiB
C++
Raw Normal View History

This breaks the existing Plasma applet API, see the contentSize() comments below. * New Flow Layout. This provides simple icon view-esque layout of items. Useful for icons for documents , applications or other tasks on the desktop for example. Supports non-equally sized items. Works well when used with the LayoutAnimator class to animate insertions and removals. * Re-wrote BoxLayout and removed old HBoxLayout,VBoxLayout classes which had a lot of code duplication. BoxLayout class now takes a direction argument in the constructor, ala. QBoxLayout. New BoxLayout class actually takes minimumSize() , maximumSize() of items into account. The Qt layout code for box and grid layouts is surprisingly sophisticated, so the results from BoxLayout probably will not be as good in certain situations but it should do for the panel. New BoxLayout also has support for LayoutAnimator * Fix Plasma::HBoxLayout and Plasma::VBoxLayout to use margin() rather than spacing() for the distance from the top and left margins respectively. * Fix Plasma::Applet::contentSize() to return the actual content size rather than a size hint. Added a new method contentSizeHint() which applets use to provide a hint about suitable content size. Existing implementations of contentSize() in applets need to be renamed to contentSizeHint(). The arguments and return type are the same as before. * Install the LayoutAnimator header so that applets can use it svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=707275
2007-09-01 14:34:22 +02:00
/*
* Copyright 2007 by Robert Knight <robertknight@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License 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 "flowlayout.h"
#include <limits.h>
#include <math.h>
#include <QtCore/QList>
#include <QtCore/QRectF>
#include <QtCore/QTimeLine>
#include <QtDebug>
#include "layoutanimator.h"
using namespace Plasma;
class FlowLayout::Private
{
public:
QList<LayoutItem*> items;
QRectF geometry;
};
FlowLayout::FlowLayout(LayoutItem* parent)
: Layout(parent)
, d(new Private)
{
}
FlowLayout::~FlowLayout()
{
delete d;
}
int FlowLayout::count() const
{
return d->items.count();
}
void FlowLayout::addItem(LayoutItem* item)
{
d->items << item;
if ( animator() )
animator()->setCurrentState(item,LayoutAnimator::InsertedState);
item->setManagingLayout(this);
}
void FlowLayout::removeItem(LayoutItem* item)
{
d->items.removeAll(item);
if ( animator() )
animator()->setCurrentState(item,LayoutAnimator::RemovedState);
}
int FlowLayout::indexOf(LayoutItem* item) const
{
return d->items.indexOf(item);
}
LayoutItem* FlowLayout::itemAt(int i) const
{
return d->items[i];
}
QSizeF FlowLayout::sizeHint() const
{
// TODO A proper algorithm here
//
// Idea: Return a size hint based on the golden ratio to
// make it aesthetically good
// eg. Longer side is 1.61x the length of the shorter side
//
// testing
return QSizeF(500,500);
}
LayoutItem* FlowLayout::takeAt(int i)
{
return d->items.takeAt(i);
}
QRectF FlowLayout::geometry() const
{
return d->geometry;
}
template <class T>
T qSum(const QList<T>& container)
{
T total = 0;
foreach( const T& item , container ) {
total += item;
}
return total;
}
void FlowLayout::setGeometry(const QRectF& geo)
{
QRectF geometry(geo);
geometry.adjust(margin(),margin(),-margin(),-margin());
qDebug() << "Flow layout geometry set to " << geo;
// calculate average size of items
qreal totalWidth = 0;
qreal totalHeight = 0;
foreach( LayoutItem *item , d->items ) {
totalWidth += item->sizeHint().width();
totalHeight += item->sizeHint().height();
}
// use the average item width as the column width.
// Also include the spacing either side of each item as part of the
// average width, this provides the spacing between the items and
// also allows some tolerance for small differences in item widths
const qreal averageWidth = totalWidth / d->items.count() + 2*spacing();
const int columnCount = (int)(geometry.width() / averageWidth);
int insertColumn = 0;
qreal rowPos = 0;
qreal rowHeight = 0;
// lay the items out in left-to-right , top-to-bottom order
foreach( LayoutItem *item , d->items ) {
const QSizeF& itemSize = item->sizeHint();
int columnSpan = (int)ceil(itemSize.width() / averageWidth);
if ( insertColumn + columnSpan > columnCount ) {
// start a new row
insertColumn = 0;
rowPos += rowHeight + spacing();
}
// qDebug() << "Inserting item at column" << insertColumn
// << "spanning" << columnSpan << "columns"
// << "with offset" << offset;
// try to expand the item to fill its allocated number of columns
qreal itemWidth = itemSize.width();
const qreal idealWidth = columnSpan * averageWidth - spacing();
if ( itemWidth < idealWidth &&
idealWidth < item->maximumSize().width() ) {
itemWidth = idealWidth;
}
// calculate offset to horizontally center item
qreal offset = (columnSpan * averageWidth) - itemWidth;
if ( insertColumn == 0 )
offset -= spacing();
offset /= 2;
// try to restrict the item width to the available geometry's
// width
if ( itemWidth > geometry.width() ) {
itemWidth = qMax(geometry.width(),item->minimumSize().width());
offset = 0;
}
// position the item
const QRectF newGeometry( geometry.left() +
insertColumn * averageWidth + offset,
geometry.top() + rowPos ,
itemWidth ,
itemSize.height() );
rowHeight = qMax(rowHeight,itemSize.height());
insertColumn += columnSpan;
if ( animator() )
animator()->setGeometry( item , newGeometry );
else
item->setGeometry( newGeometry );
}
d->geometry = geo;
if ( animator() && animator()->timeLine() )
animator()->timeLine()->start();
}
Qt::Orientations FlowLayout::expandingDirections() const
{
return Qt::Vertical | Qt::Horizontal;
}