kwin/focuschain.h

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/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2012 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, 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 General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#ifndef KWIN_FOCUS_CHAIN_H
#define KWIN_FOCUS_CHAIN_H
// KWin
#include <kwinglobals.h>
// Qt
#include <QObject>
#include <QHash>
namespace KWin
{
// forward declarations
class Client;
/**
* @brief Singleton class to handle the various focus chains.
*
* A focus chain is a list of Clients containing information on which Client should be activated.
*
* Internally this FocusChain holds multiple independent chains. There is one chain of most recently
* used Clients which is primarily used by TabBox to build up the list of Clients for navigation.
* The chains are organized as a normal QList of Clients with the most recently used Client being the
* last item of the list, that is a LIFO like structure.
*
* In addition there is one chain for each virtual desktop which is used to determine which Client
* should get activated when the user switches to another virtual desktop.
*
* Furthermore this class contains various helper methods for the two different kind of chains.
**/
class FocusChain : public QObject
{
Q_OBJECT
public:
enum Change {
MakeFirst,
MakeLast,
Update,
MakeFirstMinimized = MakeFirst
};
virtual ~FocusChain();
/**
* @brief Updates the position of the @p client according to the requested @p change in the
* focus chain.
*
* This method affects both the most recently used focus chain and the per virtual desktop focus
* chain.
*
* In case the client does no longer want to get focus, it is removed from all chains. In case
* the client is on all virtual desktops it is ensured that it is present in each of the virtual
* desktops focus chain. In case it's on exactly one virtual desktop it is ensured that it is only
* in the focus chain for that virtual desktop.
*
* Depending on @p change the Client is inserted at different positions in the focus chain. In case
* of @c MakeFirst it is moved to the first position of the chain, in case of
* @c MakeLast it is moved to the last position of the chain. In all other cases it
* depends on whether the @p client is the currently active Client. If it is the active Client it
* becomes the first Client in the chain, otherwise it is inserted at the second position that is
* directly after the currently active Client.
*
* @param client The Client which should be moved inside the chains.
* @param change Where to move the Client
* @return void
**/
void update(Client *client, Change change);
/**
* @brief Moves @p client behind the @p reference Client in all focus chains.
*
* @param client The Client to move in the chains
* @param reference The Client behind which the @p client should be moved
* @return void
**/
void moveAfterClient(Client *client, Client *reference);
/**
* @brief Finds the best Client to become the new active Client in the focus chain for the given
* virtual @p desktop.
*
* In case that separate screen focus is used only Clients on the current screen are considered.
* If no Client for activation is found @c null is returned.
*
* @param desktop The virtual desktop to look for a Client for activation
* @return :Client* The Client which could be activated or @c null if there is none.
**/
Client *getForActivation(uint desktop) const;
/**
* @brief Finds the best Client to become the new active Client in the focus chain for the given
* virtual @p desktop on the given @p screen.
*
* This method makes only sense to use if separate screen focus is used. If separate screen focus
* is disabled the @p screen is ignored.
* If no Client for activation is found @c null is returned.
*
* @param desktop The virtual desktop to look for a Client for activation
* @param screen The screen to constrain the search on with separate screen focus
* @return :Client* The Client which could be activated or @c null if there is none.
**/
Client *getForActivation(uint desktop, int screen) const;
/**
* @brief Checks whether the most recently used focus chain contains the given @p client.
*
* Does not consider the per-desktop focus chains.
* @param client The Client to look for.
* @return bool @c true if the most recently used focus chain contains @p client, @c false otherwise.
**/
bool contains(Client *client) const;
/**
* @brief Checks whether the focus chain for the given @p desktop contains the given @p client.
*
* Does not consider the most recently used focus chain.
*
* @param client The Client to look for.
* @param desktop The virtual desktop whose focus chain should be used
* @return bool @c true if the focus chain for @p desktop contains @p client, @c false otherwise.
**/
bool contains(Client *client, uint desktop) const;
/**
* @brief Queries the most recently used focus chain for the next Client after the given
* @p reference Client.
*
* The navigation wraps around the borders of the chain. That is if the @p reference Client is
* the last item of the focus chain, the first Client will be returned.
*
* If the @p reference Client cannot be found in the focus chain, the first element of the focus
* chain is returned.
*
* @param reference The start point in the focus chain to search
* @return :Client* The relatively next Client in the most recently used chain.
**/
Client *nextMostRecentlyUsed(Client *reference) const;
/**
* @brief Queries the focus chain for @p desktop for the next Client in relation to the given
* @p reference Client.
*
* The method finds the first usable Client which is not the @p reference Client. If no Client
* can be found @c null is returned
*
* @param reference The reference Client which should not be returned
* @param desktop The virtual desktop whose focus chain should be used
* @return :Client* The next usable Client or @c null if none can be found.
**/
Client *nextForDesktop(Client *reference, uint desktop) const;
/**
* @brief Returns the first Client in the most recently used focus chain. First Client in this
* case means really the first Client in the chain and not the most recently used Client.
*
* @return :Client* The first Client in the most recently used chain.
**/
Client *firstMostRecentlyUsed() const;
public slots:
/**
* @brief Resizes the per virtual desktop focus chains from @p previousSize to @p newSize.
* This means that for each virtual desktop between previous and new size a new focus chain is
* created and in case the number is reduced the focus chains are destroyed.
*
* @param previousSize The previous number of virtual desktops
* @param newSize The new number of virtual desktops
* @return void
**/
void resize(uint previousSize, uint newSize);
/**
* @brief Removes @p client from all focus chains.
*
* @param client The Client to remove from all focus chains.
* @return void
**/
void remove(KWin::Client *client);
void setSeparateScreenFocus(bool enabled);
void setActiveClient(KWin::Client *client);
void setCurrentDesktop(uint previous, uint newDesktop);
bool isUsableFocusCandidate(Client *c, Client *prev) const;
private:
/**
* @brief Makes @p client the first Client in the given focus @p chain.
*
* This means the existing position of @p client is dropped and @p client is appended to the
* @p chain which makes it the first item.
*
* @param client The Client to become the first in @p chain
* @param chain The focus chain to operate on
* @return void
**/
void makeFirstInChain(Client *client, QList<Client*> &chain);
/**
* @brief Makes @p client the last Client in the given focus @p chain.
*
* This means the existing position of @p client is dropped and @p client is prepended to the
* @p chain which makes it the last item.
*
* @param client The Client to become the last in @p chain
* @param chain The focus chain to operate on
* @return void
**/
void makeLastInChain(Client *client, QList<Client*> &chain);
void moveAfterClientInChain(Client *client, Client *reference, QList<Client*> &chain);
void updateClientInChain(Client *client, Change change, QList<Client*> &chain);
void insertClientIntoChain(Client *client, QList<Client*> &chain);
typedef QHash<uint, QList<Client*> > DesktopChains;
QList<Client*> m_mostRecentlyUsed;
DesktopChains m_desktopFocusChains;
bool m_separateScreenFocus;
Client *m_activeClient;
uint m_currentDesktop;
KWIN_SINGLETON_VARIABLE(FocusChain, s_manager)
};
inline
bool FocusChain::contains(Client *client) const
{
return m_mostRecentlyUsed.contains(client);
}
inline
void FocusChain::setSeparateScreenFocus(bool enabled)
{
m_separateScreenFocus = enabled;
}
inline
void FocusChain::setActiveClient(Client *client)
{
m_activeClient = client;
}
inline
void FocusChain::setCurrentDesktop(uint previous, uint newDesktop)
{
Q_UNUSED(previous)
m_currentDesktop = newDesktop;
}
} // namespace
#endif // KWIN_FOCUS_CHAIN_H