helper.h

/*
  SPDX-FileCopyrightText: 2005 Reinhold Kainhofer <reinhold@kainhofer.com>
 
  SPDX-License-Identifier: GPL-2.0-or-later WITH Qt-Commercial-exception-1.0
*/
#pragma once
 
#include "eventviews_export.h"
 
#include <QColor>
#include <QSharedPointer>
 
namespace Akonadi
{
class Collection;
class Item;
}
 
class QPixmap;
class QDate;
 
// This include file declares static methods that are useful to all views.
/**
 * Namespace EventViews provides facilities for displaying incidences,
 * including events, to-dos, and journal entries.
 */
namespace EventViews
{
class Prefs;
using PrefsPtr = QSharedPointer<Prefs>;
 
/**
 Returns a nice QColor for text, give the input color &c.
*/
[[nodiscard]] QColor getTextColor(const QColor &c);
 
/**
 * Determines if the @p color is "dark" or "light" by looking at its luminance.
 * idea taken from:
 * https://stackoverflow.com/questions/9780632/how-do-i-determine-if-a-color-is-closer-to-white-or-black
 *
 * @return true if the specified color is closer to black than white.
 */
[[nodiscard]] bool isColorDark(const QColor &color);
 
/**
  This method returns the proper resource / subresource color for the view.
  If a value is stored in the preferences, we use it, else we try to find a
  CollectionColorAttribute in the collection. If everything else fails, a
  random color can be set.
  It is preferred to use this function instead of the
  EventViews::Prefs::resourceColor function.
  @return The resource color for the incidence. If the incidence belongs
  to a subresource, the color for the subresource is returned (if set).
  @param calendar the calendar for which the resource color should be obtained
  @param incidence the incidence for which the color is needed (to
                   determine which  subresource needs to be used)
*/
[[nodiscard]] EVENTVIEWS_EXPORT QColor resourceColor(const Akonadi::Collection &collection, const PrefsPtr &preferences);
 
/**
  This method sets the resource color as an Akonadi collection attribute and
  in the local preferences. It is preferred to use this
  instead of the EventViews::Prefs::setResourceColor function.
  @param collection the collection for which the resource color should be stored
  @param color the color to stored
  @param preferences a pointer to the EventViews::Prefs to use
*/
EVENTVIEWS_EXPORT void setResourceColor(const Akonadi::Collection &collection, const QColor &color, const PrefsPtr &preferences);
 
/**
  Returns the number of years between the @p start QDate and the @p end QDate
  (i.e. the difference in the year number of both dates)
*/
[[nodiscard]] int yearDiff(QDate start, QDate end);
 
/**
   Equivalent to SmallIcon( name ), but uses QPixmapCache.
   KIconLoader already uses a cache, but it's 20x slower on my tests.
 
   @return A new pixmap if it isn't yet in cache, otherwise returns the
           cached one.
*/
[[nodiscard]] QPixmap cachedSmallIcon(const QString &name);
}