Mithat Konar (the wiki)

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---

Something like this:

MainWindow::buildIcon

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
#include <QDebug>
#include <QIcon>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
//    QIcon::setThemeName("Gion");
//    ui->action_Open->setIcon(QIcon::fromTheme("document-open"));
//    ui->actionSave_as->setIcon(QIcon::fromTheme("document-save-as"));
//    ui->action_Quit->setIcon(QIcon::fromTheme("exit"));
 
    // we need a function that takes QIcon ands the sub-icons automatically:
    // theQIcon, formatString (with placeholder for size, int array of sizes)
 
    QIcon documentOpenIcon;
    documentOpenIcon.addFile(
                ":myIcons/16x16/document-open.png",QSize(16, 16));
    documentOpenIcon.addFile(
                ":myIcons/24x24/document-open.png", QSize(24, 24));
    documentOpenIcon.addFile(
                ":myIcons/24x24/document-open.png", QSize(32, 32));
    ui->action_Open->setIcon(documentOpenIcon);
 
    QIcon saveAsIcon;
    saveAsIcon.addFile(
                ":myIcons/16x16/document-save-as.png", QSize(16, 16));
    saveAsIcon.addFile(
                ":myIcons/24x24/document-save-as.png", QSize(24, 24));
    saveAsIcon.addFile(
                ":myIcons/24x24/document-save-as.png", QSize(32, 32));
    ui->actionSave_as->setIcon(saveAsIcon);
 
    QIcon exitIcon;
    exitIcon.addFile(
                ":myIcons/16x16/application-exit.png", QSize(16, 16));
    exitIcon.addFile(
                ":myIcons/24x24/application-exit.png", QSize(24, 24));
    exitIcon.addFile(
                ":myIcons/24x24/application-exit.png", QSize(32, 32));
    ui->action_Quit->setIcon(exitIcon);
 
//    This mess doesn't work!
//    setActionIcon(ui->action_Open, "document-open", "Gion");
//    setActionIcon(ui->actionSave_as, "document-save-as", "Gion");
//    setActionIcon(ui->action_Quit, "exit", "Gion");
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
bool MainWindow::setActionIcon(QAction *theAction,
                               QString const &iconName,
                               QString const &backupTheme)
// Try to set theAction's icon from the iconName in the system icon theme.
// If the iconName isn't found in the system theme, try the backupTheme.
// Return true iff the icon was set.
// Ha! This doesn't work because setting the theme name is dynamic!
// trying to see what happens when we make a local QIcon to store the icon ...
// that doesn't work either!
{
    QString systemTheme = QIcon::themeName();
    qDebug() << "iconName: " << iconName <<
                "systemTheme: " << systemTheme <<
                "backupTheme: " << backupTheme;
 
    if ( !systemTheme.isEmpty() && QIcon::hasThemeIcon(iconName) )
    {
        QIcon theIcon = QIcon::fromTheme(iconName);
        theAction->setIcon(theIcon);
        qDebug() << "set system theme icon for " << iconName;
        return true;
    }
 
    if (!backupTheme.isEmpty())
    {
        QIcon::setThemeName(backupTheme);
        if (QIcon::hasThemeIcon(iconName))
        {
            QIcon theIcon = QIcon::fromTheme(iconName);
            theAction->setIcon(theIcon);
            qDebug() << "Haz backup icon";
        }
        QIcon::setThemeName(systemTheme);
 
        qDebug() << "set backup theme icon for " << iconName;
        return true;
    }
    qDebug() << "did not set icon for " << iconName;
    return false;
}
 
void MainWindow::on_action_Quit_triggered()
{
    this->close();
}
 
/**
 * Append a regularly defined set of different sized icon images to a QIcon.
 *
 * The following usage example assumes the resources ":myIcons/16x16/exit.png",
 * ":myIcons/24x24/exit.png", and ":myIcons/32x32/exit.png" are available and
 * that we want to bundle them together into exitIcon.
 * 
 * \code
 *   QList<int> sizes; sizes << 16 << 24 << 32;
 *   QIcon exitIcon;
 *   buildIcon(&exitIcon, ":myIcons/%size%/exit.png", sizes);
 * \endcode
 * 
 * Does NOT check whether the referenced resources actually exist.
 *
 * @return void
 */
void MainWindow::buildIcon(QIcon* const theIcon,           ///< Pointer to the icon that will be built/appened to.
                           QString const &iconRscTemplate, ///< A tag-based template string for the icon resource. Two tags are recognized in iconRscTemplate: \%size\% and \%dim\%. When the iconRscTemplate is expanded, the tag \%dim\% will be replaced by {iconSize} and \%size\% will be replaced by {iconSize}x{iconSize}, where {iconSize} is a string cast of an element in sizeList.
                           QList const &sizeList           ///< A list of single-dimension sizes to be added to the icon.
                          )
{
    foreach (const int iconSize in sizeList)
    {
        QString theResource = iconRscTemplate;
        theResource.replace(QString("%size%"), iconSize+"x"+iconSize);  // does this work?
        theResource.replace(QString("%dim%"), iconSize+"");             // does this work?
 
        theIcon->addFile(theResource, QSize(iconSize, iconSize))
    }
}