Add StyleHelper functions for icon font

Change-Id: I783f3405dafbd51bf7433084709a2362ed2bd759
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/stylehelper.cpp

@@ -28,6 +28,8 @@
 #include "theme/theme.h"
 #include "hostosinfo.h"
 
+#include <utils/qtcassert.h>
+
 #include <QPixmapCache>
 #include <QPainter>
 #include <QApplication>
@@ -35,6 +37,7 @@
 #include <QCommonStyle>
 #include <QStyleOption>
 #include <QWindow>
+#include <QFontDatabase>
 #include <qmath.h>
 
 // Clamps float color values within (0, 255)
@@ -542,6 +545,48 @@ QLinearGradient StyleHelper::statusBarGradient(const QRect &statusBarRect)
     return grad;
 }
 
+QIcon StyleHelper::getIconFromIconFont(const QString &fontName, const QString &iconSymbol, int fontSize, int iconSize, QColor color)
+{
+    QFontDatabase a;
+
+    QTC_ASSERT(a.hasFamily(fontName), {});
+
+    if (a.hasFamily(fontName)) {
+
+        QIcon icon;
+        QSize size(iconSize, iconSize);
+
+        const int maxDpr = qRound(qApp->devicePixelRatio());
+        for (int dpr = 1; dpr <= maxDpr; dpr++) {
+            QPixmap pixmap(size * dpr);
+            pixmap.setDevicePixelRatio(dpr);
+            pixmap.fill(Qt::transparent);
+
+            QFont font(fontName);
+            font.setPixelSize(fontSize * dpr);
+
+            QPainter painter(&pixmap);
+            painter.save();
+            painter.setPen(color);
+            painter.setFont(font);
+            painter.drawText(QRectF(QPoint(0, 0), size), iconSymbol);
+            painter.restore();
+
+            icon.addPixmap(pixmap);
+        }
+
+        return icon;
+    }
+
+    return {};
+}
+
+QIcon StyleHelper::getIconFromIconFont(const QString &fontName, const QString &iconSymbol, int fontSize, int iconSize)
+{
+    QColor penColor = QApplication::palette("QWidget").color(QPalette::Normal, QPalette::ButtonText);
+    return getIconFromIconFont(fontName, iconSymbol, fontSize, iconSize, penColor);
+}
+
 QString StyleHelper::dpiSpecificImageFile(const QString &fileName)
 {
     // See QIcon::addFile()

src/libs/utils/stylehelper.h

@@ -93,6 +93,9 @@ public:
     static void tintImage(QImage &img, const QColor &tintColor);
     static QLinearGradient statusBarGradient(const QRect &statusBarRect);
 
+    static QIcon getIconFromIconFont(const QString &fontName, const QString &iconSymbol, int fontSize, int iconSize, QColor color);
+    static QIcon getIconFromIconFont(const QString &fontName, const QString &iconSymbol, int fontSize, int iconSize);
+
     static QString dpiSpecificImageFile(const QString &fileName);
     static QString imageFileWithResolution(const QString &fileName, int dpr);
     static QList<int> availableImageResolutions(const QString &fileName);