QmlDesigner: Refactor font collector

Fixes: QDS-3643
Change-Id: Iacc26eb0d0cbaad9d9242b548588f3afa3eba2ac
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/designercore/imagecache/imagecachefontcollector.cpp

@@ -56,43 +56,44 @@ QByteArray fileToByteArray(QString const &filename)
     return {};
 }
 
-} // namespace
+// Returns font id or -1 in case of failure
-
+static int resolveFont(const QString &fontFile, QFont &outFont)
-void ImageCacheFontCollector::start(Utils::SmallStringView name,
-                                    Utils::SmallStringView,
-                                    const ImageCache::AuxiliaryData &auxiliaryDataValue,
-                                    CaptureCallback captureCallback,
-                                    AbortCallback abortCallback)
 {
-    auto &&auxiliaryData = Utils::get<ImageCache::FontCollectorSizeAuxiliaryData>(auxiliaryDataValue);
+    int fontId = -1;
-    QColor textColor = auxiliaryData.colorName;
+    QByteArray fontData(fileToByteArray(fontFile));
-    QSize size = auxiliaryData.size;
-    QRect rect({0, 0}, size);
-
-    QByteArray fontData(fileToByteArray(QString(name)));
     if (!fontData.isEmpty()) {
-        int fontId = QFontDatabase::addApplicationFontFromData(fontData);
+        fontId = QFontDatabase::addApplicationFontFromData(fontData);
         if (fontId != -1) {
             QRawFont rawFont(fontData, 10.); // Pixel size is irrelevant, we only need style/weight
             const QStringList families = QFontDatabase::applicationFontFamilies(fontId);
             if (!families.isEmpty()) {
                 QString fontFamily = families.first();
-                QString text = fontFamily + "\n\n" + auxiliaryData.text;
+                outFont.setFamily(fontFamily);
-                QFont font(fontFamily);
+                outFont.setStyle(rawFont.style());
-                font.setStyle(rawFont.style());
+                outFont.setStyleName(rawFont.styleName());
-                font.setStyleName(rawFont.styleName());
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-                font.setWeight(QFont::Weight(rawFont.weight()));
+                outFont.setWeight(QFont::Weight(rawFont.weight()));
 #else
-                font.setWeight(rawFont.weight());
+                outFont.setWeight(rawFont.weight());
 #endif
+            }
+        }
+    }
+    return fontId;
+}
+
+static QImage createFontImage(const QString &text, const QColor &textColor, const QFont &font,
+                              const QSize &size)
+{
+    QRect rect({0, 0}, size);
     QImage image(size, QImage::Format_ARGB32);
     image.fill(Qt::transparent);
     int pixelSize(200);
     int flags = Qt::AlignCenter;
+    QFont renderFont = font;
     while (pixelSize >= 2) {
-                    font.setPixelSize(pixelSize);
+        renderFont.setPixelSize(pixelSize);
-                    QFontMetrics fm(font, &image);
+        QFontMetrics fm(renderFont, &image);
         QRect bounds = fm.boundingRect(rect, flags, text);
         if (bounds.width() < rect.width() && bounds.height() < rect.height()) {
             break;
@@ -111,14 +112,33 @@ void ImageCacheFontCollector::start(Utils::SmallStringView name,
 
     QPainter painter(&image);
     painter.setPen(textColor);
-                painter.setFont(font);
+    painter.setFont(renderFont);
     painter.drawText(rect, flags, text);
 
+    return image;
+}
+
+} // namespace
+
+void ImageCacheFontCollector::start(Utils::SmallStringView name,
+                                    Utils::SmallStringView,
+                                    const ImageCache::AuxiliaryData &auxiliaryDataValue,
+                                    CaptureCallback captureCallback,
+                                    AbortCallback abortCallback)
+{
+    QFont font;
+    if (int fontId = resolveFont(QString(name), font) >= 0) {
+        auto &&auxiliaryData = Utils::get<ImageCache::FontCollectorSizeAuxiliaryData>(auxiliaryDataValue);
+        QColor textColor = auxiliaryData.colorName;
+        QSize size = auxiliaryData.size;
+        QString text = font.family() + "\n\n" + auxiliaryData.text;
+
+        QImage image = createFontImage(text, textColor, font, size);
+
+        if (!image.isNull()) {
             captureCallback(std::move(image), {});
             return;
         }
-            QFontDatabase::removeApplicationFont(fontId);
-        }
     }
     abortCallback();
 }
@@ -128,63 +148,18 @@ std::pair<QImage, QImage> ImageCacheFontCollector::createImage(
     Utils::SmallStringView,
     const ImageCache::AuxiliaryData &auxiliaryDataValue)
 {
+    QFont font;
+    if (int fontId = resolveFont(QString(name), font) >= 0) {
         auto &&auxiliaryData = Utils::get<ImageCache::FontCollectorSizeAuxiliaryData>(auxiliaryDataValue);
         QColor textColor = auxiliaryData.colorName;
         QSize size = auxiliaryData.size;
-    QRect rect({0, 0}, size);
+        QString text = font.family() + "\n\n" + auxiliaryData.text;
 
-    QByteArray fontData(fileToByteArray(QString(name)));
+        QImage image = createFontImage(text, textColor, font, size);
-    if (!fontData.isEmpty()) {
-        int fontId = QFontDatabase::addApplicationFontFromData(fontData);
-        if (fontId != -1) {
-            QRawFont rawFont(fontData, 10.); // Pixel size is irrelevant, we only need style/weight
-            const QStringList families = QFontDatabase::applicationFontFamilies(fontId);
-            if (!families.isEmpty()) {
-                QString fontFamily = families.first();
-                QString text = fontFamily + "\n\n" + auxiliaryData.text;
-                QFont font(fontFamily);
-                font.setStyle(rawFont.style());
-                font.setStyleName(rawFont.styleName());
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-                font.setWeight(QFont::Weight(rawFont.weight()));
-#else
-                font.setWeight(rawFont.weight());
-#endif
-                QImage image(size, QImage::Format_ARGB32);
-                image.fill(Qt::transparent);
-                int pixelSize(200);
-                int flags = Qt::AlignCenter;
-                while (pixelSize >= 2) {
-                    font.setPixelSize(pixelSize);
-                    QFontMetrics fm(font, &image);
-                    QRect bounds = fm.boundingRect(rect, flags, text);
-                    if (bounds.width() < rect.width() && bounds.height() < rect.height()) {
-                        break;
-                    } else {
-                        int newPixelSize = pixelSize - 1;
-                        if (bounds.width() >= rect.width())
-                            newPixelSize = int(qreal(pixelSize) * qreal(rect.width())
-                                               / qreal(bounds.width()));
-                        else if (bounds.height() >= rect.height())
-                            newPixelSize = int(qreal(pixelSize) * qreal(rect.height())
-                                               / qreal(bounds.height()));
-                        if (newPixelSize < pixelSize)
-                            pixelSize = newPixelSize;
-                        else
-                            --pixelSize;
-                    }
-                }
-
-                QPainter painter(&image);
-                painter.setPen(textColor);
-                painter.setFont(font);
-                painter.drawText(rect, flags, text);
 
+        if (!image.isNull())
             return {image, {}};
     }
-            QFontDatabase::removeApplicationFont(fontId);
-        }
-    }
 
     return {};
 }
@@ -193,67 +168,19 @@ QIcon ImageCacheFontCollector::createIcon(Utils::SmallStringView name,
                                           Utils::SmallStringView,
                                           const ImageCache::AuxiliaryData &auxiliaryDataValue)
 {
-    auto &&auxiliaryData = Utils::get<ImageCache::FontCollectorSizesAuxiliaryData>(auxiliaryDataValue);
-    QColor textColor = auxiliaryData.colorName;
-    auto sizes = auxiliaryData.sizes;
-
     QIcon icon;
 
-    QByteArray fontData(fileToByteArray(QString(name)));
+    QFont font;
-    if (!fontData.isEmpty()) {
+    if (int fontId = resolveFont(QString(name), font) >= 0) {
-        int fontId = QFontDatabase::addApplicationFontFromData(fontData);
+        auto &&auxiliaryData = Utils::get<ImageCache::FontCollectorSizesAuxiliaryData>(auxiliaryDataValue);
-        if (fontId != -1) {
+        QColor textColor = auxiliaryData.colorName;
-            QRawFont rawFont(fontData, 10.); // Pixel size is irrelevant, we only need style/weight
+        const auto sizes = auxiliaryData.sizes;
-            const QStringList families = QFontDatabase::applicationFontFamilies(fontId);
-            if (!families.isEmpty()) {
-                QString fontFamily = families.first();
         QString text = auxiliaryData.text;
-                QFont font(fontFamily);
+
-                font.setStyle(rawFont.style());
-                font.setStyleName(rawFont.styleName());
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-                font.setWeight(QFont::Weight(rawFont.weight()));
-#else
-                font.setWeight(rawFont.weight());
-#endif
         for (QSize size : sizes) {
-                    QPixmap pixmap(size);
+            QImage image = createFontImage(text, textColor, font, size);
-                    pixmap.fill(Qt::transparent);
+            if (!image.isNull())
-                    int pixelSize(200);
+                icon.addPixmap(QPixmap::fromImage(image));
-                    int flags = Qt::AlignCenter;
-                    QRect rect({0, 0}, size);
-                    while (pixelSize >= 2) {
-                        font.setPixelSize(pixelSize);
-                        QFontMetrics fm(font, &pixmap);
-                        QRect bounds = fm.boundingRect(rect, flags, text);
-                        if (bounds.width() < rect.width() && bounds.height() < rect.height()) {
-                            break;
-                        } else {
-                            int newPixelSize = pixelSize - 1;
-                            if (bounds.width() >= rect.width())
-                                newPixelSize = int(qreal(pixelSize) * qreal(rect.width())
-                                                   / qreal(bounds.width()));
-                            else if (bounds.height() >= rect.height())
-                                newPixelSize = int(qreal(pixelSize) * qreal(rect.height())
-                                                   / qreal(bounds.height()));
-                            if (newPixelSize < pixelSize)
-                                pixelSize = newPixelSize;
-                            else
-                                --pixelSize;
-                        }
-                    }
-
-                    QPainter painter(&pixmap);
-                    painter.setPen(textColor);
-                    painter.setFont(font);
-                    painter.drawText(rect, flags, text);
-
-                    icon.addPixmap(pixmap);
-                }
-
-            } else {
-                QFontDatabase::removeApplicationFont(fontId);
-            }
         }
     }