Show building_block icon in header stock, expand button and build costs

src/ui/IconCaption.cpp

@@ -0,0 +1,48 @@
+#include "IconCaption.h"
+
+#include <QFontMetrics>
+#include <QGuiApplication>
+#include <QPainter>
+#include <QRect>
+
+QPixmap renderCaptionWithIcon(const QString& text, const QPixmap& icon,
+                              const QFont& font, const QColor& textColor)
+{
+    const QFontMetrics metrics(font);
+    const int textWidth = metrics.horizontalAdvance(text);
+    const int gap = icon.isNull() ? 0 : 6;
+
+    // The icon is drawn at the caption's device-independent pixel size; the source
+    // pixmap may be larger (rasterized at a target size / device pixel ratio), so
+    // divide by its own dpr to get its logical size.
+    const qreal iconDpr = icon.isNull() ? 1.0 : icon.devicePixelRatio();
+    const int iconW = icon.isNull() ? 0
+        : static_cast<int>(icon.width()  / iconDpr);
+    const int iconH = icon.isNull() ? 0
+        : static_cast<int>(icon.height() / iconDpr);
+
+    const int width  = textWidth + gap + iconW;
+    const int height = qMax(metrics.height(), iconH);
+
+    const qreal dpr = qApp ? qApp->devicePixelRatio() : 1.0;
+    QPixmap pixmap(static_cast<int>(width * dpr), static_cast<int>(height * dpr));
+    pixmap.setDevicePixelRatio(dpr);
+    pixmap.fill(Qt::transparent);
+
+    QPainter painter(&pixmap);
+    painter.setRenderHint(QPainter::Antialiasing, true);
+    painter.setRenderHint(QPainter::SmoothPixmapTransform, true);
+    painter.setFont(font);
+    painter.setPen(textColor);
+    painter.drawText(QRect(0, 0, textWidth, height),
+                     Qt::AlignLeft | Qt::AlignVCenter, text);
+
+    if (!icon.isNull())
+    {
+        const int iconX = textWidth + gap;
+        const int iconY = (height - iconH) / 2;
+        painter.drawPixmap(QRect(iconX, iconY, iconW, iconH), icon);
+    }
+
+    return pixmap;
+}