Adopt style colour for button icons

src/qt/scicon.cpp

@@ -0,0 +1,84 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "scicon.h"
+
+#include <QApplication>
+#include <QColor>
+#include <QIcon>
+#include <QImage>
+#include <QPalette>
+#include <QPixmap>
+
+static void MakeSingleColorImage(QImage& img, const QColor& colorbase)
+{
+    img = img.convertToFormat(QImage::Format_ARGB32);
+    for (int x = img.width(); x--; )
+    {
+        for (int y = img.height(); y--; )
+        {
+            const QRgb rgb = img.pixel(x, y);
+            img.setPixel(x, y, qRgba(colorbase.red(), colorbase.green(), colorbase.blue(), qAlpha(rgb)));
+        }
+    }
+}
+
+QImage SingleColorImage(const QString& filename, const QColor& colorbase)
+{
+    QImage img(filename);
+    MakeSingleColorImage(img, colorbase);
+    return img;
+}
+
+QIcon SingleColorIcon(const QIcon& ico, const QColor& colorbase)
+{
+    QIcon new_ico;
+    QSize sz;
+    Q_FOREACH(sz, ico.availableSizes())
+    {
+        QImage img(ico.pixmap(sz).toImage());
+        MakeSingleColorImage(img, colorbase);
+        new_ico.addPixmap(QPixmap::fromImage(img));
+    }
+    return new_ico;
+}
+
+QIcon SingleColorIcon(const QString& filename, const QColor& colorbase)
+{
+    return QIcon(QPixmap::fromImage(SingleColorImage(filename, colorbase)));
+}
+
+QColor SingleColor()
+{
+    const QColor colorHighlightBg(QApplication::palette().color(QPalette::Highlight));
+    const QColor colorHighlightFg(QApplication::palette().color(QPalette::HighlightedText));
+    const QColor colorText(QApplication::palette().color(QPalette::WindowText));
+    const int colorTextLightness = colorText.lightness();
+    QColor colorbase;
+    if (abs(colorHighlightBg.lightness() - colorTextLightness) < abs(colorHighlightFg.lightness() - colorTextLightness))
+        colorbase = colorHighlightBg;
+    else
+        colorbase = colorHighlightFg;
+    return colorbase;
+}
+
+QIcon SingleColorIcon(const QString& filename)
+{
+    return SingleColorIcon(filename, SingleColor());
+}
+
+static QColor TextColor()
+{
+    return QColor(QApplication::palette().color(QPalette::WindowText));
+}
+
+QIcon TextColorIcon(const QString& filename)
+{
+    return SingleColorIcon(filename, TextColor());
+}
+
+QIcon TextColorIcon(const QIcon& ico)
+{
+    return SingleColorIcon(ico, TextColor());
+}