Qt: HiDPI (retina) support for splash screen

- remove splash screen images (reduce binary size)
- dynamicly draw splash screen with available icon.
- remove testnet icon
- dynamicly colorize testnet icon

10 files changed, 119 insertions, 28 deletions

diff --git a/src/qt/bitcoin.qrc b/src/qt/bitcoin.qrc
index cd71b4b3fc..b54f2e2ed6 100644
--- a/src/qt/bitcoin.qrc
+++ b/src/qt/bitcoin.qrc
@@ -25,7 +25,6 @@
         <file alias="editpaste">res/icons/editpaste.png</file>
         <file alias="editcopy">res/icons/editcopy.png</file>
         <file alias="add">res/icons/add.png</file>
-        <file alias="bitcoin_testnet">res/icons/bitcoin_testnet.png</file>
         <file alias="edit">res/icons/edit.png</file>
         <file alias="history">res/icons/history.png</file>
         <file alias="overview">res/icons/overview.png</file>
@@ -52,8 +51,6 @@
     </qresource>
     <qresource prefix="/images">
         <file alias="about">res/images/about.png</file>
-        <file alias="splash">res/images/splash.png</file>
-        <file alias="splash_testnet">res/images/splash_testnet.png</file>
     </qresource>
     <qresource prefix="/movies">
         <file alias="spinner-000">res/movies/spinner-000.png</file>
diff --git a/src/qt/networkstyle.cpp b/src/qt/networkstyle.cpp
index 62c44703f4..b8112799df 100644
--- a/src/qt/networkstyle.cpp
+++ b/src/qt/networkstyle.cpp
@@ -11,22 +11,22 @@
 static const struct {
     const char *networkId;
     const char *appName;
-    const char *appIcon;
+    const int iconColorHueShift;
+    const int iconColorSaturationReduction;
     const char *titleAddText;
-    const char *splashImage;
 } network_styles[] = {
-    {"main", QAPP_APP_NAME_DEFAULT, ":/icons/bitcoin", "", ":/images/splash"},
-    {"test", QAPP_APP_NAME_TESTNET, ":/icons/bitcoin_testnet", QT_TRANSLATE_NOOP("SplashScreen", "[testnet]"), ":/images/splash_testnet"},
-    {"regtest", QAPP_APP_NAME_TESTNET, ":/icons/bitcoin_testnet", "[regtest]", ":/images/splash_testnet"}
+    {"main", QAPP_APP_NAME_DEFAULT, 0, 0, ""},
+    {"test", QAPP_APP_NAME_TESTNET, 70, 30, QT_TRANSLATE_NOOP("SplashScreen", "[testnet]")},
+    {"regtest", QAPP_APP_NAME_TESTNET, 70, 30, "[regtest]"}
 };
 static const unsigned network_styles_count = sizeof(network_styles)/sizeof(*network_styles);
 
 // titleAddText needs to be const char* for tr()
-NetworkStyle::NetworkStyle(const QString &appName, const QString &appIcon, const char *titleAddText, const QString &splashImage):
+NetworkStyle::NetworkStyle(const QString &appName, const int iconColorHueShift, const int iconColorSaturationReduction, const char *titleAddText):
     appName(appName),
-    appIcon(appIcon),
-    titleAddText(qApp->translate("SplashScreen", titleAddText)),
-    splashImage(splashImage)
+    iconColorHueShift(iconColorHueShift),
+    iconColorSaturationReduction(iconColorSaturationReduction),
+    titleAddText(qApp->translate("SplashScreen", titleAddText))
 {
 }
 
@@ -38,10 +38,78 @@ const NetworkStyle *NetworkStyle::instantiate(const QString &networkId)
         {
             return new NetworkStyle(
                     network_styles[x].appName,
-                    network_styles[x].appIcon,
-                    network_styles[x].titleAddText,
-                    network_styles[x].splashImage);
+                    network_styles[x].iconColorHueShift,
+                    network_styles[x].iconColorSaturationReduction,
+                    network_styles[x].titleAddText);
         }
     }
     return 0;
 }
+
+QIcon NetworkStyle::getAppIcon() const
+{
+    return getAppIcon(QSize(256,256));
+}
+
+QIcon NetworkStyle::getAppIcon(const QSize size) const
+{
+    // load pixmap
+    QPixmap pixmap(":/icons/bitcoin");
+
+    if(pixmap.size().width() != size.width() && pixmap.size().height() != size.height())
+    {
+        QPixmap scaledPixmap = pixmap.scaled(size, Qt::KeepAspectRatio);
+        if(!scaledPixmap.isNull())
+        {
+            pixmap = scaledPixmap;
+        }
+    }
+
+    if(iconColorHueShift != 0 && iconColorSaturationReduction != 0)
+    {
+        // copy the pixmap because on linux the original pixmap will be affected
+        pixmap = pixmap.copy();
+
+        // generate QImage from QPixmap
+        QImage img = pixmap.toImage();
+
+        int h,s,l,a;
+
+        // traverse though lines
+        for(int y=0;y<img.height();y++)
+        {
+            QRgb *scL = reinterpret_cast< QRgb *>( img.scanLine( y ) );
+
+            // loop through pixels
+            for(int x=0;x<img.width();x++)
+            {
+                // preserve alpha because QColor::getHsl doesen't return the alpha value
+                a = qAlpha(scL[x]);
+                QColor col(scL[x]);
+
+                // get hue value
+                col.getHsl(&h,&s,&l);
+
+                // rotate color on RGB color circle
+                // 70° should end up with the typical "testnet" green
+                h+=iconColorHueShift;
+
+                // change saturation value
+                if(s>iconColorSaturationReduction)
+                {
+                    s -= iconColorSaturationReduction;
+                }
+                col.setHsl(h,s,l,a);
+
+                // set the pixel
+                scL[x] = col.rgba();
+            }
+        }
+
+        //convert back to QPixmap
+        pixmap.convertFromImage(img);
+    }
+
+    QIcon icon(pixmap);
+    return icon;
+}
diff --git a/src/qt/networkstyle.h b/src/qt/networkstyle.h
index e49b86c950..2bfb3c1d55 100644
--- a/src/qt/networkstyle.h
+++ b/src/qt/networkstyle.h
@@ -17,17 +17,17 @@ public:
     static const NetworkStyle *instantiate(const QString &networkId);
 
     const QString &getAppName() const { return appName; }
-    const QIcon &getAppIcon() const { return appIcon; }
     const QString &getTitleAddText() const { return titleAddText; }
-    const QPixmap &getSplashImage() const { return splashImage; }
 
+    QIcon getAppIcon() const;
+    QIcon getAppIcon(const QSize size) const;
 private:
-    NetworkStyle(const QString &appName, const QString &appIcon, const char *titleAddText, const QString &splashImage);
+    NetworkStyle(const QString &appName, const int iconColorHueShift, const int iconColorSaturationReduction, const char *titleAddText);
 
     QString appName;
-    QIcon appIcon;
+    int iconColorHueShift;
+    int iconColorSaturationReduction;
     QString titleAddText;
-    QPixmap splashImage;
 };
 
 #endif // BITCOIN_QT_NETWORKSTYLE_H
diff --git a/src/qt/res/bitcoin-qt-res.rc b/src/qt/res/bitcoin-qt-res.rc
index 809235be5f..a72dfc02f6 100644
--- a/src/qt/res/bitcoin-qt-res.rc
+++ b/src/qt/res/bitcoin-qt-res.rc
@@ -1,5 +1,4 @@
 IDI_ICON1 ICON DISCARDABLE "icons/bitcoin.ico"
-IDI_ICON2 ICON DISCARDABLE "icons/bitcoin_testnet.ico"
 
 #include <windows.h>             // needed for VERSIONINFO
 #include "../../clientversion.h" // holds the needed client version information
diff --git a/src/qt/res/icons/bitcoin.png b/src/qt/res/icons/bitcoin.png
index ce5fbb0c2c..705a20260a 100644
--- a/src/qt/res/icons/bitcoin.png
+++ b/src/qt/res/icons/bitcoin.png
diff --git a/src/qt/res/icons/bitcoin_testnet.ico b/src/qt/res/icons/bitcoin_testnet.ico
deleted file mode 100755
index d67d9d5ce5..0000000000
--- a/src/qt/res/icons/bitcoin_testnet.ico
+++ /dev/null
diff --git a/src/qt/res/icons/bitcoin_testnet.png b/src/qt/res/icons/bitcoin_testnet.png
deleted file mode 100644
index 1202021f53..0000000000
--- a/src/qt/res/icons/bitcoin_testnet.png
+++ /dev/null
diff --git a/src/qt/res/images/splash.png b/src/qt/res/images/splash.png
deleted file mode 100644
index 3f2b2fb2bf..0000000000
--- a/src/qt/res/images/splash.png
+++ /dev/null
diff --git a/src/qt/res/images/splash_testnet.png b/src/qt/res/images/splash_testnet.png
deleted file mode 100644
index 786dc9c3bb..0000000000
--- a/src/qt/res/images/splash_testnet.png
+++ /dev/null
diff --git a/src/qt/splashscreen.cpp b/src/qt/splashscreen.cpp
index b4b81440ca..bfc69636bb 100644
--- a/src/qt/splashscreen.cpp
+++ b/src/qt/splashscreen.cpp
@@ -19,6 +19,7 @@
 #include <QCloseEvent>
 #include <QDesktopWidget>
 #include <QPainter>
+#include <QRadialGradient>
 
 SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle) :
     QWidget(0, f), curAlignment(0)
@@ -30,6 +31,10 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
     int titleCopyrightVSpace    = 40;
 
     float fontFactor            = 1.0;
+    float devicePixelRatio      = 1.0;
+#if QT_VERSION > 0x050100
+    devicePixelRatio = ((QGuiApplication*)QCoreApplication::instance())->devicePixelRatio();
+#endif
 
     // define text to place
     QString titleText       = tr("Bitcoin Core");
@@ -39,12 +44,34 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
 
     QString font            = "Arial";
 
-    // load the bitmap for writing some text over it
-    pixmap     = networkStyle->getSplashImage();
+    // create a bitmap according to device pixelratio
+    QSize splashSize(480*devicePixelRatio,320*devicePixelRatio);
+    pixmap = QPixmap(splashSize);
+
+#if QT_VERSION > 0x050100
+    // change to HiDPI if it makes sense
+    pixmap.setDevicePixelRatio(devicePixelRatio);
+#endif
 
     QPainter pixPaint(&pixmap);
     pixPaint.setPen(QColor(100,100,100));
 
+    // draw a slighly radial gradient
+    QRadialGradient gradient(QPoint(0,0), splashSize.width()/devicePixelRatio);
+    gradient.setColorAt(0, Qt::white);
+    gradient.setColorAt(1, QColor(247,247,247));
+    QRect rGradient(QPoint(0,0), splashSize);
+    pixPaint.fillRect(rGradient, gradient);
+
+    // draw the bitcoin icon, expected size of PNG: 1024x1024
+    QRect rectIcon(QPoint(-150,-122), QSize(430,430));
+
+    const QSize requiredSize(1024,1024);
+    QIcon appIcon = networkStyle->getAppIcon(requiredSize);
+    QPixmap icon(appIcon.pixmap(requiredSize));
+
+    pixPaint.drawPixmap(rectIcon, icon);
+
     // check font size and drawing with
     pixPaint.setFont(QFont(font, 33*fontFactor));
     QFontMetrics fm = pixPaint.fontMetrics();
@@ -57,7 +84,7 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
     pixPaint.setFont(QFont(font, 33*fontFactor));
     fm = pixPaint.fontMetrics();
     titleTextWidth  = fm.width(titleText);
-    pixPaint.drawText(pixmap.width()-titleTextWidth-paddingRight,paddingTop,titleText);
+    pixPaint.drawText(pixmap.width()/devicePixelRatio-titleTextWidth-paddingRight,paddingTop,titleText);
 
     pixPaint.setFont(QFont(font, 15*fontFactor));
 
@@ -68,11 +95,11 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
         pixPaint.setFont(QFont(font, 10*fontFactor));
         titleVersionVSpace -= 5;
     }
-    pixPaint.drawText(pixmap.width()-titleTextWidth-paddingRight+2,paddingTop+titleVersionVSpace,versionText);
+    pixPaint.drawText(pixmap.width()/devicePixelRatio-titleTextWidth-paddingRight+2,paddingTop+titleVersionVSpace,versionText);
 
     // draw copyright stuff
     pixPaint.setFont(QFont(font, 10*fontFactor));
-    pixPaint.drawText(pixmap.width()-titleTextWidth-paddingRight,paddingTop+titleCopyrightVSpace,copyrightText);
+    pixPaint.drawText(pixmap.width()/devicePixelRatio-titleTextWidth-paddingRight,paddingTop+titleCopyrightVSpace,copyrightText);
 
     // draw additional text if special network
     if(!titleAddText.isEmpty()) {
@@ -81,7 +108,7 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
         pixPaint.setFont(boldFont);
         fm = pixPaint.fontMetrics();
         int titleAddTextWidth  = fm.width(titleAddText);
-        pixPaint.drawText(pixmap.width()-titleAddTextWidth-10,15,titleAddText);
+        pixPaint.drawText(pixmap.width()/devicePixelRatio-titleAddTextWidth-10,15,titleAddText);
     }
 
     pixPaint.end();
@@ -90,7 +117,7 @@ SplashScreen::SplashScreen(Qt::WindowFlags f, const NetworkStyle *networkStyle)
     setWindowTitle(titleText + " " + titleAddText);
 
     // Resize window and move to center of desktop, disallow resizing
-    QRect r(QPoint(), pixmap.size());
+    QRect r(QPoint(), QSize(pixmap.size().width()/devicePixelRatio,pixmap.size().height()/devicePixelRatio));
     resize(r.size());
     setFixedSize(r.size());
     move(QApplication::desktop()->screenGeometry().center() - r.center());