QWin32PrintEnginePrivate: Brush up the code

- Use nullptr
- Use member initialization
- Remove C-style casts

Pick-to: 6.6
Task-number: QTBUG-114604
Change-Id: I6f9519010bfbd7c5afa07d9a8752b40c3b29673e
Reviewed-by: Wladimir Leuschner <wladimir.leuschner@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

3 files changed, 56 insertions, 68 deletions

diff --git a/src/printsupport/dialogs/qpagesetupdialog_win.cpp b/src/printsupport/dialogs/qpagesetupdialog_win.cpp
index d7004ec3f1..8e735369b2 100644
--- a/src/printsupport/dialogs/qpagesetupdialog_win.cpp
+++ b/src/printsupport/dialogs/qpagesetupdialog_win.cpp
@@ -20,7 +20,7 @@ QPageSetupDialog::QPageSetupDialog(QPrinter *printer, QWidget *parent)
 }
 
 QPageSetupDialog::QPageSetupDialog(QWidget *parent)
-    : QDialog(*(new QPageSetupDialogPrivate(0)), parent)
+    : QDialog(*(new QPageSetupDialogPrivate(nullptr)), parent)
 {
     setWindowTitle(QCoreApplication::translate("QPrintPreviewDialog", "Page Setup"));
     setAttribute(Qt::WA_DontShowOnScreen);
@@ -41,7 +41,7 @@ int QPageSetupDialog::exec()
     psd.lStructSize = sizeof(PAGESETUPDLG);
 
     // we need a temp DEVMODE struct if we don't have a global DEVMODE
-    HGLOBAL hDevMode = 0;
+    HGLOBAL hDevMode = nullptr;
     int devModeSize = 0;
     if (!engine->globalDevMode()) {
         devModeSize = sizeof(DEVMODE) + ep->devMode->dmDriverExtra;
@@ -63,9 +63,10 @@ int QPageSetupDialog::exec()
     parent = parent ? parent->window() : QApplication::activeWindow();
     Q_ASSERT(!parent ||parent->testAttribute(Qt::WA_WState_Created));
 
-    QWindow *parentWindow = parent ? parent->windowHandle() : 0;
-    psd.hwndOwner = parentWindow ? (HWND)QGuiApplication::platformNativeInterface()->nativeResourceForWindow("handle", parentWindow) : 0;
-
+    QWindow *parentWindow = parent ? parent->windowHandle() : nullptr;
+    psd.hwndOwner = parentWindow
+        ? HWND(QGuiApplication::platformNativeInterface()->nativeResourceForWindow("handle", parentWindow))
+        : nullptr;
     psd.Flags = PSD_MARGINS;
     QPageLayout layout = d->printer->pageLayout();
     switch (layout.units()) {
@@ -133,7 +134,7 @@ int QPageSetupDialog::exec()
             // Make sure memory is allocated
             if (ep->ownsDevMode && ep->devMode)
                 free(ep->devMode);
-            ep->devMode = (DEVMODE *) malloc(devModeSize);
+            ep->devMode = reinterpret_cast<DEVMODE *>(malloc(devModeSize));
             ep->ownsDevMode = true;
 
             // Copy
diff --git a/src/printsupport/platform/windows/qprintengine_win.cpp b/src/printsupport/platform/windows/qprintengine_win.cpp
index 681f58903e..753b60153e 100644
--- a/src/printsupport/platform/windows/qprintengine_win.cpp
+++ b/src/printsupport/platform/windows/qprintengine_win.cpp
@@ -259,7 +259,7 @@ void QWin32PrintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem
 
     if (!fallBack) {
         bool deleteFont = false;
-        HFONT hfont = NULL;
+        HFONT hfont = nullptr;
         if (ti.fontEngine->type() == QFontEngine::Win) {
             hfont = static_cast<HFONT>(ti.fontEngine->handle());
         }
@@ -433,7 +433,7 @@ void QWin32PrintEngine::updateClipPath(const QPainterPath &clipPath, Qt::ClipOpe
 
     bool doclip = true;
     if (op == Qt::NoClip) {
-        SelectClipRgn(d->hdc, 0);
+        SelectClipRgn(d->hdc, nullptr);
         doclip = false;
     }
 
@@ -722,7 +722,7 @@ void QWin32PrintEnginePrivate::strokePath_dev(const QPainterPath &path, const QC
         joinStyle = PS_JOIN_ROUND;
 
     HPEN pen = ExtCreatePen(PS_GEOMETRIC | PS_SOLID | capStyle | joinStyle,
-                            (penWidth == 0) ? 1 : penWidth, &brush, 0, 0);
+                            (penWidth == 0) ? 1 : penWidth, &brush, 0, nullptr);
 
     HGDIOBJ old_pen = SelectObject(hdc, pen);
     StrokePath(hdc);
@@ -842,7 +842,8 @@ void QWin32PrintEnginePrivate::initialize()
     txop = QTransform::TxNone;
 
     QString printerName = m_printDevice.id();
-    bool ok = OpenPrinter((LPWSTR)printerName.utf16(), (LPHANDLE)&hPrinter, 0);
+    bool ok = OpenPrinter(reinterpret_cast<LPWSTR>(const_cast<ushort *>(printerName.utf16())),
+                          reinterpret_cast<LPHANDLE>(&hPrinter), nullptr);
     if (!ok) {
         qErrnoWarning("QWin32PrintEngine::initialize: OpenPrinter failed");
         return;
@@ -851,10 +852,10 @@ void QWin32PrintEnginePrivate::initialize()
     // Fetch the PRINTER_INFO_2 with DEVMODE data containing the
     // printer settings.
     DWORD infoSize, numBytes;
-    GetPrinter(hPrinter, 2, NULL, 0, &infoSize);
+    GetPrinter(hPrinter, 2, nullptr, 0, &infoSize);
     hMem = GlobalAlloc(GHND, infoSize);
-    pInfo = (PRINTER_INFO_2*) GlobalLock(hMem);
-    ok = GetPrinter(hPrinter, 2, (LPBYTE)pInfo, infoSize, &numBytes);
+    pInfo = reinterpret_cast<PRINTER_INFO_2*>(GlobalLock(hMem));
+    ok = GetPrinter(hPrinter, 2, reinterpret_cast<LPBYTE>(pInfo), infoSize, &numBytes);
 
     if (!ok) {
         qErrnoWarning("QWin32PrintEngine::initialize: GetPrinter failed");
@@ -872,23 +873,25 @@ void QWin32PrintEnginePrivate::initialize()
         // Attempt to get the DEVMODE a different way.
 
         // Allocate the required buffer
-        LONG result = DocumentProperties(NULL, hPrinter, (LPWSTR)printerName.utf16(),
-                                         NULL, NULL, 0);
-        devMode = (DEVMODE *) malloc(result);
+        auto *lpwPrinterName = reinterpret_cast<LPWSTR>(const_cast<ushort *>(printerName.utf16()));
+        LONG result = DocumentProperties(nullptr, hPrinter, lpwPrinterName,
+                                         nullptr, nullptr, 0);
+        devMode = reinterpret_cast<DEVMODE *>(malloc(result));
         ownsDevMode = true;
 
          // Get the default DevMode
-        result = DocumentProperties(NULL, hPrinter, (LPWSTR)printerName.utf16(),
-                                    devMode, NULL, DM_OUT_BUFFER);
+        result = DocumentProperties(nullptr, hPrinter, lpwPrinterName,
+                                    devMode, nullptr, DM_OUT_BUFFER);
         if (result != IDOK) {
             qErrnoWarning("QWin32PrintEngine::initialize: Failed to obtain devMode");
             free(devMode);
-            devMode = NULL;
+            devMode = nullptr;
             ownsDevMode = false;
         }
     }
 
-    hdc = CreateDC(NULL, (LPCWSTR)printerName.utf16(), 0, devMode);
+    hdc = CreateDC(nullptr, reinterpret_cast<LPCWSTR>(printerName.utf16()),
+                   nullptr, devMode);
 
     if (!hdc) {
         qErrnoWarning("QWin32PrintEngine::initialize: CreateDC failed");
@@ -917,11 +920,11 @@ void QWin32PrintEnginePrivate::initHDC()
 {
     Q_ASSERT(hdc);
 
-    HDC display_dc = GetDC(0);
+    HDC display_dc = GetDC(nullptr);
     dpi_x = GetDeviceCaps(hdc, LOGPIXELSX);
     dpi_y = GetDeviceCaps(hdc, LOGPIXELSY);
     dpi_display = GetDeviceCaps(display_dc, LOGPIXELSY);
-    ReleaseDC(0, display_dc);
+    ReleaseDC(nullptr, display_dc);
     if (dpi_display == 0) {
         qWarning("QWin32PrintEngine::metric: GetDeviceCaps() failed, "
                 "might be a driver problem");
@@ -964,11 +967,11 @@ void QWin32PrintEnginePrivate::release()
     if (ownsDevMode)
         free(devMode);
 
-    hdc = 0;
-    hPrinter = 0;
-    pInfo = 0;
-    hMem = 0;
-    devMode = 0;
+    hdc = nullptr;
+    hPrinter = nullptr;
+    pInfo = nullptr;
+    hMem = nullptr;
+    devMode = nullptr;
     ownsDevMode = false;
 }
 
@@ -1572,7 +1575,7 @@ void QWin32PrintEngine::setGlobalDevMode(HGLOBAL globalDevNames, HGLOBAL globalD
             d->ownsDevMode = false;
         }
         d->devMode = dm;
-        d->hdc = CreateDC(NULL, reinterpret_cast<const wchar_t *>(d->m_printDevice.id().utf16()), 0, dm);
+        d->hdc = CreateDC(nullptr, reinterpret_cast<LPCWSTR>(d->m_printDevice.id().utf16()), nullptr, dm);
 
         d->num_copies = d->devMode->dmCopies;
         d->updatePageLayout();
@@ -1715,7 +1718,7 @@ static void draw_text_item_win(const QPointF &pos, const QTextItemInt &ti, HDC h
 
     const bool has_kerning = ti.f && ti.f->kerning();
 
-    HFONT hfont = 0;
+    HFONT hfont = nullptr;
     bool deleteFont = false;
 
     if (ti.fontEngine->type() == QFontEngine::Win) {
diff --git a/src/printsupport/platform/windows/qprintengine_win_p.h b/src/printsupport/platform/windows/qprintengine_win_p.h
index 54e3cf2814..f9b5e77c28 100644
--- a/src/printsupport/platform/windows/qprintengine_win_p.h
+++ b/src/printsupport/platform/windows/qprintengine_win_p.h
@@ -83,25 +83,9 @@ class QWin32PrintEnginePrivate : public QAlphaPaintEnginePrivate
     Q_DECLARE_PUBLIC(QWin32PrintEngine)
 public:
     QWin32PrintEnginePrivate() :
-        hPrinter(0),
-        globalDevMode(0),
-        devMode(0),
-        pInfo(0),
-        hMem(0),
-        hdc(0),
-        ownsDevMode(false),
-        mode(QPrinter::ScreenResolution),
-        state(QPrinter::Idle),
-        resolution(0),
-        m_pageLayout(QPageLayout(QPageSize(QPageSize::A4), QPageLayout::Portrait, QMarginsF(0, 0, 0, 0))),
-        stretch_x(1), stretch_y(1), origin_x(0), origin_y(0),
-        dpi_x(96), dpi_y(96), dpi_display(96),
-        num_copies(1),
-        printToFile(false),
-        reinit(false),
+        printToFile(false), reinit(false),
         complex_xform(false), has_pen(false), has_brush(false), has_custom_paper_size(false),
-        embed_fonts(true),
-        txop(0 /* QTransform::TxNone */)
+        embed_fonts(true)
     {
     }
 
@@ -142,19 +126,19 @@ public:
     void debugMetrics() const;
 
     // Windows GDI printer references.
-    HANDLE hPrinter;
+    HANDLE hPrinter = nullptr;
 
-    HGLOBAL globalDevMode;
-    DEVMODE *devMode;
-    PRINTER_INFO_2 *pInfo;
-    HGLOBAL hMem;
+    HGLOBAL globalDevMode = nullptr;
+    DEVMODE *devMode = nullptr;
+    PRINTER_INFO_2 *pInfo = nullptr;
+    HGLOBAL hMem = nullptr;
 
-    HDC hdc;
+    HDC hdc = nullptr;
 
     // True if devMode was allocated separately from pInfo.
-    bool ownsDevMode;
+    bool ownsDevMode = false;
 
-    QPrinter::PrinterMode mode;
+    QPrinter::PrinterMode mode = QPrinter::ScreenResolution;
 
     // Print Device
     QPrintDevice m_printDevice;
@@ -164,26 +148,26 @@ public:
     QString m_creator;
     QString fileName;
 
-    QPrinter::PrinterState state;
-    int resolution;
+    QPrinter::PrinterState state = QPrinter::Idle;
+    int resolution = 0;
 
     // Page Layout
-    QPageLayout m_pageLayout;
-
+    QPageLayout m_pageLayout{QPageSize(QPageSize::A4),
+                             QPageLayout::Portrait, QMarginsF{0, 0, 0, 0}};
     // Page metrics cache
     QRect m_paintRectPixels;
     QSize m_paintSizeMM;
 
     // Windows painting
-    qreal stretch_x;
-    qreal stretch_y;
-    int origin_x;
-    int origin_y;
+    qreal stretch_x = 1;
+    qreal stretch_y = 1;
+    int origin_x = 0;
+    int origin_y = 0;
 
-    int dpi_x;
-    int dpi_y;
-    int dpi_display;
-    int num_copies;
+    int dpi_x = 96;
+    int dpi_y = 96;
+    int dpi_display = 96;
+    int num_copies = 1;
 
     uint printToFile : 1;
     uint reinit : 1;
@@ -194,7 +178,7 @@ public:
     uint has_custom_paper_size : 1;
     uint embed_fonts : 1;
 
-    uint txop;
+    uint txop = 0; // QTransform::TxNone
 
     QColor brush_color;
     QPen pen;