Revert "[QtWin] using of direct WinAPI call."

It has to be resolved at runtime to provide the same binary
compatibility with Windows versions older than Vista.

This reverts commit 2db89f50bf.

src/defines.pri

@@ -13,10 +13,6 @@ unix: VERSION = 1.3.5
 win32-msvc* {
     DEFINES *= W7API
     LIBS += User32.lib Ole32.lib Shell32.lib ShlWapi.lib Gdi32.lib ComCtl32.lib
-    # QSysInfo::WV_VISTA is 128
-    !lessThan(QMAKE_HOST.version, 128) {
-        LIBS += Dwmapi.lib
-    }
 }
 
 # Check for pkg-config availability

src/lib/3rdparty/qtwin.cpp

@@ -1,6 +1,6 @@
 /* ============================================================
 * QupZilla - WebKit based browser
-* Copyright (C) 2010-2013  David Rosca <nowrep@gmail.com>
+* Copyright (C) 2010-2012  David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -25,6 +25,7 @@
 ****************************************************************************/
 
 #include "qtwin.h"
+#include <QLibrary>
 #include <QApplication>
 #include <QWidget>
 #include <QList>
@@ -33,15 +34,37 @@
 
 #ifdef Q_OS_WIN
 #include <qt_windows.h>
-#if WINVER >= _WIN32_WINNT_VISTA
-#include "Dwmapi.h"
-const bool Vista_Or_Newer = true;
-#else
-const bool Vista_Or_Newer = false;
-#endif
 
+// Blur behind data structures
+#define DWM_BB_ENABLE                 0x00000001  // fEnable has been specified
+#define DWM_BB_BLURREGION             0x00000002  // hRgnBlur has been specified
+#define DWM_BB_TRANSITIONONMAXIMIZED  0x00000004  // fTransitionOnMaximized has been specified
 #define WM_DWMCOMPOSITIONCHANGED        0x031E    // Composition changed window message
 
+typedef struct _DWM_BLURBEHIND {
+    DWORD dwFlags;
+    BOOL fEnable;
+    HRGN hRgnBlur;
+    BOOL fTransitionOnMaximized;
+} DWM_BLURBEHIND, *PDWM_BLURBEHIND;
+
+typedef struct _MARGINS {
+    int cxLeftWidth;
+    int cxRightWidth;
+    int cyTopHeight;
+    int cyBottomHeight;
+} MARGINS, *PMARGINS;
+
+typedef HRESULT(WINAPI* PtrDwmIsCompositionEnabled)(BOOL* pfEnabled);
+typedef HRESULT(WINAPI* PtrDwmExtendFrameIntoClientArea)(HWND hWnd, const MARGINS* pMarInset);
+typedef HRESULT(WINAPI* PtrDwmEnableBlurBehindWindow)(HWND hWnd, const DWM_BLURBEHIND* pBlurBehind);
+typedef HRESULT(WINAPI* PtrDwmGetColorizationColor)(DWORD* pcrColorization, BOOL* pfOpaqueBlend);
+
+static PtrDwmIsCompositionEnabled pDwmIsCompositionEnabled = 0;
+static PtrDwmEnableBlurBehindWindow pDwmEnableBlurBehindWindow = 0;
+static PtrDwmExtendFrameIntoClientArea pDwmExtendFrameIntoClientArea = 0;
+static PtrDwmGetColorizationColor pDwmGetColorizationColor = 0;
+
 QHash<QWidget*, bool> widgetsBlurState = QHash<QWidget*, bool>();
 
 /*
@@ -70,7 +93,20 @@ public:
 private:
     QWidgetList widgets;
 };
-#endif // Q_OS_WIN
+
+static bool resolveLibs()
+{
+    if (!pDwmIsCompositionEnabled) {
+        QLibrary dwmLib(QString::fromLatin1("dwmapi"));
+        pDwmIsCompositionEnabled = (PtrDwmIsCompositionEnabled)dwmLib.resolve("DwmIsCompositionEnabled");
+        pDwmExtendFrameIntoClientArea = (PtrDwmExtendFrameIntoClientArea)dwmLib.resolve("DwmExtendFrameIntoClientArea");
+        pDwmEnableBlurBehindWindow = (PtrDwmEnableBlurBehindWindow)dwmLib.resolve("DwmEnableBlurBehindWindow");
+        pDwmGetColorizationColor = (PtrDwmGetColorizationColor)dwmLib.resolve("DwmGetColorizationColor");
+    }
+    return pDwmIsCompositionEnabled != 0;
+}
+
+#endif
 
 /*!
   * Chekcs and returns true if Windows version
@@ -102,10 +138,10 @@ bool QtWin::isRunningWindows7()
 bool QtWin::isCompositionEnabled()
 {
 #ifdef Q_OS_WIN
-    if (Vista_Or_Newer) {
+    if (resolveLibs()) {
         HRESULT hr = S_OK;
         BOOL isEnabled = false;
-        hr = DwmIsCompositionEnabled(&isEnabled);
+        hr = pDwmIsCompositionEnabled(&isEnabled);
         if (SUCCEEDED(hr)) {
             return isEnabled;
         }
@@ -126,7 +162,7 @@ bool QtWin::enableBlurBehindWindow(QWidget* widget, bool enable)
     Q_ASSERT(widget);
     bool result = false;
 #ifdef Q_OS_WIN
-    if (Vista_Or_Newer) {
+    if (resolveLibs()) {
         DWM_BLURBEHIND bb = {0};
         HRESULT hr = S_OK;
         bb.fEnable = enable;
@@ -138,7 +174,7 @@ bool QtWin::enableBlurBehindWindow(QWidget* widget, bool enable)
         // Qt5: setting WA_TranslucentBackground without the following line hides the widget!!
         widget->setWindowOpacity(1);
 
-        hr = DwmEnableBlurBehindWindow(hwndOfWidget(widget) , &bb);
+        hr = pDwmEnableBlurBehindWindow(hwndOfWidget(widget) , &bb);
         if (SUCCEEDED(hr)) {
             result = true;
             windowNotifier()->addWidget(widget);
@@ -173,10 +209,11 @@ bool QtWin::extendFrameIntoClientArea(QWidget* widget, int left, int top, int ri
 
     bool result = false;
 #ifdef Q_OS_WIN
-    if (Vista_Or_Newer) {
+    if (resolveLibs()) {
+        QLibrary dwmLib(QString::fromLatin1("dwmapi"));
         HRESULT hr = S_OK;
         MARGINS m = {left, right, top, bottom};
-        hr = DwmExtendFrameIntoClientArea(hwndOfWidget(widget), &m);
+        hr = pDwmExtendFrameIntoClientArea(hwndOfWidget(widget), &m);
         if (SUCCEEDED(hr)) {
             result = true;
             windowNotifier()->addWidget(widget);
@@ -200,11 +237,12 @@ QColor QtWin::colorizationColor()
     QColor resultColor = QApplication::palette().window().color();
 
 #ifdef Q_OS_WIN
-    if (Vista_Or_Newer) {
+    if (resolveLibs()) {
         DWORD color = 0;
         BOOL opaque = FALSE;
+        QLibrary dwmLib(QString::fromLatin1("dwmapi"));
         HRESULT hr = S_OK;
-        hr = DwmGetColorizationColor(&color, &opaque);
+        hr = pDwmGetColorizationColor(&color, &opaque);
         if (SUCCEEDED(hr)) {
             resultColor = QColor(color);
         }