tdf#106265 ScopedHDC to clean-up hDC when rendering glyphs

Change-Id: I96ecf625126740610200c012c3c7002fac7e1548
Reviewed-on: https://gerrit.libreoffice.org/37347
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
(cherry picked from commit dae61482df7ae540a1fb8feefbb92b5e7238444d)
Reviewed-on: https://gerrit.libreoffice.org/37495
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>

2 files changed, 51 insertions, 6 deletions

diff --git a/vcl/inc/win/ScopedHDC.hxx b/vcl/inc/win/ScopedHDC.hxx
new file mode 100644
index 000000000000..bd4642ee6642
--- /dev/null
+++ b/vcl/inc/win/ScopedHDC.hxx
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_VCL_INC_WIN_SCOPEDHDC_HXX
+#define INCLUDED_VCL_INC_WIN_SCOPEDHDC_HXX
+
+class ScopedHDC
+{
+private:
+    HDC m_hDC;
+
+public:
+    explicit ScopedHDC(HDC hDC)
+        : m_hDC(hDC)
+    {}
+
+    ScopedHDC(const ScopedHDC&) = delete;
+    ScopedHDC& operator=(const ScopedHDC&) = delete;
+
+    ~ScopedHDC()
+    {
+        if (m_hDC)
+            DeleteDC(m_hDC);
+    }
+
+    HDC get() const
+    {
+        return m_hDC;
+    }
+
+    explicit operator bool() const
+    {
+        return m_hDC != nullptr;
+    }
+};
+
+#endif // INCLUDED_VCL_INC_WIN_SCOPEDHDC_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/win/gdi/winlayout.cxx b/vcl/win/gdi/winlayout.cxx
index 782f56c31e48..18c17b02abc2 100644
--- a/vcl/win/gdi/winlayout.cxx
+++ b/vcl/win/gdi/winlayout.cxx
@@ -33,6 +33,7 @@
 #include "sft.hxx"
 #include "sallayout.hxx"
 #include "CommonSalLayout.hxx"
+#include "win/ScopedHDC.hxx"
 
 #include <cstdio>
 #include <cstdlib>
@@ -77,17 +78,17 @@ bool WinFontInstance::CacheGlyphToAtlas(bool bRealGlyphIndices, HDC hDC, HFONT h
     std::vector<uint32_t> aCodePointsOrGlyphIndices(1);
     aCodePointsOrGlyphIndices[0] = nGlyphIndex;
 
-    HDC hNewDC = CreateCompatibleDC(hDC);
-    if (hNewDC == nullptr)
+    ScopedHDC aHDC(CreateCompatibleDC(hDC));
+
+    if (!aHDC)
     {
         SAL_WARN("vcl.gdi", "CreateCompatibleDC failed: " << WindowsErrorString(GetLastError()));
         return false;
     }
-    HFONT hOrigFont = static_cast<HFONT>(SelectObject(hNewDC, hFont));
+    HFONT hOrigFont = static_cast<HFONT>(SelectObject(aHDC.get(), hFont));
     if (hOrigFont == nullptr)
     {
         SAL_WARN("vcl.gdi", "SelectObject failed: " << WindowsErrorString(GetLastError()));
-        DeleteDC(hNewDC);
         return false;
     }
 
@@ -96,10 +97,9 @@ bool WinFontInstance::CacheGlyphToAtlas(bool bRealGlyphIndices, HDC hDC, HFONT h
     if (!pTxt)
         return false;
 
-    if (!pTxt->BindFont(hNewDC))
+    if (!pTxt->BindFont(aHDC.get()))
     {
         SAL_WARN("vcl.gdi", "Binding of font failed. The font might not be supported by Direct Write.");
-        DeleteDC(hNewDC);
         return false;
     }