move some CanvasHelper::implDrawBitmap inside vcl

part of making mask and alpha internal details of Bitmap/BitmapEx

Change-Id: I87ca24af18a29f5eb8a5761c5d95ae2806d97e77
Reviewed-on: https://gerrit.libreoffice.org/55078
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Jenkins <ci@libreoffice.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/include/vcl/BitmapAlphaClampFilter.hxx b/include/vcl/BitmapAlphaClampFilter.hxx
new file mode 100644
index 000000000000..0fc6274b6d4e
--- /dev/null
+++ b/include/vcl/BitmapAlphaClampFilter.hxx
@@ -0,0 +1,36 @@
+/* -*- 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_INCLUDE_VCL_BITMAPMONOCHROMEFILTER_HXX
+#define INCLUDED_INCLUDE_VCL_BITMAPMONOCHROMEFILTER_HXX
+
+#include <tools/color.hxx>
+
+#include <vcl/BitmapFilter.hxx>
+
+/** If the alpha is beyond a certain threshold, make it fully transparent
+ */
+class VCL_DLLPUBLIC BitmapAlphaClampFilter : public BitmapFilter
+{
+public:
+    BitmapAlphaClampFilter(sal_uInt8 cThreshold)
+        : mcThreshold(cThreshold)
+    {
+    }
+
+    virtual BitmapEx execute(BitmapEx const& rBitmapEx) override;
+
+private:
+    sal_uInt8 mcThreshold;
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */