add PixelFormat enum that replaces bit count in Bitmap/BitmapEx

Bit count for the image is a numeric value (sal_uInt16) but only
a handful of values make sense - namely 1,4,8,24 and 32. This
replaces the numeric value with an enum, which only accepts those
values and checks the correct values are used at compile time.

Change-Id: I0fc137c62bce3b0d021f05019a1648da628521bc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112408
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

4 files changed, 73 insertions, 7 deletions

diff --git a/include/vcl/BitmapTools.hxx b/include/vcl/BitmapTools.hxx
index 12cdb1947b2c..d7ce4be9e90f 100644
--- a/include/vcl/BitmapTools.hxx
+++ b/include/vcl/BitmapTools.hxx
@@ -44,9 +44,9 @@ void loadFromSvg(SvStream& rStream, const OUString& sPath, BitmapEx& rBitmapEx,
     @param pData
     The block of data to copy
     @param nStride
-    The number of bytes in a scanline, must be >= (width * nBitCount / 8)
+    The number of bytes in a scanline, must be >= (width * bitcount / 8)
 */
-BitmapEx VCL_DLLPUBLIC CreateFromData( sal_uInt8 const *pData, sal_Int32 nWidth, sal_Int32 nHeight, sal_Int32 nStride, sal_uInt16 nBitCount );
+BitmapEx VCL_DLLPUBLIC CreateFromData( sal_uInt8 const *pData, sal_Int32 nWidth, sal_Int32 nHeight, sal_Int32 nStride, vcl::PixelFormat ePixelFormat);
 
 BitmapEx VCL_DLLPUBLIC CreateFromData( RawBitmap && data );
 
diff --git a/include/vcl/bitmap.hxx b/include/vcl/bitmap.hxx
index d9d6c81d7661..3a2baf9e24c7 100644
--- a/include/vcl/bitmap.hxx
+++ b/include/vcl/bitmap.hxx
@@ -27,6 +27,7 @@
 #include <vcl/mapmod.hxx>
 #include <vcl/region.hxx>
 #include <vcl/scopedbitmapaccess.hxx>
+#include <vcl/bitmap/BitmapTypes.hxx>
 
 #include <o3tl/typed_flags_set.hxx>
 
@@ -114,7 +115,7 @@ public:
 
                             Bitmap();
                             Bitmap( const Bitmap& rBitmap );
-                            Bitmap( const Size& rSizePixel, sal_uInt16 nBitCount, const BitmapPalette* pPal = nullptr );
+                            Bitmap( const Size& rSizePixel, vcl::PixelFormat ePixelFormat, const BitmapPalette* pPal = nullptr );
     explicit                Bitmap( std::shared_ptr<SalBitmap> const & xSalBitmap );
     virtual                 ~Bitmap();
 
@@ -135,6 +136,7 @@ public:
 
     Size                    GetSizePixel() const;
 
+    vcl::PixelFormat getPixelFormat() const;
     sal_uInt16              GetBitCount() const;
     inline sal_Int64        GetColorCount() const;
     inline sal_uLong        GetSizeBytes() const;
@@ -538,8 +540,8 @@ public:
     typedef vcl::ScopedBitmapAccess<BitmapInfoAccess, Bitmap, &Bitmap::AcquireInfoAccess> ScopedInfoAccess;
 
 private:
-    SAL_DLLPRIVATE bool ImplConvertUp(sal_uInt16 nBitCount, Color const* pExtColor = nullptr);
-    SAL_DLLPRIVATE bool ImplConvertDown(sal_uInt16 nBitCount, Color const* pExtColor = nullptr);
+    SAL_DLLPRIVATE bool ImplConvertUp(vcl::PixelFormat ePixelFormat, Color const* pExtColor = nullptr);
+    SAL_DLLPRIVATE bool ImplConvertDown(vcl::PixelFormat ePixelFormat, Color const* pExtColor = nullptr);
 
 private:
     std::shared_ptr<SalBitmap> mxSalBmp;
diff --git a/include/vcl/bitmap/BitmapTypes.hxx b/include/vcl/bitmap/BitmapTypes.hxx
new file mode 100644
index 000000000000..866cf0b2950e
--- /dev/null
+++ b/include/vcl/bitmap/BitmapTypes.hxx
@@ -0,0 +1,55 @@
+/* -*- 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/.
+ *
+ */
+
+#pragma once
+
+namespace vcl
+{
+/** Pixel format of the bitmap in bits per pixel */
+enum class PixelFormat
+{
+    INVALID = 0,
+    N1_BPP = 1,
+    N4_BPP = 4,
+    N8_BPP = 8,
+    N24_BPP = 24,
+    N32_BPP = 32
+};
+
+/** Is it a pixel format that forces creation of a palette */
+constexpr bool isPalettePixelFormat(PixelFormat ePixelFormat)
+{
+    assert(ePixelFormat != PixelFormat::INVALID);
+    return sal_uInt16(ePixelFormat) <= 8;
+}
+
+constexpr PixelFormat bitDepthToPixelFormat(sal_uInt16 nBitDepth)
+{
+    switch (nBitDepth)
+    {
+        case 1:
+            return PixelFormat::N1_BPP;
+        case 4:
+            return PixelFormat::N4_BPP;
+        case 8:
+            return PixelFormat::N8_BPP;
+        case 24:
+            return PixelFormat::N24_BPP;
+        case 32:
+            return PixelFormat::N32_BPP;
+        default:
+            break;
+    }
+    return PixelFormat::INVALID;
+}
+
+} // end namespace vcl
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/include/vcl/bitmapex.hxx b/include/vcl/bitmapex.hxx
index 506901134719..5736e4d38b6a 100644
--- a/include/vcl/bitmapex.hxx
+++ b/include/vcl/bitmapex.hxx
@@ -49,7 +49,7 @@ public:
     explicit            BitmapEx( const OUString& rIconName );
                         BitmapEx( const BitmapEx& rBitmapEx );
                         BitmapEx( const BitmapEx& rBitmapEx, Point aSrc, Size aSize );
-                        BitmapEx( Size aSize, sal_uInt16 nBitCount );
+                        BitmapEx(Size aSize, vcl::PixelFormat ePixelFormat);
     explicit            BitmapEx( const Bitmap& rBmp );
                         BitmapEx( const Bitmap& rBmp, const Bitmap& rMask );
                         BitmapEx( const Bitmap& rBmp, const AlphaMask& rAlphaMask );
@@ -90,7 +90,16 @@ public:
     const MapMode&      GetPrefMapMode() const { return maBitmap.GetPrefMapMode(); }
     void                SetPrefMapMode( const MapMode& rPrefMapMode ) { maBitmap.SetPrefMapMode( rPrefMapMode ); }
 
-    sal_uInt16          GetBitCount() const { return maBitmap.GetBitCount(); }
+    sal_uInt16          GetBitCount() const
+    {
+        return maBitmap.GetBitCount();
+    }
+
+    vcl::PixelFormat getPixelFormat() const
+    {
+        return maBitmap.getPixelFormat();
+    }
+
     sal_uLong           GetSizeBytes() const;
     BitmapChecksum      GetChecksum() const;