gdiplus: Added GdipBitmapConvertFormat stub.

dlls/gdiplus/gdiplus.spec

@@ -620,7 +620,7 @@
 620 stdcall GdipBitmapApplyEffect(ptr ptr ptr long ptr ptr)
 621 stub GdipBitmapGetHistogram
 622 stub GdipBitmapGetHistogramSize
-623 stub GdipBitmapConvertFormat
+623 stdcall GdipBitmapConvertFormat(ptr long long long ptr float)
 624 stdcall GdipImageSetAbort(ptr ptr)
 625 stub GdipGraphicsSetAbort
 626 stub GdipDrawImageFX

dlls/gdiplus/image.c

@@ -5268,3 +5268,13 @@ GpStatus WINGDIPAPI GdipImageSetAbort(GpImage *image, GdiplusAbort *pabort)
     FIXME("(%p, %p): stub\n", image, pabort);
     return NotImplemented;
 }
+
+/*****************************************************************************
+ * GdipBitmapConvertFormat [GDIPLUS.@]
+ */
+GpStatus WINGDIPAPI GdipBitmapConvertFormat(GpBitmap *bitmap, PixelFormat format, DitherType dithertype,
+    PaletteType palettetype, ColorPalette *palette, REAL alphathreshold)
+{
+    FIXME("(%p, 0x%08x, %d, %d, %p, %f): stub\n", bitmap, format, dithertype, palettetype, palette, alphathreshold);
+    return NotImplemented;
+}

include/gdipluspixelformats.h

@@ -102,4 +102,33 @@ typedef struct ColorPalette
 
 #endif  /* end of c typedefs */
 
+typedef enum DitherType
+{
+    DitherTypeNone,
+    DitherTypeSolid,
+    DitherTypeOrdered4x4,
+    DitherTypeOrdered8x8,
+    DitherTypeOrdered16x16,
+    DitherTypeSpiral4x4,
+    DitherTypeSpiral8x8,
+    DitherTypeDualSpiral4x4,
+    DitherTypeDualSpiral8x8,
+    DitherTypeErrorDiffusion,
+    DitherTypeMax
+} DitherType;
+
+typedef enum PaletteType
+{
+    PaletteTypeCustom,
+    PaletteTypeOptimal,
+    PaletteTypeFixedBW,
+    PaletteTypeFixedHalftone8,
+    PaletteTypeFixedHalftone27,
+    PaletteTypeFixedHalftone64,
+    PaletteTypeFixedHalftone125,
+    PaletteTypeFixedHalftone216,
+    PaletteTypeFixedHalftone252,
+    PaletteTypeFixedHalftone256
+} PaletteType;
+
 #endif