gdi32: Use the get_mono_dc_colors() helper.

dlls/gdi32/bitblt.c

@@ -222,7 +222,7 @@ static DWORD blend_bits( const BITMAPINFO *src_info, const struct gdi_image_bits
 }
 
 /* helper to retrieve either both colors or only the background color for monochrome blits */
-static void get_mono_dc_colors( HDC hdc, BITMAPINFO *info, int count )
+void get_mono_dc_colors( HDC hdc, BITMAPINFO *info, int count )
 {
     RGBQUAD *colors = info->bmiColors;
     COLORREF color = GetBkColor( hdc );

dlls/gdi32/dib.c

@@ -581,14 +581,7 @@ INT nulldrv_StretchDIBits( PHYSDEV dev, INT xDst, INT yDst, INT widthDst, INT he
         if (dst_info->bmiHeader.biBitCount == 1 && !dst_colors)
         {
             if (src_info->bmiHeader.biBitCount > 1)
-            {
-                COLORREF color = GetBkColor( dev->hdc );
-                dst_info->bmiColors[0].rgbRed      = GetRValue( color );
-                dst_info->bmiColors[0].rgbGreen    = GetGValue( color );
-                dst_info->bmiColors[0].rgbBlue     = GetBValue( color );
-                dst_info->bmiColors[0].rgbReserved = 0;
-                dst_info->bmiHeader.biClrUsed = 1;
-            }
+                get_mono_dc_colors( dev->hdc, dst_info, 1 );
             else
             {
                 memcpy( dst_info->bmiColors, src_info->bmiColors, 2 * sizeof(dst_info->bmiColors[0]) );

dlls/gdi32/gdi_private.h

@@ -205,6 +205,7 @@ extern BOOL intersect_vis_rectangles( struct bitblt_coords *dst, struct bitblt_c
 extern DWORD stretch_bits( const BITMAPINFO *src_info, struct bitblt_coords *src,
                            BITMAPINFO *dst_info, struct bitblt_coords *dst,
                            struct gdi_image_bits *bits, int mode ) DECLSPEC_HIDDEN;
+extern void get_mono_dc_colors( HDC hdc, BITMAPINFO *info, int count ) DECLSPEC_HIDDEN;
 
 /* brush.c */
 extern BOOL store_brush_pattern( LOGBRUSH *brush, struct brush_pattern *pattern ) DECLSPEC_HIDDEN;