Re: [PATCH 3/4] gdi32: Make EMFDRV_StretchBlt() compatible with display drivers.

[Huw Davies]

On Mon, May 17, 2021 at 05:00:21PM +0800, Zhiyi Zhang wrote:

The commit msg could be a bit better.  Prehaps "gdi32: Use a common helper for StretchBlt and AlphaBlend"?
> Signed-off-by: Zhiyi Zhang
>
> dlls/gdi32/enhmfdrv/bitblt.c | 121 +++++------------------------------
>  dlls/gdi32/tests/metafile.c  |  29 ++++-----
>  2 files changed, 27 insertions(+), 123 deletions(-)
>
> diff --git a/dlls/gdi32/enhmfdrv/bitblt.c b/dlls/gdi32/enhmfdrv/bitblt.c
> index 597a6110abd..0fa6226ebaa 100644
> --- a/dlls/gdi32/enhmfdrv/bitblt.c
> +++ b/dlls/gdi32/enhmfdrv/bitblt.c
> @@ -27,14 +27,15 @@
>  #include "enhmetafiledrv.h"
>  #include "wine/debug.h"
>
> -BOOL CDECL EMFDRV_AlphaBlend( PHYSDEV dev_dst, struct bitblt_coords *dst,
> -
>                          PHYSDEV dev_src, struct bitblt_coords *src, BLENDFUNCTION func )
>
> +/* Generate an EMRSTRETCHBLT or EMRALPHABLEND record depending on the alpha_blend parameter */
> +static BOOL emfdrv_stretchblt( PHYSDEV dev_dst, struct bitblt_coords *dst, PHYSDEV dev_src,
> -
>                           struct bitblt_coords *src, DWORD rop, BOOL alpha_blend )

I would change the final param to be DWORD type (i.e. explicitly pass EMR_STRETCHBLT/ALPHABLEND).
> @@ -155,106 +163,7 @@ BOOL CDECL EMFDRV_PatBlt( PHYSDEV dev, struct bitblt_coords *dst, DWORD rop )
>  BOOL CDECL EMFDRV_StretchBlt( PHYSDEV devDst, struct bitblt_coords *dst,
>                                PHYSDEV devSrc, struct bitblt_coords *src, DWORD rop )
>  {
> - BOOL ret;
> - PEMRBITBLT pEMR;
> - UINT emrSize;
> - UINT bmiSize;
> - UINT bitsSize;
> - UINT size;
> - BITMAP  BM;
> - WORD nBPP = 0;
> - LPBITMAPINFOHEADER lpBmiH;
> - HBITMAP hBitmap = NULL;
> - DWORD emrType;
> -
> - if (devSrc->funcs == devDst->funcs) return FALSE;  /* can't use a metafile DC as source */
> -
> - if (src->log_width == dst->log_width && src->log_height == dst->log_height)
> - {
> -
>    emrType = EMR_BITBLT;
> -
>    emrSize = sizeof(EMRBITBLT);
> - }
> - else
> - {
> -
>    emrType = EMR_STRETCHBLT;
> -
>    emrSize = sizeof(EMRSTRETCHBLT);
> - }

Presumably calls to BitBlt() get encoded as EMR_BITBLT (even if non-stretch
StretchBlt()s don't).  Assuming that's the case, I think it would make sense
to retain what we did here and use EMR_BITBLT where we can (another reason
for passing the type to the helper function).

Huw.