[PATCH 3/5] usp10: Do not fall back to presentation form B if the contextual feature exists in ContextualShape_Arabic().

[Aric Stewart]

Signed-off-by: Aric Stewart <aric at codeweavers.com>

On 3/7/17 1:57 AM, Henri Verbeet wrote:
> E.g., the base form of 'ا' may be the same as the isolated form, in which case
> the "isol" feature may not have a substitution for it. At the same time, while
> the presentation form B glyph may look the same or similar as the base form,
> it may have a different glyph ID. This can break e.g.
> GSUB_LOOKUP_CONTEXT_CHAINED substitutions because of the unexpected glyph ID.
> 
> Signed-off-by: Henri Verbeet <hverbeet at codeweavers.com>
> ---
>  dlls/usp10/shape.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/dlls/usp10/shape.c b/dlls/usp10/shape.c
> index ce19465..9d07e5b 100644
> --- a/dlls/usp10/shape.c
> +++ b/dlls/usp10/shape.c
> @@ -1129,8 +1129,14 @@ static void ContextualShape_Arabic(HDC hdc, ScriptCache *psc, SCRIPT_ANALYSIS *p
>                      offset = *pcGlyphs - prevCount;
>                      glyph_index += dirL * (offset + 1);
>                  }
> +                shaped = TRUE;
> +            }
> +            else if (nextIndex == GSUB_E_NOGLYPH)
> +            {
> +                char_index += dirL;
> +                glyph_index += dirL;
> +                shaped = TRUE;
>              }
> -            shaped = (nextIndex > GSUB_E_NOGLYPH);
>          }
>  
>          if (!shaped)
>