[PATCH] gdi32: Implement GetCharWidthFloat().

[Huw Davies]

On Thu, Sep 26, 2019 at 09:17:03AM -0500, Zebediah Figura wrote:
> diff --git a/dlls/gdi32/tests/font.c b/dlls/gdi32/tests/font.c
> index b57effd349d..ccae09edc19 100644
> --- a/dlls/gdi32/tests/font.c
> +++ b/dlls/gdi32/tests/font.c
> @@ -7189,6 +7189,51 @@ static void test_GetCharWidthInfo(void)
>      ReleaseDC(NULL, hdc);
>  }
>  
> +static int CALLBACK get_char_width_proc(const LOGFONTA *lf,
> +        const TEXTMETRICA *tm, DWORD type, LPARAM ctx)
> +{
> +    HFONT font = CreateFontIndirectA(lf);
> +    HDC dc = GetDC(NULL);
> +    const char c = 'm';
> +    ABCFLOAT abcf;
> +    int i, i32;
> +    BOOL ret;
> +    float f;
> +    ABC abc;
> +
> +    SelectObject(dc, font);
> +
> +    ret = GetCharWidthFloatA(dc, c, c, &f);
> +    ok(ret, "%s: GetCharWidthFloat() failed\n", lf->lfFaceName);
> +    ret = GetCharWidth32A(dc, c, c, &i32);
> +    ok(ret, "%s: GetCharWidth32A() failed\n", lf->lfFaceName);
> +    ret = GetCharWidthA(dc, c, c, &i);
> +    ok(ret, "%s: GetCharWidthA() failed\n", lf->lfFaceName);
> +    ok(i == i32, "%s: mismatched widths %d/%d\n", lf->lfFaceName, i, i32);
> +    ok((float)i / 16.0f == f, "%s: mismatched widths %d/%.8e\n", lf->lfFaceName, i, f);
> +

This factor of sixteen is strange.  Is it perhaps possible that the
selected font has a ppem of sixteen and that GetCharWidthFloat()
returns widths as a fraction of the em square width?

Huw.