Re: [PATCH 2/2] [v4] user32: Implement EC_USEFONTINFO margins in the CJK case.

[Huw Davies]

On Wed, Mar 27, 2019 at 10:25:48PM +0900, Akihiro Sagawa wrote:
> Signed-off-by: Akihiro Sagawa
>
> dlls/user32/edit.c       | 91 ++++++++++++++++++++++++++++++++++++++++++++++--
>  dlls/user32/tests/edit.c |  4 +--
>  2 files changed, 90 insertions(+), 5 deletions(-)
> diff --git a/dlls/user32/edit.c b/dlls/user32/edit.c
> index d1659b4..c0cb056 100644
> --- a/dlls/user32/edit.c
> +++ b/dlls/user32/edit.c
> @@ -2842,6 +2842,70 @@ static void EDIT_EM_SetLimitText(EDITSTATE *es, UINT limit)
>  }
>
> +static BOOL is_cjk_charset(HDC dc)
> +{
> - switch (GdiGetCodePage(dc)) {
> - case 932: case 936: case 949: case 950: case 1361:
> -
>    return TRUE;
> - default:
> -
>    return FALSE;
> - }
>
> +}
> -
>
> +#ifdef WORDS_BIGENDIAN
> +#define GET_BE_WORD(x) (x)
> +#else
> +#define GET_BE_WORD(x) MAKEWORD(HIBYTE(x), LOBYTE(x))
> +#endif
> -
>
> +#define MS_MAKE_TAG(ch0, ch1, ch2, ch3)                               \
> -
>                ((DWORD)(BYTE)(ch0) | ((DWORD)(BYTE)(ch1) << 8) | \
> -
>                ((DWORD)(BYTE)(ch2) << 16) | ((DWORD)(BYTE)(ch3) << 24))
> -
>
> +static BOOL get_side_bearings(HDC hdc, short *min_lsb, short *min_rsb)
> +{
> - const DWORD hhea_tag = MS_MAKE_TAG('h','h','e','a');
>
> +#include "pshpack2.h"
> - struct {
> -
>    unsigned short majorVersion;
> -
>    unsigned short minorVersion;
> -
>    short ascender;
> -
>    short descender;
> -
>    short lineGap;
> -
>    unsigned short advanceWidthMax;
> -
>    short minLeftSideBearing;
> -
>    short minRightSideBearing;
> -
>    short xMaxExtent;
> -
>    short caretSlopeRise;
> -
>    short caretSlopeRun;
> -
>    short caretOffset;
> -
>    short reserved[4];
> -
>    short metricDataFormat;
> -
>    short numberOfHMetrics;
> - } hhea_table;
>
> +#include "poppack.h"
> - LONG size;
> -
> - size = GetFontData(hdc, hhea_tag, 0, &hhea_table, sizeof(hhea_table));
> - if (size != sizeof(hhea_table))
> -
>    return FALSE;
> - *min_lsb = GET_BE_WORD(hhea_table.minLeftSideBearing);
> - *min_rsb = GET_BE_WORD(hhea_table.minRightSideBearing);
> - return TRUE;
>
> +}

The undocumented gdi32 export GetCharWidthInfo() could help here.
Its prototype seems to be:

struct width_info
{
    INT lsb;
    INT rsb;
    INT unknown;
};

INT WINAPI GetCharWidthInfo(HDC hdc, struct width_info *info);

You'd first want to implement and write tests for this in gdi32.

Huw.