[PATCH 3/4] d3dx9: Implement clipping of glyphs in ID3DXFont_DrawText.

[Sven Baars]

On 18-11-2020 13:23, Matteo Bruni wrote:
> On Tue, Nov 17, 2020 at 3:34 PM Sven Baars <sbaars at codeweavers.com> wrote:
>>
>> Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=49546
>> Signed-off-by: Sven Baars <sbaars at codeweavers.com>
>> ---
>>  dlls/d3dx9_36/font.c | 16 +++++++++++++++-
>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/dlls/d3dx9_36/font.c b/dlls/d3dx9_36/font.c
>> index 235ae11072b..f5775384da3 100644
>> --- a/dlls/d3dx9_36/font.c
>> +++ b/dlls/d3dx9_36/font.c
>> @@ -583,7 +583,6 @@ static const WCHAR *read_line(HDC hdc, const WCHAR *str, unsigned int *count,
>>          }
>>          else if (format & DT_SINGLELINE)
>>          {
>> -            *dest_len = num_fit;
>>              *count = 0;
>>          }
>>      }
> 
> IIUC this is to allow drawing partial glyphs in the DT_SINGLELINE
> case, is that right?
That is true.

> 
>> @@ -768,6 +767,21 @@ static INT WINAPI ID3DXFontImpl_DrawTextW(ID3DXFont *iface, ID3DXSprite *sprite,
>>              pos.y = cell_inc.y + y;
>>              pos.z = 0;
>>
>> +            if (!(format & DT_NOCLIP))
>> +            {
>> +                if (pos.x > rect->right)
>> +                {
>> +                    IDirect3DTexture9_Release(texture);
>> +                    continue;
>> +                }
>> +
>> +                if (pos.x + black_box.right - black_box.left > rect->right)
>> +                    black_box.right = black_box.left + rect->right - pos.x;
>> +
>> +                if (pos.y + black_box.bottom - black_box.top > rect->bottom)
>> +                    black_box.bottom = black_box.top + rect->bottom - pos.y;
>> +            }
>> +
>>              ID3DXSprite_Draw(target, texture, &black_box, NULL, &pos, color);
>>              IDirect3DTexture9_Release(texture);
>>          }
> 
> This certainly looks correct. I'm curious how this fixes bug 49546
> though. I'm not questioning that it does, just wondering how not
> clipping to the rect makes the text disappear altogether...
> 
Because it passes DT_SINGLELINE | DT_NOCLIP with a 0x0 rect. This means
that previously the number of characters that fit was 0. Now we don't
set dest_len anymore, so we actually draw something.