> Thanks for you comments. The answer is yes, as you guessed. > Typically, native GetGlyphOutlineW(hdc, ' ', GGO_BITMAP, &gm, 0, NULL, ...) > returns gm.gmBlackBoxX = 1 instead of 0. Unfortunately, Wine's didn't, > and existing source codes (winex11, gdiplus, gdi32) expect 0 in this > case.
I don't think the existing code for finding the mask size would have a problem with gmBlackBoxX being 0. But it would be best to skip updating min_x, min_y, max_x, and max_y in this case, since we don't really need the mask to include the position of an empty glyph. Does Wine's GGO return a non-zero value currently? That would mean a regression in gdiplus drawing only empty glyphs when you fix GGO. > Native GGO returns GDI_ERROR in GetGlyphOutlineW(hdc, ' ', GGO_BITMAP, > &gm, bufsize, buf, ...) case. Please note that bufsize and buf are > specified and guess they aren't null. > > The second loop is for creating mask bitmaps. We don't need to update > bitmaps if the character is empty. However, we also need to update the > bitmap mask after that character. So, I just ignore the error and > continue at that point. I think a comment saying just /* empty glyph */ inside the if blocks for these new cases would make the code much clearer.
