Re: [PATCH] uxtheme: Support images in GetThemeBackgroundRegion. (try 2)

[Alexandre Julliard]

Mark Harmstone  writes:
> - /* loop through the image looking for transparent pixels,
> -
> * grouping together horizontal runs into one rect */
> - ptr = bits;
> - for (y = 0; y < r.bottom; y++) {
> -
>    BOOL trans = FALSE;
> -
>    int transstart;
> -
> -
>    for (x = 0; x < r.right; x++) {
> -
>        COLORREF colour = ptr[2] << 16 | ptr[1] << 8 | ptr[0];
> -
>        ptr += 4;
> -
> -
>        if (colour == transcolour) {
> -
>            if (!trans) {
> -
>                transstart = x;
> -
>                trans = TRUE;
> -
>            }
> -
>        } else if (trans) {
> -
>            rgntemp = CreateRectRgn(transstart, y, x, y+1);
> -
>            CombineRgn(hrgn, hrgn, rgntemp, RGN_DIFF);
> -
>            DeleteObject(rgntemp);
> -
>            trans = FALSE;
> -
>        }
> -
>    }
> -
> -
>    if (trans) {
> -
>        rgntemp = CreateRectRgn(transstart, y, r.right, y+1);
> -
>        CombineRgn(hrgn, hrgn, rgntemp, RGN_DIFF);
> -
>        DeleteObject(rgntemp);
> -
>    }
> - }

That's going to be pretty slow. There's a better implementation in
winex11.drv:update_surface_region(), you could just copy that.