28 procedure PrettifySurfaceAlpha(surf: PSDL_Surface; pixels: PLongwordArray);

    29 procedure PrettifyAlpha2D(pixels: TLandArray; height, width: LongWord);

   126 { this will make invisible pixels that have a visible neighbor have the

   127   same color as their visible neighbor, so that bilinear filtering won't

   128   display a "wrongly" colored border when zoomed in }

   129 procedure PrettifyAlpha(row1, row2: PLongwordArray; firsti, lasti, ioffset: LongWord);

   130 var

   131     i: Longword;

   132     lpi, cpi, bpi: boolean; // was last/current/bottom neighbor pixel invisible?

   133 begin

   134     // suppress incorrect warning

   135     lpi:= true;

   136     for i:=firsti to lasti do

   137         begin

   138         // use first pixel in row1 as starting point

   139         if i = firsti then

   140             cpi:= ((row1^[i] and AMask) = 0)

   141         else

   142             begin

   143             cpi:= ((row1^[i] and AMask) = 0);

   144             if cpi <> lpi then

   145                 begin

   146                 // invisible pixels get colors from visible neighbors

   147                 if cpi then

   148                     begin

   149                     row1^[i]:= row1^[i-1] and not AMask;

   150                     // as this pixel is invisible and already colored correctly now, no point in further comparing it

   151                     lpi:= cpi;

   152                     continue;

   153                     end

   154                 else

   155                     row1^[i-1]:= row1^[i] and not AMask;

   156                 end;

   157             end;

   158         lpi:= cpi;

   159         // also check bottom neighbor

   160         if row2 <> nil then

   161             begin

   162             bpi:= ((row2^[i+ioffset] and AMask) = 0);

   163             if cpi <> bpi then

   164                 begin

   165                 if cpi then

   166                     row1^[i]:= row2^[i+ioffset] and not AMask

   167                 else

   168                     row2^[i+ioffset]:= row1^[i] and not AMask;

   169                 end;

   170             end;

   171         end;

   172 end;

   173 

   174 procedure PrettifySurfaceAlpha(surf: PSDL_Surface; pixels: PLongwordArray);

   175 var

   176     // current row index, second last row index of array, width and first/last i of row

   177     r, slr, w, si, li: LongWord;

   178 begin

   179     w:= surf^.w;

   180     slr:= surf^.h - 2;

   181     si:= 0;

   182     li:= w - 1;

   183     for r:= 0 to slr do

   184         begin

   185         PrettifyAlpha(pixels, pixels, si, li, w);

   186         // move indices to next row

   187         si:= si + w;

   188         li:= li + w;

   189         end;

   190     // don't forget last row

   191     PrettifyAlpha(pixels, nil, si, li, w);

   192 end;

   193 

   194 procedure PrettifyAlpha2D(pixels: TLandArray; height, width: LongWord);

   195 var

   196     // current y; last x, second last y of array;

   197     y, lx, sly: LongWord;

   198 begin

   199     sly:= height - 2;

   200     lx:= width - 1;

   201     for y:= 0 to sly do

   202         begin

   203         PrettifyAlpha(PLongWordArray(pixels[y]), PLongWordArray(pixels[y+1]), 0, lx, 0);

   204         end;

   205     // don't forget last row

   206     PrettifyAlpha(PLongWordArray(pixels[sly+1]), nil, 0, lx, 0);

   207 end;

   246 

   247 PrettifySurfaceAlpha(surf, fromP4);