Data commit

Task/Bitmap-Flood-fill/XPL0/bitmap-flood-fill.xpl0

@@ -0,0 +1,60 @@
+include c:\cxpl\codes;
+
+proc    Flood(X, Y, C, C0);     \Fill an area of color C0 with color C
+int     X, Y,   \seed coordinate (where to start)
+        C, C0;  \color to fill with and color to replace
+def     S=8000; \size of queue (must be an even number)
+int     Q(S),   \queue (FIFO)
+        F, E;   \fill and empty indexes
+
+        proc    EnQ(X, Y);      \Enqueue coordinate
+        int     X, Y;
+        [Q(F):= X;
+        F:= F+1;
+        Q(F):= Y;
+        F:= F+1;
+        if F >= S then F:= 0;
+        ];      \EnQ
+
+        proc    DeQ;            \Dequeue coordinate
+        [X:= Q(E);
+        E:= E+1;
+        Y:= Q(E);
+        E:= E+1;
+        if E >= S then E:= 0;
+        ];      \DeQ
+
+[F:= 0;  E:= 0;
+EnQ(X, Y);
+while E # F do
+        [DeQ;
+        if ReadPix(X, Y) = C0 then
+                [Point(X, Y, C);
+                EnQ(X+1, Y);    \enqueue adjacent pixels
+                EnQ(X-1, Y);
+                EnQ(X, Y+1);
+                EnQ(X, Y-1);
+                ];
+        ];
+];      \Flood
+
+def     Size = 30.0;
+int     X, Y;
+real    Ang, Dist;
+[SetVid($101);                  \set 640x480 graphics with 256 colors
+
+Ang:= 0.0;                      \draw some flower petals
+repeat  Dist:= Size*(Cos(Ang*3.0) - 1.0);
+        X:= fix(Dist*Cos(Ang));
+        Y:= fix(Dist*Sin(Ang));
+        Point(X+320, 240-Y, $F);
+        Ang:= Ang + 0.001;      \draw dots close together to prevent leaks
+until   Ang >= 2.0*3.14159;
+
+Flood(330, 240, $2A, 0);        \color the petals
+Flood(310, 230, $2C, 0);
+Flood(310, 250, $2E, 0);
+
+if ChIn(1) then [];             \wait for keystroke
+SetVid(3);                      \restore normal text mode
+]