Scilab keyword

alufunctions - description and number of pixel drawing modes.

### Description

src is the source ie the "value of the pixel" which we want to draw. dst is the destination ie "value of the pixel" which is already drawn.

0: clear ie "0"

1: and ie "src AND dst"

2: and reverse ie "src AND NOT dst"

3: copy ie "src"

4: and inverted ie "(NOT src) AND dst"

5: noop ie "dst"

6: xor ie "src XOR dst"

7: or ie "src OR dst"

8: nor ie "(NOT src) AND (NOT dst)"

9: equiv ie "(NOT src) XOR dst"

10: invert ie "NOT dst"

11: or reverse ie "src OR (NOT dst)"

12: copy inverted ie "NOT src"

13: or inverted ie "(NOT src) OR dst"

14: nand ie "(NOT src) OR (NOT dst)"

15: set ie "1"