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Bitmap/Bresenham's line algorithm: Difference between revisions
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Images <tt>test0.png</tt> and <tt>test1.png</tt> look different since Imlib2 draw lines with antialiasing.
=={{header|PL/I}}==
<lang PL/I>
/* Draw a line fom (x0, y0) to (x1, y1). 13 May 2010 */
/* Based on Rosetta code proforma. */
draw_line: procedure (xi, yi, xf, yf );
declare (xi, yi, xf, yf) fixed binary (31) nonassignable;
declare (x0, y0, x1, y1) fixed binary (31);
declare (deltax, deltay, x, y, ystep) fixed binary;
declare (error initial (0), delta_error) float;
declare steep bit (1);
x0 = xi; y = YI; y0 = yi; x1 = xf; y1 = yf;
steep = abs(y1 - y0) > abs (x1 - x0);
if steep then
do; call swap (x0, y0); call swap (x1, y1); end;
if x0 > x1 then
do; call swap (x0, x1); call swap (y0, y1); end;
deltax = x1 - x0; deltay = abs(y1 - y0);
delta_error = deltay/deltax;
if y0 < y1 then ystep = 1; else ystep = -1;
do x = x0 to x1;
if steep then image(y, x) = color; else image(x, y) = color;
if steep then put skip list (y, x); else put skip list (x, y);
error = error + delta_error;
if error >= 0.5 then do; y = y + ystep; error = error - 1; end;
end;
swap: procedure (a, b);
declare (a, b) fixed binary (31);
declare t fixed binary (31);
t = a; a = b; b = t;
end swap;
end draw_line;
</lang>
=={{header|PureBasic}}==
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