On 24/06/2018 19:36, Abdur-Rahmaan Janhangeer wrote:
see for example
https://en.m.wikipedia.org/wiki/Bresenham%27s_line_algorithm
see the pseudocode, i was implementing some raster algos when i found
myself aux anges
so close to py. i guess it was written in prehistoric times with the author
trying to simplify stuffs
I'm sorry, but that kind of code is a mish-mash of old
Algol/Pascal-style languages. I doubt it was meant to be Python.
Python doesn't have a monopoly on clear syntax.
This is the first example from that link (I've taken out comments):
function line(x0, y0, x1, y1)
real deltax := x1 - x0
real deltay := y1 - y0
real deltaerr := abs(deltay / deltax)
real error := 0.0
int y := y0
for x from x0 to x1
plot(x,y)
error := error + deltaerr
while error ≥ 0.5 then
y := y + sign(deltay) * 1
error := error - 1.0
This has some problems: it's using 'function' when it doesn't return a
value (those languages used 'proc' or 'procedure' in that case). It
doesn't give a type for the parameters, and it uses while/then rather
than the usual while/do.
So it's rather sloppy even for pseudo code. The only similarity with
Python is the lack of block delimiters, but then with later examples
they /are/ used, for if-else-endif.
Below, the first block is that code tweaked to a static language of
mine. The second is the same code tweaked to Python.
It was less work to adapt it my syntax rather than Python. All versions
however use a decidedly un-Pythonic style, which means the difference
between the two below isn't that great, even though they are different
languages. But imagine trying to adapt Pythonic code to work in the
other language; it would be much harder (apart from one being dynamic
and the other not).
---------------------------------
proc line(int x0, y0, x1, y1)=
real deltax := x1 - x0
real deltay := y1 - y0
real deltaerr := abs(deltay / deltax)
real error := 0.0
int y := y0
int x
for x := x0 to x1 do
plot(x,y)
error := error + deltaerr
while error = 0.5 do
y := y + sign(deltay) * 1
error := error - 1.0
end
end
end
----------------------------------
def line(x0, y0, x1, y1):
deltax = x1 - x0
deltay = y1 - y0
deltaerr = abs(deltay / deltax)
error = 0.0
y = y0
for x in range(x0,x1+1):
plot(x,y)
error = error + deltaerr
while error == 0.5:
y = y + sign(deltay) * 1
error = error - 1.0
--
bart
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