~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~                    Using the "Draw to" Command                     ~
~                        Jonathan Rutherford                         ~
~                                                                    ~
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One of the other most important  commands  that we will be using later
on in one  of  the  other  Beginners  articles,  about  writing a LOGO
programming language in Amos  is  the  "Draw  to"  command. It will be
useful as we  can  register  the  last  set  point  using  "GR Locate"
(explained in the LOGO article) and then  draw from that position to a
new position using "Draw to".  It  saves  fiddling  about with lots of
different variables holding  information  about  the  co-ordinates and
drawing from those different positions, setting it manually.

The usage of the command "Draw to" is:-

        Draw to x,y

Where x and y are co-ordinates of the point you want to draw to. It is
basically just the Draw command but instead of putting:-

        Draw x,y to x,y

Where you have from co-ordinates followed  by to co-ordinates you just
put "Draw to" and the line  is  drawn  from the current graphic cursor
position to the x and y co-ordinates.

eg. Try this:

        Do
        Gr Locate 100,100
        X=Rnd(320)
        Y=Rnd(250)
        Draw to X,Y
        Loop

This might be a bit fast, so we  might  have to slow it down by adding
in the command "Wait 5" just before the "Loop" command.

Here's another piece of sourcecode to try.


        '*** Draw the N
        Gr Locate 100,100
        Draw To 100,50 : Wait 5
        Draw to 120,100 : Wait 5
        Draw to 120,50 : Wait 5
        '
        '*** Draw the B
        Gr Locate 130,50
        Draw to 130,100 : Wait 5
        Draw to 150,100 : Wait 5
        Draw to 140,75 : Wait 5
        Draw to 150,50 : Wait 5
        Draw to 130,50 : Wait 5
        '
        '*** Draw the A
        Gr Locate 160,100
        Draw to 170,50 : Wait 5
        Draw to 180,100 : Wait 5
        Gr Locate 165,75
        Draw to 175,75 : Wait 5
        '
        '*** Draw the M
        Gr Locate 190,100
        Draw to 190,50 : Wait 5
        Draw to 200,75 : Wait 5
        Draw to 210,50 : Wait 5
        Draw to 210,100 : Wait 5
        '
        '*** Draw the O
        Gr Locate 220,50
        Draw to 240,50 : Wait 5
        Draw to 240,100 : Wait 5
        Draw to 220,100 : Wait 5
        Draw to 220,50 : Wait 5
        '
        '*** Draw the S
        Gr Locate 270,50
        Draw to 250,50 : Wait 5
        Draw to 250,75 : Wait 5
        Draw to 270,75 : Wait 5
        Draw to 270,100 : Wait 5
        Draw to 250,100
        Wait 100
        End

Notice how most  of  the  above  program  relies  on Co-ordinates. Co-
ordinates are very important in Amos programming as they are used when
positioning Bobs, Sprites, Text etc. and a lot of commands rely on the
use of co-ordinates so you need  to  be  fairly competent at using co-
ordinates to program well.

Catch you next month.

Jonathan.