[futurebasic] Re: Drawing to the screen

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From: "Deepesh Letap" <DLetap@...>
Date: Sat, 26 Sep 1998 09:27:49 +0100

Dear Lazlo

Before the programming effort starts, see if you can make the job easier.
Firstly, try and see if decimal coordinates are really practical.

For example, if you plot the whole range on screen from 0 to 500 for the
first coordinate and 0 to 200 for the second coordinate, are your users
likely to view a difference of 0.08 on screen? Even a 300 dpi printer would
not reliably display the difference.

Alternatively, If you are plotting only 420 to 435 for the first coordinate
and 180 to 200 for the second coordinate, the resolution may become more
relevant.

Remember, I am referring to display only. Obviously, the original data
should be stored in full in case it is needed for computations.

After this hurdle, decide if it is better to use the 72 dpi pixel basis and
adjust your data to the nearest pixel coordinate. Alternatively, look at the
COORDINATE function in the FB manuals.

Finally, decide if window or GWorld drawing is the better method. Direct
window drawing is easier to implement but slower when running. Gworlds are
technically the better way especially if fast updating is needed. This is a
matter or choice.

Hope this helps,

Deep





----------
>From: Lazlo Toth <ArtVandals@...>
>To: "FB Mailing list" <futurebasic@...>
>Subject: [FB] Drawing to the screen
>Date: Fri, Sep 25, 1998, 9:43 pm
>

>Hi All,
>
>I do a lot of work with X Y coordinates. Up until now I have not needed 
>to draw these to the screen, but now I would like to.
>
>I know 6/10ths of stuff all about this, so if there is anyone with a few 
>code snippets out there to get me started, I would appreciate this.
>
>The coordinates would be in the form more or less...
>
>> 423.96 -180 P
>> 424.04 -182.08
>> 424.4 -184.08
>> 424.88 -186.04 P
>> 425.56 -187.88 P
>> 426.4 -189.68 P
>> 427.44 -191.36 P
>> 428.6 -192.92 P
>> 429.92 -194.36 P
>> 431.36 -195.68 P
>> 432.92 -196.84 P
>
>Don't worry about the p's. It's all basic move to, draw to either as 
>lines or polys.
>
>As you can see, the coordinates are not to screen scale and would need to 
>be scaled etc. Since all of this is vectors, and no bitmaps etc, would 
>you need gworlds? I would not have thought so.
>
>Any help greatly appreciated.
>
>JC
>
>
>==========================================================================
>John Clark                    
>Aeronaut Automation
>30 Kennedy Place Bayview 2104 Australia
>Phone:   61 2 99 97 28 42              Fax: 61 2 99 79 56 15
>email:   johnc@...
>http://www.AeronautAuto.com
>==========================================================================
>
>
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