Some questions Split from: Lazarus cannot handle simple calculations?
lazarus / 13-General

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Waco · 2009-08-28 08:04

I won't start another topic because I don't think it's necessary, even
though this is another topic.

1. Does Lazarus free all the space taken by local variables after
ending a procedure?

2. This problem irritates me really much, it seems that Lazarus draws
on canvas quite inaccurately. I made a procedure to draw an angle, but
when I measure the angle (yes, holding a goniometer on the screen),
the declension varies from 0 up to 3 degrees, which is just too much.
Does anyone have an explanation for this? Of course, my procedure
might be incorrect, which is quite probable I have to say, but if
someone is able to justify this imprecision, I would be really
thankful. Otherwise I will post an example.

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Marc · 2009-08-28 09:26

These are complete different questions. This is not just a personal
messageboard where you can continuing writing questions.

@1: Yes. Except classes you have created (since they aren't allocated
locally, only the reference to it is)

@2: Calibrate your monitor/screen. Make sure a square is displayed as
square.
Lines are drawn with simple math, with begin and endpoint, so there
shouldn't be a deviation

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Waco · 2009-08-28 11:07

Regarding your remark, I did exactly the same in my previous topic and
you always helped me without saying anything, so I thought it's
alright  But I understand and I won't mix problems anymore.

1. OK, I thought so, but I wasn't sure.

2. I'll try to test the screen and calibrate it somehow, but lines are
fine, my only problem are angles, they just won't display correctly.
Anyway, it probably still is a screen issue.

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sasa · 2009-08-28 15:00

To draw on the screen canvas (for examply) you have to keep attention
on horizontal/vertical ratio of the screen resolution (200 dots height
are not the same as 200 dots width). The ratio you can calculate
retrieving information from API functions - X/Y dots per inch for
specific canvas (for screen/printer).

Also keep attention if monitor is 4:3, 16:9 or 16:10 and monitor
driver can handle the resolution correctly. For example, 800x600 on
16:10 monitor is quite unnatural if driver (or there is no buttion or
function on the monitor) cannot move the margin to emulate 800x600
screen width  correctly (4:3). That is actually about a user should
keep attention.

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Waco · 2009-08-29 11:31

Thanks for tips, I'll play with it some more.