PureBasic Forums - English

Restored from previous forum. Originally posted by tinman.

Hi, I was playing around with line drawing today, and was not having fun.

I have lines to draw and the data comes as co-ordinates for the start and end of a line. No problem, I thought, just do x2-x1 and y2-y1 to get the width and height and then correct them if they are negative.

Which works OK up to a point (pun intended . However, I also noticed that I needed to add 1 to get the line drawn up to the exact pixel position I want. For example, the line needs to go from 0,5 to 20,5 so I need to draw 21 pixels wide.

Again, it's not that simple, because vertically you do not want the height to have 1 added or the line goes at an angle incorrectly. And it gets even worse, because the component (width or height) which you need to add 1 to changes with the angle of your line.

(Implemented as 'LineXY()')

Anyway, this is the code I use for drawing lines now: And I'm still not sure if it handles all possibilities of line sizes. Of course, it would be much nicer to have this done inside PB's Line command


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It's not minimalist - I'm increasing efficiency by reducing input effort.

Restored from previous forum. Originally posted by PB.

[quote]
; Draw line here with stupid PB Line command syntax
w = x2 - x1 : h = y2 - y1
If w


PB - Registered PureBasic Coder

Restored from previous forum. Originally posted by tinman.

I haven't tried this, but I think you can change the above code to the following
single line, and lose the test for negative numbers. Give it a try... it may be
better for what you're doing?

w=Abs(x2-x1) : h=Abs(y2-y1)

No because I need to change the start co-ordinates if the width or height is negative, so using Abs does not give any advantage.

Oh, and the Line syntax isn't stupid; it's powerful. If it didn't have the
width and height properties, then trying to draw a line with a variable width
and height would be impossible. So it's a good thing that it uses them, and
when you need to use a start/end instead you just make a procedure, as you've
done.

The way the PB Line command works has no advantages over using a line command where you specify two co-ordinates, so it's not what I would call powerful. I don't know how you come up with drawing a line with variable width and height being impossible, because all you have to do is change the second co-ordinate (and given the way images are displayed on a computer, you are more likely to have or it is easier to get sets of co-ordinates rather than widths and heights of lines).



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It's not minimalist - I'm increasing efficiency by reducing input effort.

Restored from previous forum. Originally posted by PB.

The way the PB Line command works has no advantages over using a line command where you specify two co-ordinates, so it's not what I would call powerful. I don't know how you come up with drawing a line with variable width and height being impossible, because all you have to do is change the second co-ordinate

You're right... I wasn't thinking properly when I posted that. Sorry!


PB - Registered PureBasic Coder

Restored from previous forum. Originally posted by tinman.

don't know how you come up with drawing a line with variable width and height being impossible, because all you have to do is change the second co-ordinate

You're right... I wasn't thinking properly when I posted that. Sorry!

I guess you were thinking of the thickness of the line...now that would be a cool feature


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It's not minimalist - I'm increasing efficiency by reducing input effort.