Wish B4xPoint

[stevel05]

I quite often need to use a Point construct that holds 2 values. They are usually Doubles, but Floats would be fine if that's is more cross platform compatible.

I have used Types for this as needed, but end up with the same types in different libraries and then either have to go back and create a dependency and remove one of them, or rename one, or just use an array, which is quite an ugly solution.

It would be far better from a library perspective it there was a B4xPoint(X,Y) object in the XUI library along with B4xRect, which I am using more and more when dealing with Bounds etc. as well as drawing.

 

[William Lancee]

I have used Types and Classes for this object, but as you say there are annoyances in both approaches.
One could create a template that automatically adds a Point class to one's project.
I am thinking of doing that. For our 64bit machines, double is rarely slower that float.
So that would be my preference.

It would also be nice to have built-in functions.

Dim pt1 As Point
pt1.Initialize(2.67, 3.12)

Dim pt2 As Point
pt2.Initialize(2.67, 9.257)

pt1.X
pt1.Y
pt1.Copy
pt1.Add(pt2)
pt1.Subtract(pt2)
pt1.AddScalar(100.55)
pt1.MultScalar(100.55)
pt1.DistanceTo(pt2)
pt1.MidTo(pt2)
pt1.FractionTo(pt2, .75)

 

[William Lancee]

I did the template thing, and now it works much better for me. All my future projects will have automatic inclusion of my Point class.
But a XUI version would be more consistent with B4XRect.

 

[emexes]

I often just use an array, has the advantage that it can also represent a series of points eg path, polygon, rectangular area.

Dim TappedXY() As Float

Dim RectangleXYXY() As Float = Array As Float( _
    Button1.Left                , Button1.Top, _
    Button1.Left + Button1.Width, Button1.Top + Button1.Height _
)

Dim PathXY() As Float = Array As Float(X1, Y1, X2, Y2, X3, Y3, X4, Y4)

 

[emexes]

For our 64bit machines, double is rarely slower that float.

Even more rarely less than twice the size of float.

And for point references are screen-related, the extra 29 bits of precision doesn't do much other than exercise the silicon.

But I agree it would be useful if you have points that are close together in a coordinate system with origin far away, eg latitude/longitude outside of England.

 

[emexes]

or just use an array, which is quite an ugly solution.

Lol I just spotted this.

That seems a bit harsh.

Arrays are just trying to help. Personally, I quite like them, but maybe that's coming from a C-background where you can cast arrays into rows and step through an array using a pointer of a type composed of multiple single elements of the array.

eg the array looks like this in memory:

x, y, x, y, x, y, x, y, x, y

and it is easy to step through them in groups of (x, y)

 

[stevel05]

That seems a bit harsh.

Possibly, but to my mind, a simple Point structure that has little use for anything else would lead to zero confusion or thinking time when going back over old code.

 

[peacemaker]

Maybe better to make once just universal set:

Type B4X2Dpoint (x As Float, y As Float)
Type B4X3Dpoint (x As Float, y As Float, z As Float)
Type B4X4Dpoint (x As Float, y As Float, z As Float, t As Long)