kicad-developers team mailing list archive

[Vladimir Uryvaev <vovanius@xxxxx>]

As I see, there's no more (or very little) activity on this task.

I developed the approach on how to convert KiCAD to metric unit. This approach 
is fully based on OOP.

There are several stages on converting:

1. Preparation:

Create class of length:

class LENGTH {
    int m_Units; // internal representstion
    ...

There's would be no direct casts between any regular numeric types, and code 
like:

LENGTH aLength = 50;

or

int value = aLength;

would cause an error. Any conversion then should be made explicit:

LENGTH aLength = 50 * mil;

int value = x / mil

'mil' is predefined constant of length 1 mil which is then scaled or used as 
reference, other constants, like 'millimeter' are follow. Actually they may be 
static methods of LENGTH and actually invoked as LENGTH::mil();

Also classes for 2D point (say LENGTH_XY) and other convenient classes could 
be written.

2. Converting data storage:

Find all the vital classes where length data are stored. They would be classes 
for graphic primitives, PINs etc.

Change type for the data to the brand new classes. Then find all access points 
for such data and insert data conversion code to/from legacy types.

E.G.
int m_Radius; - would become => LENGTH m_Radius;
m_Radius = x => m_Radius = LENGTH::mil * x
x = m_Radius => x = m_Radius / LENGTH::mil
(mil is for example, would change it to the actual units involved)

3. Convert data processing
There would be iterative process on arithmetic, like

m_Radius / LENGTH::mil * 2 => m_Radius * 2 / LENGTH::mil

4. Cleaning up
We would end up with dummy coversion pairs, like

x = (y / LENGTH::mil) * LENGTH::mil;

So they need to be removed.

This approach when implemeted carefully would not break an application in any 
stage, so there no need to make any fork or delay development in any other 
manner. So I am ready to begin.

Let me know if I missed something, or if there's need to coordinate the work. 
I would also like to know if someone is done something on this task so I would 
coordinate with.

I saw Brian Bidulock started doing conversion but his branch seem to be 
abandoned.

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