Help Me for rotate ARC

Guys I need real help.
I’m writing a program to read a DXF file.
So far, so good …
Circle, ellipse, line, text, polyline all ok if not for the fact that the result, then the design that get results upside down on the horizontal side.
But this thing I was able to resolve it by detecting the maximum size of the drawing coordinates and then tilt axis values X.
The only thing however was not able to do (I have not studied trigonometry in school … when there was a lesson I walked through the door and ran away from the window) is to overturn a bow on the horizontal side.
for example if I have an arc with these coordinates: x = 195.90, y = 186.52, 12.95 radius 11:37 start angle and end angle 167.04 how do I make the calculations for precisely execute the tilting bow on the horizontal side?

Remember that start and end angle are in radians while you give degree angles, maybe you have to convert these

YESS Antonio …

Protected Function deg2rad(deg As Double) as Double
  Return (deg * PI / 180.0)
End Function

Simple use the startangle and angle in negative value (-) ;
And now is OK;

I also tried to load a polyline with about 100,000 vertices, I had to use inmemorydb because sqlite just to load 100,000 the procedure took 2 hours … with sqlite db few seconds.
Now I still have some entity to be developed as ‘Pline’ and other things.
… i’m ill …

The start angle (0) is at 3h15mn…


before another question, you may check the Object2D section of the Language Reference: you may find interesting informations there.

Using (Coding as in prototypes with) Object2D may also help you found solutions for your real project.

Sometimes ago, I would talk about wikipedia, but not since I searched (for an AppleScript prototype) how to code a MOD feature. There is an entry there, but so easy to understand that I took a nap and come back with a simple solution (beside using Xojo !).

Se ho capito bene quello che ti serve potrebbe esserti utile:

Pagina Rotazione_(matematica) su Wikipedia

I would say dear Emilie before you speak you have to know people.
I am disabled, are suffering from Systemic Lupus, I go back and forth from the hospital. my illness has also affected part of the brain cortex.
Now, I’m not stupid, nor deficient. But for me, something that seems simple to you, not at all.
For example, remember things in terms of short-term memory.
This morning I took a shower and after five minutes I made another because I forgot.
To resolve this issue with arches, I got help, I understand the concept now, you’ll probably have studied at the university, but I do not remember.
So maybe next time, before you make fun of someone, try to help him, maybe who really need it.


you were wrong, I do not do what you wrote. I tried to help.

There are two ways to DrawOval (for example):
a. Graphics.DrawOval
b. Object2D.OvalShape .

I assume you were using the standard (like Graphics.DrawOval) not the vectorial (Object2D.OvalShape).

I feel it is easier to make a testing window with some TextField (to hold the values) and a button to (draw the graphics).
Also, sometimes ago, I shared a tool - in this forum - that allows the drawing of ArcShapes… (I do not have the url handy): context sensitive, allows to change every properties and draw the result on screen (in the window).

I found the link to the folder (Object2D.xojo_binary_project):
ArcShape Demo
You can get an eye on the two screen shots (macOS and Windows XP) before downloading the zip file. A PopupWindow can appears after a click in the Download button. In that case, close that window, this is an advertising window sent by the web server (not me).

Now, I am sorry, as an autodidact, I follow the same path: I have to search - usually by my own - issue a real quest, sometimes, before been able to resolve my problems (and sometimes I fail).

I just checkd the project against Xojo 2017r1 (in demo mode) and it works.

However, I do not expose the values: you cannot type numbers for the rotate, start angle, etc.

BUT: you have the project and maybe find your way understand to it.

I shared it on 2014-08-21 on this forum.