HyperPics: Beyond the UI

What APIs and Developer Documentation are Available for AutoCAD?

There are a wide range of APIs (Application Programming Interfaces) that are available for creating custom applications in AutoCAD.  Which API is right for you depends greatly on your experience and the time you can commit to learning, but for many the first API that they are ever exposed to is AutoLISP because of its ease of use and the sheer number of programs that are available for download from the Internet.

AutoLISP allows you to channel your knowledge of AutoCAD commands, and begin to combine them in ways that you might have never thought possible or maybe you have and that is what kick started your interest in programming.  Where you go from there is often different for many.  Many simply learn AutoLISP and that is enough for them to improve the tasks that they perform on a daily basis. For others, AutoLISP is simply a stepping stone towards Managed .NET or even ObjectARX.

The available AutoCAD APIs are:

• AutoLISP
• ActiveX/COM
  • AutoCAD
  • Transmittal (eTransmit/Archive)
  • Sheet Set Object (Sheet Set Manager)
  • CAD Standards Plug-in (CAD Standards and Batch Standards Checker)
  • Connectivity Automation Object (dbConnect)
• JavaScript
• ObjectARX
• Managed .NET

The JavaScript API is the newest of all the AutoCAD APIs; it was introduced with AutoCAD 2014.

The documentation for all of the available AutoCAD APIs can be located under the AutoCAD Developer Center. Based on which API you want to work with, you might find that some of the documentation is available through the product's help, installed locally with the product, or available with the ObjectARX SDK.

Sincerely,
  Lee

Working with Raw Input from a User with AutoLISP

AutoLISP is one of the most used programming languages for creating custom AutoCAD applications. Many custom commands that are created with AutoLISP, request input from the user.  Input requests are commongly made with the GetXXX functions.  While these functions are great for getting basic input such as points, numbers, strings, and keywords; they are also limited as well.

The GetInt function while it limits the return value to an integer value, it allows the user to enter any character they want.  Once the user presses Enter or Space, the text entered is then validated to see if it is an integer.  The GetString function allows you to enter a text string, but does not provide a way to mask the characters as they are entered.

This is where the Grread function comes in; an often over looked function by many AutoLISP programmers. This function can be helpful in creating your own custom Get behavior as it works with keyboard, mouse, and digitizer input. For example, you could create functionality that only allows numbers to be entered or masks the text being entered for a password like feature.

Syntax for the Grread function is:

(grread [cursor_tracking] [input_filters [cursor_type]])

For information on the arguments and values that the Grread function supports, see GRREAD (AutoLISP) in the AutoCAD online help.

The following example code, allows the user to enter a numeric value and masks the entered text as it is displayed at the Command prompt. While it does not show all the possible error handling that is needed, it does show how you can prompt the user for input and then determine if the value supplied is what is desired.

(defun c:MyPINCode ( / number code ch)
  (setq number "")
  (prompt "\nEnter a whole number [backspace to clear]: ")
  (setq code (grread))

  (while (and (= 2 (car code))
              (and (/= 13 (cadr code))
                      (/= 32 (cadr code))))
    (if (and (>= (cadr code) 48)
                (<= (cadr code) 57))
      (progn
        (setq ch (chr (cadr code)))
        (setq number (strcat number ch))
        (princ "*")
      )
    )

    ;; Support backspace
    (if (= (cadr code) 8)
      (progn
        (repeat (strlen number)
          (princ (chr 8))
        )
        (setq number "")
      )
    )

    ;; Ask for more input if the user did not press Enter or Space
    (if (or (/= 13 (cadr code))(/= 32 (cadr code)))
      (setq code (grread))
    )
  )

  (prompt (strcat "\nPIN entered was: " number))
 (princ)
)

Once the code is loaded into AutoCAD, you will see the following prompt after the command MyPINCode is executed:

Enter a whole number [Backspace to clear]:

As you type values on the keyboard, only whole numbers 0 - 9 are accepted. Pressing keys such as 'A', 'c', or ';' are ignored by the program. When a valid number is entered, an asterick appears at the Command prompt in its place. Pressing Spacebar or Enter ends input and displays the entered value, while pressing Backspace clears all the numbers that the has user entered.

Example of input and return value at the Command prompt:

Enter a whole number [Backspace to clear]: *****
PIN entered was: 63537

Sincerely,
   Lee

CAD Management Documentation

CAD management does not mean the same to everyone, and the role it plays is different from company to company.  The same can be said about the CAD Manager title.  I personally, never held the title but performed many CAD management related tasks over the years.  Where I worked, the CAD Manager was the individual that managed the CAD drafters, but never actually customized, programmed, or installed software.  IT performed the installs and the senior drafters in each CAD department kind of did their own thing when it came to CAD standards.

Sound a bit familiar maybe? Maybe it doesn't.

After many years, two things always stood out around CAD management for me:

• What is CAD management and what things do I need to consider?
• How do I make the transition from my current release to the latest release as smooth as possible?

To help answer both questions, a set of documentation was created.  This documentation was added to the AutoCAD 2014 release and it covers:

• Basics of CAD management
• Customization and program compatibility
• What is new or changed in the product
• Where to find information on installing the product
• Much more...

The CAD Management documentation can be accessed from the AutoCAD 2014 help landing page.

If you have any comments on or additions you would like to see added to the CAD Management documentation, please post a comment on this posting.  Comments are not posted automatically on this blog.

Sincerely,
  Lee