These functions can be
used to make changes to the graphical screen. The graphical screen is
the drawing area of AutoCAD.
(grclear)
This function is used to
clean th active view port of the drawing area. The information is not
erased, but made invisible.
If the REDRAW command is
used, then the information is visible again.
(grdraw
<p1> <p2> <color> [<highlight>])
This function is used to
draw a line between the points p1 and p2. The points can be 2D points
and 3D points.
The color argument sets
the color of the line. If the color argument is -1, then the line is
drawn in the color in a complimentary color.
If another vector is drawn
over the same points with the color, then the complete line is made
invisible.
If the highlight argument
is present and unequal to zero, then the line is drawn in a
highlighted format.
(grtext
[<box> <text> [<higlight>])
With this function you can
write text to the screen menu of AutoCAD. I'm afraid screen menus are
no longer used. So forget it.
(grread
[<track>])
With this function you can
read input from devices such as keyboard, digitizer, mouse, etc. But
most of the time GET functions are used.
If a mouse is used, then
this is what could be given back by the GRREAD fucntion:
(3 (-13.9732 13.0249
0.000000))
The first element is the
the code of the device. These are the codes that are available:
2 Keyboard and the ASCII
code of the character.
3 Mouse. The point is put
in a list.
4 Screen menu cell with
the number of the cell.
5 A list of the point for
the drag mode. Only if the TRACK argument is unequal to nil.
6 Button number of the
mouse.
7 Selected item in TABLET
1 menu.
8 Selected item in TABLET
2 menu.
9 Selected item in TABLET
3 menu.
10 Selected item in TABLET
4 menu.
11 Selected item in AUX 1
menu.
12 Point of the mouse.
13 Selected screen menu
item.
(menucmd
<text>)
This is another function
that works with the screen menu. We are not using it. So you can
forget about it.
Exercise
Now we are going to create
an AutoLISP program, that draws circles and lines. The center points
of the circles are picked.
To create the AutoLISP
program the WHILE function is used. Here is the drawing that is
created. Four circles have been drawn. But more circles could be
drawn.
These functions can be
used to make changes to the graphical screen. The graphical screen is
the drawing area of AutoCAD.
(grclear)
This function is used to
clean th active view port of the drawing area. The information is not
erased, but made invisible.
If the REDRAW command is
used, then the information is visible again.
(grdraw
<p1> <p2> <color> [<highlight>])
This function is used to
draw a line between the points p1 and p2. The points can be 2D points
and 3D points.
The color argument sets
the color of the line. If the color argument is -1, then the line is
drawn in the color in a complimentary color.
If another vector is drawn
over the same points with the color, then the complete line is made
invisible.
If the highlight argument
is present and unequal to zero, then the line is drawn in a
highlighted format.
(grtext
[<box> <text> [<higlight>])
With this function you can
write text to the screen menu of AutoCAD. I'm afraid screen menus are
no longer used. So forget it.
(grread
[<track>])
With this function you can
read input from devices such as keyboard, digitizer, mouse, etc. But
most of the time GET functions are used.
If a mouse is used, then
this is what could be given back by the GRREAD fucntion:
(3 (-13.9732 13.0249
0.000000))
The first element is the
the code of the device. These are the codes that are available:
2 Keyboard and the ASCII
code of the character.
3 Mouse. The point is put
in a list.
4 Screen menu cell with
the number of the cell.
5 A list of the point for
the drag mode. Only if the TRACK argument is unequal to nil.
6 Button number of the
mouse.
7 Selected item in TABLET
1 menu.
8 Selected item in TABLET
2 menu.
9 Selected item in TABLET
3 menu.
10 Selected item in TABLET
4 menu.
11 Selected item in AUX 1
menu.
12 Point of the mouse.
13 Selected screen menu
item.
(menucmd
<text>)
This is another function
that works with the screen menu. We are not using it. So you can
forget about it.
Exercise
Now we are going to create
an AutoLISP program, that draws circles and lines. The center points
of the circles are picked.
To create the AutoLISP
program the WHILE function is used. Here is the drawing that is
created. Four circles have been drawn. But more circles could be
drawn.
Text
Screen Functions
Hari
Raya
Sorry. I could not add a
new post to my blog for two weeks. It was not my fault. It has to do
with Hari Raya.
I live in Malaysia. And
you find a lot of Muslims here. They celebrate Ramadan every year.
Ramadan is a month of fasting.
When Ramadan is over, then
we have Hari Raya. It lasts a couple of days, when everybody has a
national holiday.
But the majority of the
people take a holiday. And if they have a shop, they close it. Even
Chinese shops and Indian shops are closed.
I do my Internet in an
Internet cafe. And my Internet cafe was closed too. So I could not
add a new post to my blog.
Don't worry. I keep on
adding new posts to my blog. I didn't give up. I still have a lot
that I want to say.
Text
Screen Functions
In AutoLISP we have the
following functions that can be used for giving an AutoLISP program a
presentation. They are:
- Text screen functions
- Graphical screen
functions
- Text functions
- Conversion functions
Now we are going to talk
about the text screen functions. Later we are going to talk about the
other functions.
(graphscr)
(textscr)
You can switch from the
text screen to the graphic screen with the (graphscr) functions and
go to the text screen with the (textscr) function.
System
Variables
AutoCAD works with system
variables. You can check the value of a system variable with the
following function:
(getvar
<variabele name>)
Examples:
(getvar “dwgname”) TEST
(getvar “cmdecho”) 1
Some system variables are
read only. You cannot change their value. But if you can, you can
change the value with:
(setvar
<variable name> <value>)
Examples:
(setvar “filletrad”
200) 200
(setvar “cmdecho”
0) 0
It is advisable to set the
system variable to its original value after the value has been
changed. This is how it can be done:
(setq ce (getvar
“cmdecho”)
(setvar “cmdecho” 0)
(setvar “cmdecho” ce)
Printing
Data
(princ
<expression> [<file description>])
This function writes the
expression to the text screen and gives as a result the expression.
The expression can be a text or a number.
The file description
argument is optional and is used if the expression is written to an
external file. We will talk about it later.
Examples:
(setq a 123)
(setq b '(a))
(princ 'a) A
(princ a) 123
(princ b) (A)
(princ “Hello”) “Hello”
If the expression is a
text, then control codes can be added to it. The following control
codes are available.
\\ the \ character
\e escape
\n new line
\r return
\t tab
\nnn the character with
the octal code nnn
The PRINC function can
also be used without an argument. Then an empty string is written to
the screen. That is often at the end of a program.
Example:
(defun c:setng ()
(setvar “lunits” 4)
(setvar “blipmode” 0)
(princ)
)
After the AutoLISP program
has been loaded into AutoCAD it is started by typing its name at the
command prompt.
At the end of the AutoLISP
program the command prompt is shown again without any additional
information. There is no 0.
(prin1
<expression> [<file description>])
This function is the same
as the previous function, but control codes are not evaluated.
Examples:
(setq a 123)
(setq b '(a))
(princ 'a) A
(princ a) 123
(princ b) (A)
(princ “Hello”) “Hello”
(print <expression>
<file description>)
This function is the same
as the previous function. But the expression is print on a new line
and after the expression is a tab.
(prompt
<text>)
Now you can only print a
text to the text screen. The function prints the text and gives back
nil.
Example:
(prompt “New
value”) New value
Exercise
For this exercisxe the
REPEAT function is used. Write an AutoLISP program, that draws five
circles with the number of the circle in it.
This is the drawing that
is created by the AutoLISP program.
