[Art_beyond_sight_theory_and_research] Drawing program for visually impaired
Lisa Yayla
fnugg at online.no
Mon Sep 19 02:15:46 UTC 2011
Forwarding very interesting news about a drawing tool for the visually
impaired created by Richard Baldwin, Professor of Computer Information
Technology Austin Community College.
This message is intended mainly for teachers of blind or visually
impaired students in STEM courses. Of course, this is a public forum and
everyone is welcome to read the message and provide comments as
appropriate.
Having been the sighted teacher of a blind student for several years, I
firmly believe that making it possible for blind and visually impaired
people, and particularly blind and visually impaired students in STEM
courses, to communicate using accurate printed and tactile graphics will
improve the quality of life and the likelihood of academic success for
those students.
I have written a computer program that makes it possible, for the first
time in history, for blind and visually impaired people to create such
graphics in an accessible and user-friendly way.
Version 0.0.8 of my drawing program for blind students is now posted and
available for free and immediate download at:
http://www.austincc.edu/baldwin/SWT-SVG/SVGDraw01.zip
Three components are necessary to accomplish the goal of widespread
graphics communication among blind and visually impaired students and
their teachers:
* Availability of a robust and universally accepted graphics standard.
* Availability of a robust, accessible, and user-friendly drawing
program that allows blind people to take advantage of the SVG
standard.
* Availability of high-quality, economical, and readily available
graphics embossing equipment.
A robust graphics standard - SVG
A robust and universally accepted graphics standard is already available
in the form of Scalable Vector Graphics (SVG). See Scalable Vector
Graphics (SVG) 1.1 (Second Edition) <http://www.w3.org/TR/SVG/>
An accessible and user-friendly drawing program - SVGDraw01
I have written and provided, free of charge, a drawing program that
blind and visually impaired people can use to draw pictures. To the best
of my knowledge, no other existing program provides that capability. (If
such a program exists, it is a well-kept secret.) Thus, for the first
time in history, your students can express themselves using graphics.
While many drawing programs exist, they are written for use by sighted
people and not for use by blind people. My program is designed and
written specifically for use by blind and visually impaired people.
Even though my program is still under development, it already provides
the capability for STEM students to create graphics that mirror many of
the figures and diagrams typically found in STEM textbooks.
A graph board on steroids
As a teacher of blind or visually impaired students, you might think of
this program as bringing the old-fashioned graph board into the computer
age. Students and others using this program can create both printed and
tactile graphics using many of the same thought processes that they
would use when constructing a "drawing" on a graph board using pushpins,
rubber bands, a protractor, and a measuring stick.
For example, one student might use this program to create and send an
SVG file to a friend with the message "Take a look at the cool floor
plan of my new apartment."
Another student might use this program to create and send an SVG file to
a college professor with the message "This is a free body diagram
showing the magnitude and directions of forces F21 and F23 caused by the
interactions among charges q1, q2, and q3."
Getting an immediate visual output
I will be adding new capabilities over time. However, I probably won't
add capabilities that would not be useful to blind and visually impaired
users. For example, the program does not, by default, produce an
immediate visual output. The primary output is intended to be a printer,
a graphics embosser, or both. But, if you are sighted, or if you are
blind and using the vOICe sonification software to view the progress of
your drawing, you can use a procedure described in the attached file to
view your drawing as it progresses.
High-quality, economical, and readily-available graphics embossing
equipment
This is the area where we fall short relative to achieving our
widespread graphics communications goal. Although high-quality embossing
equipment is available in the marketplace, it is not economical (by
computer standards) nor is it readily available for the personal use of
most blind students.
I view this as a supply and demand problem. Prior to the release of my
program, there were no robust, accessible, and user-friendly tools that
made it possible for blind people to create accurate graphics for use
with a high-quality embosser. Thus, the demand for such embossing
equipment has been very limited. My hope is that by making it possible
for all blind people to create accurate graphics, the demand for such
embossing equipment will go up and the costs for the equipment will come
down.
Even today, however, many schools, colleges, and other organizations own
high-quality graphics embossing equipment that they can make available
to their blind and visually impaired clientele on some basis. In those
cases, there is no reason for blind people to hold back from learning to
communicate using graphics.
My drawing program is freely available for you and your students to use.
As a teacher, it is up to you to connect your blind and visually
impaired students to those available hardware embossing resources.
The attached HTML file is the User-Instruction file for my drawing
program named SVGDraw01.
Please feel free to forward this message to others who may have an
interest in the use of graphics by blind and visually impaired people.
Richard Baldwin
Professor of Computer Information Technology
Austin Community College
baldwin at austincc.edu <mailto:baldwin at austincc.edu>
http://www.austincc.edu/baldwin/
Instructions.htm
Brief instructions for using the program named SVGDraw01
Updated 09/17/11
At any time, you can tab down to the button labeled "Press this button
to return to the Action List," and use that button to abandon this
Instructional document and return to the Action List. Do not press the
Esc key.
Index
* Purpose
o A robust graphics standard - SVG
o An accessible and user-friendly drawing program SVGDraw01
o High-quality, economical, and readily-available graphics
embossing equipment
* A note about drawing orientation
* Program startup
* General user instructions
o Selecting actions from the Action List
o Performing the action
o Pressing the Esc key
o Text field objects
o Checkbox objects
o Button objects
o Message box objects
o Polylines, polygons, and paths
o The name and path of the output file
o Rotation, translation, and scaling
o A note about page size
* Action items
o User instructions
o Open existing drawing
o Start a new drawing
o Draw a line
o Draw a rectangle
o Draw a circle
o Draw an ellipse
o Draw a polyline, a polygon, or a path
+ A csv file
+ A path file
+ Sample files
o Draw line of text
o Rotate shapes
o Translate shapes
o Scale shapes
o Delete shapes
o Stop program
o Write drawing file
* Please provide feedback
Purpose
Select A note about drawing orientation to skip this section and go
directly to the next major section.
I firmly believe that making it possible for blind and visually impaired
people, and particularly blind and visually impaired students in
Science, Technology, Engineering, and Mathematics (STEM) to communicate
using accurate printed and tactile graphics will improve the quality of
life for those people. The purpose of this program is to make it
possible for blind and visually impaired people to create such graphics
in an accessible and user-friendly way.
Three components are necessary to accomplish that goal:
* Availability of a robust and universally accepted graphics standard.
* Availability of an accessible and user-friendly drawing program
that allows blind people to take advantage of that standard.
* Availability of high-quality, economical, and readily available
graphics embossing equipment.
A robust graphics standard - SVG
A robust and universally accepted graphics standard is already available
in the form of Scalable Vector Graphics (SVG). See Scalable Vector
Graphics (SVG) 1.1 (Second Edition) <http://www.w3.org/TR/SVG/>
An accessible and user-friendly drawing program - SVGDraw01
This program is my attempt to provide, free of charge, a drawing program
that makes it possible for blind and visually impaired people to take
advantage of many of the capabilities of SVG. Even though the program is
still under development, it already makes it possible for STEM students
to create graphics that mirror many of the figures and diagrams
typically found in STEM textbooks.
A graph board on steroids
One might think of this program as bringing the old-fashioned graph
board that uses pushpins and rubber bands to convey graphic information
into the computer age. Students and others using this program can create
both printed and tactile graphics using much the same thought processes
that they would use when constructing a "drawing" on a graph board using
pushpins, rubber bands, a protractor, and a measuring stick.
For example, one person might use this program to create and send an SVG
file to a friend with the message "Take a look at the cool floor plan of
my new apartment."
Another person might use this program to create and send an SVG file to
a college professor with the message "This is a free body diagram
showing the magnitude and directions of forces F21 and F23 caused by the
interactions among charges q1, q2, and q3."
Getting an immediate visual output
I will be adding new capabilities over time. However, I probably won't
add capabilities that would not be useful to blind users. For example,
the program does not, by default, produce a visual output. But, if you
are sighted, or if you are a blind user using the vOICe sonification
software to view the progress of your drawing, you can use the following
procedure to create a visual output.
Start the program and select the following two actions in sequence in
the Action List:
1. "Start a new drawing"
2. "Write drawing file"
Provide the requested information for both actions including the path
and file name for the output SVG file.
Then open the output SVG file in Firefox or IE9 (earlier versions of IE
won't work) . You should see an empty drawing in the browser window.
Return to the Action List and start drawing shapes. Each time you want
to see an updated drawing, select and process "Write drawing file" and
then refresh your browser. Your updated drawing should appear in the
browser window. You should be able to continue adding shapes and viewing
them so long as you don't select "Open existing drawing" or "Start a new
drawing."
High-quality, economical, and readily-available graphics embossing
equipment
This is the area where we fall short relative to achieving the
communications goal. Although high-quality embossing equipment is
available, it is neither economical nor readily available for the
majority of blind people.
I view this as something of a supply and demand problem. Prior to the
release of the developmental versions of this program, to the best of my
knowledge, there have been no readily-available tools that make it
possible for blind people to create accurate graphics for use with a
high-quality embosser. Thus, the demand for such equipment has been very
limited. My hope is that by making it possible for all blind people to
create accurate graphics, the demand for such equipment will go up and
the costs for the equipment will come down.
Even today, however, many schools, colleges, and other organizations own
high-quality graphics embossing equipment that they can make available
to their clientele on some basis. In those cases, there is no reason for
blind people to hold back from learning to communicate using accurate
graphics.
A note about drawing orientation
In most STEM courses , you typically learn to draw graphs and other
diagrams with the 0,0 origin in the lower-left corner of the drawing.
Positive values along the y-axis go up the page and positive values
along the x-axis go to the right.
Unfortunately, in SVG, and most other computer graphics programming
systems, the situation is reversed insofar as the y-axis is concerned.
In SVG, and in this program as well, the 0,0 origin is at the top-left
corner of the drawing and positive values along the y-axis go down the page.
This not only has an impact on the physical locations of shape objects
in your drawings, it also has an impact on the orientation of those
objects. for example, this causes the reference corner for a rectangle
to be the upper-left corner. It causes the location of the y-coordinate
values for all shapes to be measured down from the top of the drawing
instead of up from the bottom of the drawing.
Note, however, that it does not change the fact that the reference
location for a line of text is at the lower-left corner of the first
character in the line.
At some point, I may attempt to correct this issue arithmetically. In
the meantime, however, you will simply need to get used to an
upside-down coordinate system, and unfortunately, you may need to refer
your teacher or professor to this section in this document.
Program startup
When the program starts, you will land in an Action List that provides
the following actions:
* User instructions - opens this HTML file containing instructions
in a browser window.
* Open existing drawing - opens a drawing file that was previously
created and saved using SVGDraw01.
* Start a new drawing - starts fresh and creates a new drawing.
* Draw a line - draw a straight line segment between two specified
points.
* Draw a rectangle - draw a rectangle at a specified location with a
specified width and height.
* Draw a circle - draw a circle at a specified location with a
specified radius.
* Draw an ellipse - draw an ellipse at a specified location with
specified width and height.
* Draw a polyline, a polygon, or a path - draw a polyline, a
polygon, or a path based on csv data or path data that is imported
into the program.
* Draw a line of text - draw a line of text at a specified location
with a specified point size and other parameters as well.
* Rotate shapes - rotate any one or more shapes by a specified angle
in degrees clockwise around a specified center of rotation. See
Rotation, translation, and scaling below for cautions regarding
the use of this action.
* Translate shapes - translate any one or more shapes by a specified
distance along both the x-axis and the y-axis. See Rotation,
translation, and scaling below.
* Scale shapes - Multiply the coordinate values that make up one or
more shapes by a scale factor to enlarge or shrink the shape. See
Rotation, translation, and scaling below.
* Delete shapes - delete one or more shapes from the current drawing.
* Stop program - just what it says. Be sure to write your drawing
into an output file before selecting this action.
* Write drawing file - write the current drawing into an SVG file.
The first action that you select should be "User Instructions", "Open
existing drawing", or "Start a new drawing." You should always select
either "Open existing drawing" or "Start a new drawing" and provide the
requested information before selecting any of the actions below those
two with the possible exception of the action titled "Stop program."
General user instructions
If you are reading this document from inside the program, you must have
already opened this HTML document in an SWT browser widget. If so, keep
reading.
On the other hand, you may also have opened this document in a standard
browser without running the program named SVGDraw01. If so, keep reading.
Selecting actions from the Action List
With the exception of the action named "Stop program", when you select
an item in the Action List and press the Enter key, an action page will
open containing labels, text fields, check boxes, radio buttons, push
buttons, and other Graphical User Input (GUI) objects. That action page
will enable you to provide the information needed and to perform the
steps necessary to execute that action.
Navigate down through those GUI objects with the tab key. Navigate up
through the objects with the shift-tab key combination.
Navigate through radio buttons and the items in lists using the arrow
keys. Press the tab key to escape from a set of radio buttons or from a
list without making a selection.
Performing the action
With the exception of the action labeled "Stop the program," there is a
button on each Action Page that you must press to cause the action to be
performed. If you tab past that button and return to the Action List,
the selected action will not have been performed.
Pressing the Esc key
If you press the Esc key when any read/write object on any page has the
focus, the current action will be abandoned and focus will return to the
Action List where you can select another action.
This html viewer is a read-only object and does not behave well if you
press the Esc key. If you do accidentally press the Esc key while
reading this document, use the tab key to work your way back to the
Action List.
A few of the other objects are read-only objects and do not respond at
all to the Esc key. They only respond to the tab key.
Text field objects
Press the tab key to accept the default value in a text field. To change
the value in the field, type the new value and press the tab key.
Normally, it should not be necessary for you to delete the current
contents of a text field in order to change it. However, you may find
situations where it is necessary for you to delete the current contents
so be on the lookout for those situations.
Checkbox objects
You must press the space bar to check or uncheck a check box. (The Enter
key won't do the job.)
Button objects
You can press either the space bar or the Enter key to activate a button
when it has the focus.
Message box objects
A message box will appear to announce the completion of those actions
where completion is not obvious such as writing the output file, for
example.
Most errors will also result in the appearance of a message box. In most
cases, you can press either the space bar or the Enter key to dismiss a
message box. However, in some cases you must select one of two buttons
labeled Yes and No.
If you discover errors that do not result in a message box, please let
me know.
Polylines, polygons, and paths
The polyline, the polygon, and the path are by far the most versatile
shapes that you can draw with this program. For example, if you need to
plot a function such as y = x^2, the polyline shape or the path shape
are probably your best choices.
I will explain how to draw these three types of shapes in more detail later.
The name and path of the output file
When you select "Write Drawing File" in the Action List, you will be
prompted to enter a file name for the output file. If you are running
the program from an executable jar file, you should provide both a path
and a file name, or you probably won't be able to find your output file
on your disk.
Rotation, translation, and scaling
These three features, which fall in the general category of SVG
transforms, are relatively easy to use as long as you don't combine them
on a single shape. However, once you combine them, the topic of SVG
transforms becomes an advanced topic and will probably require outside
study on your part for proper use.
Among other things, when you apply a combination of rotation,
translation, and/or scaling transforms, the order in which you perform
the operations is critically important to the outcome. A good
understanding of the use of transforms in SVG is needed in order to
understand those outcomes.
A note about page size
Your printer is probably not capable of printing from the extreme left
edge to the extreme right edge, or from the extreme top edge to the
extreme bottom edge of the largest paper size that it is advertised to
accommodate. For example my HP Deskjet 6940 printer advertises
"Borderless Printing up to 8.5 x 24 in." However, the largest rectangle
that it will actually print is 8.14 x 10.63 inches on a sheet of paper
that is 8.5 inches wide and 11 inches high. Therefore, you should
probably allow for some loss of print width and print height on the
right side and the bottom of the page.
If you plan to emboss your drawing on a tactile graphics embosser, you
may also need to purposely leave a margin on both sides of your drawing
to accommodate the width of the mechanical embossing mechanism. Check
the specifications of the embosser that you plan to use to determine
what those margins need to be..
Action items
As mentioned earlier, when you first start the program you will land in
an Action List that allows you to select and perform any one of more
than one dozen different drawing actions. I will discuss each of those
actions in this section so that you will know what to expect when you
select one of them.
User instructions
If you select "User instructions" in the Action List and press the Enter
key, you will land on a page containing a button labeled "Press this
button to open instructions in a browser." When you press that button,
this HTML document will open in a separate browser window. Note that the
browser window is an SWT Widget, and may appear to be different in some
respects from your standard browser. However, you should be able to
navigate and read the document just like you would read any other HTML
document in a browser window.
When you get to the end of the document, pressing the tab key will land
you on a button labeled "Press this button to return to the Action
List." As the name implies, pressing the button will cause the browser
window to close and focus will return to the Action List where you can
make another selection.
Almost every page has an "Action" button near the end. If you simply tab
past that button and don't press it, focus will return to the Action
List and the action will not be performed
Open existing drawing
Selecting this Action and pressing the Enter key will land you on a page
from which you can open a previously-saved drawing file that was created
using this program.
(SVG drawing files created using other program may or may not work, so
don't be surprised if you open a drawing file that was created using a
different program and you experience errors.)
Be aware that any work that you may have been doing on a new drawing
will be lost unless you save that work by selecting Write drawing file
before executing this action.
The Action page for this Action is relatively simple. You will be
presented with a text field and asked to "Enter name and path of drawing
file to open." The existing drawing will have an extension of .svg. Once
you have entered the requested information, press the tab key and you
will land on a button labeled "Press to open drawing file."
Pressing that button will cause a Message Box to pop up containing
information about the search for the existing drawing file. Press the OK
button on that Message Box and the search will begin. You may have to be
very patient at this point. Sometimes it takes a quite a while on my
computer for the program to find and open the existing drawing file.
If the file is not found, a Message Box will pop up with that
information. Press OK to dismiss the Message Box and focus will return
to the Action List.
If the file is found and opened, a Message Box will pop up with that
information as well. When you press the OK button on that Message Box,
focus will return to the Action List.
Start a new drawing
Select this action to start a new drawing. When you select this action
and press the Enter key, you will land on a page from which you can
provide the information required for a new drawing.
The first two text fields allow you to enter a title and a description
for your new drawing. If you simply tab past those two fields, a default
title and a default description will be recorded for your new drawing.
You will be asked to enter the width and height in inches of your new
drawing in the next two text fields. If you simply tab past those two
fields, default values will be assigned for width and height.
A very important point
This is where I need to explain a very important point. You specify the
width and height of your new drawing in inches, such as 8.5 inches and
11 inches. However, just enter the numbers. Don't enter the units. The
units of inches are understood by the program.
After you establish the width and height of your new drawing in inches
by executing this action, you will be asked later to provide coordinate
and/or dimensional information for many other actions. In those cases,
you will provide the information in units of 0.01 inch, or 100 units per
inch. For example, if you later decide to draw a rectangle that is 8.5
inches wide and 11 inches high, you will specify the width as 850 and
you will specify the height as 1100.
The Action button
Like most other Action pages, this page has an Action button near the
end that is labeled "Press to start drawing." When you press that
button, a Message Box will pop up to acknowledge that the new drawing is
started. Pressing the OK button on the Message Box will return the focus
to the Action List.
Draw a line
Selecting this action and pressing the Enter key will land you on a page
from which you can draw a line segment between any two points in your
drawing.
The title and description fields
On this page, as on may other pages, the first two fields allow you to
enter a title and description for the line object. If you tab through
these two fields, a default title and a default description will be
assigned to the object. Because this is essentially the same on all
pages, I won't mention it with respect to Action pages that I discuss in
the remaining sections of this document.
Coordinate-value fields
You will be asked to enter the x and y coordinate values for one end of
the line in the next two fields. As usual, the fields already contain
default values that you can accept by simply tabbing through the fields.
You will then be asked to enter the x and y coordinate values for the
other end of the line in the next two fields.
Stroke width and opacity
You will be asked to enter the stroke width and opacity in the next two
fields. You will encounter these same two fields on many action pages
and the meaning will always be the same. Therefore, I will explain the
meaning here and then ignore it for the remainder of this document.
The stroke width
The stroke width is the width or thickness of the line that will be
drawn. If you are planning to emboss the drawing, the stroke width
should probably be at least as wide as the distance between two dots on
the embosser. If the embosser supports 20 dots per inch, the stroke
width should probably be at least 5, which represents 0.05 inch or the
distance between the dots on a 20 dot per inch embosser.
If the embosser supports 16 dots per inch, the stroke width should
probably be at least 6.25, which represents 0.0625 inch or the distance
between the dots at 16 dots per inch.
You may find that those values aren't sufficient to provide high-quality
embossing and you may may need to make the stroke width even wider than
the values suggested above.
The opacity
If we were talking about color, opacity would be a complicated topic.
However, since we are only talking about white, black, and gray, the
concept of opacity is fairly simple.
You will be asked to enter a value between 0 and 1 for the stroke
opacity. The line will be drawn pure black for a value of 1.
The line will essentially not be drawn and therefore will be invisible
for a value of 0.
The line will be drawn with a shade of gray that is half way between
between white and black for a value of 0.5.
The greater the opacity value, the darker will be the line. The smaller
the opacity value, the lighter will be the line.
On an embosser with variable dot height, a value of 1 will produce dots
with the maximum height. For lower stroke opacity values, the height of
the dots will be lower.
(Also see The fill checkbox and fill opacity later.)
Draw a rectangle
Selecting this action and pressing the Enter key will land you on a page
from which you can draw a rectangle whose sides are parallel to the
horizontal and vertical axes. If you need a rectangle whose sides are
not parallel to the horizontal and vertical axes, you can draw it with
this action and then rotate it later or draw it as a polygon or as a path.
Using this action, you specify the x and y coordinates of the upper-left
corner of the rectangle and the width and the height of the rectangle.
As before, you also specify the stroke width and the stroke opacity.
The fill checkbox and fill opacity
This action, along with several of the other actions to be discussed
later, introduces a new parameter - fill. I will explain it here and
then ignore it when discussing actions in subsequent sections.
Because this is a closed geometric shape, you can cause it to be filled
with a color ranging from black through gray to white.
Before you reach the action button while navigating down this action
page, you will come to a checkbox labeled "Check this box for black
fill." You can check (and uncheck) the box by pressing the space bar
while the checkbox has the focus.
If you check the box, a new text field will be exposed between the
checkbox and the action button. You will be asked to "Enter value
between 0 and 1 for fill opacity." Opacity has the same meaning here
that it has for stroke opacity discussed earlier, except that this time
it doesn't simply apply to a line. Rather, it applies to an entire area
defined by a line.
A word of caution is in order here. I have been told that if you plan to
emboss your graphic using an embosser with variable dot height, you
should avoid filling large areas with large opacity values. I have been
told that this can cause undesirable paper buckling when the embosser
attempts to emboss a large area with high dots. It was suggested that
low opacity values should be used when filling.
The Action button for the rectangle
Finally, you will come to an action button labeled "Press to draw
rectangle." As usual, pressing the button will cause the rectangle
object to become a part of your drawing and focus will return to the
Action List.
Draw a circle
Selecting this action and pressing the Enter key will land you on a page
from which you can draw a circle at a given location with a given radius.
You won't find anything new on this page. You will be asked to enter the
x and y coordinates for the circle along with the radius of the circle.
Draw an ellipse
Selecting this action and pressing the Enter key will land you on a page
from which you can draw an ellipse at a given location with a given
radius along the horizontal axis and a different radius along the
vertical axis. As with the rectangle, you may need to rotate the shape
later if the default orientation is not what you need.
In case you aren't familiar with this shape, an ellipse is like a
squashed circle. It is a smooth closed shape, but its radius may be
larger along one axis than it is along the other axis.
Once again, you won't find anything new on this action page. This page
is much like the page for drawing a circle except that on this page, you
will be asked to provide both a horizontal radius and a vertical radius.
If you enter the same value for both of the radii, you will end up with
a circle.
Draw a polyline, a polygon, or a path
Selecting this action and pressing the Enter key will land you on a page
from which you can draw a polyline, a polygon, or a path.
Polyline and polygon
For either a polyline or a polygon, you provide the x and y coordinate
values for a set of points. (I will provide and example later.) The
points are connected by straight line segments in the order that you
define the points. The only difference between the two is that when you
draw a polygon, the last point is automatically connected to the first
point creating a closed shape.
A path
A path is a different kind of animal altogether. It can be used to draw
something as simple as a straight line segment, and can also be used to
draw something as complex as a cubic Bezier curve or an elliptical arc.
To use this feature of the program, you will probably need to first
study SVG paths. The best material that I have found on the topic is a
tutorial located at https://developer.mozilla.org/en/SVG/Tutorial/Paths.
Hopefully, it will be sufficiently accessible that you can read it.
To draw a path, you provide a string of characters consisting of both
SVG path commands and coordinate information. I will provide an example
later.
The action page
The action page for this action is relatively straightforward. The first
new thing on the page is a set of three radio buttons by which you
specify that you want to draw one of the following three shapes:
* Polyline
* Polygon
* Path
Then you are asked to provide the name and path of a file to import that
contains the information from which the shape will be drawn. When you
enter that information and press the tab key, you land on a button
labeled "Press this button to import data file."
If you selected either the Polyline or the Polygon radio button, you
will need to provide a csv file containing the data. This file must have
an extension of .csv or it will be rejected.
If you selected the Path radio button, you will need to provide a path
file containing the data. This file must have an extension of .pth or it
will be rejected.
A csv file
A csv file is a simple text file containing x,y coordinate value pairs
with no spaces and with each value followed by a comma. You can put one
or more values on each line so long as you are careful to follow each
value with a comma. You can omit the comma at the end of the line if you
wish. As mentioned above, the file must have an extension of .csv or it
will be rejected.
Here are the contents of a simple csv file that can be used to draw
either a polyline or a polygon
200,200
600,200
400,400
If you were to use this data to draw a polyline, the program would draw
two sides of a triangle. If you were to use it to draw a polygon, the
program would draw all three sides of the same triangle.
A path file
A path file contains the actual SVG code for the path that you want to
draw. For example, a file containing the following characters will cause
a cubic Bezier curve to be drawn:
M130 110 C 120 140, 180 140, 170 110
You will find an explanation of this SVG code in the section on Bezier
curves at https://developer.mozilla.org/en/SVG/Tutorial/Paths.
Sample files
The executable jar file containing this program contains some sample csv
files and some sample path files in a folder named Samples. You can
extract those files using a program like WinZip and use them to
experiment with the data import feature for drawing polylines, polygons,
and paths.
Many programs, including Microsoft Excel, produce csv files as a
standard output. You can also create your own csv files using a text editor.
I have never seen a program that produces path files as a standard
output format. Therefore, if you use them, you will probably need to
create them using a text editor. Although that may sound like a daunting
task, you may find it worth your while because you can squeeze a lot of
graphic information into a path file once you understand SVG paths.
For example, assume that you frequently need to draw curves in a
Cartesian coordinate system with an x-axis, a y-axis, and tic marks
along each axis, or maybe you need to draw grid lines instead of tic
marks. You could create a path file for that basic structure. Then
whenever you need to draw a graph, you could begin by importing the path
file for the axes and then draw your data points within those axes.
Draw line of text
Selecting this action and pressing the Enter key will land you on a page
from which you can draw a single line of text at a given location with a
given font face (such as Arial) and a given point size. You have three
choices for the font style (normal, italic, or oblique). You also have
four choices for the font weight (normal, bold, bolder, or lighter).
If you have worked through the discussions of the action pages in the
previous sections of this document, you shouldn't find anything new on
this action page.
The starting x and y coordinate values specify the location of the
lower-left corner of a rectangle that fully encloses the first character
in the line of text.
A point size of 72 will probably produce an upper-case "T" that is
approximately one-half inch from top to bottom on your printer. Other
point sizes produce text that is proportionally larger or smaller.
Rotate shapes
The first few actions in the Action List discussed earlier deal with
getting instructions and either starting a new drawing or opening an
existing drawing. After that, the next several actions in the Action
List, which were also discussed earlier, deal with drawing specific
shapes such as lines, rectangles, circles, paths, etc.
Beginning with this section, the next several actions in the Action List
deal with actions that you can perform on shapes that you have already
drawn. The first of these actions is the "Rotate shapes" action.
Selecting the "Rotate shapes" action and pressing the Enter key will
land you on a page from which you can select one or more existing shapes
and cause them to be rotated about a specific point by a specific angle
in degrees clockwise. (Negative angles rotate counter-clockwise.)
The action page
The action page for this action is relatively straightforward. First you
press a button labeled "Press to get list of shapes in your drawing" to
populate a physical list with identifying information about each shape
that you have thus far created in your drawing. You can navigate up and
down that list using the arrow keys.
Each shape in the list is identified as follows:
Title {Description} [Unique identifier]
The first two items in the identifying information are the title and
description that you assigned to the shape when you created it, or a
default title and description if you didn't enter a title or description.
The third item is a unique identifier that was created by the program
when the shape was created. This identifier can be used to differentiate
among different shapes having the same titles and descriptions.
Embedded instructions
Instructions are embedded among the GUI components on many of the action
pages. On this page, after you press the button to populate the list,
you will see the following instructions:
/"When you press the tab key, you will land in a Combo List Box
containing one item for each shape in your drawing. You can mark a shape
for rotation by selecting the shape using the arrow keys and then
pressing the 'r' key. Press the tab key to move out of the Combo List Box."/
After using the arrow keys and the 'r' key to mark all of the shapes
that you want to rotate around a common point, you can press the tab
key, enter the coordinates of the common rotation point, and enter the
rotation angle in degrees clockwise.
Finally, you can press a button labeled "Press to rotate shapes" to
cause the rotation to be performed. This is the point where your drawing
is actually modified. If you tab past this button and return the focus
to the Action List, your drawing will not have been modified.
Before using the rotation feature, you should read the cautions in the
Rotation, translation, and scaling section.
Translate shapes
Selecting the "Translate shapes" action and pressing the Enter key will
land you on a page from which you can select one or more existing shapes
and cause them to be translated (moved) by specific distances along the
horizontal and vertical axes.
The procedure for performing this action is essentially the same as the
procedure for rotating shapes. The differences are:
* In this case, you specify translation distances instead of the
rotation point and rotation angle required by rotation.
* In this case, you mark the shapes that are to be translated using
the 't' key instead of the 'r' key.
If you understand how to rotate shapes, you should have no problem using
this action to translate shapes.
Once again, however, before using the translation feature, you should
read the cautions in the Rotation, translation, and scaling section.
Scale shapes
Selecting the "Scale shapes" action and pressing the Enter key will land
you on a page from which you can select one or more existing shapes and
cause them to be scaled (made larger or smaller) by applying specific
multiplicative scale factors along the horizontal and vertical axes.
The procedure for performing this action is essentially the same as the
procedure for rotating shapes. The differences are:
* In this case, you specify multiplicative scale factors instead of
the rotation point and rotation angle required by rotation.
* In this case, you mark the shapes that are to be scaled using the
's' key instead of the 'r' key.
If you understand how to rotate shapes, you should have no problem using
this action to scale shapes.
Before using the scaling feature, you should read the cautions in the
Rotation, translation, and scaling section.
Delete shapes
Selecting the "Delete shapes" action and pressing the Enter key will
land you on a page from which you can select one or more existing shapes
and cause them to be deleted from your drawing.
The procedure for deleting shapes is similar to but simpler than the
procedure for rotating shapes. The differences are:
* In this case, there are no coordinate values to be provided.
Instead, you simply mark the shapes that are to be deleted and
press the button labeled "Press to delete shapes."
* In this case, you mark the shapes that are to be deleted by
pressing the 'Delete' key. Note, however, that the shapes are not
actually deleted from your drawing until you press the button
labeled "Press to delete shapes" later. Once again, if you tab
past that button and return the focus to the Action List, the
shapes that you marked will not be deleted from your drawing.
If you understand how to rotate shapes, you should have no problem using
this action to delete shapes.
Stop program
As the name implies, selecting the "Stop program" action and pressing
the Enter key will cause the program to be terminated. Make sure that
you have performed the Write drawing file action before performing this
action if you want to save your drawing.
Write drawing file
Selecting this action and pressing the Enter key will land you on a page
from which you can save your drawing with a specific file and path name.
The extension .svg will be automatically appended to the file name that
you specify so you should not include it when you enter the path and
file name.
Each time you perform this action, the current state of your drawing
will be saved in the specified file. It might be a good idea to perform
this action often while creating a drawing so that if you make a mistake
(or you have a power failure), you can re-open the most recent good
version of the drawing file.
Please provide feedback
Please let me know if you find errors in these instructions, or you find
areas that deserve a more thorough explanation.
I would also like to hear about it if there are features that you would
like to see added to this program.
Dick Baldwin
baldwin at dickbaldwin.com
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