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Please download on PC (not smartphone) and extract the ZIP file. Then double-click VCSSL.bat (batch file) to execute for Microsoft® Windows®, or execute VCSSL.jar (JAR file) on the command line for Linux® and other OSes.
For details, see How to Use.

Plotting a File on a 2D Graph

This VCSSL program plots the contents of a file containing coordinate values on a 2D graph. It's a short and simple sample code, making it suitable as a base for modifications or reuse.

When executed, the program first writes some sample coordinate values to a file named sample2d.txt, and then plots them on a 2D graph.

» Related page: Related page: 2D Graph Plotting in Java

How to Use

Download and Extract

At first, click the "Download" button at the above of the title of this page by your PC (not smartphone). A ZIP file will be downloaded.

Then, please extract the ZIP file. On general environment (Windows®, major Linux distributions, etc.), you can extract the ZIP file by selecting "Extract All" and so on from right-clicking menu.

» If the extraction of the downloaded ZIP file is stopped with security warning messages...

Execute this Program

Next, open the extracted folder and execute this VCSSL program.

For Windows

Double-click the following batch file to execute:

For Linux, etc.

Execute "VCSSL.jar" on the command-line terminal as follows:

» If the error message about non-availability of "java" command is output...

After Launching

When you launch the program, a 3D graph window opens, and the contents of an array filled with calculated coordinate values are plotted.

To change the plotted data, modify the part of the code that fills in the coordinate array (i.e., inside the for loop).

Code

Now, let's go through the code of this program. The code is written in VCSSL.

Full Code

Let's first look at the entire code. It's a very short program, around 20 lines.

coding UTF-8;

// Required to handle 2D graphs
import tool.Graph2D;


// Writing sample coordinate data to file ("wtsv" means tab-separated format)
int file = open("sample2d.txt", "wtsv");
for(int i=0; i<=10; i++){
	float x = i;
	float y = x*x;
	writeln(file, x, y);
}
close(file);


// Launching the 2D graph
int graph = newGraph2D();

// Plotting the file on the 2D graph
setGraph2DFile(graph, "sample2d.txt");

That's all. The flow is simple: the first half writes out a coordinate file, and the second half plots it on a graph.

First Part

Let's look at the first part:

coding UTF-8;

// Required to handle 2D graphs
import tool.Graph2D;

The line "coding UTF-8;" specifies the character encoding of the program. It's not strictly required, but including it helps prevent issues like garbled characters.

The line import tool.Graph2D; loads the tool.Graph2D library, which is needed to handle 2D graphs.

Writing Sample Coordinate File

Next is the part where it writes the sample coordinate data to a file:

// Writing sample coordinate data to file ("wtsv" means tab-separated format)
int file = open("sample2d.txt", "wtsv");
for(int i=0; i<=10; i++){
	float x = i;
	float y = x*x;
	writeln(file, x, y);
}
close(file);

What this code does is write the coordinates in the following format:

Each line represents a single point (x, y), with values separated by a tab character. The output file is named sample2d.txt, and its contents will look like this:

These are the coordinates of the function "y = x * x", for values of x from 0 to 10.

This format is widely supported by many graphing tools. In the standard VCSSL environment, the 2D graph plotting feature is handled by RINEARN Graph 2D, which also supports this format.

Plotting

Finally, here is the part where the file is plotted on the 2D graph:

// Launching the 2D graph
int graph = newGraph2D();

// Plotting the file on the 2D graph
setGraph2DFile(graph, "samle2d.txt");

The function newGraph2D() launches the 2D graph software. Each time it's called, a new instance of the graph software is launched and assigned a unique ID number, which is returned.

So, for example, if you launch several graph windows, they'll be assigned numbers like Graph #12, #22, #101, and so on. In this case, the returned ID number is stored in the int variable "graph".

Next, the function setGraph2DFile() is used to plot the file sample2d.txt in the graph software we just launched. The first argument is the ID number of the graph instance we want to control, which we stored in graph. This way, even if multiple graphs are open, you can specify exactly which one to use by its ID.

License

This VCSSL/Vnano code (files with the ".vcssl" or ".vnano" extensions) is released under the CC0 license, effectively placing it in the public domain. If any sample code in C, C++, or Java is included in this article, it is also released under the same terms. You are free to use, modify, or repurpose it as you wish.

* The distribution folder also includes the VCSSL runtime environment, so you can run the program immediately after downloading. The license for the runtime is included in the gLicenseh folder.
(In short, it can be used freely for both commercial and non-commercial purposes, but the developers take no responsibility for any consequences arising from its use.) For details on the files and licenses included in the distribution folder, please refer to "ReadMe.txt".

* The Vnano runtime environment is also available as open-source, so you can embed it in other software if needed. For more information, see here.

Author of This Article

Fumihiro Matsui
[ Founder of RINEARN, Doctor of Science (Physics), Applied Info Tech Engineer ]

Develops VCSSL, RINEARN Graph 3D and more. Also writes guides and articles.

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