steve1281 / java2d

Experiments in Java2d

Java 2D experiments

In this project, we create a simple java graphic application capable of displaying a variety of different 2d shapes. Color, scale, text, rotation will be added. An approach to load the elements from a file will be included.

Setup project

Using gradle, create a simple application for building, runniing, testing and packaging. (My preference, at this time is gradle, although maven could also be used.)

$ gradle init
[2] application
[3] java
[1] application
[1] groovy
[yes]
[4] junit jupiter
name: 2d
source_package: ont777767ltd.twod

This will build a gradle based project, with a default Hello World

Test the initial project

$ gradle run

> Task :app:run
Hello World!

BUILD SUCCESSFUL in 2s
2 actionable tasks: 1 executed, 1 up-to-date

and

[~/projects/home/java/2d]  $ gradle test

BUILD SUCCESSFUL in 2s
3 actionable tasks: 1 executed, 2 up-to-date

Convert to a simple tool

Things to think about:

1. Need a Shape sub-package for creating shapes.
2. Need an ui subpackage for handling mouse clicks.
3. ...

So, what I want to create here is a bunch of shape objects that I can "draw" onto a frame. I will need to create a JFrame. I'll need some UI elements.

For now, create a basic structure with some simple shapes:

app/src/main
├── java
│   └── ont777767ltd
│       └── twod
│           ├── App.java
│           ├── DrawingCanvas.java
│           ├── shapes
│           │   ├── Circle.java
│           │   ├── Cloud.java
│           │   ├── Hexagon.java
│           │   ├── Line.java
│           │   ├── MyPolygon.java
│           │   ├── Rect.java
│           │   ├── Shape.java
│           │   └── Spiral.java
│           └── ui
│               └── MyMouseListener.java
└── resources

Create a git repo for this project

At this point, need to track changes and such.

git init

Need a .gitignore

The default .gitignore will be:

[~/projects/home/java/2d]  $ cat .gitignore
# Ignore Gradle project-specific cache directory
.gradle

# Ignore Gradle build output directory
build

You should add other files here too - for example, I use intellij, so I added .idea/

To check hhat will be added:

[~/projects/home/java/2d]  $ git status --untracked-files
On branch master

No commits yet

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	.gitattributes
	.gitignore
	README.md
	app/build.gradle
	app/src/main/java/ont777767ltd/twod/App.java
	app/src/main/java/ont777767ltd/twod/DrawingCanvas.java
	app/src/main/java/ont777767ltd/twod/shapes/Circle.java
	app/src/main/java/ont777767ltd/twod/shapes/Cloud.java
	app/src/main/java/ont777767ltd/twod/shapes/Hexagon.java
	app/src/main/java/ont777767ltd/twod/shapes/Line.java
	app/src/main/java/ont777767ltd/twod/shapes/MyPolygon.java
	app/src/main/java/ont777767ltd/twod/shapes/Rect.java
	app/src/main/java/ont777767ltd/twod/shapes/Shape.java
	app/src/main/java/ont777767ltd/twod/shapes/Spiral.java
	app/src/main/java/ont777767ltd/twod/ui/MyMouseListener.java
	app/src/test/java/ont777767ltd/twod/AppTest.java
	gradle/wrapper/gradle-wrapper.properties
	gradlew
	gradlew.bat
	settings.gradle

nothing added to commit but untracked files present (use "git add" to track)

Runnable JAR

Need to modify the build.gradle and add a manifest for the jar:

$ vim app/build.gradle

add in

+  34 jar {
+  35   manifest {
+  36     attributes(
+  37       'Class-Path': configurations.runtimeClasspath.files.collect { it.getName() }.join(' '),
+  38       'Main-Class': 'ont777767ltd.twod.App'
+  39     )
+  40   }
+  41 }

and then build:

[~/projects/home/java/java2d]  (main) $ gradle jar

BUILD SUCCESSFUL in 873ms
2 actionable tasks: 2 up-to-date

and run:

[~/projects/home/java/java2d]  (main) $ java -jar app/build/libs/app.jar
Hello World!

Windows 11 Notes

From stackoverflow (https://stackoverflow.com/questions/52511778/how-to-install-openjdk-11-on-windows)

Extract the zip file into a folder, e.g. C:\Program Files\Java\ and it will create a jdk-11 folder (where the bin folder is a direct sub-folder). You may need Administrator privileges to extract the zip file to this location.

Set a PATH:

Select Control Panel and then System.

Click Advanced and then Environment Variables.

Add the location of the bin folder of the JDK installation to the PATH variable in System Variables.

The following is a typical value for the PATH variable: C:\WINDOWS\system32;C:\WINDOWS;"C:\Program Files\Java\jdk-11\bin"

Set JAVA_HOME:

Under System Variables, click New.
Enter the variable name as JAVA_HOME.
Enter the variable value as the installation path of the JDK (without the bin sub-folder).
Click OK.
Click Apply Changes.