reworked Graphics to use anonymous canvas class and annotations, removed oracle download links

md/appendix.md

@@ -17,10 +17,10 @@ The graphics system draws the amount of grass per cell by shades of green. Furth
 /// file:src/main/java/grassing/sys/Graphics.java
 package grassing.sys;
 
-import com.artemis.Aspect;
-import com.artemis.BaseSystem;
+import com.artemis.BaseEntitySystem;
 import com.artemis.ComponentMapper;
-import com.artemis.EntitySubscription;
+import com.artemis.annotations.All;
+import com.artemis.annotations.One;
 import com.artemis.annotations.Wire;
 import com.artemis.utils.IntBag;
 import grassing.comp.*;
@@ -31,9 +31,9 @@ import grassing.util.MathUtil;
 import javax.swing.*;
 import java.awt.*;
 
-public class Graphics extends BaseSystem {
-
-    private EntitySubscription grasserSubs;
+@All(Position.class)
+@One({IsGrassing.class, IsSearching.class})
+public class Graphics extends BaseEntitySystem {
 
     protected ComponentMapper<Position> mPosition;
     protected ComponentMapper<Heading> mHeading;
@@ -43,7 +43,7 @@ public class Graphics extends BaseSystem {
     @Wire Grass grass;
 
     final private int cellSize;
-    private Canvas canvas;
+    private JPanel canvas;
 
     public Graphics(int cellSize) {
         super();
@@ -52,13 +52,16 @@ public class Graphics extends BaseSystem {
 
     @Override
     protected void initialize() {
-        grasserSubs = world.getAspectSubscriptionManager()
-                .get(Aspect.all(Position.class).one(IsGrassing.class, IsSearching.class));
-
         var frame = new JFrame();
         frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
 
-        canvas = new Canvas();
+        canvas = new JPanel() {
+        	@Override
+            public void paint(java.awt.Graphics g) {
+                Graphics.this.paint((Graphics2D)g);
+            }
+        };
+
         var dim = new Dimension(grass.grass.width * cellSize, grass.grass.height * cellSize);
         canvas.setPreferredSize( dim );
 
@@ -72,49 +75,43 @@ public class Graphics extends BaseSystem {
     protected void processSystem() {
         canvas.paintImmediately(0, 0, grass.grass.width * cellSize, grass.grass.height * cellSize);
     }
+    
+    void paint(Graphics2D g2d) {
+        Grid.Float grass = this.grass.grass;
+        int s = cellSize;
 
-    class Canvas extends JPanel {
+        g2d.setBackground(Color.BLACK);
 
-        @Override
-        public void paint(java.awt.Graphics g) {
-            super.paintComponent(g);
-            Graphics2D g2d = (Graphics2D) g;
-            Grid.Float grass = Graphics.this.grass.grass;
-            int s = Graphics.this.cellSize;
-
-            setBackground(Color.BLACK);
-
-            for(int y=0; y<grass.height; y++) {
-                for(int x=0; x<grass.width; x++) {
-                    g2d.setPaint(new Color(0f, 0.7f * grass.get(x, y), 0f));
-                    g2d.fillRect(x*s, y*s, s, s);
-                }
+        for(int y=0; y<grass.height; y++) {
+            for(int x=0; x<grass.width; x++) {
+                g2d.setPaint(new Color(0f, 0.7f * grass.get(x, y), 0f));
+                g2d.fillRect(x*s, y*s, s, s);
             }
+        }
 
-            int[] x = new int[3];
-            int[] y = new int[3];
-            IntBag grassers = Graphics.this.grasserSubs.getEntities();
-            for (int i = 0; i < grassers.size(); i++) {
-                int entity = grassers.get(i);
-                var pos = mPosition.get(entity);
-                var head = mHeading.get(entity);
-                if(mGrassing.has(entity)) {
-                    g2d.setPaint(Color.WHITE);
-                } else if(mSearching.has(entity)) {
-                    g2d.setPaint(Color.ORANGE);
-                } else {
-                    g2d.setPaint(Color.MAGENTA);
-                }
-                var f = MathUtil.heading(head.angle);
-                var r = MathUtil.heading(head.angle + 0.5f * (float) Math.PI);
-                x[0] = (int) ((pos.x + f.x) * s);
-                y[0] = (int) ((pos.y + f.y) * s);
-                x[1] = (int) ((pos.x + 0.4f * r.x) * s);
-                y[1] = (int) ((pos.y + 0.4f * r.y) * s);
-                x[2] = (int) ((pos.x - 0.4f * r.x) * s);
-                y[2] = (int) ((pos.y - 0.4f * r.y) * s);
-                g2d.fillPolygon(x, y, 3);
+        int[] x = new int[3];
+        int[] y = new int[3];
+        IntBag grassers = subscription.getEntities();
+        for (int i = 0; i < grassers.size(); i++) {
+            int entity = grassers.get(i);
+            var pos = mPosition.get(entity);
+            var head = mHeading.get(entity);
+            if(mGrassing.has(entity)) {
+                g2d.setPaint(Color.WHITE);
+            } else if(mSearching.has(entity)) {
+                g2d.setPaint(Color.ORANGE);
+            } else {
+                g2d.setPaint(Color.MAGENTA);
             }
+            var f = MathUtil.heading(head.angle);
+            var r = MathUtil.heading(head.angle + 0.5f * (float) Math.PI);
+            x[0] = (int) ((pos.x + f.x) * s);
+            y[0] = (int) ((pos.y + f.y) * s);
+            x[1] = (int) ((pos.x + 0.4f * r.x) * s);
+            y[1] = (int) ((pos.y + 0.4f * r.y) * s);
+            x[2] = (int) ((pos.x - 0.4f * r.x) * s);
+            y[2] = (int) ((pos.y - 0.4f * r.y) * s);
+            g2d.fillPolygon(x, y, 3);
         }
     }
 }

md/howto.md

@@ -17,7 +17,7 @@ After following any of the following sections, you should see a window with gras
 
 The [downloads](https://git.ufz.de/oesa/ecs-tutorial/-/jobs/artifacts/master/download?job=build) contain a file `Grassing.zip`. Extract it and navigate into folder `Grassing/bin`. Double-click or run file `Grassing` (or `Grassing.bat` if you are on Windows).
 
-> This required [Java](https://www.java.com) 11 or newer to be installed on your machine. Simply try running the model, and install Java in case you get a respective error. Download Java [here](https://www.oracle.com/de/java/technologies/javase-downloads.html) or [here](https://adoptopenjdk.net/) (OpenJDK).
+> This required [Java](https://www.java.com) 11 or newer to be installed on your machine. Simply try running the model, and install Java in case you get a respective error. Download Java [here](https://adoptopenjdk.net/).
 
 ## Browse the plain Java code
 
@@ -35,7 +35,7 @@ You can build and run the project with the following command executed inside fol
 gradle run
 ```
 
-> This requires Gradle and Java JDK 11 or newer to be installed on your machine. Download Java [here](https://www.oracle.com/de/java/technologies/javase-downloads.html) or [here](https://adoptopenjdk.net/) (OpenJDK), and Gradle [here](https://gradle.org/releases/).
+> This requires Gradle and Java JDK 11 or newer to be installed on your machine. Download Java [here](https://adoptopenjdk.net/), and Gradle [here](https://gradle.org/releases/).
 
 ## Clone, extract, build
 
@@ -67,4 +67,4 @@ cd code
 gradle run
 ```
 
-> This requires Gradle and the Java JDK 11 or newer to be installed on your machine. Download Java [here](https://www.oracle.com/de/java/technologies/javase-downloads.html) or [here](https://adoptopenjdk.net/) (OpenJDK), and Gradle [here](https://gradle.org/releases/).
+> This requires Gradle and the Java JDK 11 or newer to be installed on your machine. Download Java [here](https://adoptopenjdk.net/), and Gradle [here](https://gradle.org/releases/).