Memory view is now performance-optimized and a lot of minor UX issues have been resolved.

src/main/java/jace/apple2e/Apple2e.java

@@ -314,6 +314,7 @@ public class Apple2e extends Computer {
             if (cheatEngine.getValue() == null) {
                 if (activeCheatEngine != null) {
                     activeCheatEngine.detach();
+                    motherboard.miscDevices.remove(activeCheatEngine);
                 }
                 activeCheatEngine = null;
             } else {
@@ -324,6 +325,7 @@ public class Apple2e extends Computer {
                     } else {
                         activeCheatEngine.detach();
                         activeCheatEngine = null;
+                        motherboard.miscDevices.remove(activeCheatEngine);
                     }
                 }
                 if (startCheats) {
@@ -333,6 +335,7 @@ public class Apple2e extends Computer {
                         Logger.getLogger(Apple2e.class.getName()).log(Level.SEVERE, null, ex);
                     }
                     activeCheatEngine.attach();
+                    motherboard.miscDevices.add(activeCheatEngine);
                 }
             }
         } catch (IOException ex) {

src/main/java/jace/cheat/Cheats.java

@@ -89,6 +89,11 @@ public abstract class Cheats extends Device {
         listeners.clear();
     }
 
+    public void removeListener(RAMListener l) {
+        computer.getMemory().removeListener(l);
+        listeners.remove(l);
+    }
+    
     @Override
     public void reconfigure() {
         unregisterListeners();

src/main/java/jace/cheat/MetaCheat.java

@@ -4,14 +4,21 @@ import jace.Emulator;
 import jace.JaceApplication;
 import jace.core.Computer;
 import jace.core.RAM;
+import jace.core.RAMEvent;
 import jace.core.RAMListener;
 import jace.state.State;
 import jace.ui.MetacheatUI;
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.IntegerProperty;
 import javafx.beans.property.Property;
 import javafx.beans.property.SimpleBooleanProperty;
+import javafx.beans.property.SimpleIntegerProperty;
 import javafx.beans.property.SimpleStringProperty;
 import javafx.beans.property.StringProperty;
+import javafx.beans.value.ChangeListener;
 import javafx.beans.value.ObservableValue;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
@@ -26,6 +33,60 @@ public class MetaCheat extends Cheats {
         NO_CHANGE, ANY_CHANGE, LESS, GREATER, AMOUNT
     }
 
+    public static class MemoryCell  implements Comparable<MemoryCell>{
+
+        public static ChangeListener<MemoryCell> listener;
+        public int address;
+        public IntegerProperty value = new SimpleIntegerProperty();
+        public IntegerProperty readCount = new SimpleIntegerProperty();
+        public IntegerProperty execCount = new SimpleIntegerProperty();
+        public IntegerProperty writeCount = new SimpleIntegerProperty();
+        public ObservableList<Integer> readInstructions = FXCollections.observableList(new ArrayList<>());
+        public ObservableList<Integer> writeInstructions = FXCollections.observableList(new ArrayList<>());
+        private int x;
+        private int y;
+        private int width;
+        private int height;
+
+        public static void setListener(ChangeListener<MemoryCell> l) {
+            listener = l;
+        }
+
+        public MemoryCell() {
+            ChangeListener<Number> changeListener = (ObservableValue<? extends Number> val, Number oldVal, Number newVal) -> {
+                if (listener != null) {
+                    listener.changed(null, this, this);
+                }
+            };
+            value.addListener(changeListener);
+        }
+
+        public void setRect(int x, int y, int w, int h) {
+            this.x = x;
+            this.y = y;
+            this.width = w;
+            this.height = h;
+        }
+        
+        public int getX() {
+            return x;
+        }
+        public int getY() {
+            return y;            
+        }
+        public int getWidth() {
+            return width;
+        }
+        public int getHeight() {
+            return height;
+        }
+
+        @Override
+        public int compareTo(MemoryCell o) {
+            return address - o.address;
+        }
+    }
+
     public static class SearchResult {
 
         int address;
@@ -43,11 +104,16 @@ public class MetaCheat extends Cheats {
     }
 
     MetacheatUI ui;
+
+    public int fadeRate = 2;
+    public int lightRate = 20;
+    public int historyLength = 10;
+
     private int startAddress = 0;
     private int endAddress = 0x0ffff;
-    private final StringProperty startAddressProperty = new SimpleStringProperty("0");
+    private final StringProperty startAddressProperty = new SimpleStringProperty(Integer.toHexString(startAddress));
-    private final StringProperty endAddressProperty = new SimpleStringProperty("FFFF");
+    private final StringProperty endAddressProperty = new SimpleStringProperty(Integer.toHexString(endAddress));
-    private boolean byteSized = false;
+    private boolean byteSized = true;
     private SearchType searchType = SearchType.VALUE;
     private SearchChangeType searchChangeType = SearchChangeType.NO_CHANGE;
     private final BooleanProperty signedProperty = new SimpleBooleanProperty(false);
@@ -64,10 +130,10 @@ public class MetaCheat extends Cheats {
         addNumericValidator(searchValueProperty);
         addNumericValidator(changeByProperty);
         startAddressProperty.addListener((prop, oldVal, newVal) -> {
-            startAddress = parseInt(newVal);
+            startAddress = Math.max(0, Math.min(65535, parseInt(newVal)));
         });
         endAddressProperty.addListener((prop, oldVal, newVal) -> {
-            endAddress = parseInt(newVal);
+            endAddress = Math.max(0, Math.min(65535, parseInt(newVal)));
         });
     }
 
@@ -83,6 +149,9 @@ public class MetaCheat extends Cheats {
     }
 
     public int parseInt(String s) throws NumberFormatException {
+        if (s == null || s.isEmpty()) {
+            return 0;
+        }
         if (s.matches("(\\+|-)?[0-9]+")) {
             return Integer.parseInt(s);
         } else if (s.matches("(\\+|-)?[0-9a-fA-F]+")) {
@@ -116,10 +185,6 @@ public class MetaCheat extends Cheats {
         return "MetaCheat";
     }
 
-    @Override
-    public void tick() {
-    }
-
     @Override
     public void detach() {
         super.detach();
@@ -210,7 +275,7 @@ public class MetaCheat extends Cheats {
                     ? signed ? memory.readRaw(result.address) : memory.readRaw(result.address) & 0x0ff
                     : signed ? memory.readWordRaw(result.address) : memory.readWordRaw(result.address) & 0x0ffff;
             int last = result.lastObservedValue;
-            result.lastObservedValue = val; 
+            result.lastObservedValue = val;
             switch (searchType) {
                 case VALUE:
                     int compare = parseInt(searchValueProperty.get());
@@ -237,4 +302,81 @@ public class MetaCheat extends Cheats {
         });
     }
 
+    RAMListener memoryViewListener = null;
+    private final Map<Integer, MemoryCell> memoryCells = new ConcurrentHashMap<>();
+
+    public MemoryCell getMemoryCell(int address) {
+        return memoryCells.get(address);
+    }
+
+    public void initMemoryView() {
+        RAM memory = Emulator.computer.getMemory();
+        for (int addr = getStartAddress(); addr <= getEndAddress(); addr++) {
+            if (getMemoryCell(addr) == null) {
+                MemoryCell cell = new MemoryCell();
+                cell.address = addr;
+                cell.value.set(memory.readRaw(addr));
+                memoryCells.put(addr, cell);
+            }
+        }
+        if (memoryViewListener == null) {
+            memoryViewListener = memory.observe(RAMEvent.TYPE.ANY, startAddress, endAddress, this::processMemoryEvent);
+            listeners.add(memoryViewListener);
+        }
+    }
+
+    int fadeCounter = 0;
+    int FADE_TIMER_VALUE = (int) (Emulator.computer.getMotherboard().cyclesPerSecond / 60);
+
+    @Override
+    public void tick() {
+        if (fadeCounter-- <= 0) {
+            fadeCounter = FADE_TIMER_VALUE;
+            memoryCells.values().stream().forEach((cell) -> {
+                boolean change = false;
+                if (cell.execCount.get() > 0) {
+                    cell.execCount.set(Math.max(0, cell.execCount.get() - fadeRate));
+                    change = true;
+                }
+                if (cell.readCount.get() > 0) {
+                    cell.readCount.set(Math.max(0, cell.readCount.get() - fadeRate));
+                    change = true;
+                }
+                if (cell.writeCount.get() > 0) {
+                    cell.writeCount.set(Math.max(0, cell.writeCount.get() - fadeRate));
+                    change = true;
+                }
+                if (change) {
+                    cell.listener.changed(null, cell, cell);
+                }
+            });
+        }
+    }
+
+    private void processMemoryEvent(RAMEvent e) {
+        MemoryCell cell = getMemoryCell(e.getAddress());
+        if (cell != null) {
+            int programCounter = Emulator.computer.getCpu().getProgramCounter();
+            switch (e.getType()) {
+                case EXECUTE:
+                case READ_OPERAND:
+                    cell.execCount.set(Math.min(255, cell.execCount.get() + lightRate));
+                    break;
+                case WRITE:
+                    cell.writeCount.set(Math.min(255, cell.writeCount.get() + lightRate));
+                    cell.writeInstructions.add(programCounter);
+                    if (cell.writeInstructions.size() > historyLength) {
+                        cell.writeInstructions.remove(0);
+                    }
+                    break;
+                default:
+                    cell.readCount.set(Math.min(255, cell.readCount.get() + lightRate));
+                    cell.readInstructions.add(programCounter);
+                    if (cell.readInstructions.size() > historyLength) {
+                        cell.readInstructions.remove(0);
+                    }
+            }
+            cell.value.set(e.getNewValue());
+        }
+    }
 }

src/main/java/jace/ui/MetacheatUI.java

@@ -5,28 +5,38 @@ import jace.Emulator;
 import jace.cheat.MetaCheat;
 import jace.cheat.MetaCheat.SearchChangeType;
 import jace.cheat.MetaCheat.SearchType;
-import jace.core.RAMEvent;
 import jace.core.RAMListener;
 import jace.state.State;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 import javafx.application.Platform;
+import javafx.beans.value.ChangeListener;
 import javafx.beans.value.ObservableValue;
 import javafx.collections.FXCollections;
 import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
+import javafx.scene.canvas.Canvas;
+import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.control.Button;
 import javafx.scene.control.CheckBox;
 import javafx.scene.control.Label;
 import javafx.scene.control.ListView;
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.ScrollPane;
-import javafx.scene.control.SingleSelectionModel;
-import javafx.scene.control.Tab;
 import javafx.scene.control.TabPane;
 import javafx.scene.control.TableView;
 import javafx.scene.control.TextField;
 import javafx.scene.control.Toggle;
 import javafx.scene.control.ToggleGroup;
+import javafx.scene.layout.AnchorPane;
+import javafx.scene.layout.StackPane;
 import javafx.scene.layout.TilePane;
+import javafx.scene.paint.Color;
 
 public class MetacheatUI {
 
@@ -87,6 +97,9 @@ public class MetacheatUI {
     @FXML
     private ListView<MetaCheat.SearchResult> searchResultsListView;
 
+    @FXML
+    private CheckBox showValuesCheckbox;
+
     @FXML
     private TilePane watchesPane;
 
@@ -199,7 +212,6 @@ public class MetacheatUI {
         searchTypesTabPane.getTabs().get(1).setUserData(SearchType.CHANGE);
         searchTypesTabPane.getTabs().get(2).setUserData(SearchType.TEXT);
         searchTypesTabPane.getSelectionModel().selectedItemProperty().addListener((prop, oldVal, newVal) -> {
-            System.out.println("Tab selected: " + newVal.getText());
             if (cheatEngine != null) {
                 cheatEngine.setSearchType((SearchType) newVal.getUserData());
             }
@@ -222,7 +234,7 @@ public class MetacheatUI {
             if (cheatEngine != null) {
                 cheatEngine.setByteSized((boolean) newVal.getUserData());
             }
-        });
+        });        
     }
 
     MetaCheat cheatEngine = null;
@@ -239,21 +251,91 @@ public class MetacheatUI {
         searchValueField.textProperty().bindBidirectional(cheatEngine.searchValueProperty());
         searchChangeByField.textProperty().bindBidirectional(cheatEngine.searchChangeByProperty());
 
-        engine.addCheat(RAMEvent.TYPE.ANY, this::processMemoryEvent, 0, 0x0ffff);
+        searchStartAddressField.textProperty().addListener(addressRangeListener);
+        searchEndAddressField.textProperty().addListener(addressRangeListener);
+
+        memoryViewPane.boundsInParentProperty().addListener((prop, oldVal, newVal) -> redrawMemoryView());
+        Application.invokeLater(this::redrawMemoryView);
+    }
+
+    ChangeListener<String> addressRangeListener = (prop, oldVal, newVal) -> Application.invokeLater(this::redrawMemoryView);
+
+    Canvas memoryView = null;
+    public static final int MEMORY_BOX_SIZE = 4;
+    public static final int MEMORY_BOX_GAP = 2;
+    public static final int MEMORY_BOX_TOTAL_SIZE = (MEMORY_BOX_SIZE + MEMORY_BOX_GAP);
+
+    public static Set<MetaCheat.MemoryCell> redrawNodes = new ConcurrentSkipListSet<>();
+    ScheduledExecutorService animationTimer = new ScheduledThreadPoolExecutor(1);
+    ScheduledFuture animationFuture = null;
+
+    private void processMemoryViewUpdates() {
+        Application.invokeLater(() -> {
+            GraphicsContext context = memoryView.getGraphicsContext2D();
+            Set<MetaCheat.MemoryCell> draw = new HashSet<>(redrawNodes);
+            redrawNodes.clear();
+            draw.stream().forEach((cell) -> {
+                if (showValuesCheckbox.isSelected()) {
+                    int val = cell.value.get() & 0x0ff;
+                    context.setFill(Color.rgb(val, val, val));
+                } else {
+                    context.setFill(Color.rgb(
+                            cell.writeCount.get(),
+                            cell.readCount.get(),
+                            cell.execCount.get()));
+                }
+                context.fillRect(cell.getX(), cell.getY(), cell.getWidth(), cell.getHeight());
+            });
+        });
+    }
+
+    public void redrawMemoryView() {
+        boolean resume = Emulator.computer.pause();
+        if (memoryViewPane.getContent() != null && memoryView != null) {
+            memoryViewPane.setContent(null);
+        }
+
+        if (animationFuture != null) {
+            animationFuture.cancel(false);
+        }
+
+        animationFuture = animationTimer.scheduleAtFixedRate(this::processMemoryViewUpdates, 1000 / 60, 1000 / 60, TimeUnit.MILLISECONDS);
+
+        cheatEngine.initMemoryView();
+        int pixelsPerBlock = 16 * MEMORY_BOX_TOTAL_SIZE;
+        int cols = ((int) memoryViewPane.getWidth()) / pixelsPerBlock * 16;
+        int rows = ((cheatEngine.getEndAddress() - cheatEngine.getStartAddress()) / cols) + 1;
+        memoryView = new Canvas(memoryViewPane.getWidth(), rows * MEMORY_BOX_TOTAL_SIZE);
+        StackPane pane = new StackPane(memoryView);
+        memoryViewPane.setContent(pane);
+        GraphicsContext context = memoryView.getGraphicsContext2D();
+        context.setFill(Color.rgb(40, 40, 40));
+        context.fillRect(0, 0, memoryView.getWidth(), memoryView.getHeight());
+        for (int addr = cheatEngine.getStartAddress(); addr <= cheatEngine.getEndAddress(); addr++) {
+            int col = (addr - cheatEngine.getStartAddress()) % cols;
+            int row = (addr - cheatEngine.getStartAddress()) / cols;
+            MetaCheat.MemoryCell cell = cheatEngine.getMemoryCell(addr);
+            cell.setRect(col * MEMORY_BOX_TOTAL_SIZE, row * MEMORY_BOX_TOTAL_SIZE, MEMORY_BOX_SIZE, MEMORY_BOX_SIZE);
+            redrawNodes.add(cell);
+        }
+        MetaCheat.MemoryCell.setListener((prop, oldCell, newCell) -> {
+            redrawNodes.add(newCell);
+        });
+        
+        if (resume) {
+            Emulator.computer.resume();
+        }
     }
 
     private void changeZoom(double amount) {
-        double zoom = memoryViewPane.getScaleX();
+        if (memoryView != null) {
-        zoom += amount;
+            double zoom = memoryView.getScaleX();
-        memoryViewPane.setScaleX(zoom);
+            zoom += amount;
-        memoryViewPane.setScaleY(zoom);
+            memoryView.setScaleX(zoom);
-    }
+            memoryView.setScaleY(zoom);
-
+            StackPane scrollArea = (StackPane) memoryView.getParent();
-    private void processMemoryEvent(RAMEvent e) {
+            scrollArea.setPrefSize(memoryView.getWidth() * zoom, memoryView.getHeight() * zoom);
-        if (e.getAddress() < cheatEngine.getStartAddress() || e.getAddress() > cheatEngine.getEndAddress()) {
-            return;
         }
-
     }
 
     public void detach() {

src/main/resources/fxml/Metacheat.fxml

@@ -14,9 +14,10 @@
             <Button mnemonicParsing="false" onAction="#zoomIn" text="Zoom in" />
             <Button mnemonicParsing="false" onAction="#zoomOut" text="Zoom out" />
             <Label text="Start:" />
-            <TextField fx:id="searchStartAddressField" prefHeight="26.0" prefWidth="50.0" text="0000" />
+            <TextField fx:id="searchStartAddressField" prefHeight="26.0" prefWidth="60.0" text="0000" />
             <Label text="End:" />
-            <TextField fx:id="searchEndAddressField" prefHeight="26.0" prefWidth="48.0" text="FFFF" />
+            <TextField fx:id="searchEndAddressField" prefHeight="26.0" prefWidth="60.0" text="FFFF" />
+            <CheckBox fx:id="showValuesCheckbox" mnemonicParsing="false" text="Show Values" />
          </items>
       </ToolBar>
       <SplitPane dividerPositions="0.6304347826086957" prefHeight="363.0" prefWidth="600.0" VBox.vgrow="ALWAYS">