Add bugfixes from testing

j3270/src/main/java/haus/nightmare/j3270/J3270App.java

@@ -1002,8 +1002,72 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
                 "About j3270", JOptionPane.INFORMATION_MESSAGE);
     }
 
+    /**
+     * Configure application logging. When debug is false, disables all logging
+     * to console and file, preventing creation of j3270.log.
+     */
+    public static void configureLogging(boolean debug) {
+        Logger globalRoot = Logger.getLogger("");
+        for (java.util.logging.Handler h : globalRoot.getHandlers()) {
+            globalRoot.removeHandler(h);
+            try {
+                h.close();
+            } catch (Exception ignored) {
+            }
+        }
+
+        if (debug) {
+            Level logLevel = Level.ALL;
+            globalRoot.setLevel(Level.ALL);
+
+            java.util.logging.Filter appFilter = record -> record.getLoggerName() != null &&
+                    (record.getLoggerName().startsWith("haus.nightmare") || record.getLoggerName().startsWith("org.pubvm"));
+
+            ConsoleHandler consoleHandler = new ConsoleHandler();
+            consoleHandler.setLevel(Level.ALL);
+            consoleHandler.setFormatter(new SimpleFormatter());
+            consoleHandler.setFilter(appFilter);
+            globalRoot.addHandler(consoleHandler);
+
+            Logger.getLogger("haus.nightmare").setLevel(Level.ALL);
+            Logger.getLogger("haus.nightmare.j3270").setLevel(Level.ALL);
+            Logger.getLogger("haus.nightmare.lib3270j").setLevel(Level.ALL);
+
+            try {
+                java.util.logging.FileHandler fileHandler = new java.util.logging.FileHandler("j3270.log", 10 * 1024 * 1024, 1, false) {
+                    @Override
+                    public synchronized void publish(java.util.logging.LogRecord record) {
+                        super.publish(record);
+                        flush();
+                    }
+                };
+                fileHandler.setLevel(Level.ALL);
+                fileHandler.setFormatter(new SimpleFormatter());
+                fileHandler.setFilter(appFilter);
+                globalRoot.addHandler(fileHandler);
+                log.info("Logging protocol trace to j3270.log (debug=" + debug + ", level=" + logLevel + ")");
+            } catch (Exception e) {
+                System.err.println("Could not create j3270.log: " + e.getMessage());
+            }
+        } else {
+            globalRoot.setLevel(Level.OFF);
+            for (String pkg : new String[]{"haus.nightmare", "haus.nightmare.j3270", "haus.nightmare.lib3270j", "org.pubvm"}) {
+                Logger l = Logger.getLogger(pkg);
+                l.setLevel(Level.OFF);
+                for (java.util.logging.Handler h : l.getHandlers()) {
+                    l.removeHandler(h);
+                    try {
+                        h.close();
+                    } catch (Exception ignored) {
+                    }
+                }
+            }
+        }
+    }
+
     // ========== Main ==========
 
+
     public static void main(String[] args) {
         boolean debug = false;
         boolean cliTls = false;
@@ -1045,42 +1109,8 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
             }
         }
 
-        Level logLevel = debug ? Level.FINE : Level.INFO;
+        configureLogging(debug);
 
-        Logger globalRoot = Logger.getLogger("");
-        for (java.util.logging.Handler h : globalRoot.getHandlers()) {
-            globalRoot.removeHandler(h);
-        }
-
-        java.util.logging.Filter appFilter = record -> record.getLoggerName() != null &&
-                (record.getLoggerName().startsWith("haus.nightmare") || record.getLoggerName().startsWith("org.pubvm"));
-
-        ConsoleHandler consoleHandler = new ConsoleHandler();
-        consoleHandler.setLevel(Level.ALL);
-        consoleHandler.setFormatter(new SimpleFormatter());
-        consoleHandler.setFilter(appFilter);
-        globalRoot.addHandler(consoleHandler);
-
-        Logger.getLogger("haus.nightmare").setLevel(Level.ALL);
-        Logger.getLogger("haus.nightmare.j3270").setLevel(Level.ALL);
-        Logger.getLogger("haus.nightmare.lib3270j").setLevel(Level.ALL);
-
-        try {
-            java.util.logging.FileHandler fileHandler = new java.util.logging.FileHandler("j3270.log", 10 * 1024 * 1024, 1, false) {
-                @Override
-                public synchronized void publish(java.util.logging.LogRecord record) {
-                    super.publish(record);
-                    flush();
-                }
-            };
-            fileHandler.setLevel(Level.ALL);
-            fileHandler.setFormatter(new SimpleFormatter());
-            fileHandler.setFilter(appFilter);
-            globalRoot.addHandler(fileHandler);
-            log.info("Logging protocol trace to j3270.log (debug=" + debug + ", level=" + logLevel + ")");
-        } catch (Exception e) {
-            System.err.println("Could not create j3270.log: " + e.getMessage());
-        }
 
         if (configFile != null) {
             try {

j3270/src/test/java/haus/nightmare/j3270/LoggingConfigurationTest.java

@@ -0,0 +1,93 @@
+package haus.nightmare.j3270;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.PrintStream;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class LoggingConfigurationTest {
+
+    private PrintStream originalOut;
+    private PrintStream originalErr;
+
+    @BeforeEach
+    public void setUp() {
+        originalOut = System.out;
+        originalErr = System.err;
+    }
+
+    @AfterEach
+    public void tearDown() {
+        System.setOut(originalOut);
+        System.setErr(originalErr);
+        // Ensure all handlers are closed and logging reset
+        J3270App.configureLogging(false);
+    }
+
+    @Test
+    public void testLoggingDisabledWhenDebugFalse() {
+        File logFile = new File("j3270.log");
+        if (logFile.exists()) {
+            logFile.delete();
+        }
+
+        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+        ByteArrayOutputStream errContent = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outContent));
+        System.setErr(new PrintStream(errContent));
+
+        J3270App.configureLogging(false);
+
+        // Root logger should have no handlers attached
+        Logger rootLogger = Logger.getLogger("");
+        assertEquals(0, rootLogger.getHandlers().length, "Root logger should have no handlers when debug is disabled");
+        assertEquals(Level.OFF, rootLogger.getLevel(), "Root logger level should be OFF when debug is disabled");
+
+        // Application loggers should be OFF
+        assertEquals(Level.OFF, Logger.getLogger("haus.nightmare").getLevel());
+        assertEquals(Level.OFF, Logger.getLogger("haus.nightmare.j3270").getLevel());
+        assertEquals(Level.OFF, Logger.getLogger("haus.nightmare.lib3270j").getLevel());
+
+        // Emit log records at all levels
+        Logger appLogger = Logger.getLogger("haus.nightmare.j3270.J3270App");
+        appLogger.severe("Test SEVERE message");
+        appLogger.warning("Test WARNING message");
+        appLogger.info("Test INFO message");
+        appLogger.fine("Test FINE message");
+
+        // Verify nothing was written to stdout or stderr
+        assertEquals(0, outContent.size(), "Standard output should be empty when debug is disabled");
+        assertEquals(0, errContent.size(), "Standard error should be empty when debug is disabled");
+
+        // Verify j3270.log was NOT created
+        assertFalse(logFile.exists(), "j3270.log should NOT be created when debug is disabled");
+    }
+
+    @Test
+    public void testLoggingEnabledWhenDebugTrue() {
+        J3270App.configureLogging(true);
+
+        Logger rootLogger = Logger.getLogger("");
+        Handler[] handlers = rootLogger.getHandlers();
+        assertTrue(handlers.length >= 2, "Root logger should have at least ConsoleHandler and FileHandler when debug is enabled");
+
+        assertEquals(Level.ALL, rootLogger.getLevel());
+        assertEquals(Level.ALL, Logger.getLogger("haus.nightmare").getLevel());
+        assertEquals(Level.ALL, Logger.getLogger("haus.nightmare.j3270").getLevel());
+        assertEquals(Level.ALL, Logger.getLogger("haus.nightmare.lib3270j").getLevel());
+
+        File logFile = new File("j3270.log");
+        assertTrue(logFile.exists(), "j3270.log should be created when debug is enabled");
+
+        // Clean up
+        J3270App.configureLogging(false);
+    }
+}

lib3270j/src/main/java/haus/nightmare/lib3270j/ConnectionConfig.java

@@ -435,6 +435,14 @@ public class ConnectionConfig {
             }
         }
 
+        // Parse [lu@]host[:port] (e.g. "00C2@mvs.host.com:1023")
+        String parsedLu = null;
+        int atIdx = s.indexOf('@');
+        if (atIdx > 0 && atIdx < s.length() - 1) {
+            parsedLu = s.substring(0, atIdx).trim();
+            s = s.substring(atIdx + 1).trim();
+        }
+
         String host = s;
         int port = (defaultPort > 0) ? defaultPort : (tls ? 992 : 23);
 
@@ -458,6 +466,9 @@ public class ConnectionConfig {
         }
 
         ConnectionConfig config = new ConnectionConfig(host, port, defaultModel != null ? defaultModel : TerminalModel.IBM_3279_4);
+        if (parsedLu != null && !parsedLu.isEmpty()) {
+            config.setLuName(parsedLu);
+        }
         config.setUseTls(tls);
         config.setTn3270eEnabled(tn3270e);
         config.setKeepAliveEnabled(keepAlive);

lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java

@@ -54,6 +54,12 @@ public class DataStreamProcessor {
     private boolean unlockSysPending = false;
     private boolean rcvdRead = false;
 
+    // Modal SA (set attribute) character attributes
+    private byte currentFg = 0;
+    private byte currentBg = 0;
+    private byte currentGr = 0;
+    private byte currentCs = 0;
+
     /** Functional interface for sending output back through the telnet stack. */
     @FunctionalInterface
     public interface OutputSender {
@@ -240,6 +246,10 @@ public class DataStreamProcessor {
                     programSymbolManager.commitStagedSymbols();
                     log.info(">>> EAU: erasing all unprotected fields");
                     screen.eraseAllUnprotected();
+                    currentFg = 0;
+                    currentBg = 0;
+                    currentGr = 0;
+                    currentCs = 0;
                     break;
                 case CMD_WSF:
                 case SNA_CMD_WSF:
@@ -378,11 +388,19 @@ public class DataStreamProcessor {
         if (wccReset(wcc)) {
             // Reset all character attributes to defaults
             log.fine("WCC reset: clearing default attributes");
+            currentFg = 0;
+            currentBg = 0;
+            currentGr = 0;
+            currentCs = 0;
         }
 
         if (eraseFirst) {
             screen.clear();
             log.fine("Cleared screen for Erase/Write");
+            currentFg = 0;
+            currentBg = 0;
+            currentGr = 0;
+            currentCs = 0;
         }
 
         // Process orders and data starting at byte 2
@@ -390,9 +408,6 @@ public class DataStreamProcessor {
         int end = offset + length;
         int baddr = screen.getBufferAddress();
         int size = screen.getRows() * screen.getCols();
-
-        // Current SA (set attribute) values for character-mode
-        byte currentFg = 0, currentBg = 0, currentGr = 0, currentCs = 0;
         boolean lastWasOrder = false;
 
         while (pos < end) {
@@ -427,10 +442,6 @@ public class DataStreamProcessor {
                     // FA position is a display position that shows as blank
                     ea.ec = 0;
                     ea.ucs4 = ' ';
-                    currentFg = 0;
-                    currentBg = 0;
-                    currentGr = 0;
-                    currentCs = 0;
                     screen.setFormatted(true);
                     baddr = (baddr + 1) % size;
                     screen.setBufferAddress(baddr);
@@ -455,10 +466,6 @@ public class DataStreamProcessor {
                     ea.clear();
                     ea.ec = 0;
                     ea.ucs4 = ' ';
-                    currentFg = 0;
-                    currentBg = 0;
-                    currentGr = 0;
-                    currentCs = 0;
 
                     for (int i = 0; i < nPairs; i++) {
                         int attrType = data[pos + 2 + i * 2] & 0xFF;
@@ -485,6 +492,12 @@ public class DataStreamProcessor {
                     int attrType = data[pos + 1] & 0xFF;
                     int attrValue = data[pos + 2] & 0xFF;
                     switch (attrType) {
+                        case XA_ALL:
+                            currentFg = 0;
+                            currentBg = 0;
+                            currentGr = 0;
+                            currentCs = 0;
+                            break;
                         case XA_FOREGROUND:
                             currentFg = (byte) attrValue;
                             break;
@@ -984,7 +997,13 @@ public class DataStreamProcessor {
                     break;
                 case haus.nightmare.lib3270j.graphics.GocaConstants.SF_OBJDATA: // 0x85: Graphics Object Data / GOCA
                     if (fieldLen > 3) {
+                        graphicsPlane.setCharDimensions(qrBuilder.getCharWidth(), qrBuilder.getCharHeight());
                         graphicsPlane.setScreenDimensions(screen.getCols(), screen.getRows());
+                        int targetW = screen.getCols() * qrBuilder.getCharWidth();
+                        int targetH = screen.getRows() * qrBuilder.getCharHeight();
+                        if (graphicsPlane.getCanvasWidth() != targetW || graphicsPlane.getCanvasHeight() != targetH) {
+                            graphicsPlane.resize(targetW, targetH);
+                        }
                         gocaDecoder.decodeStream(data, pos + 3, fieldLen - 3);
                         notifyScreenUpdated();
                     }
@@ -1298,9 +1317,10 @@ public class DataStreamProcessor {
                     int orderOffset = (fieldLen >= 7) ? (offset + 7) : (offset + 4);
                     int orderLen = Math.max(0, fieldLen - (orderOffset - offset));
 
+                    graphicsPlane.setCharDimensions(qrBuilder.getCharWidth(), qrBuilder.getCharHeight());
                     graphicsPlane.setScreenDimensions(screen.getCols(), screen.getRows());
-                    int targetW = screen.getCols() * 9;
-                    int targetH = screen.getRows() * 16;
+                    int targetW = screen.getCols() * qrBuilder.getCharWidth();
+                    int targetH = screen.getRows() * qrBuilder.getCharHeight();
                     if (graphicsPlane.getCanvasWidth() != targetW || graphicsPlane.getCanvasHeight() != targetH) {
                         graphicsPlane.resize(targetW, targetH);
                     }

lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/QueryReplyBuilder.java

@@ -424,8 +424,8 @@ public class QueryReplyBuilder {
         out.write((Yr_HOD >> 16) & 0xFF);
         out.write((Yr_HOD >> 8) & 0xFF);
         out.write(Yr_HOD & 0xFF);
-        int charW = getCharWidth();
-        int charH = getCharHeight();
+        int charW = getCharWidth(maxRows);
+        int charH = getCharHeight(maxRows);
         out.write(charW);                    // AW
         out.write(charH);                    // AH
         int buf = maxCols * maxRows;
@@ -435,6 +435,11 @@ public class QueryReplyBuilder {
     }
 
     public int getCharWidth() {
+        int rows = (screen != null) ? screen.getMaxRows() : MODEL_2_ROWS;
+        return getCharWidth(rows);
+    }
+
+    public int getCharWidth(int rows) {
         if (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS()) {
             return 12;
         }
@@ -442,18 +447,11 @@ public class QueryReplyBuilder {
     }
 
     public int getCharHeight() {
-        // ARCHITECTURAL NOTE ON 3179G GOCA VERTICAL ALIGNMENT & QUERY REPLIES:
-        // Why hardcoding SH = 12 (0x0C) in Character Sets & Usable Area failed in past iterations:
-        // When SDH/AH is declared as 12 (0x0C) in Query Reply, the mainframe host GDDM engine computes
-        // total presentation space as rows * 12 (e.g. 43 * 12 = 516 units, yMax = 257).
-        // GDDM then places the top menu bar at Row 1 (gy = 187..200).
-        // Meanwhile, the client emulator rendered into a 16-pitch grid (43 * 16 = 688 units, yMax = 343).
-        // On a 688-unit canvas, gy = 200 mapped to Row 9.2 (middle of the screen), leaving a massive void above.
-        // When the user clicked on the visual menu drawn at Row 9, the client emitted gy = 189 with cursor at Row 9,
-        // which GDDM rejected as outside its menu hit box (causing terminal alarm beeps).
-        //
-        // Solution: Declare SDH = 16 (0x10) when Vector Graphics is enabled (3179G standard), ensuring host GDDM
-        // and client GraphicsPlane share the exact same 16-pitch presentation space (720x688, yMax = 343).
+        int rows = (screen != null) ? screen.getMaxRows() : MODEL_2_ROWS;
+        return getCharHeight(rows);
+    }
+
+    public int getCharHeight(int rows) {
         return graphicsMode.isVectorGraphicsEnabled() ? 0x10 : SH_3279_2;
     }
 

lib3270j/src/main/java/haus/nightmare/lib3270j/graphics/GocaDecoder.java

@@ -395,13 +395,16 @@ public class GocaDecoder {
         if (order == GocaConstants.G_NOP1 || order == 0xFF || order == 0x00 || order == GocaConstants.G_COMT) {
             return 1;
         }
-        // Orders with optional 0x00 trailing length/qualifier byte (e.g. 3E 00, 71 00, 60 00, 7E 00, 3F 00, 93 00, 91 00)
+        // Orders with optional 0x00 trailing length/qualifier byte (e.g. 3E 00, 71 00, 60 00, 7E 00, 3F 00)
         if (order == GocaConstants.G_ENDPROLOGUE || order == GocaConstants.G_ENDSEGM ||
             order == GocaConstants.G_GEAR || order == GocaConstants.G_GERASE ||
-            order == GocaConstants.G_GPOP || order == GocaConstants.G_GEIMG ||
-            (inImage && order == GocaConstants.G_GEIMG_ALT)) {
+            order == GocaConstants.G_GPOP) {
             return (idx + 1 < end && data[idx + 1] == 0x00) ? 2 : 1;
         }
+        // G_GEIMG (0x93 End Image): self-defining draw order (e.g. 93 02 00 00 or 93 00 or 93)
+        if (order == GocaConstants.G_GEIMG) {
+            return (idx + 1 < end) ? ((data[idx + 1] & 0xFF) + 2) : 1;
+        }
         if (idx + 1 >= end) {
             return -1;
         }
@@ -552,31 +555,45 @@ public class GocaDecoder {
                     idx += orderLen;
                     break;
                 }
-                case GocaConstants.G_GEIMG: // 0x93
-                case GocaConstants.G_GEIMG_ALT: { // 0x91
-                    if (inImage || order == GocaConstants.G_GEIMG) {
+                case GocaConstants.G_GEIMG: { // 0x93 End Image
+                    endImage();
+                    idx += orderLen;
+                    break;
+                }
+                case GocaConstants.G_GBIMGC: { // 0x91: Begin Image at Current Position (G_GBIMGC)
+                    if (inImage) {
                         endImage();
-                        idx += orderLen;
-                    } else {
-                        // 0x91: Begin Image at Current Position (G_GBIMGC)
-                        if (payloadLen >= 4 && idx + 2 + payloadLen <= end) {
-                            int w = readCoord(inputData, idx + 2);
-                            int h = readCoord(inputData, idx + 4);
-                            int bitDepth = GocaConstants.BPP_1;
-                            int compression = GocaConstants.IMG_UNCOMPRESSED;
-                            if (payloadLen >= 5) {
-                                int fmt = inputData[idx + 6] & 0xFF;
-                                if (fmt == 2) bitDepth = GocaConstants.BPP_2;
-                                else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
-                                else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
-                            }
-                            if (payloadLen >= 6) {
-                                compression = inputData[idx + 7] & 0xFF;
-                            }
-                            beginImage(curX, curY, w, h, bitDepth, compression);
-                        }
-                        idx += orderLen;
                     }
+                    int w = 0, h = 0;
+                    int bitDepth = GocaConstants.BPP_1;
+                    int compression = GocaConstants.IMG_UNCOMPRESSED;
+                    if (payloadLen >= 6 && idx + 2 + payloadLen <= end) {
+                        w = readCoord(inputData, idx + 4);
+                        h = readCoord(inputData, idx + 6);
+                        if (payloadLen >= 7) {
+                            int fmt = inputData[idx + 8] & 0xFF;
+                            if (fmt == 2) bitDepth = GocaConstants.BPP_2;
+                            else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
+                            else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
+                        }
+                        if (payloadLen >= 8) {
+                            compression = inputData[idx + 9] & 0xFF;
+                        }
+                    } else if (payloadLen >= 4 && idx + 2 + payloadLen <= end) {
+                        w = readCoord(inputData, idx + 2);
+                        h = readCoord(inputData, idx + 4);
+                        if (payloadLen >= 5) {
+                            int fmt = inputData[idx + 6] & 0xFF;
+                            if (fmt == 2) bitDepth = GocaConstants.BPP_2;
+                            else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
+                            else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
+                        }
+                        if (payloadLen >= 6) {
+                            compression = inputData[idx + 7] & 0xFF;
+                        }
+                    }
+                    beginImage(curX, curY, w, h, bitDepth, compression);
+                    idx += orderLen;
                     break;
                 }
                 case GocaConstants.G_BEGSEGM: { // Begin Segment (0x70)
@@ -986,21 +1003,39 @@ public class GocaDecoder {
                     break;
                 }
                 case GocaConstants.G_GBIMG: { // Begin Image (0xD1)
+                    if (inImage) {
+                        endImage();
+                    }
                     if (payloadLen >= 8 && idx + 2 + payloadLen <= end) {
                         int x = readCoord(inputData, idx + 2);
                         int y = readCoord(inputData, idx + 4);
-                        int w = readCoord(inputData, idx + 6);
-                        int h = readCoord(inputData, idx + 8);
+                        int w, h;
                         int bitDepth = GocaConstants.BPP_1;
                         int compression = GocaConstants.IMG_UNCOMPRESSED;
-                        if (payloadLen >= 9) {
-                            int fmt = inputData[idx + 10] & 0xFF;
-                            if (fmt == 2) bitDepth = GocaConstants.BPP_2;
-                            else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
-                            else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
-                        }
                         if (payloadLen >= 10) {
-                            compression = inputData[idx + 11] & 0xFF;
+                            w = readCoord(inputData, idx + 8);
+                            h = readCoord(inputData, idx + 10);
+                            if (payloadLen >= 11) {
+                                int fmt = inputData[idx + 12] & 0xFF;
+                                if (fmt == 2) bitDepth = GocaConstants.BPP_2;
+                                else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
+                                else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
+                            }
+                            if (payloadLen >= 12) {
+                                compression = inputData[idx + 13] & 0xFF;
+                            }
+                        } else {
+                            w = readCoord(inputData, idx + 6);
+                            h = readCoord(inputData, idx + 8);
+                            if (payloadLen >= 9) {
+                                int fmt = inputData[idx + 10] & 0xFF;
+                                if (fmt == 2) bitDepth = GocaConstants.BPP_2;
+                                else if (fmt == 4) bitDepth = GocaConstants.BPP_4;
+                                else if (fmt == 8) bitDepth = GocaConstants.BPP_8;
+                            }
+                            if (payloadLen >= 10) {
+                                compression = inputData[idx + 11] & 0xFF;
+                            }
                         }
                         beginImage(x, y, w, h, bitDepth, compression);
                     }

lib3270j/src/main/java/haus/nightmare/lib3270j/graphics/GraphicsPlane.java

@@ -418,9 +418,27 @@ public class GraphicsPlane implements PixelBuffer {
         return transform;
     }
 
+    // Character cell dimensions matching Query Reply presentation space
+    private int charWidth = 9;
+    private int charHeight = 16;
+
+    public synchronized void setCharDimensions(int width, int height) {
+        if (width > 0) this.charWidth = width;
+        if (height > 0) this.charHeight = height;
+        this.transform.setDefaultCharMetrics(this.charWidth, this.charHeight);
+    }
+
+    public int getCharWidth() {
+        return charWidth;
+    }
+
+    public int getCharHeight() {
+        return charHeight;
+    }
+
     public int getTotalWidth() {
         int cols = screenCols > 0 ? screenCols : 80;
-        return cols * 9;
+        return cols * charWidth;
     }
 
     /**
@@ -457,7 +475,7 @@ public class GraphicsPlane implements PixelBuffer {
      */
     public int getTotalHeight() {
         int rows = screenRows > 0 ? screenRows : 24;
-        return rows * 16;
+        return rows * charHeight;
     }
 
     public int getXMax() {

lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java

@@ -70,8 +70,22 @@ public class TelnetFSM {
 
     private List<String> getCandidateTerminalTypes() {
         List<String> list = new ArrayList<>();
+        String currentLu = null;
+        List<String> lus = config.getLuNames();
+        if (lus != null && !lus.isEmpty() && luIndex < lus.size()) {
+            currentLu = lus.get(luIndex);
+        } else if (config.getLuName() != null && !config.getLuName().trim().isEmpty()) {
+            currentLu = config.getLuName().trim();
+        }
+
         if (config.getTerminalName() != null && !config.getTerminalName().trim().isEmpty()) {
-            list.add(config.getTerminalName().trim());
+            String tName = config.getTerminalName().trim();
+            if (currentLu != null && !currentLu.isEmpty() && !tName.contains("@")) {
+                list.add(tName + "@" + currentLu);
+                list.add(tName);
+            } else {
+                list.add(tName);
+            }
             return list;
         }
         if (config.isDynamicModel()) {
@@ -82,24 +96,41 @@ public class TelnetFSM {
             list.add("IBM-3279-2");
             list.add("IBM-3278-2");
             list.add("UNKNOWN");
-            return list;
+        } else {
+            TerminalModel model = config.getModel();
+            list.add(model.getTerminalType());
+            list.add(model.getBaseTerminalType());
+            if (model.isColor()) {
+                try {
+                    TerminalModel mono = TerminalModel.forModel(model.getModelNumber(), false);
+                    list.add(mono.getTerminalType());
+                    list.add(mono.getBaseTerminalType());
+                } catch (Exception ignored) {}
+            }
+            if (model.getModelNumber() != 2) {
+                list.add("IBM-3279-2-E");
+                list.add("IBM-3279-2");
+                list.add("IBM-3278-2");
+            }
+            list.add("UNKNOWN");
         }
-        TerminalModel model = config.getModel();
-        list.add(model.getTerminalType());
-        list.add(model.getBaseTerminalType());
-        if (model.isColor()) {
-            try {
-                TerminalModel mono = TerminalModel.forModel(model.getModelNumber(), false);
-                list.add(mono.getTerminalType());
-                list.add(mono.getBaseTerminalType());
-            } catch (Exception ignored) {}
+
+        if (currentLu != null && !currentLu.isEmpty()) {
+            List<String> luCandidates = new ArrayList<>();
+            for (String item : list) {
+                if (!"UNKNOWN".equalsIgnoreCase(item) && !item.contains("@")) {
+                    luCandidates.add(item + "@" + currentLu);
+                }
+            }
+            for (String item : list) {
+                if (!"UNKNOWN".equalsIgnoreCase(item)) {
+                    luCandidates.add(item);
+                }
+            }
+            luCandidates.add("UNKNOWN");
+            return luCandidates;
         }
-        if (model.getModelNumber() != 2) {
-            list.add("IBM-3279-2-E");
-            list.add("IBM-3279-2");
-            list.add("IBM-3278-2");
-        }
-        list.add("UNKNOWN");
+
         return list;
     }
 
@@ -589,6 +620,9 @@ public class TelnetFSM {
             out.write(IAC);
             out.write(SE);
             sendBytes(out.toByteArray());
+            if (termType.contains("@")) {
+                connectedLu = termType.substring(termType.indexOf('@') + 1).trim();
+            }
             log.warning(">>> SENT SB TTYPE IS " + termType + " SE");
         }
     }

lib3270j/src/test/java/haus/nightmare/lib3270j/datastream/DataStreamProcessorTest.java

@@ -82,4 +82,120 @@ public class DataStreamProcessorTest {
         assertNotNull(sentData.get());
         assertEquals((byte) AID_ENTER, sentData.get()[0], "ReadBuffer must transmit operator's stored AID");
     }
+
+    @Test
+    public void testCharacterAttributesPersistAcrossStartField() throws java.io.IOException {
+        // User's exact ISPF Option 0 sequence:
+        // SBA(7, 1) -> SF(prot,skip) -> SA(yellow) -> '   4 ' -> SBA(7, 7) -> SF(prot,skip) -> 'DISPLAY'
+        java.io.ByteArrayOutputStream stream = new java.io.ByteArrayOutputStream();
+        stream.write(CMD_EW);
+        stream.write(0xC3); // WCC
+
+        // SBA(7, 1) -> address 7*80 + 1 = 561
+        byte[] addr1 = encodeAddress(561, 24, 80);
+        stream.write(ORDER_SBA);
+        stream.write(addr1);
+
+        // SF(prot, skip)
+        stream.write(ORDER_SF);
+        stream.write(FA_PRINTABLE | FA_PROTECT | FA_NUMERIC);
+
+        // SA(yellow) -> XA_FOREGROUND, COLOR_YELLOW (0xF6)
+        stream.write(ORDER_SA);
+        stream.write(XA_FOREGROUND);
+        stream.write(0xF6);
+
+        // Data: '   4 '
+        stream.write(translator.stringToEbcdic("   4 "));
+
+        // SBA(7, 7) -> address 7*80 + 7 = 567
+        byte[] addr2 = encodeAddress(567, 24, 80);
+        stream.write(ORDER_SBA);
+        stream.write(addr2);
+
+        // SF(prot, skip)
+        stream.write(ORDER_SF);
+        stream.write(FA_PRINTABLE | FA_PROTECT | FA_NUMERIC);
+
+        // Data: 'DISPLAY'
+        stream.write(translator.stringToEbcdic("DISPLAY"));
+
+        byte[] record = stream.toByteArray();
+        processor.processRecord(record, 0, record.length, true);
+
+        // Positions 562..566 ('   4 ') must be yellow (0xF6)
+        for (int i = 562; i <= 566; i++) {
+            assertEquals((byte) 0xF6, screen.getCell(i).fg, "Cell at " + i + " should have yellow foreground (0xF6)");
+        }
+
+        // Positions 568..574 ('DISPLAY') across the second SF must also retain yellow (0xF6)
+        for (int i = 568; i <= 574; i++) {
+            assertEquals((byte) 0xF6, screen.getCell(i).fg, "Cell at " + i + " ('DISPLAY') should retain yellow foreground (0xF6)");
+        }
+
+        // Now test that SA with XA_ALL resets character attributes to default (0)
+        java.io.ByteArrayOutputStream resetStream = new java.io.ByteArrayOutputStream();
+        resetStream.write(CMD_W);
+        resetStream.write(0xC3);
+        resetStream.write(ORDER_SA);
+        resetStream.write(XA_ALL);
+        resetStream.write(0x00);
+        resetStream.write(translator.stringToEbcdic("TEST"));
+        byte[] resetRecord = resetStream.toByteArray();
+        processor.processRecord(resetRecord, 0, resetRecord.length, true);
+
+        for (int i = 575; i < 579; i++) {
+            assertEquals((byte) 0, screen.getCell(i).fg, "Cell at " + i + " should have default foreground (0) after SA(XA_ALL)");
+        }
+    }
+
+    @Test
+    public void testCharacterAttributesPersistAcrossStartFieldExtended() throws java.io.IOException {
+        java.io.ByteArrayOutputStream stream = new java.io.ByteArrayOutputStream();
+        stream.write(CMD_EW);
+        stream.write(0xC3);
+
+        // SA(yellow)
+        stream.write(ORDER_SA);
+        stream.write(XA_FOREGROUND);
+        stream.write(0xF6);
+
+        // SFE with 1 pair (3270 FA)
+        stream.write(ORDER_SFE);
+        stream.write(0x01); // 1 pair
+        stream.write(XA_3270);
+        stream.write(FA_PRINTABLE);
+
+        // Data 'HELLO'
+        stream.write(translator.stringToEbcdic("HELLO"));
+
+        byte[] record = stream.toByteArray();
+        processor.processRecord(record, 0, record.length, true);
+
+        // Check cells of HELLO (positions 1..5) have fg == 0xF6
+        for (int i = 1; i <= 5; i++) {
+            assertEquals((byte) 0xF6, screen.getCell(i).fg, "Cell at " + i + " should retain yellow foreground across SFE");
+        }
+    }
+
+    @Test
+    public void testCharacterAttributesResetOnErase() throws java.io.IOException {
+        java.io.ByteArrayOutputStream stream = new java.io.ByteArrayOutputStream();
+        stream.write(CMD_EW);
+        stream.write(0xC3);
+        stream.write(ORDER_SA);
+        stream.write(XA_FOREGROUND);
+        stream.write(0xF6);
+        stream.write(translator.stringToEbcdic("A"));
+        processor.processRecord(stream.toByteArray(), 0, stream.size(), true);
+        assertEquals((byte) 0xF6, screen.getCell(0).fg);
+
+        // New EW command resets attributes
+        java.io.ByteArrayOutputStream ewStream = new java.io.ByteArrayOutputStream();
+        ewStream.write(CMD_EW);
+        ewStream.write(0xC3);
+        ewStream.write(translator.stringToEbcdic("B"));
+        processor.processRecord(ewStream.toByteArray(), 0, ewStream.size(), true);
+        assertEquals((byte) 0, screen.getCell(0).fg);
+    }
 }

lib3270j/src/test/java/haus/nightmare/lib3270j/graphics/GocaDecoderTest.java

@@ -285,6 +285,79 @@ public class GocaDecoderTest {
         assertTrue(plane.hasContent(), "Expected plane to have content after image decoding");
     }
 
+    @Test
+    public void testImonGddmImageRendering() throws Exception {
+        GraphicsPlane plane = new GraphicsPlane(1040, 1118);
+        plane.setCharDimensions(13, 26);
+        plane.setScreenDimensions(80, 43);
+        GocaDecoder decoder = new GocaDecoder(plane);
+
+        assertEquals(1040, plane.getTotalWidth());
+        assertEquals(1118, plane.getTotalHeight());
+        assertEquals(520, plane.getXMax());
+        assertEquals(558, plane.getYMax());
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        // GSCP: Set Current Position (377, 494)
+        out.write(GocaConstants.G_GSCP);
+        out.write(0x04);
+        out.write(0x01); out.write(0x79); // X = 377
+        out.write(0x01); out.write(0xEE); // Y = 494
+
+        // GSCOL: Color 1 = Blue
+        out.write(GocaConstants.G_GSCOL);
+        out.write(0x01);
+
+        // G_GBIMGC (0x91): Begin Image Current Position: len=6, flags=0, w=80, h=80
+        out.write(GocaConstants.G_GBIMGC);
+        out.write(0x06);
+        out.write(0x00); out.write(0x00); // flags/format
+        out.write(0x00); out.write(0x50); // w = 80
+        out.write(0x00); out.write(0x50); // h = 80
+
+        // G_GIMD (0x92): 10 bytes scanline
+        out.write(GocaConstants.G_GIMD);
+        out.write(0x0A);
+        out.write(new byte[] { (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF });
+
+        // G_GEIMG (0x93): End Image with 2-byte operand (02 00 00 as sent by IMON)
+        out.write(GocaConstants.G_GEIMG);
+        out.write(0x02);
+        out.write(0x00); out.write(0x00);
+
+        // Subsequent order to verify stream synchronization: GSCOL Color 2 = Red
+        out.write(GocaConstants.G_GSCOL);
+        out.write(0x02);
+
+        // G_GBIMGC (0x91): Second image tile
+        out.write(GocaConstants.G_GBIMGC);
+        out.write(0x06);
+        out.write(0x00); out.write(0x00);
+        out.write(0x00); out.write(0x50);
+        out.write(0x00); out.write(0x50);
+
+        out.write(GocaConstants.G_GIMD);
+        out.write(0x0A);
+        out.write(new byte[] { (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA, (byte)0xAA });
+
+        out.write(GocaConstants.G_GEIMG);
+        out.write(0x02);
+        out.write(0x00); out.write(0x00);
+
+        byte[] stream = out.toByteArray();
+        decoder.decodeStream(stream, 0, stream.length);
+
+        assertTrue(plane.hasContent(), "Expected plane to have content after IMON GOCA decoding");
+        int mappedX = plane.mapX(377);
+        int mappedY = plane.mapY(494);
+        assertEquals(897, mappedX);
+        assertEquals(64, mappedY);
+
+        int[] rgb = plane.getRgbBuffer();
+        int pixelAtImg = rgb[mappedY * 1040 + mappedX];
+        assertNotEquals(0, pixelAtImg, "Pixel at image location should be rendered");
+    }
+
     @Test
     public void testDirectObjectControlSf24() {
         haus.nightmare.lib3270j.screen.ScreenBuffer sb = new haus.nightmare.lib3270j.screen.ScreenBuffer(

lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMTest.java

@@ -84,6 +84,41 @@ public class TelnetFSMTest {
         ConnectionConfig c4 = ConnectionConfig.parseHostString("non-e:vm.ibm.com", 23, TerminalModel.IBM_3279_4);
         assertFalse(c4.isTn3270eEnabled());
         assertEquals("vm.ibm.com", c4.getHost());
+
+        ConnectionConfig c5 = ConnectionConfig.parseHostString("00C2@mvs.hugfreevikings.wtf:1023", 23, TerminalModel.IBM_3279_4);
+        assertEquals("mvs.hugfreevikings.wtf", c5.getHost());
+        assertEquals(1023, c5.getPort());
+        assertEquals("00C2", c5.getLuName());
+
+        ConnectionConfig c6 = ConnectionConfig.parseHostString("L:TSO01@secure.mvs.com:992", 23, TerminalModel.IBM_3279_4);
+        assertTrue(c6.isUseTls());
+        assertEquals("secure.mvs.com", c6.getHost());
+        assertEquals(992, c6.getPort());
+        assertEquals("TSO01", c6.getLuName());
+    }
+
+    @Test
+    public void testPlainTn3270TTypeWithLuName() {
+        config.setTn3270eEnabled(false);
+        config.setLuName("00C2");
+        fsm.onConnected();
+
+        feedBytes(TelnetConstants.IAC, TelnetConstants.DO, TelnetConstants.TELOPT_TTYPE);
+        // Host sends SB TTYPE SEND
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TTYPE,
+                  TelnetConstants.TELQUAL_SEND,
+                  TelnetConstants.IAC, TelnetConstants.SE);
+
+        boolean foundTtypeLu = false;
+        for (byte[] pkt : connection.sentData) {
+            String s = new String(pkt, java.nio.charset.StandardCharsets.ISO_8859_1);
+            if (s.contains("IBM-3279-4-E@00C2")) {
+                foundTtypeLu = true;
+                break;
+            }
+        }
+        assertTrue(foundTtypeLu, "Plain TN3270 TTYPE IS must append @<luName> when configured");
+        assertEquals("00C2", fsm.getConnectedLu());
     }
 
     @Test