#103 Push screens from ECMA48 to TTerminalWidget

src/jexer/TTerminalWidget.java

@@ -135,12 +135,7 @@ public class TTerminalWidget extends TScrollableWidget
     /**
      * If true, the display has changed and needs updating.
      */
-    private List<String> dirtyQueue = new ArrayList<String>();
-
-    /**
-     * Time that the display was last updated.
-     */
-    private long lastUpdateTime = 0;
+    private List<List<DisplayLine>> dirtyQueue = new ArrayList<List<DisplayLine>>();
 
     /**
      * If true, hide the mouse after typing a keystroke.
@@ -642,50 +637,21 @@ public class TTerminalWidget extends TScrollableWidget
 
         int width = getDisplayWidth();
 
-        boolean syncEmulator = false;
+        // Get the very first display.
+        if (display == null) {
+            width = readEmulatorDisplay();
+        }
 
         // If the emulator notified of an update, sync.
         synchronized (dirtyQueue) {
             if (dirtyQueue.size() > 0) {
-                dirtyQueue.remove(dirtyQueue.size() - 1);
-                syncEmulator = true;
+                // We will be dropping frames to keep up.
+                display = dirtyQueue.remove(dirtyQueue.size() - 1);
+                dirtyQueue.clear();
             }
         }
 
-        // If it has been longer than 250 milliseconds, sync.
-        long now = System.currentTimeMillis();
-        if ((now - lastUpdateTime) > 250) {
-            syncEmulator = true;
-        }
-        lastUpdateTime = now;
-
-        if ((syncEmulator == true)
-            || (display == null)
-        ) {
-            // We want to minimize the amount of time we have the emulator
-            // locked.  Grab a copy of its display.
-            synchronized (emulator) {
-                // Update the scroll bars
-                reflowData();
-
-                if (!isDrawable()) {
-                    // We lost the connection, onShellExit() called an action
-                    // that ultimately removed this widget from the UI
-                    // hierarchy, so no one cares if we update the display.
-                    // Bail out.
-                    return;
-                }
-
-                if ((display == null) || emulator.isReading()) {
-                    display = emulator.getVisibleDisplay(getHeight(),
-                        -getVerticalValue());
-                    assert (display.size() == getHeight());
-                }
-                width = emulator.getWidth();
-            }
-        }
-
-        // Now draw the emulator screen
+        // Draw the emulator screen.
         int row = 0;
         for (DisplayLine line: display) {
             int widthMax = width;
@@ -840,14 +806,10 @@ public class TTerminalWidget extends TScrollableWidget
     // ------------------------------------------------------------------------
 
     /**
-     * Set the dirty flag.
+     * Update the display to account for a change in scrollback.
      */
-    public void setDirty() {
-        synchronized (dirtyQueue) {
-            if (dirtyQueue.size() == 0) {
-                dirtyQueue.add("dirty");
-            }
-        }
+    private void setDirty() {
+        readEmulatorDisplay();
     }
 
     /**
@@ -914,6 +876,9 @@ public class TTerminalWidget extends TScrollableWidget
      */
     public boolean hasHiddenMouse() {
         if (emulator != null) {
+            if (!emulator.isReading()) {
+                typingHidMouse = false;
+            }
             boolean hiddenMouse = (emulator.hasHiddenMousePointer()
                 || typingHidMouse);
             if (hiddenMouse) {
@@ -1429,30 +1394,42 @@ public class TTerminalWidget extends TScrollableWidget
     }
 
     /**
-     * Get the scrollback buffer from the emulator.
+     * Get the visible display buffer from the emulator.
      *
-     * @return the scrollback buffer, all the lines that have scrolled off
-     * screen
+     * @return the width of the display, or -1 if the display was not read
      */
-    public final List<DisplayLine> getScrollbackBuffer() {
-        ArrayList<DisplayLine> buffer = new ArrayList<DisplayLine>();
-        for (DisplayLine line: emulator.getScrollbackBuffer()) {
-            buffer.add(new DisplayLine(line));
-        }
-        return buffer;
+    private int readEmulatorDisplay() {
+
+        List<DisplayLine> currentDisplay = null;
+        int width = 80;
+
+        // Synchronize against the emulator so we don't stomp on its reader
+        // thread.
+        synchronized (emulator) {
+            // Update the scroll bars
+            reflowData();
+
+            if (!isDrawable()) {
+                // We lost the connection, onShellExit() called an action
+                // that ultimately removed this widget from the UI hierarchy,
+                // so no one cares if we update the display.  Bail out.
+                return -1;
             }
 
-    /**
-     * Get the display buffer from the emulator.
-     *
-     * @return the display buffer, the lines that are on the visible screen
-     */
-    public final List<DisplayLine> getDisplayBuffer() {
-        ArrayList<DisplayLine> buffer = new ArrayList<DisplayLine>();
-        for (DisplayLine line: emulator.getDisplayBuffer()) {
-            buffer.add(new DisplayLine(line));
+            if (emulator.isReading()) {
+                currentDisplay = emulator.getVisibleDisplay(getHeight(),
+                    -getVerticalValue());
+                assert (display.size() == getHeight());
             }
-        return buffer;
+            width = emulator.getWidth();
+        }
+        if (currentDisplay != null) {
+            synchronized (dirtyQueue) {
+                dirtyQueue.add(currentDisplay);
+            }
+        }
+
+        return width;
     }
 
     /**
@@ -1506,6 +1483,18 @@ public class TTerminalWidget extends TScrollableWidget
     // DisplayListener --------------------------------------------------------
     // ------------------------------------------------------------------------
 
+    /**
+     * Called by emulator when fresh data has come in (push).
+     *
+     * @param display the updated display
+     */
+    public void updateDisplay(final List<DisplayLine> display) {
+        synchronized (dirtyQueue) {
+            dirtyQueue.add(display);
+        }
+        getApplication().doRepaint();
+    }
+
     /**
      * Called by emulator when fresh data has come in.
      *
@@ -1514,22 +1503,30 @@ public class TTerminalWidget extends TScrollableWidget
      */
     public void displayChanged(final boolean cursorOnly) {
         if (cursorOnly) {
-            TApplication app = getApplication();
-            if (app != null) {
-                app.postEvent(new TMenuEvent(null, TMenu.MID_REPAINT));
-            }
+            getApplication().doRepaint();
             return;
         }
 
+        boolean readDisplay = false;
         synchronized (dirtyQueue) {
-            if (dirtyQueue.size() == 0) {
-                dirtyQueue.add("dirty");
-                TApplication app = getApplication();
-                if (app != null) {
-                    app.postEvent(new TMenuEvent(null, TMenu.MID_REPAINT));
+            if (dirtyQueue.size() > 0) {
+                display = dirtyQueue.remove(0);
             }
         }
+        if (readDisplay) {
+            readEmulatorDisplay();
         }
+        getApplication().doRepaint();
+    }
+
+    /**
+     * Function to call to obtain the number of rows from the bottom to
+     * scroll back when sending updates via updateDisplay().
+     *
+     * @return the number of rows from the bottom to scroll back
+     */
+    public int getScrollBottom() {
+        return -getVerticalValue();
     }
 
     /**

src/jexer/TTextPicture.java

@@ -278,7 +278,7 @@ public class TTextPicture extends TScrollableWidget
     // ------------------------------------------------------------------------
 
     /**
-     * Called by emulator when fresh data has come in.
+     * Called by emulator when fresh data has come in (request poll).
      *
      * @param cursorOnly if true, the screen has not changed but the cursor
      * may be on a different location.
@@ -287,6 +287,25 @@ public class TTextPicture extends TScrollableWidget
         // Do nothing
     }
 
+    /**
+     * Called by emulator when fresh data has come in (push).
+     *
+     * @param display the updated display
+     */
+    public void updateDisplay(final List<DisplayLine> display) {
+        // Do nothing
+    }
+
+    /**
+     * Function to call to obtain the number of rows from the bottom to
+     * scroll back when sending updates via updateDisplay().
+     *
+     * @return the number of rows from the bottom to scroll back
+     */
+    public int getScrollBottom() {
+        return -getVerticalValue();
+    }
+
     /**
      * Function to call to obtain the display width.
      *

src/jexer/tterminal/DisplayListener.java

@@ -28,6 +28,8 @@
  */
 package jexer.tterminal;
 
+import java.util.List;
+
 /**
  * DisplayListener is used to callback into external UI when data has come in
  * from the remote side.
@@ -35,13 +37,28 @@ package jexer.tterminal;
 public interface DisplayListener {
 
     /**
-     * Function to call when the display needs to be updated.
+     * Function to call when the display needs to be updated (request poll).
      *
      * @param cursorOnly if true, the screen has not changed but the cursor
      * may be on a different location.
      */
     public void displayChanged(final boolean cursorOnly);
 
+    /**
+     * Function to call when the display has updated (push).
+     *
+     * @param display the updated display
+     */
+    public void updateDisplay(final List<DisplayLine> display);
+
+    /**
+     * Function to call to obtain the number of rows from the bottom to
+     * scroll back when sending updates via updateDisplay().
+     *
+     * @return the number of rows from the bottom to scroll back
+     */
+    public int getScrollBottom();
+
     /**
      * Function to call to obtain the display width.
      *

src/jexer/tterminal/ECMA48.java

@@ -266,6 +266,12 @@ public class ECMA48 implements Runnable {
      */
     private boolean screenIsDirty = true;
 
+    /**
+     * When true, synchronized update has already pushed a screen to the
+     * display, so run() should not do it again.
+     */
+    private boolean doNotUpdateDisplay = false;
+
     /**
      * When true, the reader thread is expected to exit.
      */
@@ -860,15 +866,17 @@ public class ECMA48 implements Runnable {
                         }
                     }
                     // Permit my enclosing UI to know that I updated.
-                    if (displayListener != null) {
+                    if ((displayListener != null) && !doNotUpdateDisplay) {
                         if (screenIsDirty) {
-                            displayListener.displayChanged(false);
+                            displayListener.updateDisplay(getVisibleDisplay(
+                                height, displayListener.getScrollBottom()));
                             screenIsDirty = false;
                         } else {
                             displayListener.displayChanged(true);
                             screenIsDirty = false;
                         }
                     }
+                    doNotUpdateDisplay = false;
                 }
                 // System.err.println("end while loop"); System.err.flush();
             } catch (IOException e) {
@@ -2288,7 +2296,8 @@ public class ECMA48 implements Runnable {
                 printCharacter(keypress.getChar());
             }
             if (displayListener != null) {
-                displayListener.displayChanged(false);
+                displayListener.updateDisplay(getVisibleDisplay(
+                    height, displayListener.getScrollBottom()));
                 screenIsDirty = false;
             }
         }
@@ -3804,7 +3813,8 @@ public class ECMA48 implements Runnable {
                             withinSynchronizedUpdate = false;
                             // Permit my enclosing UI to know that I updated.
                             if (displayListener != null) {
-                                displayListener.displayChanged(false);
+                                displayListener.updateDisplay(lastVisibleDisplay);
+                                doNotUpdateDisplay = true;
                             }
                         }
                     }