fix mouse selection
[fanfix.git] / src / jexer / TEditorWidget.java
index 6fed1fc818f05356f02e34b88dc7f9bd429e20e9..a329dfa347b770dcb279140a1c5ef170f72aab64 100644 (file)
@@ -3,7 +3,7 @@
  *
  * The MIT License (MIT)
  *
- * Copyright (C) 2017 Kevin Lamonte
+ * Copyright (C) 2019 Kevin Lamonte
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  */
 package jexer;
 
+import java.io.IOException;
+
 import jexer.bits.CellAttributes;
+import jexer.bits.StringUtils;
+import jexer.event.TCommandEvent;
 import jexer.event.TKeypressEvent;
 import jexer.event.TMouseEvent;
+import jexer.event.TResizeEvent;
 import jexer.teditor.Document;
 import jexer.teditor.Line;
 import jexer.teditor.Word;
+import static jexer.TCommand.*;
 import static jexer.TKeypress.*;
 
 /**
  * TEditorWidget displays an editable text document.  It is unaware of
  * scrolling behavior, but can respond to mouse and keyboard events.
  */
-public final class TEditorWidget extends TWidget {
+public class TEditorWidget extends TWidget implements EditMenuUser {
+
+    // ------------------------------------------------------------------------
+    // Constants --------------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * The number of lines to scroll on mouse wheel up/down.
+     */
+    private static final int wheelScrollSize = 3;
+
+    // ------------------------------------------------------------------------
+    // Variables --------------------------------------------------------------
+    // ------------------------------------------------------------------------
 
     /**
      * The document being edited.
      */
     private Document document;
 
+    /**
+     * The default color for the TEditor class.
+     */
+    private CellAttributes defaultColor = null;
+
+    /**
+     * The topmost line number in the visible area.  0-based.
+     */
+    private int topLine = 0;
+
+    /**
+     * The leftmost column number in the visible area.  0-based.
+     */
+    private int leftColumn = 0;
+
+    /**
+     * If true, the mouse is dragging a selection.
+     */
+    private boolean inSelection = false;
+
+    /**
+     * Selection starting column.
+     */
+    private int selectionColumn0;
+
+    /**
+     * Selection starting line.
+     */
+    private int selectionLine0;
+
+    /**
+     * Selection ending column.
+     */
+    private int selectionColumn1;
+
+    /**
+     * Selection ending line.
+     */
+    private int selectionLine1;
+
+    // ------------------------------------------------------------------------
+    // Constructors -----------------------------------------------------------
+    // ------------------------------------------------------------------------
+
     /**
      * Public constructor.
      *
@@ -64,57 +127,148 @@ public final class TEditorWidget extends TWidget {
         super(parent, x, y, width, height);
 
         setCursorVisible(true);
-        document = new Document(text);
+
+        defaultColor = getTheme().getColor("teditor");
+        document = new Document(text, defaultColor);
     }
 
+    // ------------------------------------------------------------------------
+    // Event handlers ---------------------------------------------------------
+    // ------------------------------------------------------------------------
+
     /**
-     * Draw the text box.
+     * Handle mouse press events.
+     *
+     * @param mouse mouse button press event
      */
     @Override
-    public void draw() {
-        // Setup my color
-        CellAttributes color = getTheme().getColor("teditor");
+    public void onMouseDown(final TMouseEvent mouse) {
+        if (mouse.isMouseWheelUp()) {
+            for (int i = 0; i < wheelScrollSize; i++) {
+                if (topLine > 0) {
+                    topLine--;
+                    alignDocument(false);
+                }
+            }
+            return;
+        }
+        if (mouse.isMouseWheelDown()) {
+            for (int i = 0; i < wheelScrollSize; i++) {
+                if (topLine < document.getLineCount() - 1) {
+                    topLine++;
+                    alignDocument(true);
+                }
+            }
+            return;
+        }
 
-        int lineNumber = document.getLineNumber();
-        for (int i = 0; i < getHeight(); i++) {
-            // Background line
-            getScreen().hLineXY(0, i, getWidth(), ' ', color);
+        if (mouse.isMouse1()) {
+            // Selection.
+            inSelection = true;
+            selectionColumn0 = leftColumn + mouse.getX();
+            selectionLine0 = topLine + mouse.getY();
+            selectionColumn1 = selectionColumn0;
+            selectionLine1 = selectionLine0;
 
-            // Now draw document's line
-            if (lineNumber + i < document.getLineCount()) {
-                Line line = document.getLine(lineNumber + i);
-                int x = 0;
-                for (Word word: line.getWords()) {
-                    getScreen().putStringXY(x, i, word.getText(),
-                        word.getColor());
-                    x += word.getDisplayLength();
-                    if (x > getWidth()) {
-                        break;
-                    }
+            // Set the row and column
+            int newLine = topLine + mouse.getY();
+            int newX = leftColumn + mouse.getX();
+            if (newLine > document.getLineCount() - 1) {
+                // Go to the end
+                document.setLineNumber(document.getLineCount() - 1);
+                document.end();
+                if (newLine > document.getLineCount() - 1) {
+                    setCursorY(document.getLineCount() - 1 - topLine);
+                } else {
+                    setCursorY(mouse.getY());
+                }
+                alignCursor();
+                if (inSelection) {
+                    selectionColumn1 = document.getCursor();
+                    selectionLine1 = document.getLineNumber();
                 }
+                return;
             }
+
+            document.setLineNumber(newLine);
+            setCursorY(mouse.getY());
+            if (newX >= document.getCurrentLine().getDisplayLength()) {
+                document.end();
+                alignCursor();
+            } else {
+                document.setCursor(newX);
+                setCursorX(mouse.getX());
+            }
+            if (inSelection) {
+                selectionColumn1 = document.getCursor();
+                selectionLine1 = document.getLineNumber();
+            }
+            return;
+        } else {
+            inSelection = false;
         }
 
+        // Pass to children
+        super.onMouseDown(mouse);
     }
 
     /**
-     * Handle mouse press events.
+     * Handle mouse motion events.
      *
-     * @param mouse mouse button press event
+     * @param mouse mouse motion event
      */
     @Override
-    public void onMouseDown(final TMouseEvent mouse) {
-        if (mouse.isMouseWheelUp()) {
-            document.up();
-            return;
-        }
-        if (mouse.isMouseWheelDown()) {
-            document.down();
+    public void onMouseMotion(final TMouseEvent mouse) {
+
+        if (mouse.isMouse1()) {
+            // Selection.
+            if (inSelection) {
+                selectionColumn1 = leftColumn + mouse.getX();
+                selectionLine1 = topLine + mouse.getY();
+            } else {
+                inSelection = true;
+                selectionColumn0 = leftColumn + mouse.getX();
+                selectionLine0 = topLine + mouse.getY();
+                selectionColumn1 = selectionColumn0;
+                selectionLine1 = selectionLine0;
+            }
+
+            // Set the row and column
+            int newLine = topLine + mouse.getY();
+            int newX = leftColumn + mouse.getX();
+            if (newLine > document.getLineCount() - 1) {
+                // Go to the end
+                document.setLineNumber(document.getLineCount() - 1);
+                document.end();
+                if (newLine > document.getLineCount() - 1) {
+                    setCursorY(document.getLineCount() - 1 - topLine);
+                } else {
+                    setCursorY(mouse.getY());
+                }
+                alignCursor();
+                if (inSelection) {
+                    selectionColumn1 = document.getCursor();
+                    selectionLine1 = document.getLineNumber();
+                }
+                return;
+            }
+
+            document.setLineNumber(newLine);
+            setCursorY(mouse.getY());
+            if (newX >= document.getCurrentLine().getDisplayLength()) {
+                document.end();
+                alignCursor();
+            } else {
+                document.setCursor(newX);
+                setCursorX(mouse.getX());
+            }
+            if (inSelection) {
+                selectionColumn1 = document.getCursor();
+                selectionLine1 = document.getLineNumber();
+            }
             return;
         }
 
-        // TODO: click sets row and column
-
         // Pass to children
         super.onMouseDown(mouse);
     }
@@ -126,44 +280,695 @@ public final class TEditorWidget extends TWidget {
      */
     @Override
     public void onKeypress(final TKeypressEvent keypress) {
-        if (keypress.equals(kbLeft)) {
+        if (keypress.getKey().isShift()) {
+            // Selection.
+            if (!inSelection) {
+                inSelection = true;
+                selectionColumn0 = document.getCursor();
+                selectionLine0 = document.getLineNumber();
+                selectionColumn1 = selectionColumn0;
+                selectionLine1 = selectionLine0;
+            }
+        } else {
+            if (keypress.equals(kbLeft)
+                || keypress.equals(kbRight)
+                || keypress.equals(kbUp)
+                || keypress.equals(kbDown)
+                || keypress.equals(kbPgDn)
+                || keypress.equals(kbPgUp)
+                || keypress.equals(kbHome)
+                || keypress.equals(kbEnd)
+            ) {
+                // Non-shifted navigation keys disable selection.
+                inSelection = false;
+            }
+        }
+
+        if (keypress.equals(kbLeft)
+            || keypress.equals(kbShiftLeft)
+        ) {
             document.left();
-        } else if (keypress.equals(kbRight)) {
+            alignTopLine(false);
+        } else if (keypress.equals(kbRight)
+            || keypress.equals(kbShiftRight)
+        ) {
             document.right();
-        } else if (keypress.equals(kbUp)) {
+            alignTopLine(true);
+        } else if (keypress.equals(kbAltLeft)
+            || keypress.equals(kbCtrlLeft)
+            || keypress.equals(kbAltShiftLeft)
+            || keypress.equals(kbCtrlShiftLeft)
+        ) {
+            document.backwardsWord();
+            alignTopLine(false);
+        } else if (keypress.equals(kbAltRight)
+            || keypress.equals(kbCtrlRight)
+            || keypress.equals(kbAltShiftRight)
+            || keypress.equals(kbCtrlShiftRight)
+        ) {
+            document.forwardsWord();
+            alignTopLine(true);
+        } else if (keypress.equals(kbUp)
+            || keypress.equals(kbShiftUp)
+        ) {
             document.up();
-        } else if (keypress.equals(kbDown)) {
+            alignTopLine(false);
+        } else if (keypress.equals(kbDown)
+            || keypress.equals(kbShiftDown)
+        ) {
             document.down();
-        } else if (keypress.equals(kbPgUp)) {
+            alignTopLine(true);
+        } else if (keypress.equals(kbPgUp)
+            || keypress.equals(kbShiftPgUp)
+        ) {
             document.up(getHeight() - 1);
-        } else if (keypress.equals(kbPgDn)) {
+            alignTopLine(false);
+        } else if (keypress.equals(kbPgDn)
+            || keypress.equals(kbShiftPgDn)
+        ) {
             document.down(getHeight() - 1);
-        } else if (keypress.equals(kbHome)) {
-            document.home();
-        } else if (keypress.equals(kbEnd)) {
-            document.end();
-        } else if (keypress.equals(kbCtrlHome)) {
+            alignTopLine(true);
+        } else if (keypress.equals(kbHome)
+            || keypress.equals(kbShiftHome)
+        ) {
+            if (document.home()) {
+                leftColumn = 0;
+                if (leftColumn < 0) {
+                    leftColumn = 0;
+                }
+                setCursorX(0);
+            }
+        } else if (keypress.equals(kbEnd)
+            || keypress.equals(kbShiftEnd)
+        ) {
+            if (document.end()) {
+                alignCursor();
+            }
+        } else if (keypress.equals(kbCtrlHome)
+            || keypress.equals(kbCtrlShiftHome)
+        ) {
             document.setLineNumber(0);
             document.home();
-        } else if (keypress.equals(kbCtrlEnd)) {
+            topLine = 0;
+            leftColumn = 0;
+            setCursorX(0);
+            setCursorY(0);
+        } else if (keypress.equals(kbCtrlEnd)
+            || keypress.equals(kbCtrlShiftEnd)
+        ) {
             document.setLineNumber(document.getLineCount() - 1);
             document.end();
+            alignTopLine(false);
         } else if (keypress.equals(kbIns)) {
             document.setOverwrite(!document.getOverwrite());
         } else if (keypress.equals(kbDel)) {
-            document.del();
-        } else if (keypress.equals(kbBackspace)) {
-            document.backspace();
+            if (inSelection) {
+                deleteSelection();
+            } else {
+                document.del();
+            }
+            alignCursor();
+        } else if (keypress.equals(kbBackspace)
+            || keypress.equals(kbBackspaceDel)
+        ) {
+            if (inSelection) {
+                deleteSelection();
+            } else {
+                document.backspace();
+            }
+            alignTopLine(false);
+        } else if (keypress.equals(kbTab)) {
+            deleteSelection();
+            // Add spaces until we hit modulo 8.
+            for (int i = document.getCursor(); (i + 1) % 8 != 0; i++) {
+                document.addChar(' ');
+            }
+            alignCursor();
+        } else if (keypress.equals(kbEnter)) {
+            deleteSelection();
+            document.enter();
+            alignTopLine(true);
         } else if (!keypress.getKey().isFnKey()
             && !keypress.getKey().isAlt()
             && !keypress.getKey().isCtrl()
         ) {
             // Plain old keystroke, process it
+            deleteSelection();
             document.addChar(keypress.getKey().getChar());
+            alignCursor();
         } else {
             // Pass other keys (tab etc.) on to TWidget
             super.onKeypress(keypress);
         }
+
+        if (inSelection) {
+            selectionColumn1 = document.getCursor();
+            selectionLine1 = document.getLineNumber();
+        }
+    }
+
+    /**
+     * Method that subclasses can override to handle window/screen resize
+     * events.
+     *
+     * @param resize resize event
+     */
+    @Override
+    public void onResize(final TResizeEvent resize) {
+        // Change my width/height, and pull the cursor in as needed.
+        if (resize.getType() == TResizeEvent.Type.WIDGET) {
+            setWidth(resize.getWidth());
+            setHeight(resize.getHeight());
+            // See if the cursor is now outside the window, and if so move
+            // things.
+            if (getCursorX() >= getWidth()) {
+                leftColumn += getCursorX() - (getWidth() - 1);
+                setCursorX(getWidth() - 1);
+            }
+            if (getCursorY() >= getHeight()) {
+                topLine += getCursorY() - (getHeight() - 1);
+                setCursorY(getHeight() - 1);
+            }
+        } else {
+            // Let superclass handle it
+            super.onResize(resize);
+        }
+    }
+
+    /**
+     * Handle posted command events.
+     *
+     * @param command command event
+     */
+    @Override
+    public void onCommand(final TCommandEvent command) {
+        if (command.equals(cmCut)) {
+            // Copy text to clipboard, and then remove it.
+            copySelection();
+            deleteSelection();
+            return;
+        }
+
+        if (command.equals(cmCopy)) {
+            // Copy text to clipboard.
+            copySelection();
+            return;
+        }
+
+        if (command.equals(cmPaste)) {
+            // Delete selected text, then paste text from clipboard.
+            deleteSelection();
+
+            String text = getClipboard().pasteText();
+            if (text != null) {
+                for (int i = 0; i < text.length(); ) {
+                    int ch = text.codePointAt(i);
+                    onKeypress(new TKeypressEvent(false, 0, ch, false, false,
+                            false));
+                    i += Character.charCount(ch);
+                }
+            }
+            return;
+        }
+
+        if (command.equals(cmClear)) {
+            // Remove text.
+            deleteSelection();
+            return;
+        }
+
+    }
+
+    // ------------------------------------------------------------------------
+    // TWidget ----------------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * Draw the text box.
+     */
+    @Override
+    public void draw() {
+        CellAttributes selectedColor = getTheme().getColor("teditor.selected");
+
+        int startCol = selectionColumn0;
+        int startRow = selectionLine0;
+        int endCol = selectionColumn1;
+        int endRow = selectionLine1;
+
+        if (((selectionColumn1 < selectionColumn0)
+                && (selectionLine1 <= selectionLine0))
+            || ((selectionColumn1 <= selectionColumn0)
+                && (selectionLine1 < selectionLine0))
+        ) {
+            // The user selected from bottom-right to top-left.  Reverse the
+            // coordinates for the inverted section.
+            startCol = selectionColumn1;
+            startRow = selectionLine1;
+            endCol = selectionColumn0;
+            endRow = selectionLine0;
+        }
+
+        for (int i = 0; i < getHeight(); i++) {
+            // Background line
+            getScreen().hLineXY(0, i, getWidth(), ' ', defaultColor);
+
+            // Now draw document's line
+            if (topLine + i < document.getLineCount()) {
+                Line line = document.getLine(topLine + i);
+                int x = 0;
+                for (Word word: line.getWords()) {
+                    // For now, we are cheating: draw outside the left region
+                    // if needed and let screen do the clipping.
+                    getScreen().putStringXY(x - leftColumn, i, word.getText(),
+                        word.getColor());
+                    x += word.getDisplayLength();
+                    if (x - leftColumn > getWidth()) {
+                        break;
+                    }
+                }
+
+                // Highlight selected region
+                if (inSelection) {
+                    if (startRow == endRow) {
+                        if (topLine + i == startRow) {
+                            for (x = startCol; x <= endCol; x++) {
+                                putAttrXY(x - leftColumn, i, selectedColor);
+                            }
+                        }
+                    } else {
+                        if (topLine + i == startRow) {
+                            for (x = startCol; x < line.getDisplayLength(); x++) {
+                                putAttrXY(x - leftColumn, i, selectedColor);
+                            }
+                        } else if (topLine + i == endRow) {
+                            for (x = 0; x <= endCol; x++) {
+                                putAttrXY(x - leftColumn, i, selectedColor);
+                            }
+                        } else if ((topLine + i >= startRow)
+                            && (topLine + i <= endRow)
+                        ) {
+                            for (x = 0; x < getWidth(); x++) {
+                                putAttrXY(x, i, selectedColor);
+                            }
+                        }
+                    }
+                }
+
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    // TEditorWidget ----------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * Align visible area with document current line.
+     *
+     * @param topLineIsTop if true, make the top visible line the document
+     * current line if it was off-screen.  If false, make the bottom visible
+     * line the document current line.
+     */
+    private void alignTopLine(final boolean topLineIsTop) {
+        int line = document.getLineNumber();
+
+        if ((line < topLine) || (line > topLine + getHeight() - 1)) {
+            // Need to move topLine to bring document back into view.
+            if (topLineIsTop) {
+                topLine = line - (getHeight() - 1);
+                if (topLine < 0) {
+                    topLine = 0;
+                }
+                assert (topLine >= 0);
+            } else {
+                topLine = line;
+                assert (topLine >= 0);
+            }
+        }
+
+        /*
+        System.err.println("line " + line + " topLine " + topLine);
+        */
+
+        // Document is in view, let's set cursorY
+        assert (line >= topLine);
+        setCursorY(line - topLine);
+        alignCursor();
+    }
+
+    /**
+     * Align document current line with visible area.
+     *
+     * @param topLineIsTop if true, make the top visible line the document
+     * current line if it was off-screen.  If false, make the bottom visible
+     * line the document current line.
+     */
+    private void alignDocument(final boolean topLineIsTop) {
+        int line = document.getLineNumber();
+        int cursor = document.getCursor();
+
+        if ((line < topLine) || (line > topLine + getHeight() - 1)) {
+            // Need to move document to ensure it fits view.
+            if (topLineIsTop) {
+                document.setLineNumber(topLine);
+            } else {
+                document.setLineNumber(topLine + (getHeight() - 1));
+            }
+            if (cursor < document.getCurrentLine().getDisplayLength()) {
+                document.setCursor(cursor);
+            }
+        }
+
+        /*
+        System.err.println("getLineNumber() " + document.getLineNumber() +
+            " topLine " + topLine);
+        */
+
+        // Document is in view, let's set cursorY
+        setCursorY(document.getLineNumber() - topLine);
+        alignCursor();
+    }
+
+    /**
+     * Align visible cursor with document cursor.
+     */
+    private void alignCursor() {
+        int width = getWidth();
+
+        int desiredX = document.getCursor() - leftColumn;
+        if (desiredX < 0) {
+            // We need to push the screen to the left.
+            leftColumn = document.getCursor();
+        } else if (desiredX > width - 1) {
+            // We need to push the screen to the right.
+            leftColumn = document.getCursor() - (width - 1);
+        }
+
+        /*
+        System.err.println("document cursor " + document.getCursor() +
+            " leftColumn " + leftColumn);
+        */
+
+
+        setCursorX(document.getCursor() - leftColumn);
+    }
+
+    /**
+     * Get the number of lines in the underlying Document.
+     *
+     * @return the number of lines
+     */
+    public int getLineCount() {
+        return document.getLineCount();
+    }
+
+    /**
+     * Get the current visible top row number.  1-based.
+     *
+     * @return the visible top row number.  Row 1 is the first row.
+     */
+    public int getVisibleRowNumber() {
+        return topLine + 1;
+    }
+
+    /**
+     * Set the current visible row number.  1-based.
+     *
+     * @param row the new visible row number.  Row 1 is the first row.
+     */
+    public void setVisibleRowNumber(final int row) {
+        assert (row > 0);
+        if ((row > 0) && (row < document.getLineCount())) {
+            topLine = row - 1;
+            alignDocument(true);
+        }
+    }
+
+    /**
+     * Get the current editing row number.  1-based.
+     *
+     * @return the editing row number.  Row 1 is the first row.
+     */
+    public int getEditingRowNumber() {
+        return document.getLineNumber() + 1;
+    }
+
+    /**
+     * Set the current editing row number.  1-based.
+     *
+     * @param row the new editing row number.  Row 1 is the first row.
+     */
+    public void setEditingRowNumber(final int row) {
+        assert (row > 0);
+        if ((row > 0) && (row < document.getLineCount())) {
+            document.setLineNumber(row - 1);
+            alignTopLine(true);
+        }
+    }
+
+    /**
+     * Set the current visible column number.  1-based.
+     *
+     * @return the visible column number.  Column 1 is the first column.
+     */
+    public int getVisibleColumnNumber() {
+        return leftColumn + 1;
+    }
+
+    /**
+     * Set the current visible column number.  1-based.
+     *
+     * @param column the new visible column number.  Column 1 is the first
+     * column.
+     */
+    public void setVisibleColumnNumber(final int column) {
+        assert (column > 0);
+        if ((column > 0) && (column < document.getLineLengthMax())) {
+            leftColumn = column - 1;
+            alignDocument(true);
+        }
+    }
+
+    /**
+     * Get the current editing column number.  1-based.
+     *
+     * @return the editing column number.  Column 1 is the first column.
+     */
+    public int getEditingColumnNumber() {
+        return document.getCursor() + 1;
+    }
+
+    /**
+     * Set the current editing column number.  1-based.
+     *
+     * @param column the new editing column number.  Column 1 is the first
+     * column.
+     */
+    public void setEditingColumnNumber(final int column) {
+        if ((column > 0) && (column < document.getLineLength())) {
+            document.setCursor(column - 1);
+            alignCursor();
+        }
+    }
+
+    /**
+     * Get the maximum possible row number.  1-based.
+     *
+     * @return the maximum row number.  Row 1 is the first row.
+     */
+    public int getMaximumRowNumber() {
+        return document.getLineCount() + 1;
+    }
+
+    /**
+     * Get the maximum possible column number.  1-based.
+     *
+     * @return the maximum column number.  Column 1 is the first column.
+     */
+    public int getMaximumColumnNumber() {
+        return document.getLineLengthMax() + 1;
+    }
+
+    /**
+     * Get the dirty value.
+     *
+     * @return true if the buffer is dirty
+     */
+    public boolean isDirty() {
+        return document.isDirty();
+    }
+
+    /**
+     * Save contents to file.
+     *
+     * @param filename file to save to
+     * @throws IOException if a java.io operation throws
+     */
+    public void saveToFilename(final String filename) throws IOException {
+        document.saveToFilename(filename);
+    }
+
+    /**
+     * Delete text within the selection bounds.
+     */
+    private void deleteSelection() {
+        if (inSelection == false) {
+            return;
+        }
+        inSelection = false;
+
+        int startCol = selectionColumn0;
+        int startRow = selectionLine0;
+        int endCol = selectionColumn1;
+        int endRow = selectionLine1;
+
+        if (((selectionColumn1 < selectionColumn0)
+                && (selectionLine1 <= selectionLine0))
+            || ((selectionColumn1 <= selectionColumn0)
+                && (selectionLine1 < selectionLine0))
+        ) {
+            // The user selected from bottom-right to top-left.  Reverse the
+            // coordinates for the inverted section.
+            startCol = selectionColumn1;
+            startRow = selectionLine1;
+            endCol = selectionColumn0;
+            endRow = selectionLine0;
+        }
+
+        // Place the cursor on the selection end, and "press backspace" until
+        // the cursor matches the selection start.
+        document.setLineNumber(endRow);
+        document.setCursor(endCol + 1);
+        while (!((document.getLineNumber() == startRow)
+                && (document.getCursor() == startCol))
+        ) {
+            document.backspace();
+        }
+        alignTopLine(true);
+    }
+
+    /**
+     * Copy text within the selection bounds to clipboard.
+     */
+    private void copySelection() {
+        if (inSelection == false) {
+            return;
+        }
+
+        int startCol = selectionColumn0;
+        int startRow = selectionLine0;
+        int endCol = selectionColumn1;
+        int endRow = selectionLine1;
+
+        if (((selectionColumn1 < selectionColumn0)
+                && (selectionLine1 <= selectionLine0))
+            || ((selectionColumn1 <= selectionColumn0)
+                && (selectionLine1 < selectionLine0))
+        ) {
+            // The user selected from bottom-right to top-left.  Reverse the
+            // coordinates for the inverted section.
+            startCol = selectionColumn1;
+            startRow = selectionLine1;
+            endCol = selectionColumn0;
+            endRow = selectionLine0;
+        }
+
+        StringBuilder sb = new StringBuilder();
+
+        if (endRow > startRow) {
+            // First line
+            String line = document.getLine(startRow).getRawString();
+            int x = 0;
+            for (int i = 0; i < line.length(); ) {
+                int ch = line.codePointAt(i);
+
+                if (x >= startCol) {
+                    sb.append(Character.toChars(ch));
+                }
+                x += StringUtils.width(ch);
+                i += Character.charCount(ch);
+            }
+            sb.append("\n");
+
+            // Middle lines
+            for (int y = startRow + 1; y < endRow; y++) {
+                sb.append(document.getLine(y).getRawString());
+                sb.append("\n");
+            }
+
+            // Final line
+            line = document.getLine(endRow).getRawString();
+            x = 0;
+            for (int i = 0; i < line.length(); ) {
+                int ch = line.codePointAt(i);
+
+                if (x > endCol) {
+                    break;
+                }
+
+                sb.append(Character.toChars(ch));
+                x += StringUtils.width(ch);
+                i += Character.charCount(ch);
+            }
+        } else {
+            assert (startRow == endRow);
+
+            // Only one line
+            String line = document.getLine(startRow).getRawString();
+            int x = 0;
+            for (int i = 0; i < line.length(); ) {
+                int ch = line.codePointAt(i);
+
+                if ((x >= startCol) && (x <= endCol)) {
+                    sb.append(Character.toChars(ch));
+                }
+
+                x += StringUtils.width(ch);
+                i += Character.charCount(ch);
+            }
+        }
+
+        getClipboard().copyText(sb.toString());
+    }
+
+    // ------------------------------------------------------------------------
+    // EditMenuUser -----------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * Check if the cut menu item should be enabled.
+     *
+     * @return true if the cut menu item should be enabled
+     */
+    public boolean isEditMenuCut() {
+        return true;
+    }
+
+    /**
+     * Check if the copy menu item should be enabled.
+     *
+     * @return true if the copy menu item should be enabled
+     */
+    public boolean isEditMenuCopy() {
+        return true;
+    }
+
+    /**
+     * Check if the paste menu item should be enabled.
+     *
+     * @return true if the paste menu item should be enabled
+     */
+    public boolean isEditMenuPaste() {
+        return true;
+    }
+
+    /**
+     * Check if the clear menu item should be enabled.
+     *
+     * @return true if the clear menu item should be enabled
+     */
+    public boolean isEditMenuClear() {
+        return true;
     }
 
 }