src/jexer/TField.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2019 Kevin Lamonte
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24  * DEALINGS IN THE SOFTWARE.
  25  *
  26  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  27  * @version 1
  28  */
  29 package jexer;
  30
  31 import jexer.bits.CellAttributes;
  32 import jexer.bits.GraphicsChars;
  33 import jexer.bits.StringUtils;
  34 import jexer.event.TKeypressEvent;
  35 import jexer.event.TMouseEvent;
  36 import static jexer.TKeypress.*;
  37
  38 /**
  39  * TField implements an editable text field.
  40  */
  41 public class TField extends TWidget {
  42
  43     // ------------------------------------------------------------------------
  44     // Variables --------------------------------------------------------------
  45     // ------------------------------------------------------------------------
  46
  47     /**
  48      * Background character for unfilled-in text.
  49      */
  50     protected int backgroundChar = GraphicsChars.HATCH;
  51
  52     /**
  53      * Field text.
  54      */
  55     protected String text = "";
  56
  57     /**
  58      * If true, only allow enough characters that will fit in the width.  If
  59      * false, allow the field to scroll to the right.
  60      */
  61     protected boolean fixed = false;
  62
  63     /**
  64      * Current editing position within text.
  65      */
  66     protected int position = 0;
  67
  68     /**
  69      * Current editing position screen column number.
  70      */
  71     protected int screenPosition = 0;
  72
  73     /**
  74      * Beginning of visible portion.
  75      */
  76     protected int windowStart = 0;
  77
  78     /**
  79      * If true, new characters are inserted at position.
  80      */
  81     protected boolean insertMode = true;
  82
  83     /**
  84      * Remember mouse state.
  85      */
  86     protected TMouseEvent mouse;
  87
  88     /**
  89      * The action to perform when the user presses enter.
  90      */
  91     protected TAction enterAction;
  92
  93     /**
  94      * The action to perform when the text is updated.
  95      */
  96     protected TAction updateAction;
  97
  98     /**
  99      * The color to use when this field is active.
 100      */
 101     private String activeColorKey = "tfield.active";
 102
 103     /**
 104      * The color to use when this field is not active.
 105      */
 106     private String inactiveColorKey = "tfield.inactive";
 107
 108     // ------------------------------------------------------------------------
 109     // Constructors -----------------------------------------------------------
 110     // ------------------------------------------------------------------------
 111
 112     /**
 113      * Public constructor.
 114      *
 115      * @param parent parent widget
 116      * @param x column relative to parent
 117      * @param y row relative to parent
 118      * @param width visible text width
 119      * @param fixed if true, the text cannot exceed the display width
 120      */
 121     public TField(final TWidget parent, final int x, final int y,
 122         final int width, final boolean fixed) {
 123
 124         this(parent, x, y, width, fixed, "", null, null);
 125     }
 126
 127     /**
 128      * Public constructor.
 129      *
 130      * @param parent parent widget
 131      * @param x column relative to parent
 132      * @param y row relative to parent
 133      * @param width visible text width
 134      * @param fixed if true, the text cannot exceed the display width
 135      * @param text initial text, default is empty string
 136      */
 137     public TField(final TWidget parent, final int x, final int y,
 138         final int width, final boolean fixed, final String text) {
 139
 140         this(parent, x, y, width, fixed, text, null, null);
 141     }
 142
 143     /**
 144      * Public constructor.
 145      *
 146      * @param parent parent widget
 147      * @param x column relative to parent
 148      * @param y row relative to parent
 149      * @param width visible text width
 150      * @param fixed if true, the text cannot exceed the display width
 151      * @param text initial text, default is empty string
 152      * @param enterAction function to call when enter key is pressed
 153      * @param updateAction function to call when the text is updated
 154      */
 155     public TField(final TWidget parent, final int x, final int y,
 156         final int width, final boolean fixed, final String text,
 157         final TAction enterAction, final TAction updateAction) {
 158
 159         // Set parent and window
 160         super(parent, x, y, width, 1);
 161
 162         setCursorVisible(true);
 163         this.fixed = fixed;
 164         this.text = text;
 165         this.enterAction = enterAction;
 166         this.updateAction = updateAction;
 167     }
 168
 169     // ------------------------------------------------------------------------
 170     // Event handlers ---------------------------------------------------------
 171     // ------------------------------------------------------------------------
 172
 173     /**
 174      * Returns true if the mouse is currently on the field.
 175      *
 176      * @return if true the mouse is currently on the field
 177      */
 178     protected boolean mouseOnField() {
 179         int rightEdge = getWidth() - 1;
 180         if ((mouse != null)
 181             && (mouse.getY() == 0)
 182             && (mouse.getX() >= 0)
 183             && (mouse.getX() <= rightEdge)
 184         ) {
 185             return true;
 186         }
 187         return false;
 188     }
 189
 190     /**
 191      * Handle mouse button presses.
 192      *
 193      * @param mouse mouse button event
 194      */
 195     @Override
 196     public void onMouseDown(final TMouseEvent mouse) {
 197         this.mouse = mouse;
 198
 199         if ((mouseOnField()) && (mouse.isMouse1())) {
 200             // Move cursor
 201             int deltaX = mouse.getX() - getCursorX();
 202             screenPosition += deltaX;
 203             if (screenPosition > StringUtils.width(text)) {
 204                 screenPosition = StringUtils.width(text);
 205             }
 206             position = screenToTextPosition(screenPosition);
 207             updateCursor();
 208             return;
 209         }
 210     }
 211
 212     /**
 213      * Handle keystrokes.
 214      *
 215      * @param keypress keystroke event
 216      */
 217     @Override
 218     public void onKeypress(final TKeypressEvent keypress) {
 219
 220         if (keypress.equals(kbLeft)) {
 221             if (position > 0) {
 222                 screenPosition -= StringUtils.width(text.codePointBefore(position));
 223                 position -= Character.charCount(text.codePointBefore(position));
 224             }
 225             if (fixed == false) {
 226                 if ((screenPosition == windowStart) && (windowStart > 0)) {
 227                     windowStart -= StringUtils.width(text.codePointAt(
 228                         screenToTextPosition(windowStart)));
 229                 }
 230             }
 231             normalizeWindowStart();
 232             return;
 233         }
 234
 235         if (keypress.equals(kbRight)) {
 236             if (position < text.length()) {
 237                 screenPosition += StringUtils.width(text.codePointAt(position));
 238                 position += Character.charCount(text.codePointAt(position));
 239                 if (fixed == true) {
 240                     if (screenPosition == getWidth()) {
 241                         screenPosition--;
 242                         position -= Character.charCount(text.codePointAt(position));
 243                     }
 244                 } else {
 245                     while ((screenPosition - windowStart +
 246                             StringUtils.width(text.codePointAt(text.length() - 1)))
 247                         > getWidth()
 248                     ) {
 249                         windowStart += StringUtils.width(text.codePointAt(
 250                             screenToTextPosition(windowStart)));
 251                     }
 252                 }
 253             }
 254             assert (position <= text.length());
 255             return;
 256         }
 257
 258         if (keypress.equals(kbEnter)) {
 259             dispatch(true);
 260             return;
 261         }
 262
 263         if (keypress.equals(kbIns)) {
 264             insertMode = !insertMode;
 265             return;
 266         }
 267         if (keypress.equals(kbHome)) {
 268             home();
 269             return;
 270         }
 271
 272         if (keypress.equals(kbEnd)) {
 273             end();
 274             return;
 275         }
 276
 277         if (keypress.equals(kbDel)) {
 278             if ((text.length() > 0) && (position < text.length())) {
 279                 text = text.substring(0, position)
 280                         + text.substring(position + 1);
 281                 screenPosition = StringUtils.width(text.substring(0, position));
 282             }
 283             dispatch(false);
 284             return;
 285         }
 286
 287         if (keypress.equals(kbBackspace) || keypress.equals(kbBackspaceDel)) {
 288             if (position > 0) {
 289                 position -= Character.charCount(text.codePointBefore(position));
 290                 text = text.substring(0, position)
 291                         + text.substring(position + 1);
 292                 screenPosition = StringUtils.width(text.substring(0, position));
 293             }
 294             if (fixed == false) {
 295                 if ((screenPosition >= windowStart)
 296                     && (windowStart > 0)
 297                 ) {
 298                     windowStart -= StringUtils.width(text.codePointAt(
 299                         screenToTextPosition(windowStart)));
 300                 }
 301             }
 302             dispatch(false);
 303             normalizeWindowStart();
 304             return;
 305         }
 306
 307         if (!keypress.getKey().isFnKey()
 308             && !keypress.getKey().isAlt()
 309             && !keypress.getKey().isCtrl()
 310         ) {
 311             // Plain old keystroke, process it
 312             if ((position == text.length())
 313                 && (StringUtils.width(text) < getWidth())) {
 314
 315                 // Append case
 316                 appendChar(keypress.getKey().getChar());
 317             } else if ((position < text.length())
 318                 && (StringUtils.width(text) < getWidth())) {
 319
 320                 // Overwrite or insert a character
 321                 if (insertMode == false) {
 322                     // Replace character
 323                     text = text.substring(0, position)
 324                             + codePointString(keypress.getKey().getChar())
 325                             + text.substring(position + 1);
 326                     screenPosition += StringUtils.width(text.codePointAt(position));
 327                     position += Character.charCount(keypress.getKey().getChar());
 328                 } else {
 329                     // Insert character
 330                     insertChar(keypress.getKey().getChar());
 331                 }
 332             } else if ((position < text.length())
 333                 && (StringUtils.width(text) >= getWidth())) {
 334
 335                 // Multiple cases here
 336                 if ((fixed == true) && (insertMode == true)) {
 337                     // Buffer is full, do nothing
 338                 } else if ((fixed == true) && (insertMode == false)) {
 339                     // Overwrite the last character, maybe move position
 340                     text = text.substring(0, position)
 341                             + codePointString(keypress.getKey().getChar())
 342                             + text.substring(position + 1);
 343                     if (screenPosition < getWidth() - 1) {
 344                         screenPosition += StringUtils.width(text.codePointAt(position));
 345                         position += Character.charCount(keypress.getKey().getChar());
 346                     }
 347                 } else if ((fixed == false) && (insertMode == false)) {
 348                     // Overwrite the last character, definitely move position
 349                     text = text.substring(0, position)
 350                             + codePointString(keypress.getKey().getChar())
 351                             + text.substring(position + 1);
 352                     screenPosition += StringUtils.width(text.codePointAt(position));
 353                     position += Character.charCount(keypress.getKey().getChar());
 354                 } else {
 355                     if (position == text.length()) {
 356                         // Append this character
 357                         appendChar(keypress.getKey().getChar());
 358                     } else {
 359                         // Insert this character
 360                         insertChar(keypress.getKey().getChar());
 361                     }
 362                 }
 363             } else {
 364                 assert (!fixed);
 365
 366                 // Append this character
 367                 appendChar(keypress.getKey().getChar());
 368             }
 369             dispatch(false);
 370             return;
 371         }
 372
 373         // Pass to parent for the things we don't care about.
 374         super.onKeypress(keypress);
 375     }
 376
 377     // ------------------------------------------------------------------------
 378     // TWidget ----------------------------------------------------------------
 379     // ------------------------------------------------------------------------
 380
 381     /**
 382      * Draw the text field.
 383      */
 384     @Override
 385     public void draw() {
 386         CellAttributes fieldColor;
 387
 388         if (isAbsoluteActive()) {
 389             fieldColor = getTheme().getColor(activeColorKey);
 390         } else {
 391             fieldColor = getTheme().getColor(inactiveColorKey);
 392         }
 393
 394         int end = windowStart + getWidth();
 395         if (end > StringUtils.width(text)) {
 396             end = StringUtils.width(text);
 397         }
 398         hLineXY(0, 0, getWidth(), backgroundChar, fieldColor);
 399         putStringXY(0, 0, text.substring(screenToTextPosition(windowStart),
 400                 screenToTextPosition(end)), fieldColor);
 401
 402         // Fix the cursor, it will be rendered by TApplication.drawAll().
 403         updateCursor();
 404     }
 405
 406     // ------------------------------------------------------------------------
 407     // TField -----------------------------------------------------------------
 408     // ------------------------------------------------------------------------
 409
 410     /**
 411      * Convert a char (codepoint) to a string.
 412      *
 413      * @param ch the char
 414      * @return the string
 415      */
 416     private String codePointString(final int ch) {
 417         StringBuilder sb = new StringBuilder(1);
 418         sb.append(Character.toChars(ch));
 419         assert (Character.charCount(ch) == sb.length());
 420         return sb.toString();
 421     }
 422
 423     /**
 424      * Get field background character.
 425      *
 426      * @return background character
 427      */
 428     public final int getBackgroundChar() {
 429         return backgroundChar;
 430     }
 431
 432     /**
 433      * Set field background character.
 434      *
 435      * @param backgroundChar the background character
 436      */
 437     public void setBackgroundChar(final int backgroundChar) {
 438         this.backgroundChar = backgroundChar;
 439     }
 440
 441     /**
 442      * Get field text.
 443      *
 444      * @return field text
 445      */
 446     public final String getText() {
 447         return text;
 448     }
 449
 450     /**
 451      * Set field text.
 452      *
 453      * @param text the new field text
 454      */
 455     public void setText(final String text) {
 456         assert (text != null);
 457         this.text = text;
 458         position = 0;
 459         windowStart = 0;
 460     }
 461
 462     /**
 463      * Dispatch to the action function.
 464      *
 465      * @param enter if true, the user pressed Enter, else this was an update
 466      * to the text.
 467      */
 468     protected void dispatch(final boolean enter) {
 469         if (enter) {
 470             if (enterAction != null) {
 471                 enterAction.DO();
 472             }
 473         } else {
 474             if (updateAction != null) {
 475                 updateAction.DO();
 476             }
 477         }
 478     }
 479
 480     /**
 481      * Determine string position from screen position.
 482      *
 483      * @param screenPosition the position on screen
 484      * @return the equivalent position in text
 485      */
 486     protected int screenToTextPosition(final int screenPosition) {
 487         if (screenPosition == 0) {
 488             return 0;
 489         }
 490
 491         int n = 0;
 492         for (int i = 0; i < text.length(); i++) {
 493             n += StringUtils.width(text.codePointAt(i));
 494             if (n >= screenPosition) {
 495                 return i + 1;
 496             }
 497         }
 498         // screenPosition exceeds the available text length.
 499         throw new IndexOutOfBoundsException("screenPosition " + screenPosition +
 500             " exceeds available text length " + text.length());
 501     }
 502
 503     /**
 504      * Update the visible cursor position to match the location of position
 505      * and windowStart.
 506      */
 507     protected void updateCursor() {
 508         if ((screenPosition > getWidth()) && fixed) {
 509             setCursorX(getWidth());
 510         } else if ((screenPosition - windowStart >= getWidth()) && !fixed) {
 511             setCursorX(getWidth() - 1);
 512         } else {
 513             setCursorX(screenPosition - windowStart);
 514         }
 515     }
 516
 517     /**
 518      * Normalize windowStart such that most of the field data if visible.
 519      */
 520     protected void normalizeWindowStart() {
 521         if (fixed) {
 522             // windowStart had better be zero, there is nothing to do here.
 523             assert (windowStart == 0);
 524             return;
 525         }
 526         windowStart = screenPosition - (getWidth() - 1);
 527         if (windowStart < 0) {
 528             windowStart = 0;
 529         }
 530
 531         updateCursor();
 532     }
 533
 534     /**
 535      * Append char to the end of the field.
 536      *
 537      * @param ch char to append
 538      */
 539     protected void appendChar(final int ch) {
 540         // Append the LAST character
 541         text += codePointString(ch);
 542         position += Character.charCount(ch);
 543         screenPosition += StringUtils.width(ch);
 544
 545         assert (position == text.length());
 546
 547         if (fixed) {
 548             if (screenPosition >= getWidth()) {
 549                 position -= Character.charCount(ch);
 550                 screenPosition -= StringUtils.width(ch);
 551             }
 552         } else {
 553             if ((screenPosition - windowStart) >= getWidth()) {
 554                 windowStart++;
 555             }
 556         }
 557     }
 558
 559     /**
 560      * Insert char somewhere in the middle of the field.
 561      *
 562      * @param ch char to append
 563      */
 564     protected void insertChar(final int ch) {
 565         text = text.substring(0, position) + codePointString(ch)
 566                 + text.substring(position);
 567         position += Character.charCount(ch);
 568         screenPosition += StringUtils.width(ch);
 569         if ((screenPosition - windowStart) == getWidth()) {
 570             assert (!fixed);
 571             windowStart++;
 572         }
 573     }
 574
 575     /**
 576      * Position the cursor at the first column.  The field may adjust the
 577      * window start to show as much of the field as possible.
 578      */
 579     public void home() {
 580         position = 0;
 581         screenPosition = 0;
 582         windowStart = 0;
 583     }
 584
 585     /**
 586      * Set the editing position to the last filled character.  The field may
 587      * adjust the window start to show as much of the field as possible.
 588      */
 589     public void end() {
 590         position = text.length();
 591         screenPosition = StringUtils.width(text);
 592         if (fixed == true) {
 593             if (screenPosition >= getWidth()) {
 594                 position -= Character.charCount(text.codePointBefore(position));
 595                 screenPosition = StringUtils.width(text) - 1;
 596              }
 597         } else {
 598             windowStart = StringUtils.width(text) - getWidth() + 1;
 599             if (windowStart < 0) {
 600                 windowStart = 0;
 601             }
 602         }
 603     }
 604
 605     /**
 606      * Set the editing position.  The field may adjust the window start to
 607      * show as much of the field as possible.
 608      *
 609      * @param position the new position
 610      * @throws IndexOutOfBoundsException if position is outside the range of
 611      * the available text
 612      */
 613     public void setPosition(final int position) {
 614         if ((position < 0) || (position >= text.length())) {
 615             throw new IndexOutOfBoundsException("Max length is " +
 616                 text.length() + ", requested position " + position);
 617         }
 618         this.position = position;
 619         normalizeWindowStart();
 620     }
 621
 622     /**
 623      * Set the active color key.
 624      *
 625      * @param activeColorKey ColorTheme key color to use when this field is
 626      * active
 627      */
 628     public void setActiveColorKey(final String activeColorKey) {
 629         this.activeColorKey = activeColorKey;
 630     }
 631
 632     /**
 633      * Set the inactive color key.
 634      *
 635      * @param inactiveColorKey ColorTheme key color to use when this field is
 636      * inactive
 637      */
 638     public void setInactiveColorKey(final String inactiveColorKey) {
 639         this.inactiveColorKey = inactiveColorKey;
 640     }
 641
 642     /**
 643      * Set the action to perform when the user presses enter.
 644      *
 645      * @param action the action to perform when the user presses enter
 646      */
 647     public void setEnterAction(final TAction action) {
 648         enterAction = action;
 649     }
 650
 651     /**
 652      * Set the action to perform when the field is updated.
 653      *
 654      * @param action the action to perform when the field is updated
 655      */
 656     public void setUpdateAction(final TAction action) {
 657         updateAction = action;
 658     }
 659
 660 }