src/jexer/TButton.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.Color;
  33 import jexer.bits.GraphicsChars;
  34 import jexer.bits.MnemonicString;
  35 import jexer.bits.StringUtils;
  36 import jexer.event.TKeypressEvent;
  37 import jexer.event.TMouseEvent;
  38 import static jexer.TKeypress.kbEnter;
  39 import static jexer.TKeypress.kbSpace;
  40
  41 /**
  42  * TButton implements a simple button.  To make the button do something, pass
  43  * a TAction class to its constructor.
  44  *
  45  * @see TAction#DO()
  46  */
  47 public class TButton extends TWidget {
  48
  49     // ------------------------------------------------------------------------
  50     // Variables --------------------------------------------------------------
  51     // ------------------------------------------------------------------------
  52
  53     /**
  54      * The shortcut and button text.
  55      */
  56     private MnemonicString mnemonic;
  57
  58     /**
  59      * Remember mouse state.
  60      */
  61     private TMouseEvent mouse;
  62
  63     /**
  64      * True when the button is being pressed and held down.
  65      */
  66     private boolean inButtonPress = false;
  67
  68     /**
  69      * The action to perform when the button is clicked.
  70      */
  71     private TAction action;
  72
  73     /**
  74      * The background color used for the button "shadow", or null for "no
  75      * shadow".
  76      */
  77     private CellAttributes shadowColor;
  78
  79     // ------------------------------------------------------------------------
  80     // Constructors -----------------------------------------------------------
  81     // ------------------------------------------------------------------------
  82
  83     /**
  84      * Private constructor.
  85      *
  86      * @param parent parent widget
  87      * @param text label on the button
  88      * @param x column relative to parent
  89      * @param y row relative to parent
  90      */
  91     private TButton(final TWidget parent, final String text,
  92         final int x, final int y) {
  93
  94         // Set parent and window
  95         super(parent);
  96
  97         mnemonic = new MnemonicString(text);
  98
  99         setX(x);
 100         setY(y);
 101         super.setHeight(2);
 102         super.setWidth(StringUtils.width(mnemonic.getRawLabel()) + 3);
 103
 104         shadowColor = new CellAttributes();
 105         shadowColor.setTo(getWindow().getBackground());
 106         shadowColor.setForeColor(Color.BLACK);
 107         shadowColor.setBold(false);
 108
 109         // Since we set dimensions after TWidget's constructor, we need to
 110         // update the layout manager.
 111         if (getParent().getLayoutManager() != null) {
 112             getParent().getLayoutManager().remove(this);
 113             getParent().getLayoutManager().add(this);
 114         }
 115     }
 116
 117     /**
 118      * Public constructor.
 119      *
 120      * @param parent parent widget
 121      * @param text label on the button
 122      * @param x column relative to parent
 123      * @param y row relative to parent
 124      * @param action to call when button is pressed
 125      */
 126     public TButton(final TWidget parent, final String text,
 127         final int x, final int y, final TAction action) {
 128
 129         this(parent, text, x, y);
 130         this.action = action;
 131     }
 132
 133     // ------------------------------------------------------------------------
 134     // Event handlers ---------------------------------------------------------
 135     // ------------------------------------------------------------------------
 136
 137     /**
 138      * Returns true if the mouse is currently on the button.
 139      *
 140      * @return if true the mouse is currently on the button
 141      */
 142     private boolean mouseOnButton() {
 143         int rightEdge = getWidth() - 1;
 144         if (inButtonPress) {
 145             rightEdge++;
 146         }
 147         if ((mouse != null)
 148             && (mouse.getY() == 0)
 149             && (mouse.getX() >= 0)
 150             && (mouse.getX() < rightEdge)
 151         ) {
 152             return true;
 153         }
 154         return false;
 155     }
 156
 157     /**
 158      * Handle mouse button presses.
 159      *
 160      * @param mouse mouse button event
 161      */
 162     @Override
 163     public void onMouseDown(final TMouseEvent mouse) {
 164         this.mouse = mouse;
 165
 166         if ((mouseOnButton()) && (mouse.isMouse1())) {
 167             // Begin button press
 168             inButtonPress = true;
 169         }
 170     }
 171
 172     /**
 173      * Handle mouse button releases.
 174      *
 175      * @param mouse mouse button release event
 176      */
 177     @Override
 178     public void onMouseUp(final TMouseEvent mouse) {
 179         this.mouse = mouse;
 180
 181         if (inButtonPress && mouse.isMouse1()) {
 182             // Dispatch the event
 183             dispatch();
 184         }
 185
 186     }
 187
 188     /**
 189      * Handle mouse movements.
 190      *
 191      * @param mouse mouse motion event
 192      */
 193     @Override
 194     public void onMouseMotion(final TMouseEvent mouse) {
 195         this.mouse = mouse;
 196
 197         if (!mouseOnButton()) {
 198             inButtonPress = false;
 199         }
 200     }
 201
 202     /**
 203      * Handle keystrokes.
 204      *
 205      * @param keypress keystroke event
 206      */
 207     @Override
 208     public void onKeypress(final TKeypressEvent keypress) {
 209         if (keypress.equals(kbEnter)
 210             || keypress.equals(kbSpace)
 211         ) {
 212             // Dispatch
 213             dispatch();
 214             return;
 215         }
 216
 217         // Pass to parent for the things we don't care about.
 218         super.onKeypress(keypress);
 219     }
 220
 221     // ------------------------------------------------------------------------
 222     // TWidget ----------------------------------------------------------------
 223     // ------------------------------------------------------------------------
 224
 225     /**
 226      * Override TWidget's width: we can only set width at construction time.
 227      *
 228      * @param width new widget width (ignored)
 229      */
 230     @Override
 231     public void setWidth(final int width) {
 232         // Do nothing
 233     }
 234
 235     /**
 236      * Override TWidget's height: we can only set height at construction
 237      * time.
 238      *
 239      * @param height new widget height (ignored)
 240      */
 241     @Override
 242     public void setHeight(final int height) {
 243         // Do nothing
 244     }
 245
 246     /**
 247      * Draw a button with a shadow.
 248      */
 249     @Override
 250     public void draw() {
 251         CellAttributes buttonColor;
 252         CellAttributes menuMnemonicColor;
 253
 254         if (!isEnabled()) {
 255             buttonColor = getTheme().getColor("tbutton.disabled");
 256             menuMnemonicColor = getTheme().getColor("tbutton.disabled");
 257         } else if (isAbsoluteActive()) {
 258             buttonColor = getTheme().getColor("tbutton.active");
 259             menuMnemonicColor = getTheme().getColor("tbutton.mnemonic.highlighted");
 260         } else {
 261             buttonColor = getTheme().getColor("tbutton.inactive");
 262             menuMnemonicColor = getTheme().getColor("tbutton.mnemonic");
 263         }
 264
 265         if (inButtonPress) {
 266             putCharXY(1, 0, ' ', buttonColor);
 267             putStringXY(2, 0, mnemonic.getRawLabel(), buttonColor);
 268             putCharXY(getWidth() - 1, 0, ' ', buttonColor);
 269         } else {
 270             putCharXY(0, 0, ' ', buttonColor);
 271             putStringXY(1, 0, mnemonic.getRawLabel(), buttonColor);
 272             putCharXY(getWidth() - 2, 0, ' ', buttonColor);
 273
 274             if (shadowColor != null) {
 275                 putCharXY(getWidth() - 1, 0,
 276                     GraphicsChars.CP437[0xDC], shadowColor);
 277                 hLineXY(1, 1, getWidth() - 1,
 278                     GraphicsChars.CP437[0xDF], shadowColor);
 279             }
 280         }
 281         if (mnemonic.getScreenShortcutIdx() >= 0) {
 282             if (inButtonPress) {
 283                 putCharXY(2 + mnemonic.getScreenShortcutIdx(), 0,
 284                     mnemonic.getShortcut(), menuMnemonicColor);
 285             } else {
 286                 putCharXY(1 + mnemonic.getScreenShortcutIdx(), 0,
 287                     mnemonic.getShortcut(), menuMnemonicColor);
 288             }
 289         }
 290     }
 291
 292     // ------------------------------------------------------------------------
 293     // TButton ----------------------------------------------------------------
 294     // ------------------------------------------------------------------------
 295
 296     /**
 297      * Get the mnemonic string for this button.
 298      *
 299      * @return mnemonic string
 300      */
 301     public MnemonicString getMnemonic() {
 302         return mnemonic;
 303     }
 304
 305     /**
 306      * Act as though the button was pressed.  This is useful for other UI
 307      * elements to get the same action as if the user clicked the button.
 308      */
 309     public void dispatch() {
 310         if (action != null) {
 311             action.DO(this);
 312             inButtonPress = false;
 313         }
 314     }
 315
 316     /**
 317      * Set the background color used for the button "shadow".  If null, no
 318      * shadow will be drawn.
 319      *
 320      * @param color the new background color, or null for no shadow
 321      */
 322     public void setShadowColor(final CellAttributes color) {
 323         if (color != null) {
 324             shadowColor = new CellAttributes();
 325             shadowColor.setTo(color);
 326             shadowColor.setForeColor(Color.BLACK);
 327             shadowColor.setBold(false);
 328         } else {
 329             shadowColor = null;
 330         }
 331     }
 332
 333 }