| 1 | /* |
| 2 | * Jexer - Java Text User Interface |
| 3 | * |
| 4 | * The MIT License (MIT) |
| 5 | * |
| 6 | * Copyright (C) 2017 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.event.TMouseEvent; |
| 34 | |
| 35 | /** |
| 36 | * TVScroller implements a simple vertical scroll bar. |
| 37 | */ |
| 38 | public final class TVScroller extends TWidget { |
| 39 | |
| 40 | /** |
| 41 | * Value that corresponds to being on the top edge of the scroll bar. |
| 42 | */ |
| 43 | private int topValue = 0; |
| 44 | |
| 45 | /** |
| 46 | * Get the value that corresponds to being on the top edge of the scroll |
| 47 | * bar. |
| 48 | * |
| 49 | * @return the scroll value |
| 50 | */ |
| 51 | public int getTopValue() { |
| 52 | return topValue; |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Set the value that corresponds to being on the top edge of the scroll |
| 57 | * bar. |
| 58 | * |
| 59 | * @param topValue the new scroll value |
| 60 | */ |
| 61 | public void setTopValue(final int topValue) { |
| 62 | this.topValue = topValue; |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Value that corresponds to being on the bottom edge of the scroll bar. |
| 67 | */ |
| 68 | private int bottomValue = 100; |
| 69 | |
| 70 | /** |
| 71 | * Get the value that corresponds to being on the bottom edge of the |
| 72 | * scroll bar. |
| 73 | * |
| 74 | * @return the scroll value |
| 75 | */ |
| 76 | public int getBottomValue() { |
| 77 | return bottomValue; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Set the value that corresponds to being on the bottom edge of the |
| 82 | * scroll bar. |
| 83 | * |
| 84 | * @param bottomValue the new scroll value |
| 85 | */ |
| 86 | public void setBottomValue(final int bottomValue) { |
| 87 | this.bottomValue = bottomValue; |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * Current value of the scroll. |
| 92 | */ |
| 93 | private int value = 0; |
| 94 | |
| 95 | /** |
| 96 | * Get current value of the scroll. |
| 97 | * |
| 98 | * @return the scroll value |
| 99 | */ |
| 100 | public int getValue() { |
| 101 | return value; |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Set current value of the scroll. |
| 106 | * |
| 107 | * @param value the new scroll value |
| 108 | */ |
| 109 | public void setValue(final int value) { |
| 110 | this.value = value; |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * The increment for clicking on an arrow. |
| 115 | */ |
| 116 | private int smallChange = 1; |
| 117 | |
| 118 | /** |
| 119 | * Set the increment for clicking on an arrow. |
| 120 | * |
| 121 | * @param smallChange the new increment value |
| 122 | */ |
| 123 | public void setSmallChange(final int smallChange) { |
| 124 | this.smallChange = smallChange; |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * The increment for clicking in the bar between the box and an arrow. |
| 129 | */ |
| 130 | private int bigChange = 20; |
| 131 | |
| 132 | /** |
| 133 | * Set the increment for clicking in the bar between the box and an |
| 134 | * arrow. |
| 135 | * |
| 136 | * @param bigChange the new increment value |
| 137 | */ |
| 138 | public void setBigChange(final int bigChange) { |
| 139 | this.bigChange = bigChange; |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * When true, the user is dragging the scroll box. |
| 144 | */ |
| 145 | private boolean inScroll = false; |
| 146 | |
| 147 | /** |
| 148 | * Public constructor. |
| 149 | * |
| 150 | * @param parent parent widget |
| 151 | * @param x column relative to parent |
| 152 | * @param y row relative to parent |
| 153 | * @param height height of scroll bar |
| 154 | */ |
| 155 | public TVScroller(final TWidget parent, final int x, final int y, |
| 156 | final int height) { |
| 157 | |
| 158 | // Set parent and window |
| 159 | super(parent, x, y, 1, height); |
| 160 | } |
| 161 | |
| 162 | /** |
| 163 | * Compute the position of the scroll box (a.k.a. grip, thumb). |
| 164 | * |
| 165 | * @return Y position of the box, between 1 and height - 2 |
| 166 | */ |
| 167 | private int boxPosition() { |
| 168 | return (getHeight() - 3) * (value - topValue) / (bottomValue - topValue) + 1; |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * Draw a vertical scroll bar. |
| 173 | */ |
| 174 | @Override |
| 175 | public void draw() { |
| 176 | CellAttributes arrowColor = getTheme().getColor("tscroller.arrows"); |
| 177 | CellAttributes barColor = getTheme().getColor("tscroller.bar"); |
| 178 | getScreen().putCharXY(0, 0, GraphicsChars.CP437[0x1E], arrowColor); |
| 179 | getScreen().putCharXY(0, getHeight() - 1, GraphicsChars.CP437[0x1F], |
| 180 | arrowColor); |
| 181 | |
| 182 | // Place the box |
| 183 | if (bottomValue > topValue) { |
| 184 | getScreen().vLineXY(0, 1, getHeight() - 2, |
| 185 | GraphicsChars.CP437[0xB1], barColor); |
| 186 | getScreen().putCharXY(0, boxPosition(), GraphicsChars.BOX, |
| 187 | arrowColor); |
| 188 | } else { |
| 189 | getScreen().vLineXY(0, 1, getHeight() - 2, GraphicsChars.HATCH, |
| 190 | barColor); |
| 191 | } |
| 192 | |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * Perform a small step change up. |
| 197 | */ |
| 198 | public void decrement() { |
| 199 | if (bottomValue == topValue) { |
| 200 | return; |
| 201 | } |
| 202 | value -= smallChange; |
| 203 | if (value < topValue) { |
| 204 | value = topValue; |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * Perform a small step change down. |
| 210 | */ |
| 211 | public void increment() { |
| 212 | if (bottomValue == topValue) { |
| 213 | return; |
| 214 | } |
| 215 | value += smallChange; |
| 216 | if (value > bottomValue) { |
| 217 | value = bottomValue; |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * Perform a big step change up. |
| 223 | */ |
| 224 | public void bigDecrement() { |
| 225 | if (bottomValue == topValue) { |
| 226 | return; |
| 227 | } |
| 228 | value -= bigChange; |
| 229 | if (value < topValue) { |
| 230 | value = topValue; |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * Perform a big step change down. |
| 236 | */ |
| 237 | public void bigIncrement() { |
| 238 | if (bottomValue == topValue) { |
| 239 | return; |
| 240 | } |
| 241 | value += bigChange; |
| 242 | if (value > bottomValue) { |
| 243 | value = bottomValue; |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | /** |
| 248 | * Go to the top edge of the scroller. |
| 249 | */ |
| 250 | public void toTop() { |
| 251 | value = topValue; |
| 252 | } |
| 253 | |
| 254 | /** |
| 255 | * Go to the bottom edge of the scroller. |
| 256 | */ |
| 257 | public void toBottom() { |
| 258 | value = bottomValue; |
| 259 | } |
| 260 | |
| 261 | /** |
| 262 | * Handle mouse button releases. |
| 263 | * |
| 264 | * @param mouse mouse button release event |
| 265 | */ |
| 266 | @Override |
| 267 | public void onMouseUp(final TMouseEvent mouse) { |
| 268 | if (bottomValue == topValue) { |
| 269 | return; |
| 270 | } |
| 271 | |
| 272 | if (inScroll) { |
| 273 | inScroll = false; |
| 274 | return; |
| 275 | } |
| 276 | |
| 277 | if ((mouse.getX() == 0) |
| 278 | && (mouse.getY() == 0) |
| 279 | ) { |
| 280 | // Clicked on the top arrow |
| 281 | decrement(); |
| 282 | return; |
| 283 | } |
| 284 | |
| 285 | if ((mouse.getX() == 0) |
| 286 | && (mouse.getY() == getHeight() - 1) |
| 287 | ) { |
| 288 | // Clicked on the bottom arrow |
| 289 | increment(); |
| 290 | return; |
| 291 | } |
| 292 | |
| 293 | if ((mouse.getX() == 0) |
| 294 | && (mouse.getY() > 0) |
| 295 | && (mouse.getY() < boxPosition()) |
| 296 | ) { |
| 297 | // Clicked between the top arrow and the box |
| 298 | value -= bigChange; |
| 299 | if (value < topValue) { |
| 300 | value = topValue; |
| 301 | } |
| 302 | return; |
| 303 | } |
| 304 | |
| 305 | if ((mouse.getX() == 0) |
| 306 | && (mouse.getY() > boxPosition()) |
| 307 | && (mouse.getY() < getHeight() - 1) |
| 308 | ) { |
| 309 | // Clicked between the box and the bottom arrow |
| 310 | value += bigChange; |
| 311 | if (value > bottomValue) { |
| 312 | value = bottomValue; |
| 313 | } |
| 314 | return; |
| 315 | } |
| 316 | } |
| 317 | |
| 318 | /** |
| 319 | * Handle mouse movement events. |
| 320 | * |
| 321 | * @param mouse mouse motion event |
| 322 | */ |
| 323 | @Override |
| 324 | public void onMouseMotion(final TMouseEvent mouse) { |
| 325 | if (bottomValue == topValue) { |
| 326 | return; |
| 327 | } |
| 328 | |
| 329 | if ((mouse.isMouse1()) |
| 330 | && (inScroll) |
| 331 | && (mouse.getY() > 0) |
| 332 | && (mouse.getY() < getHeight() - 1) |
| 333 | ) { |
| 334 | // Recompute value based on new box position |
| 335 | value = (bottomValue - topValue) |
| 336 | * (mouse.getY()) / (getHeight() - 3) + topValue; |
| 337 | return; |
| 338 | } |
| 339 | |
| 340 | inScroll = false; |
| 341 | } |
| 342 | |
| 343 | /** |
| 344 | * Handle mouse press events. |
| 345 | * |
| 346 | * @param mouse mouse button press event |
| 347 | */ |
| 348 | @Override |
| 349 | public void onMouseDown(final TMouseEvent mouse) { |
| 350 | if (bottomValue == topValue) { |
| 351 | return; |
| 352 | } |
| 353 | |
| 354 | if ((mouse.getX() == 0) |
| 355 | && (mouse.getY() == boxPosition()) |
| 356 | ) { |
| 357 | inScroll = true; |
| 358 | return; |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | } |