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1: /* SizeRequirements.java -- 2: Copyright (C) 2002, 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package javax.swing; 39: 40: import java.io.Serializable; 41: 42: /** 43: * This class calculates information about the size and position requirements 44: * of components. 45: * 46: * Two types of layout are supported: 47: * <ul> 48: * <li>Tiled: the components are placed at position top-left or bottom-right 49: * position within their allocated space</li> 50: * <li>Aligned: the components are placed aligned in their allocated space 51: * according to their alignment value</li> 52: * </ul> 53: * 54: * @author Andrew Selkirk 55: * @author Roman Kennke (roman@kennke.org) 56: */ 57: public class SizeRequirements implements Serializable 58: { 59: /** 60: * The serialVersionUID. 61: */ 62: private static final long serialVersionUID = 9217749429906736553L; 63: 64: /** 65: * The minimum reasonable width or height of a component. 66: */ 67: public int minimum; 68: 69: /** 70: * The preferred width or height of a component. 71: */ 72: public int preferred; 73: 74: /** 75: * The maximum reasonable width or height of a component. 76: */ 77: public int maximum; 78: 79: /** 80: * The horizontal or vertical alignment of a component. 81: */ 82: public float alignment; 83: 84: /** 85: * Creates a SizeRequirements object with minimum, preferred and 86: * maximum size set to zero, and an alignment value of 0.5. 87: */ 88: public SizeRequirements() 89: { 90: this (0, 0, 0, 0.5F); 91: } 92: 93: /** 94: * Creates a SizeRequirements object with the specified minimum, 95: * preferred, maximum and alignment values. 96: * 97: * @param min the minimum reasonable size of the component 98: * @param pref the preferred size of the component 99: * @param max the maximum size of the component 100: * @param align the alignment of the component 101: */ 102: public SizeRequirements(int min, int pref, int max, float align) 103: { 104: minimum = min; 105: preferred = pref; 106: maximum = max; 107: alignment = align; 108: } 109: 110: /** 111: * Returns a String representation of this SizeRequirements object, 112: * containing information about the minimum, preferred, maximum and 113: * alignment value. 114: * 115: * @return a String representation of this SizeRequirements object 116: */ 117: public String toString() 118: { 119: StringBuilder b = new StringBuilder(); 120: b.append("<["); 121: b.append(minimum); 122: b.append(','); 123: b.append(preferred); 124: b.append(','); 125: b.append(maximum); 126: b.append("]@"); 127: b.append(alignment); 128: b.append('>'); 129: return b.toString(); 130: } 131: 132: /** 133: * Calculates how much space is nessecary to place a set of components 134: * end-to-end. The size requirements of the components is specified 135: * in <code>children</code>. 136: * 137: * @param children the SizeRequirements of each of the components 138: * 139: * @return the SizeRequirements that describe how much space is needed 140: * to place the components end-to-end 141: */ 142: public static SizeRequirements 143: getTiledSizeRequirements(SizeRequirements[] children) 144: { 145: SizeRequirements result = new SizeRequirements(); 146: for (int i = 0; i < children.length; i++) 147: { 148: result.minimum += children[i].minimum; 149: result.preferred += children[i].preferred; 150: result.maximum += children[i].maximum; 151: } 152: return result; 153: } 154: 155: /** 156: * Calculates how much space is nessecary to place a set of components 157: * aligned according to their alignment value. 158: * The size requirements of the components is specified in 159: * <code>children</code>. 160: * 161: * @param children the SizeRequirements of each of the components 162: * 163: * @return the SizeRequirements that describe how much space is needed 164: * to place the components aligned 165: */ 166: public static SizeRequirements 167: getAlignedSizeRequirements(SizeRequirements[] children) 168: { 169: float minLeft = 0; 170: float minRight = 0; 171: float prefLeft = 0; 172: float prefRight = 0; 173: float maxLeft = 0; 174: float maxRight = 0; 175: for (int i = 0; i < children.length; i++) 176: { 177: float myMinLeft = children[i].minimum * children[i].alignment; 178: float myMinRight = children[i].minimum - myMinLeft; 179: minLeft = Math.max(myMinLeft, minLeft); 180: minRight = Math.max(myMinRight, minRight); 181: float myPrefLeft = children[i].preferred * children[i].alignment; 182: float myPrefRight = children[i].preferred - myPrefLeft; 183: prefLeft = Math.max(myPrefLeft, prefLeft); 184: prefRight = Math.max(myPrefRight, prefRight); 185: float myMaxLeft = children[i].maximum * children[i].alignment; 186: float myMaxRight = children[i].maximum - myMaxLeft; 187: maxLeft = Math.max(myMaxLeft, maxLeft); 188: maxRight = Math.max(myMaxRight, maxRight); 189: } 190: int minSize = (int) (minLeft + minRight); 191: int prefSize = (int) (prefLeft + prefRight); 192: int maxSize = (int) (maxLeft + maxRight); 193: float align = prefLeft / (prefRight + prefLeft); 194: if (Float.isNaN(align)) 195: align = 0; 196: return new SizeRequirements(minSize, prefSize, maxSize, align); 197: } 198: 199: /** 200: * Calculate the offsets and spans of the components, when they should 201: * be placed end-to-end. 202: * 203: * You must specify the amount of allocated space in 204: * <code>allocated</code>, the total size requirements of the set of 205: * components in <code>total</code> (this can be calculated using 206: * {@link #getTiledSizeRequirements} and the size requirements of the 207: * components in <code>children</code>. 208: * 209: * The calculated offset and span values for each component are then 210: * stored in the arrays <code>offsets</code> and <code>spans</code>. 211: * 212: * The components are placed in the forward direction, beginning with 213: * an offset of 0. 214: * 215: * @param allocated the amount of allocated space 216: * @param total the total size requirements of the components 217: * @param children the size requirement of each component 218: * @param offsets will hold the offset values for each component 219: * @param spans will hold the span values for each component 220: */ 221: public static void calculateTiledPositions(int allocated, 222: SizeRequirements total, 223: SizeRequirements[] children, 224: int[] offsets, int[] spans) 225: { 226: calculateTiledPositions(allocated, total, children, offsets, spans, true); 227: } 228: 229: /** 230: * Calculate the offsets and spans of the components, when they should 231: * be placed end-to-end. 232: * 233: * You must specify the amount of allocated space in 234: * <code>allocated</code>, the total size requirements of the set of 235: * components in <code>total</code> (this can be calculated using 236: * {@link #getTiledSizeRequirements} and the size requirements of the 237: * components in <code>children</code>. 238: * 239: * The calculated offset and span values for each component are then 240: * stored in the arrays <code>offsets</code> and <code>spans</code>. 241: * 242: * Depending on the value of <code>forward</code> the components are 243: * placed in the forward direction (left-right or top-bottom), where 244: * the offsets begin with 0, or in the reverse direction 245: * (right-left or bottom-top). 246: * 247: * @param allocated the amount of allocated space 248: * @param total the total size requirements of the components 249: * @param children the size requirement of each component 250: * @param offsets will hold the offset values for each component 251: * @param spans will hold the span values for each component 252: * @param forward whether the components should be placed in the forward 253: * direction (left-right or top-bottom) or reverse direction 254: * (right-left or bottom-top) 255: */ 256: public static void calculateTiledPositions(int allocated, 257: SizeRequirements total, 258: SizeRequirements[] children, 259: int[] offsets, int[] spans, 260: boolean forward) 261: { 262: int span = 0; 263: if (forward) 264: { 265: int offset = 0; 266: for (int i = 0; i < children.length; i++) 267: { 268: offsets[i] = offset; 269: spans[i] = children[i].preferred; 270: span += spans[i]; 271: offset += children[i].preferred; 272: } 273: } 274: else 275: { 276: int offset = allocated; 277: for (int i = 0; i < children.length; i++) 278: { 279: offset -= children[i].preferred; 280: offsets[i] = offset; 281: span += spans[i]; 282: spans[i] = children[i].preferred; 283: } 284: } 285: // Adjust spans so that we exactly fill the allocated region. If 286: if (span > allocated) 287: adjustSmaller(allocated, children, spans, span); 288: else if (span < allocated) 289: adjustGreater(allocated, children, spans, span); 290: 291: // Adjust offsets. 292: if (forward) 293: { 294: int offset = 0; 295: for (int i = 0; i < children.length; i++) 296: { 297: offsets[i] = offset; 298: offset += spans[i]; 299: } 300: } 301: else 302: { 303: int offset = allocated; 304: for (int i = 0; i < children.length; i++) 305: { 306: offset -= spans[i]; 307: offsets[i] = offset; 308: } 309: } 310: } 311: 312: private static void adjustSmaller(int allocated, SizeRequirements[] children, 313: int[] spans, int span) 314: { 315: // Sum up (prefSize - minSize) over all children 316: int sumDelta = 0; 317: for (int i = 0; i < children.length; i++) 318: sumDelta += children[i].preferred - children[i].minimum; 319: 320: // If we have sumDelta == 0, then all components have prefSize == maxSize 321: // and we can't do anything about it. 322: if (sumDelta == 0) 323: return; 324: 325: // Adjust all sizes according to their preferred and minimum sizes. 326: for (int i = 0; i < children.length; i++) 327: { 328: double factor = ((double) (children[i].preferred - children[i].minimum)) 329: / ((double) sumDelta); 330: // In case we have a sumDelta of 0, the factor should also be 0. 331: if (Double.isNaN(factor)) 332: factor = 0; 333: spans[i] -= factor * (span - allocated); 334: } 335: } 336: 337: private static void adjustGreater(int allocated, SizeRequirements[] children, 338: int[] spans, int span) 339: { 340: // Sum up (maxSize - prefSize) over all children 341: int sumDelta = 0; 342: for (int i = 0; i < children.length; i++) 343: { 344: sumDelta += children[i].maximum - children[i].preferred; 345: if (sumDelta < 0) 346: sumDelta = Integer.MAX_VALUE; 347: } 348: 349: // If we have sumDelta == 0, then all components have prefSize == maxSize 350: // and we can't do anything about it. 351: if (sumDelta == 0) 352: return; 353: 354: // Adjust all sizes according to their preferred and minimum sizes. 355: for (int i = 0; i < children.length; i++) 356: { 357: double factor = ((double) (children[i].maximum - children[i].preferred)) 358: / ((double) sumDelta); 359: spans[i] -= factor * (span - allocated); 360: } 361: } 362: 363: /** 364: * Calculate the offsets and spans of the components, when they should 365: * be placed end-to-end. 366: * 367: * You must specify the amount of allocated space in 368: * <code>allocated</code>, the total size requirements of the set of 369: * components in <code>total</code> (this can be calculated using 370: * {@link #getTiledSizeRequirements} and the size requirements of the 371: * components in <code>children</code>. 372: * 373: * The calculated offset and span values for each component are then 374: * stored in the arrays <code>offsets</code> and <code>spans</code>. 375: * 376: * The components are tiled in the forward direction, beginning with 377: * an offset of 0. 378: * 379: * @param allocated the amount of allocated space 380: * @param total the total size requirements of the components 381: * @param children the size requirement of each component 382: * @param offsets will hold the offset values for each component 383: * @param spans will hold the span values for each component 384: */ 385: public static void calculateAlignedPositions(int allocated, 386: SizeRequirements total, 387: SizeRequirements[] children, 388: int[] offsets, int[] spans) 389: { 390: calculateAlignedPositions(allocated, total, children, offsets, spans, 391: true); 392: } 393: 394: /** 395: * Calculate the offsets and spans of the components, when they should 396: * be placed end-to-end. 397: * 398: * You must specify the amount of allocated space in 399: * <code>allocated</code>, the total size requirements of the set of 400: * components in <code>total</code> (this can be calculated using 401: * {@link #getTiledSizeRequirements} and the size requirements of the 402: * components in <code>children</code>. 403: * 404: * The calculated offset and span values for each component are then 405: * stored in the arrays <code>offsets</code> and <code>spans</code>. 406: * 407: * Depending on the value of <code>forward</code> the components are 408: * placed in the forward direction (left-right or top-bottom), where 409: * the offsets begin with 0, or in the reverse direction 410: * (right-left or bottom-top). 411: * 412: * @param allocated the amount of allocated space 413: * @param total the total size requirements of the components 414: * @param children the size requirement of each component 415: * @param spans will hold the span values for each component 416: * @param forward whether the components should be placed in the forward 417: * direction (left-right or top-bottom) or reverse direction 418: * (right-left or bottom-top) 419: */ 420: public static void calculateAlignedPositions(int allocated, 421: SizeRequirements total, 422: SizeRequirements[] children, 423: int[] offset, int[] spans, 424: boolean forward) 425: { 426: // First we compute the position of the baseline. 427: float baseline = allocated * total.alignment; 428: 429: // Now we can layout the components along the baseline. 430: for (int i = 0; i < children.length; i++) 431: { 432: float align = children[i].alignment; 433: // Try to fit the component into the available space. 434: int[] spanAndOffset = new int[2]; 435: if (align < .5F || baseline == 0) 436: adjustFromRight(children[i], baseline, allocated, spanAndOffset); 437: else 438: adjustFromLeft(children[i], baseline, allocated, spanAndOffset); 439: spans[i] = spanAndOffset[0]; 440: offset[i] = spanAndOffset[1]; 441: } 442: } 443: 444: /** 445: * Adjusts the span and offset of a component for the aligned layout. 446: * 447: * @param reqs 448: * @param baseline 449: * @param allocated 450: * @param spanAndOffset 451: */ 452: private static void adjustFromRight(SizeRequirements reqs, float baseline, 453: int allocated, int[] spanAndOffset) 454: { 455: float right = allocated - baseline; 456: // If the resulting span exceeds the maximum of the component, then adjust 457: // accordingly. 458: float maxRight = ((float) reqs.maximum) * (1.F - reqs.alignment); 459: if (right / (1.F - reqs.alignment) > reqs.maximum) 460: right = maxRight; 461: // If we have not enough space on the left side, then adjust accordingly. 462: if (right / (1.F - reqs.alignment) * reqs.alignment > allocated - baseline) 463: right = ((float) (allocated - baseline)) 464: / reqs.alignment * (1.F - reqs.alignment); 465: 466: spanAndOffset[0] = (int) (right / (1.F - reqs.alignment)); 467: spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment); 468: } 469: 470: /** 471: * Adjusts the span and offset of a component for the aligned layout. 472: * 473: * @param reqs 474: * @param baseline 475: * @param allocated 476: * @param spanAndOffset 477: */ 478: private static void adjustFromLeft(SizeRequirements reqs, float baseline, 479: int allocated, int[] spanAndOffset) 480: { 481: float left = baseline; 482: // If the resulting span exceeds the maximum of the component, then adjust 483: // accordingly. 484: float maxLeft = ((float) reqs.maximum) * reqs.alignment; 485: if (left / reqs.alignment > reqs.maximum) 486: left = maxLeft; 487: // If we have not enough space on the right side, then adjust accordingly. 488: if (left / reqs.alignment * (1.F - reqs.alignment) > allocated - baseline) 489: left = ((float) (allocated - baseline)) 490: / (1.F - reqs.alignment) * reqs.alignment; 491: 492: spanAndOffset[0] = (int) (left / reqs.alignment); 493: spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment); 494: } 495: 496: /** 497: * Returns an array of new preferred sizes for the children based on 498: * <code>delta</code>. <code>delta</code> specifies a change in the 499: * allocated space. The sizes of the children will be shortened or 500: * lengthened to accomodate the new allocation. 501: * 502: * @param delta the change of the size of the total allocation for 503: * the components 504: * @param children the size requirements of each component 505: * 506: * @return the new preferred sizes for each component 507: */ 508: public static int[] adjustSizes(int delta, SizeRequirements[] children) 509: { 510: return null; // TODO 511: } 512: }
GNU Classpath (0.19) |