BitmapFactory.java revision afbd777fdaf4ecc6c483c45fc8f8206a119574cc
1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.graphics; 18 19import android.content.res.AssetManager; 20import android.content.res.Resources; 21import android.os.Trace; 22import android.util.DisplayMetrics; 23import android.util.Log; 24import android.util.TypedValue; 25 26import java.io.FileDescriptor; 27import java.io.FileInputStream; 28import java.io.IOException; 29import java.io.InputStream; 30 31/** 32 * Creates Bitmap objects from various sources, including files, streams, 33 * and byte-arrays. 34 */ 35public class BitmapFactory { 36 private static final int DECODE_BUFFER_SIZE = 16 * 1024; 37 38 public static class Options { 39 /** 40 * Create a default Options object, which if left unchanged will give 41 * the same result from the decoder as if null were passed. 42 */ 43 public Options() { 44 inDither = false; 45 inScaled = true; 46 inPremultiplied = true; 47 } 48 49 /** 50 * If set, decode methods that take the Options object will attempt to 51 * reuse this bitmap when loading content. If the decode operation 52 * cannot use this bitmap, the decode method will return 53 * <code>null</code> and will throw an IllegalArgumentException. The 54 * current implementation necessitates that the reused bitmap be 55 * mutable, and the resulting reused bitmap will continue to remain 56 * mutable even when decoding a resource which would normally result in 57 * an immutable bitmap.</p> 58 * 59 * <p>You should still always use the returned Bitmap of the decode 60 * method and not assume that reusing the bitmap worked, due to the 61 * constraints outlined above and failure situations that can occur. 62 * Checking whether the return value matches the value of the inBitmap 63 * set in the Options structure will indicate if the bitmap was reused, 64 * but in all cases you should use the Bitmap returned by the decoding 65 * function to ensure that you are using the bitmap that was used as the 66 * decode destination.</p> 67 * 68 * <h3>Usage with BitmapFactory</h3> 69 * 70 * <p>As of {@link android.os.Build.VERSION_CODES#KITKAT}, any 71 * mutable bitmap can be reused by {@link BitmapFactory} to decode any 72 * other bitmaps as long as the resulting {@link Bitmap#getByteCount() 73 * byte count} of the decoded bitmap is less than or equal to the {@link 74 * Bitmap#getAllocationByteCount() allocated byte count} of the reused 75 * bitmap. This can be because the intrinsic size is smaller, or its 76 * size post scaling (for density / sample size) is smaller.</p> 77 * 78 * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT} 79 * additional constraints apply: The image being decoded (whether as a 80 * resource or as a stream) must be in jpeg or png format. Only equal 81 * sized bitmaps are supported, with {@link #inSampleSize} set to 1. 82 * Additionally, the {@link android.graphics.Bitmap.Config 83 * configuration} of the reused bitmap will override the setting of 84 * {@link #inPreferredConfig}, if set.</p> 85 * 86 * <h3>Usage with BitmapRegionDecoder</h3> 87 * 88 * <p>BitmapRegionDecoder will draw its requested content into the Bitmap 89 * provided, clipping if the output content size (post scaling) is larger 90 * than the provided Bitmap. The provided Bitmap's width, height, and 91 * {@link Bitmap.Config} will not be changed. 92 * 93 * <p class="note">BitmapRegionDecoder support for {@link #inBitmap} was 94 * introduced in {@link android.os.Build.VERSION_CODES#JELLY_BEAN}. All 95 * formats supported by BitmapRegionDecoder support Bitmap reuse via 96 * {@link #inBitmap}.</p> 97 * 98 * @see Bitmap#reconfigure(int,int, android.graphics.Bitmap.Config) 99 */ 100 public Bitmap inBitmap; 101 102 /** 103 * If set, decode methods will always return a mutable Bitmap instead of 104 * an immutable one. This can be used for instance to programmatically apply 105 * effects to a Bitmap loaded through BitmapFactory. 106 */ 107 @SuppressWarnings({"UnusedDeclaration"}) // used in native code 108 public boolean inMutable; 109 110 /** 111 * If set to true, the decoder will return null (no bitmap), but 112 * the out... fields will still be set, allowing the caller to query 113 * the bitmap without having to allocate the memory for its pixels. 114 */ 115 public boolean inJustDecodeBounds; 116 117 /** 118 * If set to a value > 1, requests the decoder to subsample the original 119 * image, returning a smaller image to save memory. The sample size is 120 * the number of pixels in either dimension that correspond to a single 121 * pixel in the decoded bitmap. For example, inSampleSize == 4 returns 122 * an image that is 1/4 the width/height of the original, and 1/16 the 123 * number of pixels. Any value <= 1 is treated the same as 1. Note: the 124 * decoder uses a final value based on powers of 2, any other value will 125 * be rounded down to the nearest power of 2. 126 */ 127 public int inSampleSize; 128 129 /** 130 * If this is non-null, the decoder will try to decode into this 131 * internal configuration. If it is null, or the request cannot be met, 132 * the decoder will try to pick the best matching config based on the 133 * system's screen depth, and characteristics of the original image such 134 * as if it has per-pixel alpha (requiring a config that also does). 135 * 136 * Image are loaded with the {@link Bitmap.Config#ARGB_8888} config by 137 * default. 138 */ 139 public Bitmap.Config inPreferredConfig = Bitmap.Config.ARGB_8888; 140 141 /** 142 * If true (which is the default), the resulting bitmap will have its 143 * color channels pre-multipled by the alpha channel. 144 * 145 * <p>This should NOT be set to false for images to be directly drawn by 146 * the view system or through a {@link Canvas}. The view system and 147 * {@link Canvas} assume all drawn images are pre-multiplied to simplify 148 * draw-time blending, and will throw a RuntimeException when 149 * un-premultiplied are drawn.</p> 150 * 151 * <p>This is likely only useful if you want to manipulate raw encoded 152 * image data, e.g. with RenderScript or custom OpenGL.</p> 153 * 154 * <p>This does not affect bitmaps without an alpha channel.</p> 155 * 156 * @see Bitmap#hasAlpha() 157 * @see Bitmap#isPremultiplied() 158 */ 159 public boolean inPremultiplied; 160 161 /** 162 * If dither is true, the decoder will attempt to dither the decoded 163 * image. 164 */ 165 public boolean inDither; 166 167 /** 168 * The pixel density to use for the bitmap. This will always result 169 * in the returned bitmap having a density set for it (see 170 * {@link Bitmap#setDensity(int) Bitmap.setDensity(int)}). In addition, 171 * if {@link #inScaled} is set (which it is by default} and this 172 * density does not match {@link #inTargetDensity}, then the bitmap 173 * will be scaled to the target density before being returned. 174 * 175 * <p>If this is 0, 176 * {@link BitmapFactory#decodeResource(Resources, int)}, 177 * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)}, 178 * and {@link BitmapFactory#decodeResourceStream} 179 * will fill in the density associated with the resource. The other 180 * functions will leave it as-is and no density will be applied. 181 * 182 * @see #inTargetDensity 183 * @see #inScreenDensity 184 * @see #inScaled 185 * @see Bitmap#setDensity(int) 186 * @see android.util.DisplayMetrics#densityDpi 187 */ 188 public int inDensity; 189 190 /** 191 * The pixel density of the destination this bitmap will be drawn to. 192 * This is used in conjunction with {@link #inDensity} and 193 * {@link #inScaled} to determine if and how to scale the bitmap before 194 * returning it. 195 * 196 * <p>If this is 0, 197 * {@link BitmapFactory#decodeResource(Resources, int)}, 198 * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)}, 199 * and {@link BitmapFactory#decodeResourceStream} 200 * will fill in the density associated the Resources object's 201 * DisplayMetrics. The other 202 * functions will leave it as-is and no scaling for density will be 203 * performed. 204 * 205 * @see #inDensity 206 * @see #inScreenDensity 207 * @see #inScaled 208 * @see android.util.DisplayMetrics#densityDpi 209 */ 210 public int inTargetDensity; 211 212 /** 213 * The pixel density of the actual screen that is being used. This is 214 * purely for applications running in density compatibility code, where 215 * {@link #inTargetDensity} is actually the density the application 216 * sees rather than the real screen density. 217 * 218 * <p>By setting this, you 219 * allow the loading code to avoid scaling a bitmap that is currently 220 * in the screen density up/down to the compatibility density. Instead, 221 * if {@link #inDensity} is the same as {@link #inScreenDensity}, the 222 * bitmap will be left as-is. Anything using the resulting bitmap 223 * must also used {@link Bitmap#getScaledWidth(int) 224 * Bitmap.getScaledWidth} and {@link Bitmap#getScaledHeight 225 * Bitmap.getScaledHeight} to account for any different between the 226 * bitmap's density and the target's density. 227 * 228 * <p>This is never set automatically for the caller by 229 * {@link BitmapFactory} itself. It must be explicitly set, since the 230 * caller must deal with the resulting bitmap in a density-aware way. 231 * 232 * @see #inDensity 233 * @see #inTargetDensity 234 * @see #inScaled 235 * @see android.util.DisplayMetrics#densityDpi 236 */ 237 public int inScreenDensity; 238 239 /** 240 * When this flag is set, if {@link #inDensity} and 241 * {@link #inTargetDensity} are not 0, the 242 * bitmap will be scaled to match {@link #inTargetDensity} when loaded, 243 * rather than relying on the graphics system scaling it each time it 244 * is drawn to a Canvas. 245 * 246 * <p>BitmapRegionDecoder ignores this flag, and will not scale output 247 * based on density. (though {@link #inSampleSize} is supported)</p> 248 * 249 * <p>This flag is turned on by default and should be turned off if you need 250 * a non-scaled version of the bitmap. Nine-patch bitmaps ignore this 251 * flag and are always scaled. 252 */ 253 public boolean inScaled; 254 255 /** 256 * If this is set to true, then the resulting bitmap will allocate its 257 * pixels such that they can be purged if the system needs to reclaim 258 * memory. In that instance, when the pixels need to be accessed again 259 * (e.g. the bitmap is drawn, getPixels() is called), they will be 260 * automatically re-decoded. 261 * 262 * For the re-decode to happen, the bitmap must have access to the 263 * encoded data, either by sharing a reference to the input 264 * or by making a copy of it. This distinction is controlled by 265 * inInputShareable. If this is true, then the bitmap may keep a shallow 266 * reference to the input. If this is false, then the bitmap will 267 * explicitly make a copy of the input data, and keep that. Even if 268 * sharing is allowed, the implementation may still decide to make a 269 * deep copy of the input data. 270 */ 271 public boolean inPurgeable; 272 273 /** 274 * This field works in conjuction with inPurgeable. If inPurgeable is 275 * false, then this field is ignored. If inPurgeable is true, then this 276 * field determines whether the bitmap can share a reference to the 277 * input data (inputstream, array, etc.) or if it must make a deep copy. 278 */ 279 public boolean inInputShareable; 280 281 /** 282 * If inPreferQualityOverSpeed is set to true, the decoder will try to 283 * decode the reconstructed image to a higher quality even at the 284 * expense of the decoding speed. Currently the field only affects JPEG 285 * decode, in the case of which a more accurate, but slightly slower, 286 * IDCT method will be used instead. 287 */ 288 public boolean inPreferQualityOverSpeed; 289 290 /** 291 * The resulting width of the bitmap. If {@link #inJustDecodeBounds} is 292 * set to false, this will be width of the output bitmap after any 293 * scaling is applied. If true, it will be the width of the input image 294 * without any accounting for scaling. 295 * 296 * <p>outWidth will be set to -1 if there is an error trying to decode.</p> 297 */ 298 public int outWidth; 299 300 /** 301 * The resulting height of the bitmap. If {@link #inJustDecodeBounds} is 302 * set to false, this will be height of the output bitmap after any 303 * scaling is applied. If true, it will be the height of the input image 304 * without any accounting for scaling. 305 * 306 * <p>outHeight will be set to -1 if there is an error trying to decode.</p> 307 */ 308 public int outHeight; 309 310 /** 311 * If known, this string is set to the mimetype of the decoded image. 312 * If not know, or there is an error, it is set to null. 313 */ 314 public String outMimeType; 315 316 /** 317 * Temp storage to use for decoding. Suggest 16K or so. 318 */ 319 public byte[] inTempStorage; 320 321 private native void requestCancel(); 322 323 /** 324 * Flag to indicate that cancel has been called on this object. This 325 * is useful if there's an intermediary that wants to first decode the 326 * bounds and then decode the image. In that case the intermediary 327 * can check, inbetween the bounds decode and the image decode, to see 328 * if the operation is canceled. 329 */ 330 public boolean mCancel; 331 332 /** 333 * This can be called from another thread while this options object is 334 * inside a decode... call. Calling this will notify the decoder that 335 * it should cancel its operation. This is not guaranteed to cancel 336 * the decode, but if it does, the decoder... operation will return 337 * null, or if inJustDecodeBounds is true, will set outWidth/outHeight 338 * to -1 339 */ 340 public void requestCancelDecode() { 341 mCancel = true; 342 requestCancel(); 343 } 344 } 345 346 /** 347 * Decode a file path into a bitmap. If the specified file name is null, 348 * or cannot be decoded into a bitmap, the function returns null. 349 * 350 * @param pathName complete path name for the file to be decoded. 351 * @param opts null-ok; Options that control downsampling and whether the 352 * image should be completely decoded, or just is size returned. 353 * @return The decoded bitmap, or null if the image data could not be 354 * decoded, or, if opts is non-null, if opts requested only the 355 * size be returned (in opts.outWidth and opts.outHeight) 356 */ 357 public static Bitmap decodeFile(String pathName, Options opts) { 358 Bitmap bm = null; 359 InputStream stream = null; 360 try { 361 stream = new FileInputStream(pathName); 362 bm = decodeStream(stream, null, opts); 363 } catch (Exception e) { 364 /* do nothing. 365 If the exception happened on open, bm will be null. 366 */ 367 Log.e("BitmapFactory", "Unable to decode stream: " + e); 368 } finally { 369 if (stream != null) { 370 try { 371 stream.close(); 372 } catch (IOException e) { 373 // do nothing here 374 } 375 } 376 } 377 return bm; 378 } 379 380 /** 381 * Decode a file path into a bitmap. If the specified file name is null, 382 * or cannot be decoded into a bitmap, the function returns null. 383 * 384 * @param pathName complete path name for the file to be decoded. 385 * @return the resulting decoded bitmap, or null if it could not be decoded. 386 */ 387 public static Bitmap decodeFile(String pathName) { 388 return decodeFile(pathName, null); 389 } 390 391 /** 392 * Decode a new Bitmap from an InputStream. This InputStream was obtained from 393 * resources, which we pass to be able to scale the bitmap accordingly. 394 */ 395 public static Bitmap decodeResourceStream(Resources res, TypedValue value, 396 InputStream is, Rect pad, Options opts) { 397 398 if (opts == null) { 399 opts = new Options(); 400 } 401 402 if (opts.inDensity == 0 && value != null) { 403 final int density = value.density; 404 if (density == TypedValue.DENSITY_DEFAULT) { 405 opts.inDensity = DisplayMetrics.DENSITY_DEFAULT; 406 } else if (density != TypedValue.DENSITY_NONE) { 407 opts.inDensity = density; 408 } 409 } 410 411 if (opts.inTargetDensity == 0 && res != null) { 412 opts.inTargetDensity = res.getDisplayMetrics().densityDpi; 413 } 414 415 return decodeStream(is, pad, opts); 416 } 417 418 /** 419 * Synonym for opening the given resource and calling 420 * {@link #decodeResourceStream}. 421 * 422 * @param res The resources object containing the image data 423 * @param id The resource id of the image data 424 * @param opts null-ok; Options that control downsampling and whether the 425 * image should be completely decoded, or just is size returned. 426 * @return The decoded bitmap, or null if the image data could not be 427 * decoded, or, if opts is non-null, if opts requested only the 428 * size be returned (in opts.outWidth and opts.outHeight) 429 */ 430 public static Bitmap decodeResource(Resources res, int id, Options opts) { 431 Bitmap bm = null; 432 InputStream is = null; 433 434 try { 435 final TypedValue value = new TypedValue(); 436 is = res.openRawResource(id, value); 437 438 bm = decodeResourceStream(res, value, is, null, opts); 439 } catch (Exception e) { 440 /* do nothing. 441 If the exception happened on open, bm will be null. 442 If it happened on close, bm is still valid. 443 */ 444 } finally { 445 try { 446 if (is != null) is.close(); 447 } catch (IOException e) { 448 // Ignore 449 } 450 } 451 452 if (bm == null && opts != null && opts.inBitmap != null) { 453 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 454 } 455 456 return bm; 457 } 458 459 /** 460 * Synonym for {@link #decodeResource(Resources, int, android.graphics.BitmapFactory.Options)} 461 * will null Options. 462 * 463 * @param res The resources object containing the image data 464 * @param id The resource id of the image data 465 * @return The decoded bitmap, or null if the image could not be decode. 466 */ 467 public static Bitmap decodeResource(Resources res, int id) { 468 return decodeResource(res, id, null); 469 } 470 471 /** 472 * Decode an immutable bitmap from the specified byte array. 473 * 474 * @param data byte array of compressed image data 475 * @param offset offset into imageData for where the decoder should begin 476 * parsing. 477 * @param length the number of bytes, beginning at offset, to parse 478 * @param opts null-ok; Options that control downsampling and whether the 479 * image should be completely decoded, or just is size returned. 480 * @return The decoded bitmap, or null if the image data could not be 481 * decoded, or, if opts is non-null, if opts requested only the 482 * size be returned (in opts.outWidth and opts.outHeight) 483 */ 484 public static Bitmap decodeByteArray(byte[] data, int offset, int length, Options opts) { 485 if ((offset | length) < 0 || data.length < offset + length) { 486 throw new ArrayIndexOutOfBoundsException(); 487 } 488 489 Bitmap bm; 490 491 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); 492 try { 493 bm = nativeDecodeByteArray(data, offset, length, opts); 494 495 if (bm == null && opts != null && opts.inBitmap != null) { 496 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 497 } 498 setDensityFromOptions(bm, opts); 499 } finally { 500 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 501 } 502 503 return bm; 504 } 505 506 /** 507 * Decode an immutable bitmap from the specified byte array. 508 * 509 * @param data byte array of compressed image data 510 * @param offset offset into imageData for where the decoder should begin 511 * parsing. 512 * @param length the number of bytes, beginning at offset, to parse 513 * @return The decoded bitmap, or null if the image could not be decode. 514 */ 515 public static Bitmap decodeByteArray(byte[] data, int offset, int length) { 516 return decodeByteArray(data, offset, length, null); 517 } 518 519 /** 520 * Set the newly decoded bitmap's density based on the Options. 521 */ 522 private static void setDensityFromOptions(Bitmap outputBitmap, Options opts) { 523 if (outputBitmap == null || opts == null) return; 524 525 final int density = opts.inDensity; 526 if (density != 0) { 527 outputBitmap.setDensity(density); 528 final int targetDensity = opts.inTargetDensity; 529 if (targetDensity == 0 || density == targetDensity || density == opts.inScreenDensity) { 530 return; 531 } 532 533 byte[] np = outputBitmap.getNinePatchChunk(); 534 final boolean isNinePatch = np != null && NinePatch.isNinePatchChunk(np); 535 if (opts.inScaled || isNinePatch) { 536 outputBitmap.setDensity(targetDensity); 537 } 538 } else if (opts.inBitmap != null) { 539 // bitmap was reused, ensure density is reset 540 outputBitmap.setDensity(Bitmap.getDefaultDensity()); 541 } 542 } 543 544 /** 545 * Decode an input stream into a bitmap. If the input stream is null, or 546 * cannot be used to decode a bitmap, the function returns null. 547 * The stream's position will be where ever it was after the encoded data 548 * was read. 549 * 550 * @param is The input stream that holds the raw data to be decoded into a 551 * bitmap. 552 * @param outPadding If not null, return the padding rect for the bitmap if 553 * it exists, otherwise set padding to [-1,-1,-1,-1]. If 554 * no bitmap is returned (null) then padding is 555 * unchanged. 556 * @param opts null-ok; Options that control downsampling and whether the 557 * image should be completely decoded, or just is size returned. 558 * @return The decoded bitmap, or null if the image data could not be 559 * decoded, or, if opts is non-null, if opts requested only the 560 * size be returned (in opts.outWidth and opts.outHeight) 561 * 562 * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT}, 563 * if {@link InputStream#markSupported is.markSupported()} returns true, 564 * <code>is.mark(1024)</code> would be called. As of 565 * {@link android.os.Build.VERSION_CODES#KITKAT}, this is no longer the case.</p> 566 */ 567 public static Bitmap decodeStream(InputStream is, Rect outPadding, Options opts) { 568 // we don't throw in this case, thus allowing the caller to only check 569 // the cache, and not force the image to be decoded. 570 if (is == null) { 571 return null; 572 } 573 574 Bitmap bm = null; 575 576 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); 577 try { 578 if (is instanceof AssetManager.AssetInputStream) { 579 final int asset = ((AssetManager.AssetInputStream) is).getAssetInt(); 580 bm = nativeDecodeAsset(asset, outPadding, opts); 581 } else { 582 bm = decodeStreamInternal(is, outPadding, opts); 583 } 584 585 if (bm == null && opts != null && opts.inBitmap != null) { 586 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 587 } 588 589 setDensityFromOptions(bm, opts); 590 } finally { 591 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 592 } 593 594 return bm; 595 } 596 597 /** 598 * Private helper function for decoding an InputStream natively. Buffers the input enough to 599 * do a rewind as needed, and supplies temporary storage if necessary. is MUST NOT be null. 600 */ 601 private static Bitmap decodeStreamInternal(InputStream is, Rect outPadding, Options opts) { 602 // ASSERT(is != null); 603 byte [] tempStorage = null; 604 if (opts != null) tempStorage = opts.inTempStorage; 605 if (tempStorage == null) tempStorage = new byte[DECODE_BUFFER_SIZE]; 606 return nativeDecodeStream(is, tempStorage, outPadding, opts); 607 } 608 609 /** 610 * Decode an input stream into a bitmap. If the input stream is null, or 611 * cannot be used to decode a bitmap, the function returns null. 612 * The stream's position will be where ever it was after the encoded data 613 * was read. 614 * 615 * @param is The input stream that holds the raw data to be decoded into a 616 * bitmap. 617 * @return The decoded bitmap, or null if the image data could not be decoded. 618 */ 619 public static Bitmap decodeStream(InputStream is) { 620 return decodeStream(is, null, null); 621 } 622 623 /** 624 * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded 625 * return null. The position within the descriptor will not be changed when 626 * this returns, so the descriptor can be used again as-is. 627 * 628 * @param fd The file descriptor containing the bitmap data to decode 629 * @param outPadding If not null, return the padding rect for the bitmap if 630 * it exists, otherwise set padding to [-1,-1,-1,-1]. If 631 * no bitmap is returned (null) then padding is 632 * unchanged. 633 * @param opts null-ok; Options that control downsampling and whether the 634 * image should be completely decoded, or just its size returned. 635 * @return the decoded bitmap, or null 636 */ 637 public static Bitmap decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts) { 638 Bitmap bm; 639 640 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeFileDescriptor"); 641 try { 642 if (nativeIsSeekable(fd)) { 643 bm = nativeDecodeFileDescriptor(fd, outPadding, opts); 644 } else { 645 FileInputStream fis = new FileInputStream(fd); 646 try { 647 bm = decodeStreamInternal(fis, outPadding, opts); 648 } finally { 649 try { 650 fis.close(); 651 } catch (Throwable t) {/* ignore */} 652 } 653 } 654 655 if (bm == null && opts != null && opts.inBitmap != null) { 656 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 657 } 658 659 setDensityFromOptions(bm, opts); 660 } finally { 661 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 662 } 663 return bm; 664 } 665 666 /** 667 * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded 668 * return null. The position within the descriptor will not be changed when 669 * this returns, so the descriptor can be used again as is. 670 * 671 * @param fd The file descriptor containing the bitmap data to decode 672 * @return the decoded bitmap, or null 673 */ 674 public static Bitmap decodeFileDescriptor(FileDescriptor fd) { 675 return decodeFileDescriptor(fd, null, null); 676 } 677 678 private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage, 679 Rect padding, Options opts); 680 private static native Bitmap nativeDecodeFileDescriptor(FileDescriptor fd, 681 Rect padding, Options opts); 682 private static native Bitmap nativeDecodeAsset(int asset, Rect padding, Options opts); 683 private static native Bitmap nativeDecodeByteArray(byte[] data, int offset, 684 int length, Options opts); 685 private static native boolean nativeIsSeekable(FileDescriptor fd); 686} 687