BitmapFactory.java revision 918997738383a847e3e019c24ec1b4f4ad39c43e
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 * <p>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.</p> 270 * 271 * <p>While inPurgeable can help avoid big Dalvik heap allocations (from 272 * API level 11 onward), it sacrifices performance predictability since any 273 * image that the view system tries to draw may incur a decode delay which 274 * can lead to dropped frames. Therefore, most apps should avoid using 275 * inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap 276 * allocations use the {@link #inBitmap} flag instead.</p> 277 * 278 * <p class="note"><strong>Note:</strong> This flag is ignored when used 279 * with {@link #decodeResource(Resources, int, 280 * android.graphics.BitmapFactory.Options)} or {@link #decodeFile(String, 281 * android.graphics.BitmapFactory.Options)}.</p> 282 */ 283 public boolean inPurgeable; 284 285 /** 286 * This field works in conjuction with inPurgeable. If inPurgeable is 287 * false, then this field is ignored. If inPurgeable is true, then this 288 * field determines whether the bitmap can share a reference to the 289 * input data (inputstream, array, etc.) or if it must make a deep copy. 290 */ 291 public boolean inInputShareable; 292 293 /** 294 * If inPreferQualityOverSpeed is set to true, the decoder will try to 295 * decode the reconstructed image to a higher quality even at the 296 * expense of the decoding speed. Currently the field only affects JPEG 297 * decode, in the case of which a more accurate, but slightly slower, 298 * IDCT method will be used instead. 299 */ 300 public boolean inPreferQualityOverSpeed; 301 302 /** 303 * The resulting width of the bitmap. If {@link #inJustDecodeBounds} is 304 * set to false, this will be width of the output bitmap after any 305 * scaling is applied. If true, it will be the width of the input image 306 * without any accounting for scaling. 307 * 308 * <p>outWidth will be set to -1 if there is an error trying to decode.</p> 309 */ 310 public int outWidth; 311 312 /** 313 * The resulting height of the bitmap. If {@link #inJustDecodeBounds} is 314 * set to false, this will be height of the output bitmap after any 315 * scaling is applied. If true, it will be the height of the input image 316 * without any accounting for scaling. 317 * 318 * <p>outHeight will be set to -1 if there is an error trying to decode.</p> 319 */ 320 public int outHeight; 321 322 /** 323 * If known, this string is set to the mimetype of the decoded image. 324 * If not know, or there is an error, it is set to null. 325 */ 326 public String outMimeType; 327 328 /** 329 * Temp storage to use for decoding. Suggest 16K or so. 330 */ 331 public byte[] inTempStorage; 332 333 private native void requestCancel(); 334 335 /** 336 * Flag to indicate that cancel has been called on this object. This 337 * is useful if there's an intermediary that wants to first decode the 338 * bounds and then decode the image. In that case the intermediary 339 * can check, inbetween the bounds decode and the image decode, to see 340 * if the operation is canceled. 341 */ 342 public boolean mCancel; 343 344 /** 345 * This can be called from another thread while this options object is 346 * inside a decode... call. Calling this will notify the decoder that 347 * it should cancel its operation. This is not guaranteed to cancel 348 * the decode, but if it does, the decoder... operation will return 349 * null, or if inJustDecodeBounds is true, will set outWidth/outHeight 350 * to -1 351 */ 352 public void requestCancelDecode() { 353 mCancel = true; 354 requestCancel(); 355 } 356 } 357 358 /** 359 * Decode a file path into a bitmap. If the specified file name is null, 360 * or cannot be decoded into a bitmap, the function returns null. 361 * 362 * @param pathName complete path name for the file to be decoded. 363 * @param opts null-ok; Options that control downsampling and whether the 364 * image should be completely decoded, or just is size returned. 365 * @return The decoded bitmap, or null if the image data could not be 366 * decoded, or, if opts is non-null, if opts requested only the 367 * size be returned (in opts.outWidth and opts.outHeight) 368 */ 369 public static Bitmap decodeFile(String pathName, Options opts) { 370 Bitmap bm = null; 371 InputStream stream = null; 372 try { 373 stream = new FileInputStream(pathName); 374 bm = decodeStream(stream, null, opts); 375 } catch (Exception e) { 376 /* do nothing. 377 If the exception happened on open, bm will be null. 378 */ 379 Log.e("BitmapFactory", "Unable to decode stream: " + e); 380 } finally { 381 if (stream != null) { 382 try { 383 stream.close(); 384 } catch (IOException e) { 385 // do nothing here 386 } 387 } 388 } 389 return bm; 390 } 391 392 /** 393 * Decode a file path into a bitmap. If the specified file name is null, 394 * or cannot be decoded into a bitmap, the function returns null. 395 * 396 * @param pathName complete path name for the file to be decoded. 397 * @return the resulting decoded bitmap, or null if it could not be decoded. 398 */ 399 public static Bitmap decodeFile(String pathName) { 400 return decodeFile(pathName, null); 401 } 402 403 /** 404 * Decode a new Bitmap from an InputStream. This InputStream was obtained from 405 * resources, which we pass to be able to scale the bitmap accordingly. 406 */ 407 public static Bitmap decodeResourceStream(Resources res, TypedValue value, 408 InputStream is, Rect pad, Options opts) { 409 410 if (opts == null) { 411 opts = new Options(); 412 } 413 414 if (opts.inDensity == 0 && value != null) { 415 final int density = value.density; 416 if (density == TypedValue.DENSITY_DEFAULT) { 417 opts.inDensity = DisplayMetrics.DENSITY_DEFAULT; 418 } else if (density != TypedValue.DENSITY_NONE) { 419 opts.inDensity = density; 420 } 421 } 422 423 if (opts.inTargetDensity == 0 && res != null) { 424 opts.inTargetDensity = res.getDisplayMetrics().densityDpi; 425 } 426 427 return decodeStream(is, pad, opts); 428 } 429 430 /** 431 * Synonym for opening the given resource and calling 432 * {@link #decodeResourceStream}. 433 * 434 * @param res The resources object containing the image data 435 * @param id The resource id of the image data 436 * @param opts null-ok; Options that control downsampling and whether the 437 * image should be completely decoded, or just is size returned. 438 * @return The decoded bitmap, or null if the image data could not be 439 * decoded, or, if opts is non-null, if opts requested only the 440 * size be returned (in opts.outWidth and opts.outHeight) 441 */ 442 public static Bitmap decodeResource(Resources res, int id, Options opts) { 443 Bitmap bm = null; 444 InputStream is = null; 445 446 try { 447 final TypedValue value = new TypedValue(); 448 is = res.openRawResource(id, value); 449 450 bm = decodeResourceStream(res, value, is, null, opts); 451 } catch (Exception e) { 452 /* do nothing. 453 If the exception happened on open, bm will be null. 454 If it happened on close, bm is still valid. 455 */ 456 } finally { 457 try { 458 if (is != null) is.close(); 459 } catch (IOException e) { 460 // Ignore 461 } 462 } 463 464 if (bm == null && opts != null && opts.inBitmap != null) { 465 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 466 } 467 468 return bm; 469 } 470 471 /** 472 * Synonym for {@link #decodeResource(Resources, int, android.graphics.BitmapFactory.Options)} 473 * will null Options. 474 * 475 * @param res The resources object containing the image data 476 * @param id The resource id of the image data 477 * @return The decoded bitmap, or null if the image could not be decoded. 478 */ 479 public static Bitmap decodeResource(Resources res, int id) { 480 return decodeResource(res, id, null); 481 } 482 483 /** 484 * Decode an immutable bitmap from the specified byte array. 485 * 486 * @param data byte array of compressed image data 487 * @param offset offset into imageData for where the decoder should begin 488 * parsing. 489 * @param length the number of bytes, beginning at offset, to parse 490 * @param opts null-ok; Options that control downsampling and whether the 491 * image should be completely decoded, or just is size returned. 492 * @return The decoded bitmap, or null if the image data could not be 493 * decoded, or, if opts is non-null, if opts requested only the 494 * size be returned (in opts.outWidth and opts.outHeight) 495 */ 496 public static Bitmap decodeByteArray(byte[] data, int offset, int length, Options opts) { 497 if ((offset | length) < 0 || data.length < offset + length) { 498 throw new ArrayIndexOutOfBoundsException(); 499 } 500 501 Bitmap bm; 502 503 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); 504 try { 505 bm = nativeDecodeByteArray(data, offset, length, opts); 506 507 if (bm == null && opts != null && opts.inBitmap != null) { 508 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 509 } 510 setDensityFromOptions(bm, opts); 511 } finally { 512 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 513 } 514 515 return bm; 516 } 517 518 /** 519 * Decode an immutable bitmap from the specified byte array. 520 * 521 * @param data byte array of compressed image data 522 * @param offset offset into imageData for where the decoder should begin 523 * parsing. 524 * @param length the number of bytes, beginning at offset, to parse 525 * @return The decoded bitmap, or null if the image could not be decoded. 526 */ 527 public static Bitmap decodeByteArray(byte[] data, int offset, int length) { 528 return decodeByteArray(data, offset, length, null); 529 } 530 531 /** 532 * Set the newly decoded bitmap's density based on the Options. 533 */ 534 private static void setDensityFromOptions(Bitmap outputBitmap, Options opts) { 535 if (outputBitmap == null || opts == null) return; 536 537 final int density = opts.inDensity; 538 if (density != 0) { 539 outputBitmap.setDensity(density); 540 final int targetDensity = opts.inTargetDensity; 541 if (targetDensity == 0 || density == targetDensity || density == opts.inScreenDensity) { 542 return; 543 } 544 545 byte[] np = outputBitmap.getNinePatchChunk(); 546 final boolean isNinePatch = np != null && NinePatch.isNinePatchChunk(np); 547 if (opts.inScaled || isNinePatch) { 548 outputBitmap.setDensity(targetDensity); 549 } 550 } else if (opts.inBitmap != null) { 551 // bitmap was reused, ensure density is reset 552 outputBitmap.setDensity(Bitmap.getDefaultDensity()); 553 } 554 } 555 556 /** 557 * Decode an input stream into a bitmap. If the input stream is null, or 558 * cannot be used to decode a bitmap, the function returns null. 559 * The stream's position will be where ever it was after the encoded data 560 * was read. 561 * 562 * @param is The input stream that holds the raw data to be decoded into a 563 * bitmap. 564 * @param outPadding If not null, return the padding rect for the bitmap if 565 * it exists, otherwise set padding to [-1,-1,-1,-1]. If 566 * no bitmap is returned (null) then padding is 567 * unchanged. 568 * @param opts null-ok; Options that control downsampling and whether the 569 * image should be completely decoded, or just is size returned. 570 * @return The decoded bitmap, or null if the image data could not be 571 * decoded, or, if opts is non-null, if opts requested only the 572 * size be returned (in opts.outWidth and opts.outHeight) 573 * 574 * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT}, 575 * if {@link InputStream#markSupported is.markSupported()} returns true, 576 * <code>is.mark(1024)</code> would be called. As of 577 * {@link android.os.Build.VERSION_CODES#KITKAT}, this is no longer the case.</p> 578 */ 579 public static Bitmap decodeStream(InputStream is, Rect outPadding, Options opts) { 580 // we don't throw in this case, thus allowing the caller to only check 581 // the cache, and not force the image to be decoded. 582 if (is == null) { 583 return null; 584 } 585 586 Bitmap bm = null; 587 588 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); 589 try { 590 if (is instanceof AssetManager.AssetInputStream) { 591 final int asset = ((AssetManager.AssetInputStream) is).getAssetInt(); 592 bm = nativeDecodeAsset(asset, outPadding, opts); 593 } else { 594 bm = decodeStreamInternal(is, outPadding, opts); 595 } 596 597 if (bm == null && opts != null && opts.inBitmap != null) { 598 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 599 } 600 601 setDensityFromOptions(bm, opts); 602 } finally { 603 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 604 } 605 606 return bm; 607 } 608 609 /** 610 * Private helper function for decoding an InputStream natively. Buffers the input enough to 611 * do a rewind as needed, and supplies temporary storage if necessary. is MUST NOT be null. 612 */ 613 private static Bitmap decodeStreamInternal(InputStream is, Rect outPadding, Options opts) { 614 // ASSERT(is != null); 615 byte [] tempStorage = null; 616 if (opts != null) tempStorage = opts.inTempStorage; 617 if (tempStorage == null) tempStorage = new byte[DECODE_BUFFER_SIZE]; 618 return nativeDecodeStream(is, tempStorage, outPadding, opts); 619 } 620 621 /** 622 * Decode an input stream into a bitmap. If the input stream is null, or 623 * cannot be used to decode a bitmap, the function returns null. 624 * The stream's position will be where ever it was after the encoded data 625 * was read. 626 * 627 * @param is The input stream that holds the raw data to be decoded into a 628 * bitmap. 629 * @return The decoded bitmap, or null if the image data could not be decoded. 630 */ 631 public static Bitmap decodeStream(InputStream is) { 632 return decodeStream(is, null, null); 633 } 634 635 /** 636 * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded 637 * return null. The position within the descriptor will not be changed when 638 * this returns, so the descriptor can be used again as-is. 639 * 640 * @param fd The file descriptor containing the bitmap data to decode 641 * @param outPadding If not null, return the padding rect for the bitmap if 642 * it exists, otherwise set padding to [-1,-1,-1,-1]. If 643 * no bitmap is returned (null) then padding is 644 * unchanged. 645 * @param opts null-ok; Options that control downsampling and whether the 646 * image should be completely decoded, or just its size returned. 647 * @return the decoded bitmap, or null 648 */ 649 public static Bitmap decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts) { 650 Bitmap bm; 651 652 Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeFileDescriptor"); 653 try { 654 if (nativeIsSeekable(fd)) { 655 bm = nativeDecodeFileDescriptor(fd, outPadding, opts); 656 } else { 657 FileInputStream fis = new FileInputStream(fd); 658 try { 659 bm = decodeStreamInternal(fis, outPadding, opts); 660 } finally { 661 try { 662 fis.close(); 663 } catch (Throwable t) {/* ignore */} 664 } 665 } 666 667 if (bm == null && opts != null && opts.inBitmap != null) { 668 throw new IllegalArgumentException("Problem decoding into existing bitmap"); 669 } 670 671 setDensityFromOptions(bm, opts); 672 } finally { 673 Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); 674 } 675 return bm; 676 } 677 678 /** 679 * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded 680 * return null. The position within the descriptor will not be changed when 681 * this returns, so the descriptor can be used again as is. 682 * 683 * @param fd The file descriptor containing the bitmap data to decode 684 * @return the decoded bitmap, or null 685 */ 686 public static Bitmap decodeFileDescriptor(FileDescriptor fd) { 687 return decodeFileDescriptor(fd, null, null); 688 } 689 690 private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage, 691 Rect padding, Options opts); 692 private static native Bitmap nativeDecodeFileDescriptor(FileDescriptor fd, 693 Rect padding, Options opts); 694 private static native Bitmap nativeDecodeAsset(int asset, Rect padding, Options opts); 695 private static native Bitmap nativeDecodeByteArray(byte[] data, int offset, 696 int length, Options opts); 697 private static native boolean nativeIsSeekable(FileDescriptor fd); 698} 699