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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 
17 package android.graphics;
18 
19 import android.content.res.AssetManager;
20 import android.content.res.Resources;
21 import android.os.Trace;
22 import android.util.DisplayMetrics;
23 import android.util.Log;
24 import android.util.TypedValue;
25 
26 import java.io.FileDescriptor;
27 import java.io.FileInputStream;
28 import java.io.IOException;
29 import java.io.InputStream;
30 
31 /**
32  * Creates Bitmap objects from various sources, including files, streams,
33  * and byte-arrays.
34  */
35 public 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          */
Options()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          * <p>Setting this flag to false while setting {@link #inScaled} to true
157          * may result in incorrect colors.</p>
158          *
159          * @see Bitmap#hasAlpha()
160          * @see Bitmap#isPremultiplied()
161          * @see #inScaled
162          */
163         public boolean inPremultiplied;
164 
165         /**
166          * If dither is true, the decoder will attempt to dither the decoded
167          * image.
168          */
169         public boolean inDither;
170 
171         /**
172          * The pixel density to use for the bitmap.  This will always result
173          * in the returned bitmap having a density set for it (see
174          * {@link Bitmap#setDensity(int) Bitmap.setDensity(int)}).  In addition,
175          * if {@link #inScaled} is set (which it is by default} and this
176          * density does not match {@link #inTargetDensity}, then the bitmap
177          * will be scaled to the target density before being returned.
178          *
179          * <p>If this is 0,
180          * {@link BitmapFactory#decodeResource(Resources, int)},
181          * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)},
182          * and {@link BitmapFactory#decodeResourceStream}
183          * will fill in the density associated with the resource.  The other
184          * functions will leave it as-is and no density will be applied.
185          *
186          * @see #inTargetDensity
187          * @see #inScreenDensity
188          * @see #inScaled
189          * @see Bitmap#setDensity(int)
190          * @see android.util.DisplayMetrics#densityDpi
191          */
192         public int inDensity;
193 
194         /**
195          * The pixel density of the destination this bitmap will be drawn to.
196          * This is used in conjunction with {@link #inDensity} and
197          * {@link #inScaled} to determine if and how to scale the bitmap before
198          * returning it.
199          *
200          * <p>If this is 0,
201          * {@link BitmapFactory#decodeResource(Resources, int)},
202          * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)},
203          * and {@link BitmapFactory#decodeResourceStream}
204          * will fill in the density associated the Resources object's
205          * DisplayMetrics.  The other
206          * functions will leave it as-is and no scaling for density will be
207          * performed.
208          *
209          * @see #inDensity
210          * @see #inScreenDensity
211          * @see #inScaled
212          * @see android.util.DisplayMetrics#densityDpi
213          */
214         public int inTargetDensity;
215 
216         /**
217          * The pixel density of the actual screen that is being used.  This is
218          * purely for applications running in density compatibility code, where
219          * {@link #inTargetDensity} is actually the density the application
220          * sees rather than the real screen density.
221          *
222          * <p>By setting this, you
223          * allow the loading code to avoid scaling a bitmap that is currently
224          * in the screen density up/down to the compatibility density.  Instead,
225          * if {@link #inDensity} is the same as {@link #inScreenDensity}, the
226          * bitmap will be left as-is.  Anything using the resulting bitmap
227          * must also used {@link Bitmap#getScaledWidth(int)
228          * Bitmap.getScaledWidth} and {@link Bitmap#getScaledHeight
229          * Bitmap.getScaledHeight} to account for any different between the
230          * bitmap's density and the target's density.
231          *
232          * <p>This is never set automatically for the caller by
233          * {@link BitmapFactory} itself.  It must be explicitly set, since the
234          * caller must deal with the resulting bitmap in a density-aware way.
235          *
236          * @see #inDensity
237          * @see #inTargetDensity
238          * @see #inScaled
239          * @see android.util.DisplayMetrics#densityDpi
240          */
241         public int inScreenDensity;
242 
243         /**
244          * When this flag is set, if {@link #inDensity} and
245          * {@link #inTargetDensity} are not 0, the
246          * bitmap will be scaled to match {@link #inTargetDensity} when loaded,
247          * rather than relying on the graphics system scaling it each time it
248          * is drawn to a Canvas.
249          *
250          * <p>BitmapRegionDecoder ignores this flag, and will not scale output
251          * based on density. (though {@link #inSampleSize} is supported)</p>
252          *
253          * <p>This flag is turned on by default and should be turned off if you need
254          * a non-scaled version of the bitmap.  Nine-patch bitmaps ignore this
255          * flag and are always scaled.
256          *
257          * <p>If {@link #inPremultiplied} is set to false, and the image has alpha,
258          * setting this flag to true may result in incorrect colors.
259          */
260         public boolean inScaled;
261 
262         /**
263          * If this is set to true, then the resulting bitmap will allocate its
264          * pixels such that they can be purged if the system needs to reclaim
265          * memory. In that instance, when the pixels need to be accessed again
266          * (e.g. the bitmap is drawn, getPixels() is called), they will be
267          * automatically re-decoded.
268          *
269          * <p>For the re-decode to happen, the bitmap must have access to the
270          * encoded data, either by sharing a reference to the input
271          * or by making a copy of it. This distinction is controlled by
272          * inInputShareable. If this is true, then the bitmap may keep a shallow
273          * reference to the input. If this is false, then the bitmap will
274          * explicitly make a copy of the input data, and keep that. Even if
275          * sharing is allowed, the implementation may still decide to make a
276          * deep copy of the input data.</p>
277          *
278          * <p>While inPurgeable can help avoid big Dalvik heap allocations (from
279          * API level 11 onward), it sacrifices performance predictability since any
280          * image that the view system tries to draw may incur a decode delay which
281          * can lead to dropped frames. Therefore, most apps should avoid using
282          * inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap
283          * allocations use the {@link #inBitmap} flag instead.</p>
284          *
285          * <p class="note"><strong>Note:</strong> This flag is ignored when used
286          * with {@link #decodeResource(Resources, int,
287          * android.graphics.BitmapFactory.Options)} or {@link #decodeFile(String,
288          * android.graphics.BitmapFactory.Options)}.</p>
289          */
290         public boolean inPurgeable;
291 
292         /**
293          * This field works in conjuction with inPurgeable. If inPurgeable is
294          * false, then this field is ignored. If inPurgeable is true, then this
295          * field determines whether the bitmap can share a reference to the
296          * input data (inputstream, array, etc.) or if it must make a deep copy.
297          */
298         public boolean inInputShareable;
299 
300         /**
301          * If inPreferQualityOverSpeed is set to true, the decoder will try to
302          * decode the reconstructed image to a higher quality even at the
303          * expense of the decoding speed. Currently the field only affects JPEG
304          * decode, in the case of which a more accurate, but slightly slower,
305          * IDCT method will be used instead.
306          */
307         public boolean inPreferQualityOverSpeed;
308 
309         /**
310          * The resulting width of the bitmap, set independent of the state of
311          * inJustDecodeBounds. However, if there is an error trying to decode,
312          * outWidth will be set to -1.
313          */
314 
315         public int outWidth;
316 
317         /**
318          * The resulting height of the bitmap, set independent of the state of
319          * inJustDecodeBounds. However, if there is an error trying to decode,
320          * outHeight will be set to -1.
321          */
322         public int outHeight;
323 
324         /**
325          * If known, this string is set to the mimetype of the decoded image.
326          * If not know, or there is an error, it is set to null.
327          */
328         public String outMimeType;
329 
330         /**
331          * Temp storage to use for decoding.  Suggest 16K or so.
332          */
333         public byte[] inTempStorage;
334 
requestCancel()335         private native void requestCancel();
336 
337         /**
338          * Flag to indicate that cancel has been called on this object.  This
339          * is useful if there's an intermediary that wants to first decode the
340          * bounds and then decode the image.  In that case the intermediary
341          * can check, inbetween the bounds decode and the image decode, to see
342          * if the operation is canceled.
343          */
344         public boolean mCancel;
345 
346         /**
347          *  This can be called from another thread while this options object is
348          *  inside a decode... call. Calling this will notify the decoder that
349          *  it should cancel its operation. This is not guaranteed to cancel
350          *  the decode, but if it does, the decoder... operation will return
351          *  null, or if inJustDecodeBounds is true, will set outWidth/outHeight
352          *  to -1
353          */
requestCancelDecode()354         public void requestCancelDecode() {
355             mCancel = true;
356             requestCancel();
357         }
358     }
359 
360     /**
361      * Decode a file path into a bitmap. If the specified file name is null,
362      * or cannot be decoded into a bitmap, the function returns null.
363      *
364      * @param pathName complete path name for the file to be decoded.
365      * @param opts null-ok; Options that control downsampling and whether the
366      *             image should be completely decoded, or just is size returned.
367      * @return The decoded bitmap, or null if the image data could not be
368      *         decoded, or, if opts is non-null, if opts requested only the
369      *         size be returned (in opts.outWidth and opts.outHeight)
370      */
decodeFile(String pathName, Options opts)371     public static Bitmap decodeFile(String pathName, Options opts) {
372         Bitmap bm = null;
373         InputStream stream = null;
374         try {
375             stream = new FileInputStream(pathName);
376             bm = decodeStream(stream, null, opts);
377         } catch (Exception e) {
378             /*  do nothing.
379                 If the exception happened on open, bm will be null.
380             */
381             Log.e("BitmapFactory", "Unable to decode stream: " + e);
382         } finally {
383             if (stream != null) {
384                 try {
385                     stream.close();
386                 } catch (IOException e) {
387                     // do nothing here
388                 }
389             }
390         }
391         return bm;
392     }
393 
394     /**
395      * Decode a file path into a bitmap. If the specified file name is null,
396      * or cannot be decoded into a bitmap, the function returns null.
397      *
398      * @param pathName complete path name for the file to be decoded.
399      * @return the resulting decoded bitmap, or null if it could not be decoded.
400      */
decodeFile(String pathName)401     public static Bitmap decodeFile(String pathName) {
402         return decodeFile(pathName, null);
403     }
404 
405     /**
406      * Decode a new Bitmap from an InputStream. This InputStream was obtained from
407      * resources, which we pass to be able to scale the bitmap accordingly.
408      */
decodeResourceStream(Resources res, TypedValue value, InputStream is, Rect pad, Options opts)409     public static Bitmap decodeResourceStream(Resources res, TypedValue value,
410             InputStream is, Rect pad, Options opts) {
411 
412         if (opts == null) {
413             opts = new Options();
414         }
415 
416         if (opts.inDensity == 0 && value != null) {
417             final int density = value.density;
418             if (density == TypedValue.DENSITY_DEFAULT) {
419                 opts.inDensity = DisplayMetrics.DENSITY_DEFAULT;
420             } else if (density != TypedValue.DENSITY_NONE) {
421                 opts.inDensity = density;
422             }
423         }
424 
425         if (opts.inTargetDensity == 0 && res != null) {
426             opts.inTargetDensity = res.getDisplayMetrics().densityDpi;
427         }
428 
429         return decodeStream(is, pad, opts);
430     }
431 
432     /**
433      * Synonym for opening the given resource and calling
434      * {@link #decodeResourceStream}.
435      *
436      * @param res   The resources object containing the image data
437      * @param id The resource id of the image data
438      * @param opts null-ok; Options that control downsampling and whether the
439      *             image should be completely decoded, or just is size returned.
440      * @return The decoded bitmap, or null if the image data could not be
441      *         decoded, or, if opts is non-null, if opts requested only the
442      *         size be returned (in opts.outWidth and opts.outHeight)
443      */
decodeResource(Resources res, int id, Options opts)444     public static Bitmap decodeResource(Resources res, int id, Options opts) {
445         Bitmap bm = null;
446         InputStream is = null;
447 
448         try {
449             final TypedValue value = new TypedValue();
450             is = res.openRawResource(id, value);
451 
452             bm = decodeResourceStream(res, value, is, null, opts);
453         } catch (Exception e) {
454             /*  do nothing.
455                 If the exception happened on open, bm will be null.
456                 If it happened on close, bm is still valid.
457             */
458         } finally {
459             try {
460                 if (is != null) is.close();
461             } catch (IOException e) {
462                 // Ignore
463             }
464         }
465 
466         if (bm == null && opts != null && opts.inBitmap != null) {
467             throw new IllegalArgumentException("Problem decoding into existing bitmap");
468         }
469 
470         return bm;
471     }
472 
473     /**
474      * Synonym for {@link #decodeResource(Resources, int, android.graphics.BitmapFactory.Options)}
475      * will null Options.
476      *
477      * @param res The resources object containing the image data
478      * @param id The resource id of the image data
479      * @return The decoded bitmap, or null if the image could not be decode.
480      */
decodeResource(Resources res, int id)481     public static Bitmap decodeResource(Resources res, int id) {
482         return decodeResource(res, id, null);
483     }
484 
485     /**
486      * Decode an immutable bitmap from the specified byte array.
487      *
488      * @param data byte array of compressed image data
489      * @param offset offset into imageData for where the decoder should begin
490      *               parsing.
491      * @param length the number of bytes, beginning at offset, to parse
492      * @param opts null-ok; Options that control downsampling and whether the
493      *             image should be completely decoded, or just is size returned.
494      * @return The decoded bitmap, or null if the image data could not be
495      *         decoded, or, if opts is non-null, if opts requested only the
496      *         size be returned (in opts.outWidth and opts.outHeight)
497      */
decodeByteArray(byte[] data, int offset, int length, Options opts)498     public static Bitmap decodeByteArray(byte[] data, int offset, int length, Options opts) {
499         if ((offset | length) < 0 || data.length < offset + length) {
500             throw new ArrayIndexOutOfBoundsException();
501         }
502 
503         Bitmap bm;
504 
505         Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap");
506         try {
507             bm = nativeDecodeByteArray(data, offset, length, opts);
508 
509             if (bm == null && opts != null && opts.inBitmap != null) {
510                 throw new IllegalArgumentException("Problem decoding into existing bitmap");
511             }
512             setDensityFromOptions(bm, opts);
513         } finally {
514             Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS);
515         }
516 
517         return bm;
518     }
519 
520     /**
521      * Decode an immutable bitmap from the specified byte array.
522      *
523      * @param data byte array of compressed image data
524      * @param offset offset into imageData for where the decoder should begin
525      *               parsing.
526      * @param length the number of bytes, beginning at offset, to parse
527      * @return The decoded bitmap, or null if the image could not be decode.
528      */
decodeByteArray(byte[] data, int offset, int length)529     public static Bitmap decodeByteArray(byte[] data, int offset, int length) {
530         return decodeByteArray(data, offset, length, null);
531     }
532 
533     /**
534      * Set the newly decoded bitmap's density based on the Options.
535      */
setDensityFromOptions(Bitmap outputBitmap, Options opts)536     private static void setDensityFromOptions(Bitmap outputBitmap, Options opts) {
537         if (outputBitmap == null || opts == null) return;
538 
539         final int density = opts.inDensity;
540         if (density != 0) {
541             outputBitmap.setDensity(density);
542             final int targetDensity = opts.inTargetDensity;
543             if (targetDensity == 0 || density == targetDensity || density == opts.inScreenDensity) {
544                 return;
545             }
546 
547             byte[] np = outputBitmap.getNinePatchChunk();
548             final boolean isNinePatch = np != null && NinePatch.isNinePatchChunk(np);
549             if (opts.inScaled || isNinePatch) {
550                 outputBitmap.setDensity(targetDensity);
551             }
552         } else if (opts.inBitmap != null) {
553             // bitmap was reused, ensure density is reset
554             outputBitmap.setDensity(Bitmap.getDefaultDensity());
555         }
556     }
557 
558     /**
559      * Decode an input stream into a bitmap. If the input stream is null, or
560      * cannot be used to decode a bitmap, the function returns null.
561      * The stream's position will be where ever it was after the encoded data
562      * was read.
563      *
564      * @param is The input stream that holds the raw data to be decoded into a
565      *           bitmap.
566      * @param outPadding If not null, return the padding rect for the bitmap if
567      *                   it exists, otherwise set padding to [-1,-1,-1,-1]. If
568      *                   no bitmap is returned (null) then padding is
569      *                   unchanged.
570      * @param opts null-ok; Options that control downsampling and whether the
571      *             image should be completely decoded, or just is size returned.
572      * @return The decoded bitmap, or null if the image data could not be
573      *         decoded, or, if opts is non-null, if opts requested only the
574      *         size be returned (in opts.outWidth and opts.outHeight)
575      *
576      * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT},
577      * if {@link InputStream#markSupported is.markSupported()} returns true,
578      * <code>is.mark(1024)</code> would be called. As of
579      * {@link android.os.Build.VERSION_CODES#KITKAT}, this is no longer the case.</p>
580      */
decodeStream(InputStream is, Rect outPadding, Options opts)581     public static Bitmap decodeStream(InputStream is, Rect outPadding, Options opts) {
582         // we don't throw in this case, thus allowing the caller to only check
583         // the cache, and not force the image to be decoded.
584         if (is == null) {
585             return null;
586         }
587 
588         Bitmap bm = null;
589 
590         Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap");
591         try {
592             if (is instanceof AssetManager.AssetInputStream) {
593                 final int asset = ((AssetManager.AssetInputStream) is).getAssetInt();
594                 bm = nativeDecodeAsset(asset, outPadding, opts);
595             } else {
596                 bm = decodeStreamInternal(is, outPadding, opts);
597             }
598 
599             if (bm == null && opts != null && opts.inBitmap != null) {
600                 throw new IllegalArgumentException("Problem decoding into existing bitmap");
601             }
602 
603             setDensityFromOptions(bm, opts);
604         } finally {
605             Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS);
606         }
607 
608         return bm;
609     }
610 
611     /**
612      * Private helper function for decoding an InputStream natively. Buffers the input enough to
613      * do a rewind as needed, and supplies temporary storage if necessary. is MUST NOT be null.
614      */
decodeStreamInternal(InputStream is, Rect outPadding, Options opts)615     private static Bitmap decodeStreamInternal(InputStream is, Rect outPadding, Options opts) {
616         // ASSERT(is != null);
617         byte [] tempStorage = null;
618         if (opts != null) tempStorage = opts.inTempStorage;
619         if (tempStorage == null) tempStorage = new byte[DECODE_BUFFER_SIZE];
620         return nativeDecodeStream(is, tempStorage, outPadding, opts);
621     }
622 
623     /**
624      * Decode an input stream into a bitmap. If the input stream is null, or
625      * cannot be used to decode a bitmap, the function returns null.
626      * The stream's position will be where ever it was after the encoded data
627      * was read.
628      *
629      * @param is The input stream that holds the raw data to be decoded into a
630      *           bitmap.
631      * @return The decoded bitmap, or null if the image data could not be decoded.
632      */
decodeStream(InputStream is)633     public static Bitmap decodeStream(InputStream is) {
634         return decodeStream(is, null, null);
635     }
636 
637     /**
638      * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded
639      * return null. The position within the descriptor will not be changed when
640      * this returns, so the descriptor can be used again as-is.
641      *
642      * @param fd The file descriptor containing the bitmap data to decode
643      * @param outPadding If not null, return the padding rect for the bitmap if
644      *                   it exists, otherwise set padding to [-1,-1,-1,-1]. If
645      *                   no bitmap is returned (null) then padding is
646      *                   unchanged.
647      * @param opts null-ok; Options that control downsampling and whether the
648      *             image should be completely decoded, or just its size returned.
649      * @return the decoded bitmap, or null
650      */
decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts)651     public static Bitmap decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts) {
652         Bitmap bm;
653 
654         Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeFileDescriptor");
655         try {
656             if (nativeIsSeekable(fd)) {
657                 bm = nativeDecodeFileDescriptor(fd, outPadding, opts);
658             } else {
659                 FileInputStream fis = new FileInputStream(fd);
660                 try {
661                     bm = decodeStreamInternal(fis, outPadding, opts);
662                 } finally {
663                     try {
664                         fis.close();
665                     } catch (Throwable t) {/* ignore */}
666                 }
667             }
668 
669             if (bm == null && opts != null && opts.inBitmap != null) {
670                 throw new IllegalArgumentException("Problem decoding into existing bitmap");
671             }
672 
673             setDensityFromOptions(bm, opts);
674         } finally {
675             Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS);
676         }
677         return bm;
678     }
679 
680     /**
681      * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded
682      * return null. The position within the descriptor will not be changed when
683      * this returns, so the descriptor can be used again as is.
684      *
685      * @param fd The file descriptor containing the bitmap data to decode
686      * @return the decoded bitmap, or null
687      */
decodeFileDescriptor(FileDescriptor fd)688     public static Bitmap decodeFileDescriptor(FileDescriptor fd) {
689         return decodeFileDescriptor(fd, null, null);
690     }
691 
nativeDecodeStream(InputStream is, byte[] storage, Rect padding, Options opts)692     private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage,
693             Rect padding, Options opts);
nativeDecodeFileDescriptor(FileDescriptor fd, Rect padding, Options opts)694     private static native Bitmap nativeDecodeFileDescriptor(FileDescriptor fd,
695             Rect padding, Options opts);
nativeDecodeAsset(int asset, Rect padding, Options opts)696     private static native Bitmap nativeDecodeAsset(int asset, Rect padding, Options opts);
nativeDecodeByteArray(byte[] data, int offset, int length, Options opts)697     private static native Bitmap nativeDecodeByteArray(byte[] data, int offset,
698             int length, Options opts);
nativeIsSeekable(FileDescriptor fd)699     private static native boolean nativeIsSeekable(FileDescriptor fd);
700 }
701