Java tutorial
/* * Copyright (C) 2007 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.graphics; import static android.graphics.BitmapFactory.Options.validate; import android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.UnsupportedAppUsage; import android.content.res.AssetManager; import android.content.res.Resources; import android.os.Trace; import android.util.DisplayMetrics; import android.util.Log; import android.util.TypedValue; import java.io.FileDescriptor; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; /** * Creates Bitmap objects from various sources, including files, streams, * and byte-arrays. */ public class BitmapFactory { private static final int DECODE_BUFFER_SIZE = 16 * 1024; public static class Options { /** * Create a default Options object, which if left unchanged will give * the same result from the decoder as if null were passed. */ public Options() { inScaled = true; inPremultiplied = true; } /** * If set, decode methods that take the Options object will attempt to * reuse this bitmap when loading content. If the decode operation * cannot use this bitmap, the decode method will throw an * {@link java.lang.IllegalArgumentException}. The * current implementation necessitates that the reused bitmap be * mutable, and the resulting reused bitmap will continue to remain * mutable even when decoding a resource which would normally result in * an immutable bitmap.</p> * * <p>You should still always use the returned Bitmap of the decode * method and not assume that reusing the bitmap worked, due to the * constraints outlined above and failure situations that can occur. * Checking whether the return value matches the value of the inBitmap * set in the Options structure will indicate if the bitmap was reused, * but in all cases you should use the Bitmap returned by the decoding * function to ensure that you are using the bitmap that was used as the * decode destination.</p> * * <h3>Usage with BitmapFactory</h3> * * <p>As of {@link android.os.Build.VERSION_CODES#KITKAT}, any * mutable bitmap can be reused by {@link BitmapFactory} to decode any * other bitmaps as long as the resulting {@link Bitmap#getByteCount() * byte count} of the decoded bitmap is less than or equal to the {@link * Bitmap#getAllocationByteCount() allocated byte count} of the reused * bitmap. This can be because the intrinsic size is smaller, or its * size post scaling (for density / sample size) is smaller.</p> * * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT} * additional constraints apply: The image being decoded (whether as a * resource or as a stream) must be in jpeg or png format. Only equal * sized bitmaps are supported, with {@link #inSampleSize} set to 1. * Additionally, the {@link android.graphics.Bitmap.Config * configuration} of the reused bitmap will override the setting of * {@link #inPreferredConfig}, if set.</p> * * <h3>Usage with BitmapRegionDecoder</h3> * * <p>BitmapRegionDecoder will draw its requested content into the Bitmap * provided, clipping if the output content size (post scaling) is larger * than the provided Bitmap. The provided Bitmap's width, height, and * {@link Bitmap.Config} will not be changed. * * <p class="note">BitmapRegionDecoder support for {@link #inBitmap} was * introduced in {@link android.os.Build.VERSION_CODES#JELLY_BEAN}. All * formats supported by BitmapRegionDecoder support Bitmap reuse via * {@link #inBitmap}.</p> * * @see Bitmap#reconfigure(int,int, android.graphics.Bitmap.Config) */ public Bitmap inBitmap; /** * If set, decode methods will always return a mutable Bitmap instead of * an immutable one. This can be used for instance to programmatically apply * effects to a Bitmap loaded through BitmapFactory. * <p>Can not be set simultaneously with inPreferredConfig = * {@link android.graphics.Bitmap.Config#HARDWARE}, * because hardware bitmaps are always immutable. */ @SuppressWarnings({ "UnusedDeclaration" }) // used in native code public boolean inMutable; /** * If set to true, the decoder will return null (no bitmap), but * the <code>out...</code> fields will still be set, allowing the caller to * query the bitmap without having to allocate the memory for its pixels. */ public boolean inJustDecodeBounds; /** * If set to a value > 1, requests the decoder to subsample the original * image, returning a smaller image to save memory. The sample size is * the number of pixels in either dimension that correspond to a single * pixel in the decoded bitmap. For example, inSampleSize == 4 returns * an image that is 1/4 the width/height of the original, and 1/16 the * number of pixels. Any value <= 1 is treated the same as 1. Note: the * decoder uses a final value based on powers of 2, any other value will * be rounded down to the nearest power of 2. */ public int inSampleSize; /** * If this is non-null, the decoder will try to decode into this * internal configuration. If it is null, or the request cannot be met, * the decoder will try to pick the best matching config based on the * system's screen depth, and characteristics of the original image such * as if it has per-pixel alpha (requiring a config that also does). * * Image are loaded with the {@link Bitmap.Config#ARGB_8888} config by * default. */ public Bitmap.Config inPreferredConfig = Bitmap.Config.ARGB_8888; /** * <p>If this is non-null, the decoder will try to decode into this * color space. If it is null, or the request cannot be met, * the decoder will pick either the color space embedded in the image * or the color space best suited for the requested image configuration * (for instance {@link ColorSpace.Named#SRGB sRGB} for * the {@link Bitmap.Config#ARGB_8888} configuration).</p> * * <p>{@link Bitmap.Config#RGBA_F16} always uses the * {@link ColorSpace.Named#LINEAR_EXTENDED_SRGB scRGB} color space). * Bitmaps in other configurations without an embedded color space are * assumed to be in the {@link ColorSpace.Named#SRGB sRGB} color space.</p> * * <p class="note">Only {@link ColorSpace.Model#RGB} color spaces are * currently supported. An <code>IllegalArgumentException</code> will * be thrown by the decode methods when setting a non-RGB color space * such as {@link ColorSpace.Named#CIE_LAB Lab}.</p> * * <p class="note">The specified color space's transfer function must be * an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve}. An * <code>IllegalArgumentException</code> will be thrown by the decode methods * if calling {@link ColorSpace.Rgb#getTransferParameters()} on the * specified color space returns null.</p> * * <p>After decode, the bitmap's color space is stored in * {@link #outColorSpace}.</p> */ public ColorSpace inPreferredColorSpace = null; /** * If true (which is the default), the resulting bitmap will have its * color channels pre-multipled by the alpha channel. * * <p>This should NOT be set to false for images to be directly drawn by * the view system or through a {@link Canvas}. The view system and * {@link Canvas} assume all drawn images are pre-multiplied to simplify * draw-time blending, and will throw a RuntimeException when * un-premultiplied are drawn.</p> * * <p>This is likely only useful if you want to manipulate raw encoded * image data, e.g. with RenderScript or custom OpenGL.</p> * * <p>This does not affect bitmaps without an alpha channel.</p> * * <p>Setting this flag to false while setting {@link #inScaled} to true * may result in incorrect colors.</p> * * @see Bitmap#hasAlpha() * @see Bitmap#isPremultiplied() * @see #inScaled */ public boolean inPremultiplied; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#N}, this is * ignored. * * In {@link android.os.Build.VERSION_CODES#M} and below, if dither is * true, the decoder will attempt to dither the decoded image. */ public boolean inDither; /** * The pixel density to use for the bitmap. This will always result * in the returned bitmap having a density set for it (see * {@link Bitmap#setDensity(int) Bitmap.setDensity(int)}). In addition, * if {@link #inScaled} is set (which it is by default} and this * density does not match {@link #inTargetDensity}, then the bitmap * will be scaled to the target density before being returned. * * <p>If this is 0, * {@link BitmapFactory#decodeResource(Resources, int)}, * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)}, * and {@link BitmapFactory#decodeResourceStream} * will fill in the density associated with the resource. The other * functions will leave it as-is and no density will be applied. * * @see #inTargetDensity * @see #inScreenDensity * @see #inScaled * @see Bitmap#setDensity(int) * @see android.util.DisplayMetrics#densityDpi */ public int inDensity; /** * The pixel density of the destination this bitmap will be drawn to. * This is used in conjunction with {@link #inDensity} and * {@link #inScaled} to determine if and how to scale the bitmap before * returning it. * * <p>If this is 0, * {@link BitmapFactory#decodeResource(Resources, int)}, * {@link BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)}, * and {@link BitmapFactory#decodeResourceStream} * will fill in the density associated the Resources object's * DisplayMetrics. The other * functions will leave it as-is and no scaling for density will be * performed. * * @see #inDensity * @see #inScreenDensity * @see #inScaled * @see android.util.DisplayMetrics#densityDpi */ public int inTargetDensity; /** * The pixel density of the actual screen that is being used. This is * purely for applications running in density compatibility code, where * {@link #inTargetDensity} is actually the density the application * sees rather than the real screen density. * * <p>By setting this, you * allow the loading code to avoid scaling a bitmap that is currently * in the screen density up/down to the compatibility density. Instead, * if {@link #inDensity} is the same as {@link #inScreenDensity}, the * bitmap will be left as-is. Anything using the resulting bitmap * must also used {@link Bitmap#getScaledWidth(int) * Bitmap.getScaledWidth} and {@link Bitmap#getScaledHeight * Bitmap.getScaledHeight} to account for any different between the * bitmap's density and the target's density. * * <p>This is never set automatically for the caller by * {@link BitmapFactory} itself. It must be explicitly set, since the * caller must deal with the resulting bitmap in a density-aware way. * * @see #inDensity * @see #inTargetDensity * @see #inScaled * @see android.util.DisplayMetrics#densityDpi */ public int inScreenDensity; /** * When this flag is set, if {@link #inDensity} and * {@link #inTargetDensity} are not 0, the * bitmap will be scaled to match {@link #inTargetDensity} when loaded, * rather than relying on the graphics system scaling it each time it * is drawn to a Canvas. * * <p>BitmapRegionDecoder ignores this flag, and will not scale output * based on density. (though {@link #inSampleSize} is supported)</p> * * <p>This flag is turned on by default and should be turned off if you need * a non-scaled version of the bitmap. Nine-patch bitmaps ignore this * flag and are always scaled. * * <p>If {@link #inPremultiplied} is set to false, and the image has alpha, * setting this flag to true may result in incorrect colors. */ public boolean inScaled; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this is * ignored. * * In {@link android.os.Build.VERSION_CODES#KITKAT} and below, if this * is set to true, then the resulting bitmap will allocate its * pixels such that they can be purged if the system needs to reclaim * memory. In that instance, when the pixels need to be accessed again * (e.g. the bitmap is drawn, getPixels() is called), they will be * automatically re-decoded. * * <p>For the re-decode to happen, the bitmap must have access to the * encoded data, either by sharing a reference to the input * or by making a copy of it. This distinction is controlled by * inInputShareable. If this is true, then the bitmap may keep a shallow * reference to the input. If this is false, then the bitmap will * explicitly make a copy of the input data, and keep that. Even if * sharing is allowed, the implementation may still decide to make a * deep copy of the input data.</p> * * <p>While inPurgeable can help avoid big Dalvik heap allocations (from * API level 11 onward), it sacrifices performance predictability since any * image that the view system tries to draw may incur a decode delay which * can lead to dropped frames. Therefore, most apps should avoid using * inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap * allocations use the {@link #inBitmap} flag instead.</p> * * <p class="note"><strong>Note:</strong> This flag is ignored when used * with {@link #decodeResource(Resources, int, * android.graphics.BitmapFactory.Options)} or {@link #decodeFile(String, * android.graphics.BitmapFactory.Options)}.</p> */ @Deprecated public boolean inPurgeable; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this is * ignored. * * In {@link android.os.Build.VERSION_CODES#KITKAT} and below, this * field works in conjuction with inPurgeable. If inPurgeable is false, * then this field is ignored. If inPurgeable is true, then this field * determines whether the bitmap can share a reference to the input * data (inputstream, array, etc.) or if it must make a deep copy. */ @Deprecated public boolean inInputShareable; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#N}, this is * ignored. The output will always be high quality. * * In {@link android.os.Build.VERSION_CODES#M} and below, if * inPreferQualityOverSpeed is set to true, the decoder will try to * decode the reconstructed image to a higher quality even at the * expense of the decoding speed. Currently the field only affects JPEG * decode, in the case of which a more accurate, but slightly slower, * IDCT method will be used instead. */ @Deprecated public boolean inPreferQualityOverSpeed; /** * The resulting width of the bitmap. If {@link #inJustDecodeBounds} is * set to false, this will be width of the output bitmap after any * scaling is applied. If true, it will be the width of the input image * without any accounting for scaling. * * <p>outWidth will be set to -1 if there is an error trying to decode.</p> */ public int outWidth; /** * The resulting height of the bitmap. If {@link #inJustDecodeBounds} is * set to false, this will be height of the output bitmap after any * scaling is applied. If true, it will be the height of the input image * without any accounting for scaling. * * <p>outHeight will be set to -1 if there is an error trying to decode.</p> */ public int outHeight; /** * If known, this string is set to the mimetype of the decoded image. * If not known, or there is an error, it is set to null. */ public String outMimeType; /** * If known, the config the decoded bitmap will have. * If not known, or there is an error, it is set to null. */ public Bitmap.Config outConfig; /** * If known, the color space the decoded bitmap will have. Note that the * output color space is not guaranteed to be the color space the bitmap * is encoded with. If not known (when the config is * {@link Bitmap.Config#ALPHA_8} for instance), or there is an error, * it is set to null. */ public ColorSpace outColorSpace; /** * Temp storage to use for decoding. Suggest 16K or so. */ public byte[] inTempStorage; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#N}, see * comments on {@link #requestCancelDecode()}. * * Flag to indicate that cancel has been called on this object. This * is useful if there's an intermediary that wants to first decode the * bounds and then decode the image. In that case the intermediary * can check, inbetween the bounds decode and the image decode, to see * if the operation is canceled. */ @Deprecated public boolean mCancel; /** * @deprecated As of {@link android.os.Build.VERSION_CODES#N}, this * will not affect the decode, though it will still set mCancel. * * In {@link android.os.Build.VERSION_CODES#M} and below, if this can * be called from another thread while this options object is inside * a decode... call. Calling this will notify the decoder that it * should cancel its operation. This is not guaranteed to cancel the * decode, but if it does, the decoder... operation will return null, * or if inJustDecodeBounds is true, will set outWidth/outHeight * to -1 */ @Deprecated public void requestCancelDecode() { mCancel = true; } static void validate(Options opts) { if (opts == null) return; if (opts.inBitmap != null && opts.inBitmap.getConfig() == Bitmap.Config.HARDWARE) { throw new IllegalArgumentException("Bitmaps with Config.HARDWARE are always immutable"); } if (opts.inMutable && opts.inPreferredConfig == Bitmap.Config.HARDWARE) { throw new IllegalArgumentException( "Bitmaps with Config.HARDWARE cannot be " + "decoded into - they are immutable"); } if (opts.inPreferredColorSpace != null) { if (!(opts.inPreferredColorSpace instanceof ColorSpace.Rgb)) { throw new IllegalArgumentException( "The destination color space must use the " + "RGB color model"); } if (((ColorSpace.Rgb) opts.inPreferredColorSpace).getTransferParameters() == null) { throw new IllegalArgumentException( "The destination color space must use an " + "ICC parametric transfer function"); } } } } /** * Decode a file path into a bitmap. If the specified file name is null, * or cannot be decoded into a bitmap, the function returns null. * * @param pathName complete path name for the file to be decoded. * @param opts null-ok; Options that control downsampling and whether the * image should be completely decoded, or just is size returned. * @return The decoded bitmap, or null if the image data could not be * decoded, or, if opts is non-null, if opts requested only the * size be returned (in opts.outWidth and opts.outHeight) * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} */ public static Bitmap decodeFile(String pathName, Options opts) { validate(opts); Bitmap bm = null; InputStream stream = null; try { stream = new FileInputStream(pathName); bm = decodeStream(stream, null, opts); } catch (Exception e) { /* do nothing. If the exception happened on open, bm will be null. */ Log.e("BitmapFactory", "Unable to decode stream: " + e); } finally { if (stream != null) { try { stream.close(); } catch (IOException e) { // do nothing here } } } return bm; } /** * Decode a file path into a bitmap. If the specified file name is null, * or cannot be decoded into a bitmap, the function returns null. * * @param pathName complete path name for the file to be decoded. * @return the resulting decoded bitmap, or null if it could not be decoded. */ public static Bitmap decodeFile(String pathName) { return decodeFile(pathName, null); } /** * Decode a new Bitmap from an InputStream. This InputStream was obtained from * resources, which we pass to be able to scale the bitmap accordingly. * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} */ @Nullable public static Bitmap decodeResourceStream(@Nullable Resources res, @Nullable TypedValue value, @Nullable InputStream is, @Nullable Rect pad, @Nullable Options opts) { validate(opts); if (opts == null) { opts = new Options(); } if (opts.inDensity == 0 && value != null) { final int density = value.density; if (density == TypedValue.DENSITY_DEFAULT) { opts.inDensity = DisplayMetrics.DENSITY_DEFAULT; } else if (density != TypedValue.DENSITY_NONE) { opts.inDensity = density; } } if (opts.inTargetDensity == 0 && res != null) { opts.inTargetDensity = res.getDisplayMetrics().densityDpi; } return decodeStream(is, pad, opts); } /** * Synonym for opening the given resource and calling * {@link #decodeResourceStream}. * * @param res The resources object containing the image data * @param id The resource id of the image data * @param opts null-ok; Options that control downsampling and whether the * image should be completely decoded, or just is size returned. * @return The decoded bitmap, or null if the image data could not be * decoded, or, if opts is non-null, if opts requested only the * size be returned (in opts.outWidth and opts.outHeight) * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} */ public static Bitmap decodeResource(Resources res, int id, Options opts) { validate(opts); Bitmap bm = null; InputStream is = null; try { final TypedValue value = new TypedValue(); is = res.openRawResource(id, value); bm = decodeResourceStream(res, value, is, null, opts); } catch (Exception e) { /* do nothing. If the exception happened on open, bm will be null. If it happened on close, bm is still valid. */ } finally { try { if (is != null) is.close(); } catch (IOException e) { // Ignore } } if (bm == null && opts != null && opts.inBitmap != null) { throw new IllegalArgumentException("Problem decoding into existing bitmap"); } return bm; } /** * Synonym for {@link #decodeResource(Resources, int, android.graphics.BitmapFactory.Options)} * with null Options. * * @param res The resources object containing the image data * @param id The resource id of the image data * @return The decoded bitmap, or null if the image could not be decoded. */ public static Bitmap decodeResource(Resources res, int id) { return decodeResource(res, id, null); } /** * Decode an immutable bitmap from the specified byte array. * * @param data byte array of compressed image data * @param offset offset into imageData for where the decoder should begin * parsing. * @param length the number of bytes, beginning at offset, to parse * @param opts null-ok; Options that control downsampling and whether the * image should be completely decoded, or just is size returned. * @return The decoded bitmap, or null if the image data could not be * decoded, or, if opts is non-null, if opts requested only the * size be returned (in opts.outWidth and opts.outHeight) * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} */ public static Bitmap decodeByteArray(byte[] data, int offset, int length, Options opts) { if ((offset | length) < 0 || data.length < offset + length) { throw new ArrayIndexOutOfBoundsException(); } validate(opts); Bitmap bm; Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); try { bm = nativeDecodeByteArray(data, offset, length, opts); if (bm == null && opts != null && opts.inBitmap != null) { throw new IllegalArgumentException("Problem decoding into existing bitmap"); } setDensityFromOptions(bm, opts); } finally { Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); } return bm; } /** * Decode an immutable bitmap from the specified byte array. * * @param data byte array of compressed image data * @param offset offset into imageData for where the decoder should begin * parsing. * @param length the number of bytes, beginning at offset, to parse * @return The decoded bitmap, or null if the image could not be decoded. */ public static Bitmap decodeByteArray(byte[] data, int offset, int length) { return decodeByteArray(data, offset, length, null); } /** * Set the newly decoded bitmap's density based on the Options. */ private static void setDensityFromOptions(Bitmap outputBitmap, Options opts) { if (outputBitmap == null || opts == null) return; final int density = opts.inDensity; if (density != 0) { outputBitmap.setDensity(density); final int targetDensity = opts.inTargetDensity; if (targetDensity == 0 || density == targetDensity || density == opts.inScreenDensity) { return; } byte[] np = outputBitmap.getNinePatchChunk(); final boolean isNinePatch = np != null && NinePatch.isNinePatchChunk(np); if (opts.inScaled || isNinePatch) { outputBitmap.setDensity(targetDensity); } } else if (opts.inBitmap != null) { // bitmap was reused, ensure density is reset outputBitmap.setDensity(Bitmap.getDefaultDensity()); } } /** * Decode an input stream into a bitmap. If the input stream is null, or * cannot be used to decode a bitmap, the function returns null. * The stream's position will be where ever it was after the encoded data * was read. * * @param is The input stream that holds the raw data to be decoded into a * bitmap. * @param outPadding If not null, return the padding rect for the bitmap if * it exists, otherwise set padding to [-1,-1,-1,-1]. If * no bitmap is returned (null) then padding is * unchanged. * @param opts null-ok; Options that control downsampling and whether the * image should be completely decoded, or just is size returned. * @return The decoded bitmap, or null if the image data could not be * decoded, or, if opts is non-null, if opts requested only the * size be returned (in opts.outWidth and opts.outHeight) * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} * * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT}, * if {@link InputStream#markSupported is.markSupported()} returns true, * <code>is.mark(1024)</code> would be called. As of * {@link android.os.Build.VERSION_CODES#KITKAT}, this is no longer the case.</p> */ @Nullable public static Bitmap decodeStream(@Nullable InputStream is, @Nullable Rect outPadding, @Nullable Options opts) { // we don't throw in this case, thus allowing the caller to only check // the cache, and not force the image to be decoded. if (is == null) { return null; } validate(opts); Bitmap bm = null; Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeBitmap"); try { if (is instanceof AssetManager.AssetInputStream) { final long asset = ((AssetManager.AssetInputStream) is).getNativeAsset(); bm = nativeDecodeAsset(asset, outPadding, opts); } else { bm = decodeStreamInternal(is, outPadding, opts); } if (bm == null && opts != null && opts.inBitmap != null) { throw new IllegalArgumentException("Problem decoding into existing bitmap"); } setDensityFromOptions(bm, opts); } finally { Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); } return bm; } /** * Private helper function for decoding an InputStream natively. Buffers the input enough to * do a rewind as needed, and supplies temporary storage if necessary. is MUST NOT be null. */ private static Bitmap decodeStreamInternal(@NonNull InputStream is, @Nullable Rect outPadding, @Nullable Options opts) { // ASSERT(is != null); byte[] tempStorage = null; if (opts != null) tempStorage = opts.inTempStorage; if (tempStorage == null) tempStorage = new byte[DECODE_BUFFER_SIZE]; return nativeDecodeStream(is, tempStorage, outPadding, opts); } /** * Decode an input stream into a bitmap. If the input stream is null, or * cannot be used to decode a bitmap, the function returns null. * The stream's position will be where ever it was after the encoded data * was read. * * @param is The input stream that holds the raw data to be decoded into a * bitmap. * @return The decoded bitmap, or null if the image data could not be decoded. */ public static Bitmap decodeStream(InputStream is) { return decodeStream(is, null, null); } /** * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded * return null. The position within the descriptor will not be changed when * this returns, so the descriptor can be used again as-is. * * @param fd The file descriptor containing the bitmap data to decode * @param outPadding If not null, return the padding rect for the bitmap if * it exists, otherwise set padding to [-1,-1,-1,-1]. If * no bitmap is returned (null) then padding is * unchanged. * @param opts null-ok; Options that control downsampling and whether the * image should be completely decoded, or just its size returned. * @return the decoded bitmap, or null * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig} * is {@link android.graphics.Bitmap.Config#HARDWARE} * and {@link BitmapFactory.Options#inMutable} is set, if the specified color space * is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer * function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve} */ public static Bitmap decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts) { validate(opts); Bitmap bm; Trace.traceBegin(Trace.TRACE_TAG_GRAPHICS, "decodeFileDescriptor"); try { if (nativeIsSeekable(fd)) { bm = nativeDecodeFileDescriptor(fd, outPadding, opts); } else { FileInputStream fis = new FileInputStream(fd); try { bm = decodeStreamInternal(fis, outPadding, opts); } finally { try { fis.close(); } catch (Throwable t) { /* ignore */} } } if (bm == null && opts != null && opts.inBitmap != null) { throw new IllegalArgumentException("Problem decoding into existing bitmap"); } setDensityFromOptions(bm, opts); } finally { Trace.traceEnd(Trace.TRACE_TAG_GRAPHICS); } return bm; } /** * Decode a bitmap from the file descriptor. If the bitmap cannot be decoded * return null. The position within the descriptor will not be changed when * this returns, so the descriptor can be used again as is. * * @param fd The file descriptor containing the bitmap data to decode * @return the decoded bitmap, or null */ public static Bitmap decodeFileDescriptor(FileDescriptor fd) { return decodeFileDescriptor(fd, null, null); } @UnsupportedAppUsage private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage, Rect padding, Options opts); @UnsupportedAppUsage private static native Bitmap nativeDecodeFileDescriptor(FileDescriptor fd, Rect padding, Options opts); @UnsupportedAppUsage private static native Bitmap nativeDecodeAsset(long nativeAsset, Rect padding, Options opts); @UnsupportedAppUsage private static native Bitmap nativeDecodeByteArray(byte[] data, int offset, int length, Options opts); private static native boolean nativeIsSeekable(FileDescriptor fd); }