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Add documentation for ImageDecoder and its Source

Browse Source 
Bug: 76448408
Bug: 76462125
Test: Iec21bad971dc9cffc807a412bb6329757c499baa

- Document DecodeException.getSource
- Add thread annotations
- slice() ByteBuffer inside createImageDecoder, so it can be reused
- Make ResourceSource thread safe by locking around mResDensity
- Specify that OnHeaderDecodedListener is necessary for changing default
  settings

Change-Id: I3b55d3ba1b0a2276938cb521449bceb7aa9f96e2
This commit is contained in:
Leon Scroggins III
2018-03-29 15:54:59 -04:00
parent d62f27250a
commit 0a87cb3128
1 changed files with 119 additions and 10 deletions
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129
graphics/java/android/graphics/ImageDecoder.java
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@@ -21,10 +21,12 @@ import static android.system.OsConstants.SEEK_SET;
import static java.lang.annotation.RetentionPolicy.SOURCE;
import android.annotation.AnyThread;
import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.TestApi;
import android.annotation.WorkerThread;
import android.content.ContentResolver;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
@@ -65,6 +67,16 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Source of the encoded image data.
*
* <p>This object references the data that will be used to decode a
* Drawable or Bitmap in {@link #decodeDrawable} or {@link #decodeBitmap}.
* Constructing a {@code Source} (with one of the overloads of
* {@code createSource}) can be done on any thread because the construction
* simply captures values. The real work is done in decodeDrawable or
* decodeBitmap.</p>
*
* <p>Further, a Source object can be reused with different settings, or
* even used simultaneously in multiple threads.</p>
*/
public static abstract class Source {
private Source() {}
@@ -120,7 +132,8 @@ public final class ImageDecoder implements AutoCloseable {
int length = mBuffer.limit() - mBuffer.position();
return nCreate(mBuffer.array(), offset, length, this);
}
return nCreate(mBuffer, mBuffer.position(), mBuffer.limit(), this);
ByteBuffer buffer = mBuffer.slice();
return nCreate(buffer, buffer.position(), buffer.limit(), this);
}
}
@@ -232,6 +245,8 @@ public final class ImageDecoder implements AutoCloseable {
/**
* For backwards compatibility, this does *not* close the InputStream.
*
* Further, unlike other Sources, this one is not reusable.
*/
private static class InputStreamSource extends Source {
InputStreamSource(Resources res, InputStream is, int inputDensity) {
@@ -322,12 +337,17 @@ public final class ImageDecoder implements AutoCloseable {
final Resources mResources;
final int mResId;
int mResDensity;
private Object mLock = new Object();
@Override
public Resources getResources() { return mResources; }
@Override
public int getDensity() { return mResDensity; }
public int getDensity() {
synchronized (mLock) {
return mResDensity;
}
}
@Override
public ImageDecoder createImageDecoder() throws IOException {
@@ -336,10 +356,12 @@ public final class ImageDecoder implements AutoCloseable {
// keep it alive.
InputStream is = mResources.openRawResource(mResId, value);
if (value.density == TypedValue.DENSITY_DEFAULT) {
mResDensity = DisplayMetrics.DENSITY_DEFAULT;
} else if (value.density != TypedValue.DENSITY_NONE) {
mResDensity = value.density;
synchronized (mLock) {
if (value.density == TypedValue.DENSITY_DEFAULT) {
mResDensity = DisplayMetrics.DENSITY_DEFAULT;
} else if (value.density != TypedValue.DENSITY_NONE) {
mResDensity = value.density;
}
}
return createFromAsset((AssetInputStream) is, this);
@@ -455,6 +477,9 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Optional listener supplied to {@link #decodeDrawable} or
* {@link #decodeBitmap}.
*
* <p>This is necessary in order to change the default settings of the
* decode.</p>
*/
public static interface OnHeaderDecodedListener {
/**
@@ -546,6 +571,9 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Retrieve the {@link Source} that was interrupted.
*
* <p>This can be used for equality checking to find the Source which
* failed to completely decode.</p>
*/
@NonNull
public Source getSource() {
@@ -658,6 +686,7 @@ public final class ImageDecoder implements AutoCloseable {
* @return a new Source object, which can be passed to
* {@link #decodeDrawable} or {@link #decodeBitmap}.
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull Resources res, int resId)
{
@@ -672,6 +701,7 @@ public final class ImageDecoder implements AutoCloseable {
* @return a new Source object, which can be passed to
* {@link #decodeDrawable} or {@link #decodeBitmap}.
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull ContentResolver cr,
@NonNull Uri uri) {
@@ -683,6 +713,7 @@ public final class ImageDecoder implements AutoCloseable {
*
* @hide
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull ContentResolver cr,
@NonNull Uri uri, @Nullable Resources res) {
@@ -692,6 +723,7 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Create a new {@link Source} from a file in the "assets" directory.
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull AssetManager assets, @NonNull String fileName) {
return new AssetSource(assets, fileName);
@@ -709,6 +741,7 @@ public final class ImageDecoder implements AutoCloseable {
* not within data.
* @hide
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull byte[] data, int offset,
int length) throws ArrayIndexOutOfBoundsException {
@@ -727,6 +760,7 @@ public final class ImageDecoder implements AutoCloseable {
* See {@link #createSource(byte[], int, int).
* @hide
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull byte[] data) {
return createSource(data, 0, data.length);
@@ -744,24 +778,35 @@ public final class ImageDecoder implements AutoCloseable {
* be modified, even after the {@code AnimatedImageDrawable} is returned.
* {@code buffer}'s contents should never be modified during decode.</p>
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull ByteBuffer buffer) {
return new ByteBufferSource(buffer.slice());
return new ByteBufferSource(buffer);
}
/**
* Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
*
* <p>Unlike other Sources, this one cannot be reused.</p>
*
* @hide
*/
@AnyThread
@NonNull
public static Source createSource(Resources res, InputStream is) {
return new InputStreamSource(res, is, Bitmap.getDefaultDensity());
}
/**
* Internal API used to generate bitmaps for use by Drawables (i.e. BitmapDrawable)
*
* <p>Unlike other Sources, this one cannot be reused.</p>
*
* @hide
*/
@AnyThread
@TestApi
@NonNull
public static Source createSource(Resources res, InputStream is, int density) {
return new InputStreamSource(res, is, density);
}
@@ -769,6 +814,7 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Create a new {@link Source} from a {@link java.io.File}.
*/
@AnyThread
@NonNull
public static Source createSource(@NonNull File file) {
return new FileSource(file);
@@ -822,6 +868,9 @@ public final class ImageDecoder implements AutoCloseable {
* <p>Only the last call to this or {@link #setTargetSampleSize} is
* respected.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @param width must be greater than 0.
* @param height must be greater than 0.
* @return this object for chaining.
@@ -888,6 +937,9 @@ public final class ImageDecoder implements AutoCloseable {
*
* <p>Only the last call to this or {@link #setTargetSize} is respected.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @param sampleSize Sampling rate of the encoded image.
* @return this object for chaining.
*/
@@ -948,7 +1000,10 @@ public final class ImageDecoder implements AutoCloseable {
/**
* Choose the backing for the pixel memory.
*
* This is ignored for animated drawables.
* <p>This is ignored for animated drawables.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @param allocator Type of allocator to use.
* @return this object for chaining.
@@ -982,6 +1037,9 @@ public final class ImageDecoder implements AutoCloseable {
* {@link Drawable} will throw an {@link java.lang.IllegalStateException}.
* </p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setUnpremultipliedRequired(boolean unpremultipliedRequired) {
@@ -1025,6 +1083,9 @@ public final class ImageDecoder implements AutoCloseable {
* {@link Canvas} will be recorded immediately and then applied to each
* frame.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setPostProcessor(@Nullable PostProcessor p) {
@@ -1046,6 +1107,9 @@ public final class ImageDecoder implements AutoCloseable {
* <p>Will be called if there is an error in the input. Without one, an
* error will result in an Exception being thrown.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setOnPartialImageListener(@Nullable OnPartialImageListener l) {
@@ -1073,6 +1137,9 @@ public final class ImageDecoder implements AutoCloseable {
* {@link BitmapRegionDecoder#decodeRegion}. This supports all formats,
* but merely crops the output.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setCrop(@Nullable Rect subset) {
@@ -1094,6 +1161,9 @@ public final class ImageDecoder implements AutoCloseable {
* If the image is a nine patch, this Rect will be set to the padding
* rectangle during decode. Otherwise it will not be modified.
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*
* @hide
@@ -1119,6 +1189,9 @@ public final class ImageDecoder implements AutoCloseable {
* order to modify. Attempting to decode a mutable {@link Drawable} will
* throw an {@link java.lang.IllegalStateException}.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setMutableRequired(boolean mutable) {
@@ -1161,6 +1234,9 @@ public final class ImageDecoder implements AutoCloseable {
* This necessarily lowers the quality of the output, but saves half
* the memory used.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setConserveMemory(boolean conserveMemory) {
@@ -1191,6 +1267,9 @@ public final class ImageDecoder implements AutoCloseable {
* {@link #decodeBitmap} throwing an
* {@link java.lang.IllegalStateException}.</p>
*
* <p>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*
* @return this object for chaining.
*/
public ImageDecoder setDecodeAsAlphaMaskEnabled(boolean enabled) {
@@ -1267,6 +1346,9 @@ public final class ImageDecoder implements AutoCloseable {
* <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>Like all setters on ImageDecoder, this must be called inside
* {@link OnHeaderDecodedListener#onHeaderDecoded}.</p>
*/
public ImageDecoder setTargetColorSpace(ColorSpace colorSpace) {
mDesiredColorSpace = colorSpace;
@@ -1334,6 +1416,7 @@ public final class ImageDecoder implements AutoCloseable {
}
}
@WorkerThread
@NonNull
private Bitmap decodeBitmapInternal() throws IOException {
checkState();
@@ -1362,10 +1445,12 @@ public final class ImageDecoder implements AutoCloseable {
* @param listener for learning the {@link ImageInfo} and changing any
* default settings on the {@code ImageDecoder}. This will be called on
* the same thread as {@code decodeDrawable} before that method returns.
* This is required in order to change any of the default settings.
* @return Drawable for displaying the image.
* @throws IOException if {@code src} is not found, is an unsupported
* format, or cannot be decoded for any reason.
*/
@WorkerThread
@NonNull
public static Drawable decodeDrawable(@NonNull Source src,
@NonNull OnHeaderDecodedListener listener) throws IOException {
@@ -1376,6 +1461,7 @@ public final class ImageDecoder implements AutoCloseable {
return decodeDrawableImpl(src, listener);
}
@WorkerThread
@NonNull
private static Drawable decodeDrawableImpl(@NonNull Source src,
@Nullable OnHeaderDecodedListener listener) throws IOException {
@@ -1436,8 +1522,18 @@ public final class ImageDecoder implements AutoCloseable {
}
/**
* See {@link #decodeDrawable(Source, OnHeaderDecodedListener)}.
* Create a {@link Drawable} from a {@code Source}.
*
* <p>Since there is no {@link OnHeaderDecodedListener}, the default
* settings will be used. In order to change any settings, call
* {@link #decodeDrawable(Source, OnHeaderDecodedListener)} instead.</p>
*
* @param src representing the encoded image.
* @return Drawable for displaying the image.
* @throws IOException if {@code src} is not found, is an unsupported
* format, or cannot be decoded for any reason.
*/
@WorkerThread
@NonNull
public static Drawable decodeDrawable(@NonNull Source src)
throws IOException {
@@ -1451,10 +1547,12 @@ public final class ImageDecoder implements AutoCloseable {
* @param listener for learning the {@link ImageInfo} and changing any
* default settings on the {@code ImageDecoder}. This will be called on
* the same thread as {@code decodeBitmap} before that method returns.
* This is required in order to change any of the default settings.
* @return Bitmap containing the image.
* @throws IOException if {@code src} is not found, is an unsupported
* format, or cannot be decoded for any reason.
*/
@WorkerThread
@NonNull
public static Bitmap decodeBitmap(@NonNull Source src,
@NonNull OnHeaderDecodedListener listener) throws IOException {
@@ -1465,6 +1563,7 @@ public final class ImageDecoder implements AutoCloseable {
return decodeBitmapImpl(src, listener);
}
@WorkerThread
@NonNull
private static Bitmap decodeBitmapImpl(@NonNull Source src,
@Nullable OnHeaderDecodedListener listener) throws IOException {
@@ -1536,8 +1635,18 @@ public final class ImageDecoder implements AutoCloseable {
}
/**
* See {@link #decodeBitmap(Source, OnHeaderDecodedListener)}.
* Create a {@link Bitmap} from a {@code Source}.
*
* <p>Since there is no {@link OnHeaderDecodedListener}, the default
* settings will be used. In order to change any settings, call
* {@link #decodeBitmap(Source, OnHeaderDecodedListener)} instead.</p>
*
* @param src representing the encoded image.
* @return Bitmap containing the image.
* @throws IOException if {@code src} is not found, is an unsupported
* format, or cannot be decoded for any reason.
*/
@WorkerThread
@NonNull
public static Bitmap decodeBitmap(@NonNull Source src) throws IOException {
return decodeBitmapImpl(src, null);