package cc.shinichi.library.view.subsampling.decoder;
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import android.content.Context;
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import android.graphics.Bitmap;
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import android.graphics.Point;
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import android.graphics.Rect;
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import android.net.Uri;
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import androidx.annotation.NonNull;
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/**
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* Interface for image decoding classes, allowing the default {@link android.graphics.BitmapRegionDecoder}
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* based on the Skia library to be replaced with a custom class.
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*/
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public interface ImageRegionDecoder {
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/**
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* Initialise the decoder. When possible, perform initial setup work once in this method. The
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* dimensions of the image must be returned. The URI can be in one of the following formats:
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* <br>
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* File: <code>file:///scard/picture.jpg</code>
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* <br>
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* Asset: <code>file:///android_asset/picture.png</code>
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* <br>
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* Resource: <code>android.resource://com.example.app/drawable/picture</code>
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*
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* @param context Application context. A reference may be held, but must be cleared on recycle.
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* @param uri URI of the image.
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* @return Dimensions of the image.
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* @throws Exception if initialisation fails.
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*/
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@NonNull
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Point init(Context context, @NonNull Uri uri) throws Exception;
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/**
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* <p>
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* Decode a region of the image with the given sample size. This method is called off the UI
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* thread so it can safely load the image on the current thread. It is called from
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* {@link android.os.AsyncTask}s running in an executor that may have multiple threads, so
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* implementations must be thread safe. Adding <code>synchronized</code> to the method signature
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* is the simplest way to achieve this, but bear in mind the {@link #recycle()} method can be
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* called concurrently.
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* </p><p>
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* See {@link SkiaImageRegionDecoder} and {@link SkiaPooledImageRegionDecoder} for examples of
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* internal locking and synchronization.
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* </p>
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*
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* @param sRect Source image rectangle to decode.
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* @param sampleSize Sample size.
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* @return The decoded region. It is safe to return null if decoding fails.
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*/
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@NonNull
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Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize);
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/**
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* Status check. Should return false before initialisation and after recycle.
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*
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* @return true if the decoder is ready to be used.
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*/
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boolean isReady();
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/**
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* This method will be called when the decoder is no longer required. It should clean up any resources still in use.
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*/
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void recycle();
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}
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