am b356f8ac: Merge "Rename LargeBitmap to BitmapRegionDecoder for having a better API." into gingerbread

Merge commit 'b356f8acec9fdfd36f01e5cca4fe3a28ecd6e628' into gingerbread-plus-aosp

* commit 'b356f8acec9fdfd36f01e5cca4fe3a28ecd6e628':
  Rename LargeBitmap to BitmapRegionDecoder for having a better API.

1 files changed, 270 insertions, 0 deletions

diff --git a/graphics/java/android/graphics/BitmapRegionDecoder.java b/graphics/java/android/graphics/BitmapRegionDecoder.java
new file mode 100644
index 0000000..bc92b05
--- /dev/null
+++ b/graphics/java/android/graphics/BitmapRegionDecoder.java
@@ -0,0 +1,270 @@
+/* Copyright (C) 2010 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 android.content.res.AssetManager;
+import android.os.MemoryFile;
+
+import java.io.BufferedInputStream;
+import java.io.FileDescriptor;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * BitmapRegionDecoder can be used to decode a rectangle region from an image.
+ * BitmapRegionDecoder is particularly useful when an original image is large and
+ * you only need parts of the image.
+ *
+ * <p>To create a BitmapRegionDecoder, call newInstance(...).
+ * Given a BitmapRegionDecoder, users can call decodeRegion() repeatedly
+ * to get a decoded Bitmap of the specified region.
+ *
+ * @hide
+ */
+public final class BitmapRegionDecoder {
+    private int mNativeBitmapRegionDecoder;
+    private boolean mRecycled;
+
+    /**
+     * Create a BitmapRegionDecoder from the specified byte array.
+     * Currently only the Jpeg format is supported.
+     *
+     * @param data byte array of compressed image data.
+     * @param offset offset into data for where the decoder should begin
+     *               parsing.
+     * @param length the number of bytes, beginning at offset, to parse
+     * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
+     *                    shallow reference to the input. If this is false,
+     *                    then the BitmapRegionDecoder 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. If an image is progressively encoded,
+     *                    allowing sharing may degrade the decoding speed.
+     * @return BitmapRegionDecoder, or null if the image data could not be decoded.
+     * @throws IOException if the image format is not supported or can not be decoded.
+     */
+    public static BitmapRegionDecoder newInstance(byte[] data,
+            int offset, int length, boolean isShareable) throws IOException {
+        if ((offset | length) < 0 || data.length < offset + length) {
+            throw new ArrayIndexOutOfBoundsException();
+        }
+        return nativeNewInstance(data, offset, length, isShareable);
+    }
+
+    /**
+     * Create a BitmapRegionDecoder from the file descriptor.
+     * The position within the descriptor will not be changed when
+     * this returns, so the descriptor can be used again as is.
+     * Currently only the Jpeg format is supported.
+     *
+     * @param fd The file descriptor containing the data to decode
+     * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
+     *                    shallow reference to the input. If this is false,
+     *                    then the BitmapRegionDecoder 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. If an image is progressively encoded,
+     *                    allowing sharing may degrade the decoding speed.
+     * @return BitmapRegionDecoder, or null if the image data could not be decoded.
+     * @throws IOException if the image format is not supported or can not be decoded.
+     */
+    public static BitmapRegionDecoder newInstance(
+            FileDescriptor fd, boolean isShareable) throws IOException {
+        if (MemoryFile.isMemoryFile(fd)) {
+            int mappedlength = MemoryFile.getSize(fd);
+            MemoryFile file = new MemoryFile(fd, mappedlength, "r");
+            InputStream is = file.getInputStream();
+            return newInstance(is, isShareable);
+        }
+        return nativeNewInstance(fd, isShareable);
+    }
+
+    /**
+     * Create a BitmapRegionDecoder from an input stream.
+     * The stream's position will be where ever it was after the encoded data
+     * was read.
+     * Currently only the Jpeg format is supported.
+     *
+     * @param is The input stream that holds the raw data to be decoded into a
+     *           BitmapRegionDecoder.
+     * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
+     *                    shallow reference to the input. If this is false,
+     *                    then the BitmapRegionDecoder 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. If an image is progressively encoded,
+     *                    allowing sharing may degrade the decoding speed.
+     * @return BitmapRegionDecoder, or null if the image data could not be decoded.
+     * @throws IOException if the image format is not supported or can not be decoded.
+     */
+    public static BitmapRegionDecoder newInstance(InputStream is,
+            boolean isShareable) throws IOException {
+        // we need mark/reset to work properly in JNI
+
+        if (!is.markSupported()) {
+            is = new BufferedInputStream(is, 16 * 1024);
+        }
+
+        if (is instanceof AssetManager.AssetInputStream) {
+            return nativeNewInstance(
+                    ((AssetManager.AssetInputStream) is).getAssetInt(),
+                    isShareable);
+        } else {
+            // pass some temp storage down to the native code. 1024 is made up,
+            // but should be large enough to avoid too many small calls back
+            // into is.read(...).
+            byte [] tempStorage = new byte[16 * 1024];
+            return nativeNewInstance(is, tempStorage, isShareable);
+        }
+    }
+
+    /**
+     * Create a BitmapRegionDecoder from a file path.
+     * Currently only the Jpeg format is supported.
+     *
+     * @param pathName complete path name for the file to be decoded.
+     * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
+     *                    shallow reference to the input. If this is false,
+     *                    then the BitmapRegionDecoder 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. If an image is progressively encoded,
+     *                    allowing sharing may degrade the decoding speed.
+     * @return BitmapRegionDecoder, or null if the image data could not be decoded.
+     * @throws IOException if the image format is not supported or can not be decoded.
+     */
+    public static BitmapRegionDecoder newInstance(String pathName,
+            boolean isShareable) throws IOException {
+        BitmapRegionDecoder decoder = null;
+        InputStream stream = null;
+
+        try {
+            stream = new FileInputStream(pathName);
+            decoder = newInstance(stream, isShareable);
+        } finally {
+            if (stream != null) {
+                try {
+                    stream.close();
+                } catch (IOException e) {
+                    // do nothing here
+                }
+            }
+        }
+        return decoder;
+    }
+
+    /*  Private constructor that must receive an already allocated native
+        region decoder int (pointer).
+
+        This can be called from JNI code.
+    */
+    private BitmapRegionDecoder(int decoder) {
+        mNativeBitmapRegionDecoder = decoder;
+        mRecycled = false;
+    }
+
+    /**
+     * Decodes a rectangle region in the image specified by rect.
+     *
+     * @param rect The rectangle that specified the region to be decode.
+     * @param options null-ok; Options that control downsampling.
+     *             inPurgeable is not supported.
+     * @return The decoded bitmap, or null if the image data could not be
+     *         decoded.
+     */
+    public Bitmap decodeRegion(Rect rect, BitmapFactory.Options options) {
+        checkRecycled("decodeRegion called on recycled region decoder");
+        if (rect.left < 0 || rect.top < 0 || rect.right > getWidth()
+                || rect.bottom > getHeight())
+            throw new IllegalArgumentException("rectangle is not inside the image");
+        return nativeDecodeRegion(mNativeBitmapRegionDecoder, rect.left, rect.top,
+                rect.right - rect.left, rect.bottom - rect.top, options);
+    }
+
+    /** Returns the original image's width */
+    public int getWidth() {
+        checkRecycled("getWidth called on recycled region decoder");
+        return nativeGetWidth(mNativeBitmapRegionDecoder);
+    }
+
+    /** Returns the original image's height */
+    public int getHeight() {
+        checkRecycled("getHeight called on recycled region decoder");
+        return nativeGetHeight(mNativeBitmapRegionDecoder);
+    }
+
+    /**
+     * Frees up the memory associated with this region decoder, and mark the
+     * region decoder as "dead", meaning it will throw an exception if decodeRegion(),
+     * getWidth() or getHeight() is called.
+     *
+     * <p>This operation cannot be reversed, so it should only be called if you are
+     * sure there are no further uses for the region decoder. This is an advanced call,
+     * and normally need not be called, since the normal GC process will free up this
+     * memory when there are no more references to this region decoder.
+     */
+    public void recycle() {
+        if (!mRecycled) {
+            nativeClean(mNativeBitmapRegionDecoder);
+            mRecycled = true;
+        }
+    }
+
+    /**
+     * Returns true if this region decoder has been recycled.
+     * If so, then it is an error to try use its method.
+     *
+     * @return true if the region decoder has been recycled
+     */
+    public final boolean isRecycled() {
+        return mRecycled;
+    }
+
+    /**
+     * Called by methods that want to throw an exception if the region decoder
+     * has already been recycled.
+     */
+    private void checkRecycled(String errorMessage) {
+        if (mRecycled) {
+            throw new IllegalStateException(errorMessage);
+        }
+    }
+
+    protected void finalize() throws Throwable {
+        try {
+            recycle();
+        } finally {
+            super.finalize();
+        }
+    }
+
+    private static native Bitmap nativeDecodeRegion(int lbm,
+            int start_x, int start_y, int width, int height,
+            BitmapFactory.Options options);
+    private static native int nativeGetWidth(int lbm);
+    private static native int nativeGetHeight(int lbm);
+    private static native void nativeClean(int lbm);
+
+    private static native BitmapRegionDecoder nativeNewInstance(
+            byte[] data, int offset, int length, boolean isShareable);
+    private static native BitmapRegionDecoder nativeNewInstance(
+            FileDescriptor fd, boolean isShareable);
+    private static native BitmapRegionDecoder nativeNewInstance(
+            InputStream is, byte[] storage, boolean isShareable);
+    private static native BitmapRegionDecoder nativeNewInstance(
+            int asset, boolean isShareable);
+}