/*
* Copyright (C) 2011 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 com.android.volley.toolbox;
import java.io.File;
import java.io.FileNotFoundException;
import com.android.volley.DefaultRetryPolicy;
import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyLog;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.net.Uri;
/**
* A canned request for getting an image at a given URL and calling back with a
* decoded Bitmap.
*/
public class ImageRequest extends Request<Bitmap> {
/** Socket timeout in milliseconds for image requests */
private static final int IMAGE_TIMEOUT_MS = 1000;
/** Default number of retries for image requests */
private static final int IMAGE_MAX_RETRIES = 2;
/** Default backoff multiplier for image requests */
private static final float IMAGE_BACKOFF_MULT = 2f;
private final Response.Listener<Bitmap> mListener;
private final Config mDecodeConfig;
private final int mMaxWidth;
private final int mMaxHeight;
private Resources mResources;
/**
* Decoding lock so that we don't decode more than one image at a time (to
* avoid OOM's)
*/
private static final Object sDecodeLock = new Object();
/**
* Creates a new image request, decoding to a maximum specified width and
* height. If both width and height are zero, the image will be decoded to
* its natural size. If one of the two is nonzero, that dimension will be
* clamped and the other one will be set to preserve the image's aspect
* ratio. If both width and height are nonzero, the image will be decoded to
* be fit in the rectangle of dimensions width x height while keeping its
* aspect ratio.
*
* @param url
* URL of the image
* @param resources
* {@link Resources} reference for parsing resource URIs. Can be
* <code>null</code> if you don't need to load resource uris
* @param listener
* Listener to receive the decoded bitmap
* @param maxWidth
* Maximum width to decode this bitmap to, or zero for none
* @param maxHeight
* Maximum height to decode this bitmap to, or zero for none
* @param decodeConfig
* Format to decode the bitmap to
* @param errorListener
* Error listener, or null to ignore errors
*/
public ImageRequest(String url, Resources resources,
Response.Listener<Bitmap> listener, int maxWidth, int maxHeight,
Config decodeConfig, Response.ErrorListener errorListener) {
super(Method.GET, url, Priority.LOW, errorListener,
new DefaultRetryPolicy(IMAGE_TIMEOUT_MS, IMAGE_MAX_RETRIES,
IMAGE_BACKOFF_MULT));
mResources = resources;
mListener = listener;
mDecodeConfig = decodeConfig;
mMaxWidth = maxWidth;
mMaxHeight = maxHeight;
}
/**
* Scales one side of a rectangle to fit aspect ratio.
*
* @param maxPrimary
* Maximum size of the primary dimension (i.e. width for max
* width), or zero to maintain aspect ratio with secondary
* dimension
* @param maxSecondary
* Maximum size of the secondary dimension, or zero to maintain
* aspect ratio with primary dimension
* @param actualPrimary
* Actual size of the primary dimension
* @param actualSecondary
* Actual size of the secondary dimension
*/
private static int getResizedDimension(int maxPrimary, int maxSecondary,
int actualPrimary, int actualSecondary) {
// If no dominant value at all, just return the actual.
if (maxPrimary == 0 && maxSecondary == 0) {
return actualPrimary;
}
// If primary is unspecified, scale primary to match secondary's scaling
// ratio.
if (maxPrimary == 0) {
double ratio = (double) maxSecondary / (double) actualSecondary;
return (int) (actualPrimary * ratio);
}
if (maxSecondary == 0) {
return maxPrimary;
}
double ratio = (double) actualSecondary / (double) actualPrimary;
int resized = maxPrimary;
if (resized * ratio > maxSecondary) {
resized = (int) (maxSecondary / ratio);
}
return resized;
}
@Override
protected Response<Bitmap> parseNetworkResponse(NetworkResponse response) {
// Serialize all decode on a global lock to reduce concurrent heap
// usage.
synchronized (sDecodeLock) {
try {
if (getUrl().startsWith("file:")) {
return doFileParse();
} else if (getUrl().startsWith("android.resource:")) {
return doResourceParse();
} else {
return doParse(response);
}
} catch (OutOfMemoryError e) {
VolleyLog.e("Caught OOM for %d byte image, url=%s",
response.data.length, getUrl());
return Response.error(new ParseError(e));
}
}
}
/**
* The real guts of parseNetworkResponse. Broken out for readability.
*
* This version is for reading a Bitmap from file
*/
private Response<Bitmap> doFileParse() {
final String requestUrl = getUrl();
// Remove the 'file://' prefix
File bitmapFile = new File(requestUrl.substring(7, requestUrl.length()));
if (!bitmapFile.exists() || !bitmapFile.isFile()) {
return Response.error(new ParseError(new FileNotFoundException(
String.format("File not found: %s",
bitmapFile.getAbsolutePath()))));
}
BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
decodeOptions.inInputShareable = true;
decodeOptions.inPurgeable = true;
decodeOptions.inPreferredConfig = mDecodeConfig;
Bitmap bitmap = null;
if (mMaxWidth == 0 && mMaxHeight == 0) {
bitmap = BitmapFactory.decodeFile(bitmapFile.getAbsolutePath(),
decodeOptions);
addMarker("read-full-size-image-from-file");
} else {
// If we have to resize this image, first get the natural bounds.
decodeOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(bitmapFile.getAbsolutePath(),
decodeOptions);
int actualWidth = decodeOptions.outWidth;
int actualHeight = decodeOptions.outHeight;
// Then compute the dimensions we would ideally like to decode to.
int desiredWidth = getResizedDimension(mMaxWidth, mMaxHeight,
actualWidth, actualHeight);
int desiredHeight = getResizedDimension(mMaxHeight, mMaxWidth,
actualHeight, actualWidth);
// Decode to the nearest power of two scaling factor.
decodeOptions.inJustDecodeBounds = false;
decodeOptions.inSampleSize = findBestSampleSize(actualWidth,
actualHeight, desiredWidth, desiredHeight);
Bitmap tempBitmap = BitmapFactory.decodeFile(
bitmapFile.getAbsolutePath(), decodeOptions);
addMarker(String.format("read-from-file-scaled-times-%d",
decodeOptions.inSampleSize));
// If necessary, scale down to the maximal acceptable size.
if (tempBitmap != null
&& (tempBitmap.getWidth() > desiredWidth || tempBitmap
.getHeight() > desiredHeight)) {
bitmap = Bitmap.createScaledBitmap(tempBitmap, desiredWidth,
desiredHeight, true);
tempBitmap.recycle();
addMarker("scaling-read-from-file-bitmap");
} else {
bitmap = tempBitmap;
}
}
if (bitmap == null) {
return Response.error(new ParseError());
} else {
return Response.success(bitmap, null);
}
}
/**
* The real guts of parseNetworkResponse. Broken out for readability.
*
* This version is for reading a Bitmap from resource
*/
private Response<Bitmap> doResourceParse() {
if (mResources == null) {
return Response.error(new ParseError("Resources instance is null"));
}
final String requestUrl = getUrl();
final int resourceId = Integer.valueOf(Uri.parse(requestUrl)
.getLastPathSegment());
BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
decodeOptions.inInputShareable = true;
decodeOptions.inPurgeable = true;
decodeOptions.inPreferredConfig = mDecodeConfig;
Bitmap bitmap = null;
if (mMaxWidth == 0 && mMaxHeight == 0) {
bitmap = BitmapFactory.decodeResource(mResources, resourceId,
decodeOptions);
addMarker("read-full-size-image-from-resource");
} else {
// If we have to resize this image, first get the natural bounds.
decodeOptions.inJustDecodeBounds = true;
BitmapFactory.decodeResource(mResources, resourceId, decodeOptions);
int actualWidth = decodeOptions.outWidth;
int actualHeight = decodeOptions.outHeight;
// Then compute the dimensions we would ideally like to decode to.
int desiredWidth = getResizedDimension(mMaxWidth, mMaxHeight,
actualWidth, actualHeight);
int desiredHeight = getResizedDimension(mMaxHeight, mMaxWidth,
actualHeight, actualWidth);
// Decode to the nearest power of two scaling factor.
decodeOptions.inJustDecodeBounds = false;
decodeOptions.inSampleSize = findBestSampleSize(actualWidth,
actualHeight, desiredWidth, desiredHeight);
Bitmap tempBitmap = BitmapFactory.decodeResource(mResources,
resourceId, decodeOptions);
addMarker(String.format("read-from-resource-scaled-times-%d",
decodeOptions.inSampleSize));
// If necessary, scale down to the maximal acceptable size.
if (tempBitmap != null
&& (tempBitmap.getWidth() > desiredWidth || tempBitmap
.getHeight() > desiredHeight)) {
bitmap = Bitmap.createScaledBitmap(tempBitmap, desiredWidth,
desiredHeight, true);
tempBitmap.recycle();
addMarker("scaling-read-from-resource-bitmap");
} else {
bitmap = tempBitmap;
}
}
if (bitmap == null) {
return Response.error(new ParseError());
} else {
return Response.success(bitmap, null);
}
}
/**
* The real guts of parseNetworkResponse. Broken out for readability.
*/
private Response<Bitmap> doParse(NetworkResponse response) {
byte[] data = response.data;
BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
decodeOptions.inInputShareable = true;
decodeOptions.inPurgeable = true;
decodeOptions.inPreferredConfig = mDecodeConfig;
Bitmap bitmap = null;
if (mMaxWidth == 0 && mMaxHeight == 0) {
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,
decodeOptions);
addMarker("downloaded-full-size-image");
} else {
// If we have to resize this image, first get the natural bounds.
decodeOptions.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
int actualWidth = decodeOptions.outWidth;
int actualHeight = decodeOptions.outHeight;
// Then compute the dimensions we would ideally like to decode to.
int desiredWidth = getResizedDimension(mMaxWidth, mMaxHeight,
actualWidth, actualHeight);
int desiredHeight = getResizedDimension(mMaxHeight, mMaxWidth,
actualHeight, actualWidth);
// Decode to the nearest power of two scaling factor.
decodeOptions.inJustDecodeBounds = false;
decodeOptions.inSampleSize = findBestSampleSize(actualWidth,
actualHeight, desiredWidth, desiredHeight);
Bitmap tempBitmap = BitmapFactory.decodeByteArray(data, 0,
data.length, decodeOptions);
addMarker(String.format("downloaded-scaled-times-%d",
decodeOptions.inSampleSize));
// If necessary, scale down to the maximal acceptable size.
if (tempBitmap != null
&& (tempBitmap.getWidth() > desiredWidth || tempBitmap
.getHeight() > desiredHeight)) {
bitmap = Bitmap.createScaledBitmap(tempBitmap, desiredWidth,
desiredHeight, true);
tempBitmap.recycle();
addMarker("scaling-downloaded-bitmap");
} else {
bitmap = tempBitmap;
}
}
if (bitmap == null) {
return Response.error(new ParseError());
} else {
return Response.success(bitmap,
HttpHeaderParser.parseCacheHeaders(response));
}
}
@Override
protected void deliverResponse(Bitmap response) {
mListener.onResponse(response);
}
/**
* Returns the largest power-of-two divisor for use in downscaling a bitmap
* that will not result in the scaling past the desired dimensions.
*
* @param actualWidth
* Actual width of the bitmap
* @param actualHeight
* Actual height of the bitmap
* @param desiredWidth
* Desired width of the bitmap
* @param desiredHeight
* Desired height of the bitmap
*/
// Visible for testing.
static int findBestSampleSize(int actualWidth, int actualHeight,
int desiredWidth, int desiredHeight) {
double wr = (double) actualWidth / desiredWidth;
double hr = (double) actualHeight / desiredHeight;
double ratio = Math.min(wr, hr);
float n = 1.0f;
while ((n * 2) <= ratio) {
n *= 2;
}
return (int) n;
}
}