/*
* 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 android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.widget.ImageView.ScaleType;
import androidx.annotation.GuardedBy;
import androidx.annotation.Nullable;
import androidx.annotation.VisibleForTesting;
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;
/** 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 */
public static final int DEFAULT_IMAGE_TIMEOUT_MS = 1000;
/** Default number of retries for image requests */
public static final int DEFAULT_IMAGE_MAX_RETRIES = 2;
/** Default backoff multiplier for image requests */
public static final float DEFAULT_IMAGE_BACKOFF_MULT = 2f;
/** Lock to guard mListener as it is cleared on cancel() and read on delivery. */
private final Object mLock = new Object();
@GuardedBy("mLock")
@Nullable
private Response.Listener<Bitmap> mListener;
private final Config mDecodeConfig;
private final int mMaxWidth;
private final int mMaxHeight;
private final ScaleType mScaleType;
/** 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 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 scaleType The ImageViews ScaleType used to calculate the needed image size.
* @param decodeConfig Format to decode the bitmap to
* @param errorListener Error listener, or null to ignore errors
*/
public ImageRequest(
String url,
Response.Listener<Bitmap> listener,
int maxWidth,
int maxHeight,
ScaleType scaleType,
Config decodeConfig,
@Nullable Response.ErrorListener errorListener) {
super(Method.GET, url, errorListener);
setRetryPolicy(
new DefaultRetryPolicy(
DEFAULT_IMAGE_TIMEOUT_MS,
DEFAULT_IMAGE_MAX_RETRIES,
DEFAULT_IMAGE_BACKOFF_MULT));
mListener = listener;
mDecodeConfig = decodeConfig;
mMaxWidth = maxWidth;
mMaxHeight = maxHeight;
mScaleType = scaleType;
}
/**
* For API compatibility with the pre-ScaleType variant of the constructor. Equivalent to the
* normal constructor with {@code ScaleType.CENTER_INSIDE}.
*/
@Deprecated
public ImageRequest(
String url,
Response.Listener<Bitmap> listener,
int maxWidth,
int maxHeight,
Config decodeConfig,
Response.ErrorListener errorListener) {
this(
url,
listener,
maxWidth,
maxHeight,
ScaleType.CENTER_INSIDE,
decodeConfig,
errorListener);
}
@Override
public Priority getPriority() {
return Priority.LOW;
}
/**
* 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
* @param scaleType The ScaleType used to calculate the needed image size.
*/
private static int getResizedDimension(
int maxPrimary,
int maxSecondary,
int actualPrimary,
int actualSecondary,
ScaleType scaleType) {
// If no dominant value at all, just return the actual.
if ((maxPrimary == 0) && (maxSecondary == 0)) {
return actualPrimary;
}
// If ScaleType.FIT_XY fill the whole rectangle, ignore ratio.
if (scaleType == ScaleType.FIT_XY) {
if (maxPrimary == 0) {
return actualPrimary;
}
return maxPrimary;
}
// 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 ScaleType.CENTER_CROP fill the whole rectangle, preserve aspect ratio.
if (scaleType == ScaleType.CENTER_CROP) {
if ((resized * ratio) < maxSecondary) {
resized = (int) (maxSecondary / ratio);
}
return resized;
}
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 {
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. */
private Response<Bitmap> doParse(NetworkResponse response) {
byte[] data = response.data;
BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
Bitmap bitmap = null;
if (mMaxWidth == 0 && mMaxHeight == 0) {
decodeOptions.inPreferredConfig = mDecodeConfig;
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
} 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, mScaleType);
int desiredHeight =
getResizedDimension(
mMaxHeight, mMaxWidth, actualHeight, actualWidth, mScaleType);
// Decode to the nearest power of two scaling factor.
decodeOptions.inJustDecodeBounds = false;
// TODO(ficus): Do we need this or is it okay since API 8 doesn't support it?
// decodeOptions.inPreferQualityOverSpeed = PREFER_QUALITY_OVER_SPEED;
decodeOptions.inSampleSize =
findBestSampleSize(actualWidth, actualHeight, desiredWidth, desiredHeight);
Bitmap tempBitmap = BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
// 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();
} else {
bitmap = tempBitmap;
}
}
if (bitmap == null) {
return Response.error(new ParseError(response));
} else {
return Response.success(bitmap, HttpHeaderParser.parseCacheHeaders(response));
}
}
@Override
public void cancel() {
super.cancel();
synchronized (mLock) {
mListener = null;
}
}
@Override
protected void deliverResponse(Bitmap response) {
Response.Listener<Bitmap> listener;
synchronized (mLock) {
listener = mListener;
}
if (listener != null) {
listener.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
*/
@VisibleForTesting
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;
}
}
