| /* |
| * Copyright (C) 2017 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.internal.content; |
| |
| import android.annotation.Nullable; |
| import android.content.res.AssetFileDescriptor; |
| import android.graphics.Bitmap; |
| import android.graphics.Point; |
| import android.graphics.Rect; |
| import android.graphics.pdf.PdfRenderer; |
| import android.os.AsyncTask; |
| import android.os.ParcelFileDescriptor; |
| |
| import libcore.io.IoUtils; |
| import libcore.io.Streams; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.File; |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| |
| /** |
| * Utils class for extracting PDF Thumbnails |
| */ |
| public final class PdfUtils { |
| |
| private PdfUtils() { |
| } |
| |
| /** |
| * Returns the front page of the pdf as a thumbnail |
| * @param file Given PDF File |
| * @param size Cropping of the front page. |
| * @return AssetFileDescriptor containing the thumbnail as a bitmap. |
| * @throws IOException if the file isn't a pdf or if the file doesn't exist. |
| */ |
| public static @Nullable AssetFileDescriptor openPdfThumbnail(File file, Point size) |
| throws IOException { |
| // Create the bitmap of the PDF's first page |
| ParcelFileDescriptor pdfDescriptor = |
| ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY); |
| PdfRenderer renderer = new PdfRenderer(pdfDescriptor); |
| PdfRenderer.Page frontPage = renderer.openPage(0); |
| Bitmap thumbnail = Bitmap.createBitmap(size.x, size.y, |
| Bitmap.Config.ARGB_8888); |
| frontPage.render(thumbnail, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY); |
| |
| // Create an AssetFileDescriptor that contains the Bitmap's information |
| final ByteArrayOutputStream out = new ByteArrayOutputStream(); |
| // Quality is an integer that determines how much compression is used. |
| // However, this integer is ignored when using the PNG format |
| int quality = 100; |
| // The use of Bitmap.CompressFormat.JPEG leads to a black PDF background on the thumbnail |
| thumbnail.compress(Bitmap.CompressFormat.PNG, quality, out); |
| |
| final ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray()); |
| |
| final ParcelFileDescriptor[] fds = ParcelFileDescriptor.createReliablePipe(); |
| new AsyncTask<Object, Object, Object>() { |
| @Override |
| protected Object doInBackground(Object... params) { |
| final FileOutputStream fos = new FileOutputStream(fds[1].getFileDescriptor()); |
| try { |
| Streams.copy(in, fos); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| IoUtils.closeQuietly(fds[1]); |
| try { |
| pdfDescriptor.close(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| return null; |
| } |
| }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR); |
| pdfDescriptor.close(); |
| return new AssetFileDescriptor(fds[0], 0, AssetFileDescriptor.UNKNOWN_LENGTH); |
| } |
| |
| } |