PdfRenderer.java revision 13f542cabd635c55ade5442764cc4a3d2f7880ea
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.graphics.pdf; 18 19import android.annotation.IntDef; 20import android.annotation.NonNull; 21import android.annotation.Nullable; 22import android.graphics.Bitmap; 23import android.graphics.Bitmap.Config; 24import android.graphics.Matrix; 25import android.graphics.Point; 26import android.graphics.Rect; 27import android.os.ParcelFileDescriptor; 28import android.system.ErrnoException; 29import android.system.OsConstants; 30import dalvik.system.CloseGuard; 31import libcore.io.Libcore; 32 33import java.io.IOException; 34import java.lang.annotation.Retention; 35import java.lang.annotation.RetentionPolicy; 36 37/** 38 * <p> 39 * This class enables rendering a PDF document. This class is not thread safe. 40 * </p> 41 * <p> 42 * If you want to render a PDF, you create a renderer and for every page you want 43 * to render, you open the page, render it, and close the page. After you are done 44 * with rendering, you close the renderer. After the renderer is closed it should not 45 * be used anymore. Note that the pages are rendered one by one, i.e. you can have 46 * only a single page opened at any given time. 47 * </p> 48 * <p> 49 * A typical use of the APIs to render a PDF looks like this: 50 * </p> 51 * <pre> 52 * // create a new renderer 53 * PdfRenderer renderer = new PdfRenderer(getSeekableFileDescriptor()); 54 * 55 * // let us just render all pages 56 * final int pageCount = renderer.getPageCount(); 57 * for (int i = 0; i < pageCount; i++) { 58 * Page page = renderer.openPage(i); 59 * 60 * // say we render for showing on the screen 61 * page.render(mBitmap, null, null, Page.RENDER_MODE_FOR_DISPLAY); 62 * 63 * // do stuff with the bitmap 64 * 65 * // close the page 66 * page.close(); 67 * } 68 * 69 * // close the renderer 70 * renderer.close(); 71 * </pre> 72 * 73 * <h3>Print preview and print output</h3> 74 * <p> 75 * If you are using this class to rasterize a PDF for printing or show a print 76 * preview, it is recommended that you respect the following contract in order 77 * to provide a consistent user experience when seeing a preview and printing, 78 * i.e. the user sees a preview that is the same as the printout. 79 * </p> 80 * <ul> 81 * <li> 82 * Respect the property whether the document would like to be scaled for printing 83 * as per {@link #shouldScaleForPrinting()}. 84 * </li> 85 * <li> 86 * When scaling a document for printing the aspect ratio should be preserved. 87 * </li> 88 * <li> 89 * Do not inset the content with any margins from the {@link android.print.PrintAttributes} 90 * as the application is responsible to render it such that the margins are respected. 91 * </li> 92 * <li> 93 * If document page size is greater than the printed media size the content should 94 * be anchored to the upper left corner of the page for left-to-right locales and 95 * top right corner for right-to-left locales. 96 * </li> 97 * </ul> 98 * 99 * @see #close() 100 */ 101public final class PdfRenderer implements AutoCloseable { 102 private final CloseGuard mCloseGuard = CloseGuard.get(); 103 104 private final Point mTempPoint = new Point(); 105 106 private final long mNativeDocument; 107 108 private final int mPageCount; 109 110 private ParcelFileDescriptor mInput; 111 112 private Page mCurrentPage; 113 114 /** @hide */ 115 @IntDef({ 116 Page.RENDER_MODE_FOR_DISPLAY, 117 Page.RENDER_MODE_FOR_PRINT 118 }) 119 @Retention(RetentionPolicy.SOURCE) 120 public @interface RenderMode {} 121 122 /** 123 * Creates a new instance. 124 * <p> 125 * <strong>Note:</strong> The provided file descriptor must be <strong>seekable</strong>, 126 * i.e. its data being randomly accessed, e.g. pointing to a file. 127 * </p> 128 * <p> 129 * <strong>Note:</strong> This class takes ownership of the passed in file descriptor 130 * and is responsible for closing it when the renderer is closed. 131 * </p> 132 * 133 * @param input Seekable file descriptor to read from. 134 */ 135 public PdfRenderer(@NonNull ParcelFileDescriptor input) throws IOException { 136 if (input == null) { 137 throw new NullPointerException("input cannot be null"); 138 } 139 140 final long size; 141 try { 142 Libcore.os.lseek(input.getFileDescriptor(), 0, OsConstants.SEEK_SET); 143 size = Libcore.os.fstat(input.getFileDescriptor()).st_size; 144 } catch (ErrnoException ee) { 145 throw new IllegalArgumentException("file descriptor not seekable"); 146 } 147 148 mInput = input; 149 mNativeDocument = nativeCreate(mInput.getFd(), size); 150 mPageCount = nativeGetPageCount(mNativeDocument); 151 mCloseGuard.open("close"); 152 } 153 154 /** 155 * Closes this renderer. You should not use this instance 156 * after this method is called. 157 */ 158 public void close() { 159 throwIfClosed(); 160 throwIfPageOpened(); 161 doClose(); 162 } 163 164 /** 165 * Gets the number of pages in the document. 166 * 167 * @return The page count. 168 */ 169 public int getPageCount() { 170 throwIfClosed(); 171 return mPageCount; 172 } 173 174 /** 175 * Gets whether the document prefers to be scaled for printing. 176 * You should take this info account if the document is rendered 177 * for printing and the target media size differs from the page 178 * size. 179 * 180 * @return If to scale the document. 181 */ 182 public boolean shouldScaleForPrinting() { 183 throwIfClosed(); 184 return nativeScaleForPrinting(mNativeDocument); 185 } 186 187 /** 188 * Opens a page for rendering. 189 * 190 * @param index The page index. 191 * @return A page that can be rendered. 192 * 193 * @see android.graphics.pdf.PdfRenderer.Page#close() PdfRenderer.Page.close() 194 */ 195 public Page openPage(int index) { 196 throwIfClosed(); 197 throwIfPageOpened(); 198 throwIfPageNotInDocument(index); 199 mCurrentPage = new Page(index); 200 return mCurrentPage; 201 } 202 203 @Override 204 protected void finalize() throws Throwable { 205 try { 206 mCloseGuard.warnIfOpen(); 207 if (mInput != null) { 208 doClose(); 209 } 210 } finally { 211 super.finalize(); 212 } 213 } 214 215 private void doClose() { 216 if (mCurrentPage != null) { 217 mCurrentPage.close(); 218 } 219 nativeClose(mNativeDocument); 220 try { 221 mInput.close(); 222 } catch (IOException ioe) { 223 /* ignore - best effort */ 224 } 225 mInput = null; 226 mCloseGuard.close(); 227 } 228 229 private void throwIfClosed() { 230 if (mInput == null) { 231 throw new IllegalStateException("Already closed"); 232 } 233 } 234 235 private void throwIfPageOpened() { 236 if (mCurrentPage != null) { 237 throw new IllegalStateException("Current page not closed"); 238 } 239 } 240 241 private void throwIfPageNotInDocument(int pageIndex) { 242 if (pageIndex >= mPageCount) { 243 throw new IllegalArgumentException("Invalid page index"); 244 } 245 } 246 247 /** 248 * This class represents a PDF document page for rendering. 249 */ 250 public final class Page implements AutoCloseable { 251 252 private final CloseGuard mCloseGuard = CloseGuard.get(); 253 254 /** 255 * Mode to render the content for display on a screen. 256 */ 257 public static final int RENDER_MODE_FOR_DISPLAY = 1; 258 259 /** 260 * Mode to render the content for printing. 261 */ 262 public static final int RENDER_MODE_FOR_PRINT = 2; 263 264 private final int mIndex; 265 private final int mWidth; 266 private final int mHeight; 267 268 private long mNativePage; 269 270 private Page(int index) { 271 Point size = mTempPoint; 272 mNativePage = nativeOpenPageAndGetSize(mNativeDocument, index, size); 273 mIndex = index; 274 mWidth = size.x; 275 mHeight = size.y; 276 mCloseGuard.open("close"); 277 } 278 279 /** 280 * Gets the page index. 281 * 282 * @return The index. 283 */ 284 public int getIndex() { 285 return mIndex; 286 } 287 288 /** 289 * Gets the page width in points (1/72"). 290 * 291 * @return The width in points. 292 */ 293 public int getWidth() { 294 return mWidth; 295 } 296 297 /** 298 * Gets the page height in points (1/72"). 299 * 300 * @return The height in points. 301 */ 302 public int getHeight() { 303 return mHeight; 304 } 305 306 /** 307 * Renders a page to a bitmap. 308 * <p> 309 * You may optionally specify a rectangular clip in the bitmap bounds. No rendering 310 * outside the clip will be performed, hence it is your responsibility to initialize 311 * the bitmap outside the clip. 312 * </p> 313 * <p> 314 * You may optionally specify a matrix to transform the content from page coordinates 315 * which are in points (1/72") to bitmap coordinates which are in pixels. If this 316 * matrix is not provided this method will apply a transformation that will fit the 317 * whole page to the destination clip if provided or the destination bitmap if no 318 * clip is provided. 319 * </p> 320 * <p> 321 * The clip and transformation are useful for implementing tile rendering where the 322 * destination bitmap contains a portion of the image, for example when zooming. 323 * Another useful application is for printing where the size of the bitmap holding 324 * the page is too large and a client can render the page in stripes. 325 * </p> 326 * <p> 327 * <strong>Note: </strong> The destination bitmap format must be 328 * {@link Config#ARGB_8888 ARGB}. 329 * </p> 330 * <p> 331 * <strong>Note: </strong> The optional transformation matrix must be affine as per 332 * {@link android.graphics.Matrix#isAffine() Matrix.isAffine()}. Hence, you can specify 333 * rotation, scaling, translation but not a perspective transformation. 334 * </p> 335 * 336 * @param destination Destination bitmap to which to render. 337 * @param destClip Optional clip in the bitmap bounds. 338 * @param transform Optional transformation to apply when rendering. 339 * @param renderMode The render mode. 340 * 341 * @see #RENDER_MODE_FOR_DISPLAY 342 * @see #RENDER_MODE_FOR_PRINT 343 */ 344 public void render(@NonNull Bitmap destination, @Nullable Rect destClip, 345 @Nullable Matrix transform, @RenderMode int renderMode) { 346 if (destination.getConfig() != Config.ARGB_8888) { 347 throw new IllegalArgumentException("Unsupported pixel format"); 348 } 349 350 if (destClip != null) { 351 if (destClip.left < 0 || destClip.top < 0 352 || destClip.right > destination.getWidth() 353 || destClip.bottom > destination.getHeight()) { 354 throw new IllegalArgumentException("destBounds not in destination"); 355 } 356 } 357 358 if (transform != null && !transform.isAffine()) { 359 throw new IllegalArgumentException("transform not affine"); 360 } 361 362 if (renderMode != RENDER_MODE_FOR_PRINT && renderMode != RENDER_MODE_FOR_DISPLAY) { 363 throw new IllegalArgumentException("Unsupported render mode"); 364 } 365 366 if (renderMode == RENDER_MODE_FOR_PRINT && renderMode == RENDER_MODE_FOR_DISPLAY) { 367 throw new IllegalArgumentException("Only single render mode supported"); 368 } 369 370 final int contentLeft = (destClip != null) ? destClip.left : 0; 371 final int contentTop = (destClip != null) ? destClip.top : 0; 372 final int contentRight = (destClip != null) ? destClip.right 373 : destination.getWidth(); 374 final int contentBottom = (destClip != null) ? destClip.bottom 375 : destination.getHeight(); 376 377 final long transformPtr = (transform != null) ? transform.native_instance : 0; 378 379 nativeRenderPage(mNativeDocument, mNativePage, destination.mNativeBitmap, contentLeft, 380 contentTop, contentRight, contentBottom, transformPtr, renderMode); 381 } 382 383 /** 384 * Closes this page. 385 * 386 * @see android.graphics.pdf.PdfRenderer#openPage(int) 387 */ 388 @Override 389 public void close() { 390 throwIfClosed(); 391 doClose(); 392 } 393 394 @Override 395 protected void finalize() throws Throwable { 396 try { 397 mCloseGuard.warnIfOpen(); 398 if (mNativePage != 0) { 399 doClose(); 400 } 401 } finally { 402 super.finalize(); 403 } 404 } 405 406 private void doClose() { 407 nativeClosePage(mNativePage); 408 mNativePage = 0; 409 mCloseGuard.close(); 410 mCurrentPage = null; 411 } 412 413 private void throwIfClosed() { 414 if (mNativePage == 0) { 415 throw new IllegalStateException("Already closed"); 416 } 417 } 418 } 419 420 private static native long nativeCreate(int fd, long size); 421 private static native void nativeClose(long documentPtr); 422 private static native int nativeGetPageCount(long documentPtr); 423 private static native boolean nativeScaleForPrinting(long documentPtr); 424 private static native void nativeRenderPage(long documentPtr, long pagePtr, long destPtr, 425 int destLeft, int destTop, int destRight, int destBottom, long matrixPtr, int renderMode); 426 private static native long nativeOpenPageAndGetSize(long documentPtr, int pageIndex, 427 Point outSize); 428 private static native void nativeClosePage(long pagePtr); 429} 430