Bitmap.java revision 2361098da3b9d9c3eeed410dc72ba62c0e9177cf
1/* 2 * Copyright (C) 2006 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; 18 19import android.os.Parcel; 20import android.os.Parcelable; 21import android.util.DisplayMetrics; 22 23import java.io.OutputStream; 24import java.nio.Buffer; 25import java.nio.ByteBuffer; 26import java.nio.IntBuffer; 27import java.nio.ShortBuffer; 28 29public final class Bitmap implements Parcelable { 30 31 /** 32 * Indicates that the bitmap was created for an unknown pixel density. 33 * 34 * @see Bitmap#getDensity() 35 * @see Bitmap#setDensity(int) 36 */ 37 public static final int DENSITY_NONE = 0; 38 39 /** 40 * Note: mNativeBitmap is used by FaceDetector_jni.cpp 41 * Don't change/rename without updating FaceDetector_jni.cpp 42 * 43 * @hide 44 */ 45 public final int mNativeBitmap; 46 47 /** 48 * Backing buffer for the Bitmap. 49 * Made public for quick access from drawing methods -- do NOT modify 50 * from outside this class. 51 * 52 * @hide 53 */ 54 public byte[] mBuffer; 55 56 @SuppressWarnings({"FieldCanBeLocal", "UnusedDeclaration"}) // Keep to finalize native resources 57 private final BitmapFinalizer mFinalizer; 58 59 private final boolean mIsMutable; 60 private byte[] mNinePatchChunk; // may be null 61 private int mWidth = -1; 62 private int mHeight = -1; 63 private boolean mRecycled; 64 65 // Package-scoped for fast access. 66 /*package*/ int mDensity = sDefaultDensity = getDefaultDensity(); 67 68 private static volatile Matrix sScaleMatrix; 69 70 private static volatile int sDefaultDensity = -1; 71 72 /** 73 * For backwards compatibility, allows the app layer to change the default 74 * density when running old apps. 75 * @hide 76 */ 77 public static void setDefaultDensity(int density) { 78 sDefaultDensity = density; 79 } 80 81 /*package*/ static int getDefaultDensity() { 82 if (sDefaultDensity >= 0) { 83 return sDefaultDensity; 84 } 85 sDefaultDensity = DisplayMetrics.DENSITY_DEVICE; 86 return sDefaultDensity; 87 } 88 89 /** 90 * @noinspection UnusedDeclaration 91 */ 92 /* Private constructor that must received an already allocated native 93 bitmap int (pointer). 94 95 This can be called from JNI code. 96 */ 97 private Bitmap(int nativeBitmap, byte[] buffer, boolean isMutable, byte[] ninePatchChunk, 98 int density) { 99 if (nativeBitmap == 0) { 100 throw new RuntimeException("internal error: native bitmap is 0"); 101 } 102 103 mBuffer = buffer; 104 // we delete this in our finalizer 105 mNativeBitmap = nativeBitmap; 106 mFinalizer = new BitmapFinalizer(nativeBitmap); 107 108 mIsMutable = isMutable; 109 mNinePatchChunk = ninePatchChunk; 110 if (density >= 0) { 111 mDensity = density; 112 } 113 } 114 115 /** 116 * <p>Returns the density for this bitmap.</p> 117 * 118 * <p>The default density is the same density as the current display, 119 * unless the current application does not support different screen 120 * densities in which case it is 121 * {@link android.util.DisplayMetrics#DENSITY_DEFAULT}. Note that 122 * compatibility mode is determined by the application that was initially 123 * loaded into a process -- applications that share the same process should 124 * all have the same compatibility, or ensure they explicitly set the 125 * density of their bitmaps appropriately.</p> 126 * 127 * @return A scaling factor of the default density or {@link #DENSITY_NONE} 128 * if the scaling factor is unknown. 129 * 130 * @see #setDensity(int) 131 * @see android.util.DisplayMetrics#DENSITY_DEFAULT 132 * @see android.util.DisplayMetrics#densityDpi 133 * @see #DENSITY_NONE 134 */ 135 public int getDensity() { 136 return mDensity; 137 } 138 139 /** 140 * <p>Specifies the density for this bitmap. When the bitmap is 141 * drawn to a Canvas that also has a density, it will be scaled 142 * appropriately.</p> 143 * 144 * @param density The density scaling factor to use with this bitmap or 145 * {@link #DENSITY_NONE} if the density is unknown. 146 * 147 * @see #getDensity() 148 * @see android.util.DisplayMetrics#DENSITY_DEFAULT 149 * @see android.util.DisplayMetrics#densityDpi 150 * @see #DENSITY_NONE 151 */ 152 public void setDensity(int density) { 153 mDensity = density; 154 } 155 156 /** 157 * Sets the nine patch chunk. 158 * 159 * @param chunk The definition of the nine patch 160 * 161 * @hide 162 */ 163 public void setNinePatchChunk(byte[] chunk) { 164 mNinePatchChunk = chunk; 165 } 166 167 /** 168 * Free up the memory associated with this bitmap's pixels, and mark the 169 * bitmap as "dead", meaning it will throw an exception if getPixels() or 170 * setPixels() is called, and will draw nothing. This operation cannot be 171 * reversed, so it should only be called if you are sure there are no 172 * further uses for the bitmap. This is an advanced call, and normally need 173 * not be called, since the normal GC process will free up this memory when 174 * there are no more references to this bitmap. 175 */ 176 public void recycle() { 177 if (!mRecycled) { 178 mBuffer = null; 179 nativeRecycle(mNativeBitmap); 180 mNinePatchChunk = null; 181 mRecycled = true; 182 } 183 } 184 185 /** 186 * Returns true if this bitmap has been recycled. If so, then it is an error 187 * to try to access its pixels, and the bitmap will not draw. 188 * 189 * @return true if the bitmap has been recycled 190 */ 191 public final boolean isRecycled() { 192 return mRecycled; 193 } 194 195 /** 196 * Returns the generation ID of this bitmap. The generation ID changes 197 * whenever the bitmap is modified. This can be used as an efficient way to 198 * check if a bitmap has changed. 199 * 200 * @return The current generation ID for this bitmap. 201 * 202 * @hide 203 */ 204 public int getGenerationId() { 205 return nativeGenerationId(mNativeBitmap); 206 } 207 208 /** 209 * This is called by methods that want to throw an exception if the bitmap 210 * has already been recycled. 211 */ 212 private void checkRecycled(String errorMessage) { 213 if (mRecycled) { 214 throw new IllegalStateException(errorMessage); 215 } 216 } 217 218 /** 219 * Common code for checking that x and y are >= 0 220 * 221 * @param x x coordinate to ensure is >= 0 222 * @param y y coordinate to ensure is >= 0 223 */ 224 private static void checkXYSign(int x, int y) { 225 if (x < 0) { 226 throw new IllegalArgumentException("x must be >= 0"); 227 } 228 if (y < 0) { 229 throw new IllegalArgumentException("y must be >= 0"); 230 } 231 } 232 233 /** 234 * Common code for checking that width and height are > 0 235 * 236 * @param width width to ensure is > 0 237 * @param height height to ensure is > 0 238 */ 239 private static void checkWidthHeight(int width, int height) { 240 if (width <= 0) { 241 throw new IllegalArgumentException("width must be > 0"); 242 } 243 if (height <= 0) { 244 throw new IllegalArgumentException("height must be > 0"); 245 } 246 } 247 248 public enum Config { 249 // these native values must match up with the enum in SkBitmap.h 250 ALPHA_8 (2), 251 RGB_565 (4), 252 ARGB_4444 (5), 253 ARGB_8888 (6); 254 255 Config(int ni) { 256 this.nativeInt = ni; 257 } 258 final int nativeInt; 259 260 /* package */ static Config nativeToConfig(int ni) { 261 return sConfigs[ni]; 262 } 263 264 private static Config sConfigs[] = { 265 null, null, ALPHA_8, null, RGB_565, ARGB_4444, ARGB_8888 266 }; 267 } 268 269 /** 270 * Copy the bitmap's pixels into the specified buffer (allocated by the 271 * caller). An exception is thrown if the buffer is not large enough to 272 * hold all of the pixels (taking into account the number of bytes per 273 * pixel) or if the Buffer subclass is not one of the support types 274 * (ByteBuffer, ShortBuffer, IntBuffer). 275 */ 276 public void copyPixelsToBuffer(Buffer dst) { 277 int elements = dst.remaining(); 278 int shift; 279 if (dst instanceof ByteBuffer) { 280 shift = 0; 281 } else if (dst instanceof ShortBuffer) { 282 shift = 1; 283 } else if (dst instanceof IntBuffer) { 284 shift = 2; 285 } else { 286 throw new RuntimeException("unsupported Buffer subclass"); 287 } 288 289 long bufferSize = (long)elements << shift; 290 long pixelSize = (long)getRowBytes() * getHeight(); 291 292 if (bufferSize < pixelSize) { 293 throw new RuntimeException("Buffer not large enough for pixels"); 294 } 295 296 nativeCopyPixelsToBuffer(mNativeBitmap, dst); 297 298 // now update the buffer's position 299 int position = dst.position(); 300 position += pixelSize >> shift; 301 dst.position(position); 302 } 303 304 /** 305 * Copy the pixels from the buffer, beginning at the current position, 306 * overwriting the bitmap's pixels. The data in the buffer is not changed 307 * in any way (unlike setPixels(), which converts from unpremultipled 32bit 308 * to whatever the bitmap's native format is. 309 */ 310 public void copyPixelsFromBuffer(Buffer src) { 311 checkRecycled("copyPixelsFromBuffer called on recycled bitmap"); 312 313 int elements = src.remaining(); 314 int shift; 315 if (src instanceof ByteBuffer) { 316 shift = 0; 317 } else if (src instanceof ShortBuffer) { 318 shift = 1; 319 } else if (src instanceof IntBuffer) { 320 shift = 2; 321 } else { 322 throw new RuntimeException("unsupported Buffer subclass"); 323 } 324 325 long bufferBytes = (long)elements << shift; 326 long bitmapBytes = (long)getRowBytes() * getHeight(); 327 328 if (bufferBytes < bitmapBytes) { 329 throw new RuntimeException("Buffer not large enough for pixels"); 330 } 331 332 nativeCopyPixelsFromBuffer(mNativeBitmap, src); 333 } 334 335 /** 336 * Tries to make a new bitmap based on the dimensions of this bitmap, 337 * setting the new bitmap's config to the one specified, and then copying 338 * this bitmap's pixels into the new bitmap. If the conversion is not 339 * supported, or the allocator fails, then this returns NULL. The returned 340 * bitmap initially has the same density as the original. 341 * 342 * @param config The desired config for the resulting bitmap 343 * @param isMutable True if the resulting bitmap should be mutable (i.e. 344 * its pixels can be modified) 345 * @return the new bitmap, or null if the copy could not be made. 346 */ 347 public Bitmap copy(Config config, boolean isMutable) { 348 checkRecycled("Can't copy a recycled bitmap"); 349 Bitmap b = nativeCopy(mNativeBitmap, config.nativeInt, isMutable); 350 if (b != null) { 351 b.mDensity = mDensity; 352 } 353 return b; 354 } 355 356 /** 357 * Creates a new bitmap, scaled from an existing bitmap. 358 * 359 * @param src The source bitmap. 360 * @param dstWidth The new bitmap's desired width. 361 * @param dstHeight The new bitmap's desired height. 362 * @param filter true if the source should be filtered. 363 * @return the new scaled bitmap. 364 */ 365 public static Bitmap createScaledBitmap(Bitmap src, int dstWidth, 366 int dstHeight, boolean filter) { 367 Matrix m; 368 synchronized (Bitmap.class) { 369 // small pool of just 1 matrix 370 m = sScaleMatrix; 371 sScaleMatrix = null; 372 } 373 374 if (m == null) { 375 m = new Matrix(); 376 } 377 378 final int width = src.getWidth(); 379 final int height = src.getHeight(); 380 final float sx = dstWidth / (float)width; 381 final float sy = dstHeight / (float)height; 382 m.setScale(sx, sy); 383 Bitmap b = Bitmap.createBitmap(src, 0, 0, width, height, m, filter); 384 385 synchronized (Bitmap.class) { 386 // do we need to check for null? why not just assign everytime? 387 if (sScaleMatrix == null) { 388 sScaleMatrix = m; 389 } 390 } 391 392 return b; 393 } 394 395 /** 396 * Returns an immutable bitmap from the source bitmap. The new bitmap may 397 * be the same object as source, or a copy may have been made. It is 398 * initialized with the same density as the original bitmap. 399 */ 400 public static Bitmap createBitmap(Bitmap src) { 401 return createBitmap(src, 0, 0, src.getWidth(), src.getHeight()); 402 } 403 404 /** 405 * Returns an immutable bitmap from the specified subset of the source 406 * bitmap. The new bitmap may be the same object as source, or a copy may 407 * have been made. It is 408 * initialized with the same density as the original bitmap. 409 * 410 * @param source The bitmap we are subsetting 411 * @param x The x coordinate of the first pixel in source 412 * @param y The y coordinate of the first pixel in source 413 * @param width The number of pixels in each row 414 * @param height The number of rows 415 */ 416 public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height) { 417 return createBitmap(source, x, y, width, height, null, false); 418 } 419 420 /** 421 * Returns an immutable bitmap from subset of the source bitmap, 422 * transformed by the optional matrix. It is 423 * initialized with the same density as the original bitmap. 424 * 425 * @param source The bitmap we are subsetting 426 * @param x The x coordinate of the first pixel in source 427 * @param y The y coordinate of the first pixel in source 428 * @param width The number of pixels in each row 429 * @param height The number of rows 430 * @param m Optional matrix to be applied to the pixels 431 * @param filter true if the source should be filtered. 432 * Only applies if the matrix contains more than just 433 * translation. 434 * @return A bitmap that represents the specified subset of source 435 * @throws IllegalArgumentException if the x, y, width, height values are 436 * outside of the dimensions of the source bitmap. 437 */ 438 public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height, 439 Matrix m, boolean filter) { 440 441 checkXYSign(x, y); 442 checkWidthHeight(width, height); 443 if (x + width > source.getWidth()) { 444 throw new IllegalArgumentException("x + width must be <= bitmap.width()"); 445 } 446 if (y + height > source.getHeight()) { 447 throw new IllegalArgumentException("y + height must be <= bitmap.height()"); 448 } 449 450 // check if we can just return our argument unchanged 451 if (!source.isMutable() && x == 0 && y == 0 && width == source.getWidth() && 452 height == source.getHeight() && (m == null || m.isIdentity())) { 453 return source; 454 } 455 456 int neww = width; 457 int newh = height; 458 Canvas canvas = new Canvas(); 459 Bitmap bitmap; 460 Paint paint; 461 462 Rect srcR = new Rect(x, y, x + width, y + height); 463 RectF dstR = new RectF(0, 0, width, height); 464 465 final Config newConfig = source.getConfig() == Config.ARGB_8888 ? 466 Config.ARGB_8888 : Config.RGB_565; 467 468 if (m == null || m.isIdentity()) { 469 bitmap = createBitmap(neww, newh, newConfig, source.hasAlpha()); 470 paint = null; // not needed 471 } else { 472 final boolean transformed = !m.rectStaysRect(); 473 474 RectF deviceR = new RectF(); 475 m.mapRect(deviceR, dstR); 476 477 neww = Math.round(deviceR.width()); 478 newh = Math.round(deviceR.height()); 479 480 bitmap = createBitmap(neww, newh, transformed ? Config.ARGB_8888 : newConfig, 481 transformed || source.hasAlpha()); 482 483 canvas.translate(-deviceR.left, -deviceR.top); 484 canvas.concat(m); 485 486 paint = new Paint(); 487 paint.setFilterBitmap(filter); 488 if (transformed) { 489 paint.setAntiAlias(true); 490 } 491 } 492 493 // The new bitmap was created from a known bitmap source so assume that 494 // they use the same density 495 bitmap.mDensity = source.mDensity; 496 497 canvas.setBitmap(bitmap); 498 canvas.drawBitmap(source, srcR, dstR, paint); 499 500 return bitmap; 501 } 502 503 /** 504 * Returns a mutable bitmap with the specified width and height. Its 505 * initial density is as per {@link #getDensity}. 506 * 507 * @param width The width of the bitmap 508 * @param height The height of the bitmap 509 * @param config The bitmap config to create. 510 * @throws IllegalArgumentException if the width or height are <= 0 511 */ 512 public static Bitmap createBitmap(int width, int height, Config config) { 513 return createBitmap(width, height, config, true); 514 } 515 516 /** 517 * Returns a mutable bitmap with the specified width and height. Its 518 * initial density is as per {@link #getDensity}. 519 * 520 * @param width The width of the bitmap 521 * @param height The height of the bitmap 522 * @param config The bitmap config to create. 523 * @param hasAlpha If the bitmap is ARGB_8888 this flag can be used to mark the 524 * bitmap as opaque. Doing so will clear the bitmap in black 525 * instead of transparent. 526 * 527 * @throws IllegalArgumentException if the width or height are <= 0 528 */ 529 private static Bitmap createBitmap(int width, int height, Config config, boolean hasAlpha) { 530 if (width <= 0 || height <= 0) { 531 throw new IllegalArgumentException("width and height must be > 0"); 532 } 533 Bitmap bm = nativeCreate(null, 0, width, width, height, config.nativeInt, true); 534 if (config == Config.ARGB_8888 && !hasAlpha) { 535 bm.eraseColor(0xff000000); 536 nativeSetHasAlpha(bm.mNativeBitmap, hasAlpha); 537 } else { 538 bm.eraseColor(0); 539 } 540 return bm; 541 } 542 543 /** 544 * Returns a immutable bitmap with the specified width and height, with each 545 * pixel value set to the corresponding value in the colors array. Its 546 * initial density is as per {@link #getDensity}. 547 * 548 * @param colors Array of {@link Color} used to initialize the pixels. 549 * @param offset Number of values to skip before the first color in the 550 * array of colors. 551 * @param stride Number of colors in the array between rows (must be >= 552 * width or <= -width). 553 * @param width The width of the bitmap 554 * @param height The height of the bitmap 555 * @param config The bitmap config to create. If the config does not 556 * support per-pixel alpha (e.g. RGB_565), then the alpha 557 * bytes in the colors[] will be ignored (assumed to be FF) 558 * @throws IllegalArgumentException if the width or height are <= 0, or if 559 * the color array's length is less than the number of pixels. 560 */ 561 public static Bitmap createBitmap(int colors[], int offset, int stride, 562 int width, int height, Config config) { 563 564 checkWidthHeight(width, height); 565 if (Math.abs(stride) < width) { 566 throw new IllegalArgumentException("abs(stride) must be >= width"); 567 } 568 int lastScanline = offset + (height - 1) * stride; 569 int length = colors.length; 570 if (offset < 0 || (offset + width > length) || lastScanline < 0 || 571 (lastScanline + width > length)) { 572 throw new ArrayIndexOutOfBoundsException(); 573 } 574 if (width <= 0 || height <= 0) { 575 throw new IllegalArgumentException("width and height must be > 0"); 576 } 577 return nativeCreate(colors, offset, stride, width, height, 578 config.nativeInt, false); 579 } 580 581 /** 582 * Returns a immutable bitmap with the specified width and height, with each 583 * pixel value set to the corresponding value in the colors array. Its 584 * initial density is as per {@link #getDensity}. 585 * 586 * @param colors Array of {@link Color} used to initialize the pixels. 587 * This array must be at least as large as width * height. 588 * @param width The width of the bitmap 589 * @param height The height of the bitmap 590 * @param config The bitmap config to create. If the config does not 591 * support per-pixel alpha (e.g. RGB_565), then the alpha 592 * bytes in the colors[] will be ignored (assumed to be FF) 593 * @throws IllegalArgumentException if the width or height are <= 0, or if 594 * the color array's length is less than the number of pixels. 595 */ 596 public static Bitmap createBitmap(int colors[], int width, int height, Config config) { 597 return createBitmap(colors, 0, width, width, height, config); 598 } 599 600 /** 601 * Returns an optional array of private data, used by the UI system for 602 * some bitmaps. Not intended to be called by applications. 603 */ 604 public byte[] getNinePatchChunk() { 605 return mNinePatchChunk; 606 } 607 608 /** 609 * Specifies the known formats a bitmap can be compressed into 610 */ 611 public enum CompressFormat { 612 JPEG (0), 613 PNG (1); 614 615 CompressFormat(int nativeInt) { 616 this.nativeInt = nativeInt; 617 } 618 final int nativeInt; 619 } 620 621 /** 622 * Number of bytes of temp storage we use for communicating between the 623 * native compressor and the java OutputStream. 624 */ 625 private final static int WORKING_COMPRESS_STORAGE = 4096; 626 627 /** 628 * Write a compressed version of the bitmap to the specified outputstream. 629 * If this returns true, the bitmap can be reconstructed by passing a 630 * corresponding inputstream to BitmapFactory.decodeStream(). Note: not 631 * all Formats support all bitmap configs directly, so it is possible that 632 * the returned bitmap from BitmapFactory could be in a different bitdepth, 633 * and/or may have lost per-pixel alpha (e.g. JPEG only supports opaque 634 * pixels). 635 * 636 * @param format The format of the compressed image 637 * @param quality Hint to the compressor, 0-100. 0 meaning compress for 638 * small size, 100 meaning compress for max quality. Some 639 * formats, like PNG which is lossless, will ignore the 640 * quality setting 641 * @param stream The outputstream to write the compressed data. 642 * @return true if successfully compressed to the specified stream. 643 */ 644 public boolean compress(CompressFormat format, int quality, OutputStream stream) { 645 checkRecycled("Can't compress a recycled bitmap"); 646 // do explicit check before calling the native method 647 if (stream == null) { 648 throw new NullPointerException(); 649 } 650 if (quality < 0 || quality > 100) { 651 throw new IllegalArgumentException("quality must be 0..100"); 652 } 653 return nativeCompress(mNativeBitmap, format.nativeInt, quality, 654 stream, new byte[WORKING_COMPRESS_STORAGE]); 655 } 656 657 /** 658 * Returns true if the bitmap is marked as mutable (i.e. can be drawn into) 659 */ 660 public final boolean isMutable() { 661 return mIsMutable; 662 } 663 664 /** Returns the bitmap's width */ 665 public final int getWidth() { 666 return mWidth == -1 ? mWidth = nativeWidth(mNativeBitmap) : mWidth; 667 } 668 669 /** Returns the bitmap's height */ 670 public final int getHeight() { 671 return mHeight == -1 ? mHeight = nativeHeight(mNativeBitmap) : mHeight; 672 } 673 674 /** 675 * Convenience for calling {@link #getScaledWidth(int)} with the target 676 * density of the given {@link Canvas}. 677 */ 678 public int getScaledWidth(Canvas canvas) { 679 return scaleFromDensity(getWidth(), mDensity, canvas.mDensity); 680 } 681 682 /** 683 * Convenience for calling {@link #getScaledHeight(int)} with the target 684 * density of the given {@link Canvas}. 685 */ 686 public int getScaledHeight(Canvas canvas) { 687 return scaleFromDensity(getHeight(), mDensity, canvas.mDensity); 688 } 689 690 /** 691 * Convenience for calling {@link #getScaledWidth(int)} with the target 692 * density of the given {@link DisplayMetrics}. 693 */ 694 public int getScaledWidth(DisplayMetrics metrics) { 695 return scaleFromDensity(getWidth(), mDensity, metrics.densityDpi); 696 } 697 698 /** 699 * Convenience for calling {@link #getScaledHeight(int)} with the target 700 * density of the given {@link DisplayMetrics}. 701 */ 702 public int getScaledHeight(DisplayMetrics metrics) { 703 return scaleFromDensity(getHeight(), mDensity, metrics.densityDpi); 704 } 705 706 /** 707 * Convenience method that returns the width of this bitmap divided 708 * by the density scale factor. 709 * 710 * @param targetDensity The density of the target canvas of the bitmap. 711 * @return The scaled width of this bitmap, according to the density scale factor. 712 */ 713 public int getScaledWidth(int targetDensity) { 714 return scaleFromDensity(getWidth(), mDensity, targetDensity); 715 } 716 717 /** 718 * Convenience method that returns the height of this bitmap divided 719 * by the density scale factor. 720 * 721 * @param targetDensity The density of the target canvas of the bitmap. 722 * @return The scaled height of this bitmap, according to the density scale factor. 723 */ 724 public int getScaledHeight(int targetDensity) { 725 return scaleFromDensity(getHeight(), mDensity, targetDensity); 726 } 727 728 /** 729 * @hide 730 */ 731 static public int scaleFromDensity(int size, int sdensity, int tdensity) { 732 if (sdensity == DENSITY_NONE || sdensity == tdensity) { 733 return size; 734 } 735 736 // Scale by tdensity / sdensity, rounding up. 737 return ( (size * tdensity) + (sdensity >> 1) ) / sdensity; 738 } 739 740 /** 741 * Return the number of bytes between rows in the bitmap's pixels. Note that 742 * this refers to the pixels as stored natively by the bitmap. If you call 743 * getPixels() or setPixels(), then the pixels are uniformly treated as 744 * 32bit values, packed according to the Color class. 745 * 746 * @return number of bytes between rows of the native bitmap pixels. 747 */ 748 public final int getRowBytes() { 749 return nativeRowBytes(mNativeBitmap); 750 } 751 752 /** 753 * If the bitmap's internal config is in one of the public formats, return 754 * that config, otherwise return null. 755 */ 756 public final Config getConfig() { 757 return Config.nativeToConfig(nativeConfig(mNativeBitmap)); 758 } 759 760 /** Returns true if the bitmap's config supports per-pixel alpha, and 761 * if the pixels may contain non-opaque alpha values. For some configs, 762 * this is always false (e.g. RGB_565), since they do not support per-pixel 763 * alpha. However, for configs that do, the bitmap may be flagged to be 764 * known that all of its pixels are opaque. In this case hasAlpha() will 765 * also return false. If a config such as ARGB_8888 is not so flagged, 766 * it will return true by default. 767 */ 768 public final boolean hasAlpha() { 769 return nativeHasAlpha(mNativeBitmap); 770 } 771 772 /** 773 * Tell the bitmap if all of the pixels are known to be opaque (false) 774 * or if some of the pixels may contain non-opaque alpha values (true). 775 * Note, for some configs (e.g. RGB_565) this call is ignore, since it does 776 * not support per-pixel alpha values. 777 * 778 * This is meant as a drawing hint, as in some cases a bitmap that is known 779 * to be opaque can take a faster drawing case than one that may have 780 * non-opaque per-pixel alpha values. 781 * 782 * @hide 783 */ 784 public void setHasAlpha(boolean hasAlpha) { 785 nativeSetHasAlpha(mNativeBitmap, hasAlpha); 786 } 787 788 /** 789 * Fills the bitmap's pixels with the specified {@link Color}. 790 * 791 * @throws IllegalStateException if the bitmap is not mutable. 792 */ 793 public void eraseColor(int c) { 794 checkRecycled("Can't erase a recycled bitmap"); 795 if (!isMutable()) { 796 throw new IllegalStateException("cannot erase immutable bitmaps"); 797 } 798 nativeErase(mNativeBitmap, c); 799 } 800 801 /** 802 * Returns the {@link Color} at the specified location. Throws an exception 803 * if x or y are out of bounds (negative or >= to the width or height 804 * respectively). 805 * 806 * @param x The x coordinate (0...width-1) of the pixel to return 807 * @param y The y coordinate (0...height-1) of the pixel to return 808 * @return The argb {@link Color} at the specified coordinate 809 * @throws IllegalArgumentException if x, y exceed the bitmap's bounds 810 */ 811 public int getPixel(int x, int y) { 812 checkRecycled("Can't call getPixel() on a recycled bitmap"); 813 checkPixelAccess(x, y); 814 return nativeGetPixel(mNativeBitmap, x, y); 815 } 816 817 /** 818 * Returns in pixels[] a copy of the data in the bitmap. Each value is 819 * a packed int representing a {@link Color}. The stride parameter allows 820 * the caller to allow for gaps in the returned pixels array between 821 * rows. For normal packed results, just pass width for the stride value. 822 * 823 * @param pixels The array to receive the bitmap's colors 824 * @param offset The first index to write into pixels[] 825 * @param stride The number of entries in pixels[] to skip between 826 * rows (must be >= bitmap's width). Can be negative. 827 * @param x The x coordinate of the first pixel to read from 828 * the bitmap 829 * @param y The y coordinate of the first pixel to read from 830 * the bitmap 831 * @param width The number of pixels to read from each row 832 * @param height The number of rows to read 833 * @throws IllegalArgumentException if x, y, width, height exceed the 834 * bounds of the bitmap, or if abs(stride) < width. 835 * @throws ArrayIndexOutOfBoundsException if the pixels array is too small 836 * to receive the specified number of pixels. 837 */ 838 public void getPixels(int[] pixels, int offset, int stride, 839 int x, int y, int width, int height) { 840 checkRecycled("Can't call getPixels() on a recycled bitmap"); 841 if (width == 0 || height == 0) { 842 return; // nothing to do 843 } 844 checkPixelsAccess(x, y, width, height, offset, stride, pixels); 845 nativeGetPixels(mNativeBitmap, pixels, offset, stride, 846 x, y, width, height); 847 } 848 849 /** 850 * Shared code to check for illegal arguments passed to getPixel() 851 * or setPixel() 852 * @param x x coordinate of the pixel 853 * @param y y coordinate of the pixel 854 */ 855 private void checkPixelAccess(int x, int y) { 856 checkXYSign(x, y); 857 if (x >= getWidth()) { 858 throw new IllegalArgumentException("x must be < bitmap.width()"); 859 } 860 if (y >= getHeight()) { 861 throw new IllegalArgumentException("y must be < bitmap.height()"); 862 } 863 } 864 865 /** 866 * Shared code to check for illegal arguments passed to getPixels() 867 * or setPixels() 868 * 869 * @param x left edge of the area of pixels to access 870 * @param y top edge of the area of pixels to access 871 * @param width width of the area of pixels to access 872 * @param height height of the area of pixels to access 873 * @param offset offset into pixels[] array 874 * @param stride number of elements in pixels[] between each logical row 875 * @param pixels array to hold the area of pixels being accessed 876 */ 877 private void checkPixelsAccess(int x, int y, int width, int height, 878 int offset, int stride, int pixels[]) { 879 checkXYSign(x, y); 880 if (width < 0) { 881 throw new IllegalArgumentException("width must be >= 0"); 882 } 883 if (height < 0) { 884 throw new IllegalArgumentException("height must be >= 0"); 885 } 886 if (x + width > getWidth()) { 887 throw new IllegalArgumentException( 888 "x + width must be <= bitmap.width()"); 889 } 890 if (y + height > getHeight()) { 891 throw new IllegalArgumentException( 892 "y + height must be <= bitmap.height()"); 893 } 894 if (Math.abs(stride) < width) { 895 throw new IllegalArgumentException("abs(stride) must be >= width"); 896 } 897 int lastScanline = offset + (height - 1) * stride; 898 int length = pixels.length; 899 if (offset < 0 || (offset + width > length) 900 || lastScanline < 0 901 || (lastScanline + width > length)) { 902 throw new ArrayIndexOutOfBoundsException(); 903 } 904 } 905 906 /** 907 * Write the specified {@link Color} into the bitmap (assuming it is 908 * mutable) at the x,y coordinate. 909 * 910 * @param x The x coordinate of the pixel to replace (0...width-1) 911 * @param y The y coordinate of the pixel to replace (0...height-1) 912 * @param color The {@link Color} to write into the bitmap 913 * @throws IllegalStateException if the bitmap is not mutable 914 * @throws IllegalArgumentException if x, y are outside of the bitmap's 915 * bounds. 916 */ 917 public void setPixel(int x, int y, int color) { 918 checkRecycled("Can't call setPixel() on a recycled bitmap"); 919 if (!isMutable()) { 920 throw new IllegalStateException(); 921 } 922 checkPixelAccess(x, y); 923 nativeSetPixel(mNativeBitmap, x, y, color); 924 } 925 926 /** 927 * Replace pixels in the bitmap with the colors in the array. Each element 928 * in the array is a packed int prepresenting a {@link Color} 929 * 930 * @param pixels The colors to write to the bitmap 931 * @param offset The index of the first color to read from pixels[] 932 * @param stride The number of colors in pixels[] to skip between rows. 933 * Normally this value will be the same as the width of 934 * the bitmap, but it can be larger (or negative). 935 * @param x The x coordinate of the first pixel to write to in 936 * the bitmap. 937 * @param y The y coordinate of the first pixel to write to in 938 * the bitmap. 939 * @param width The number of colors to copy from pixels[] per row 940 * @param height The number of rows to write to the bitmap 941 * @throws IllegalStateException if the bitmap is not mutable 942 * @throws IllegalArgumentException if x, y, width, height are outside of 943 * the bitmap's bounds. 944 * @throws ArrayIndexOutOfBoundsException if the pixels array is too small 945 * to receive the specified number of pixels. 946 */ 947 public void setPixels(int[] pixels, int offset, int stride, 948 int x, int y, int width, int height) { 949 checkRecycled("Can't call setPixels() on a recycled bitmap"); 950 if (!isMutable()) { 951 throw new IllegalStateException(); 952 } 953 if (width == 0 || height == 0) { 954 return; // nothing to do 955 } 956 checkPixelsAccess(x, y, width, height, offset, stride, pixels); 957 nativeSetPixels(mNativeBitmap, pixels, offset, stride, 958 x, y, width, height); 959 } 960 961 public static final Parcelable.Creator<Bitmap> CREATOR 962 = new Parcelable.Creator<Bitmap>() { 963 /** 964 * Rebuilds a bitmap previously stored with writeToParcel(). 965 * 966 * @param p Parcel object to read the bitmap from 967 * @return a new bitmap created from the data in the parcel 968 */ 969 public Bitmap createFromParcel(Parcel p) { 970 Bitmap bm = nativeCreateFromParcel(p); 971 if (bm == null) { 972 throw new RuntimeException("Failed to unparcel Bitmap"); 973 } 974 return bm; 975 } 976 public Bitmap[] newArray(int size) { 977 return new Bitmap[size]; 978 } 979 }; 980 981 /** 982 * No special parcel contents. 983 */ 984 public int describeContents() { 985 return 0; 986 } 987 988 /** 989 * Write the bitmap and its pixels to the parcel. The bitmap can be 990 * rebuilt from the parcel by calling CREATOR.createFromParcel(). 991 * @param p Parcel object to write the bitmap data into 992 */ 993 public void writeToParcel(Parcel p, int flags) { 994 checkRecycled("Can't parcel a recycled bitmap"); 995 if (!nativeWriteToParcel(mNativeBitmap, mIsMutable, mDensity, p)) { 996 throw new RuntimeException("native writeToParcel failed"); 997 } 998 } 999 1000 /** 1001 * Returns a new bitmap that captures the alpha values of the original. 1002 * This may be drawn with Canvas.drawBitmap(), where the color(s) will be 1003 * taken from the paint that is passed to the draw call. 1004 * 1005 * @return new bitmap containing the alpha channel of the original bitmap. 1006 */ 1007 public Bitmap extractAlpha() { 1008 return extractAlpha(null, null); 1009 } 1010 1011 /** 1012 * Returns a new bitmap that captures the alpha values of the original. 1013 * These values may be affected by the optional Paint parameter, which 1014 * can contain its own alpha, and may also contain a MaskFilter which 1015 * could change the actual dimensions of the resulting bitmap (e.g. 1016 * a blur maskfilter might enlarge the resulting bitmap). If offsetXY 1017 * is not null, it returns the amount to offset the returned bitmap so 1018 * that it will logically align with the original. For example, if the 1019 * paint contains a blur of radius 2, then offsetXY[] would contains 1020 * -2, -2, so that drawing the alpha bitmap offset by (-2, -2) and then 1021 * drawing the original would result in the blur visually aligning with 1022 * the original. 1023 * 1024 * <p>The initial density of the returned bitmap is the same as the original's. 1025 * 1026 * @param paint Optional paint used to modify the alpha values in the 1027 * resulting bitmap. Pass null for default behavior. 1028 * @param offsetXY Optional array that returns the X (index 0) and Y 1029 * (index 1) offset needed to position the returned bitmap 1030 * so that it visually lines up with the original. 1031 * @return new bitmap containing the (optionally modified by paint) alpha 1032 * channel of the original bitmap. This may be drawn with 1033 * Canvas.drawBitmap(), where the color(s) will be taken from the 1034 * paint that is passed to the draw call. 1035 */ 1036 public Bitmap extractAlpha(Paint paint, int[] offsetXY) { 1037 checkRecycled("Can't extractAlpha on a recycled bitmap"); 1038 int nativePaint = paint != null ? paint.mNativePaint : 0; 1039 Bitmap bm = nativeExtractAlpha(mNativeBitmap, nativePaint, offsetXY); 1040 if (bm == null) { 1041 throw new RuntimeException("Failed to extractAlpha on Bitmap"); 1042 } 1043 bm.mDensity = mDensity; 1044 return bm; 1045 } 1046 1047 /** 1048 * Given another bitmap, return true if it has the same dimensions, config, 1049 * and pixel data as this bitmap. If any of those differ, return false. 1050 * If other is null, return false. 1051 * 1052 * @hide (just needed internally right now) 1053 */ 1054 public boolean sameAs(Bitmap other) { 1055 return this == other || 1056 (other != null && 1057 nativeSameAs(mNativeBitmap, other.mNativeBitmap)); 1058 } 1059 1060 /** 1061 * Rebuilds any caches associated with the bitmap that are used for 1062 * drawing it. In the case of purgeable bitmaps, this call will attempt to 1063 * ensure that the pixels have been decoded. 1064 * If this is called on more than one bitmap in sequence, the priority is 1065 * given in LRU order (i.e. the last bitmap called will be given highest 1066 * priority). 1067 * 1068 * For bitmaps with no associated caches, this call is effectively a no-op, 1069 * and therefore is harmless. 1070 */ 1071 public void prepareToDraw() { 1072 nativePrepareToDraw(mNativeBitmap); 1073 } 1074 1075 private static class BitmapFinalizer { 1076 private final int mNativeBitmap; 1077 1078 BitmapFinalizer(int nativeBitmap) { 1079 mNativeBitmap = nativeBitmap; 1080 } 1081 1082 @Override 1083 public void finalize() { 1084 nativeDestructor(mNativeBitmap); 1085 } 1086 } 1087 1088 //////////// native methods 1089 1090 private static native Bitmap nativeCreate(int[] colors, int offset, 1091 int stride, int width, int height, 1092 int nativeConfig, boolean mutable); 1093 private static native Bitmap nativeCopy(int srcBitmap, int nativeConfig, 1094 boolean isMutable); 1095 private static native void nativeDestructor(int nativeBitmap); 1096 private static native void nativeRecycle(int nativeBitmap); 1097 1098 private static native boolean nativeCompress(int nativeBitmap, int format, 1099 int quality, OutputStream stream, 1100 byte[] tempStorage); 1101 private static native void nativeErase(int nativeBitmap, int color); 1102 private static native int nativeWidth(int nativeBitmap); 1103 private static native int nativeHeight(int nativeBitmap); 1104 private static native int nativeRowBytes(int nativeBitmap); 1105 private static native int nativeConfig(int nativeBitmap); 1106 private static native boolean nativeHasAlpha(int nativeBitmap); 1107 1108 private static native int nativeGetPixel(int nativeBitmap, int x, int y); 1109 private static native void nativeGetPixels(int nativeBitmap, int[] pixels, 1110 int offset, int stride, int x, 1111 int y, int width, int height); 1112 1113 private static native void nativeSetPixel(int nativeBitmap, int x, int y, 1114 int color); 1115 private static native void nativeSetPixels(int nativeBitmap, int[] colors, 1116 int offset, int stride, int x, 1117 int y, int width, int height); 1118 private static native void nativeCopyPixelsToBuffer(int nativeBitmap, 1119 Buffer dst); 1120 private static native void nativeCopyPixelsFromBuffer(int nb, Buffer src); 1121 private static native int nativeGenerationId(int nativeBitmap); 1122 1123 private static native Bitmap nativeCreateFromParcel(Parcel p); 1124 // returns true on success 1125 private static native boolean nativeWriteToParcel(int nativeBitmap, 1126 boolean isMutable, 1127 int density, 1128 Parcel p); 1129 // returns a new bitmap built from the native bitmap's alpha, and the paint 1130 private static native Bitmap nativeExtractAlpha(int nativeBitmap, 1131 int nativePaint, 1132 int[] offsetXY); 1133 1134 private static native void nativePrepareToDraw(int nativeBitmap); 1135 private static native void nativeSetHasAlpha(int nBitmap, boolean hasAlpha); 1136 private static native boolean nativeSameAs(int nb0, int nb1); 1137 1138 /* package */ final int ni() { 1139 return mNativeBitmap; 1140 } 1141} 1142