hidden api sameAs() to compare the pixels of 2 bitmaps for equality (76d1e01d) · Commits · e / os / android_frameworks_base

core/jni/android/graphics/Bitmap.cpp

+49 −1

Original line number	Diff line number	Diff line
		@@ -527,6 +527,53 @@ static void Bitmap_copyPixelsFromBuffer(JNIEnv* env, jobject,
		}
		}

		static bool Bitmap_sameAs(JNIEnv* env, jobject, const SkBitmap* bm0,
		const SkBitmap* bm1) {
		if (bm0->width() != bm1->width() \|\|
		bm0->height() != bm1->height() \|\|
		bm0->config() != bm1->config()) {
		return false;
		}

		SkAutoLockPixels alp0(*bm0);
		SkAutoLockPixels alp1(*bm1);

		// if we can't load the pixels, return false
		if (NULL == bm0->getPixels() \|\| NULL == bm1->getPixels()) {
		return false;
		}

		if (bm0->config() == SkBitmap::kIndex8_Config) {
		SkColorTable* ct0 = bm0->getColorTable();
		SkColorTable* ct1 = bm1->getColorTable();
		if (NULL == ct0 \|\| NULL == ct1) {
		return false;
		}
		if (ct0->count() != ct1->count()) {
		return false;
		}

		SkAutoLockColors alc0(ct0);
		SkAutoLockColors alc1(ct1);
		const size_t size = ct0->count() * sizeof(SkPMColor);
		if (memcmp(alc0.colors(), alc1.colors(), size) != 0) {
		return false;
		}
		}

		// now compare each scanline. We can't do the entire buffer at once,
		// since we don't care about the pixel values that might extend beyond
		// the width (since the scanline might be larger than the logical width)
		const int h = bm0->height();
		const size_t size = bm0->width() * bm0->bytesPerPixel();
		for (int y = 0; y < h; y++) {
		if (memcmp(bm0->getAddr(0, y), bm1->getAddr(0, y), size) != 0) {
		return false;
		}
		}
		return true;
		}

		static void Bitmap_prepareToDraw(JNIEnv* env, jobject, SkBitmap* bitmap) {
		bitmap->lockPixels();
		bitmap->unlockPixels();
		@@ -567,7 +614,8 @@ static JNINativeMethod gBitmapMethods[] = {
		(void*)Bitmap_copyPixelsToBuffer },
		{ "nativeCopyPixelsFromBuffer", "(ILjava/nio/Buffer;)V",
		(void*)Bitmap_copyPixelsFromBuffer },
		{ "nativePrepareToDraw", "(I)V", (void*)Bitmap_prepareToDraw }
		{ "nativeSameAs", "(II)Z", (void*)Bitmap_sameAs },
		{ "nativePrepareToDraw", "(I)V", (void*)Bitmap_prepareToDraw },
		};

		#define kClassPathName "android/graphics/Bitmap"

graphics/java/android/graphics/Bitmap.java

+14 −0

Original line number	Diff line number	Diff line
		@@ -971,6 +971,19 @@ public final class Bitmap implements Parcelable {
		return bm;
		}

		/**
		* Given another bitmap, return true if it has the same dimensions, config,
		* and pixel data as this bitmap. If any of those differ, return false.
		* If other is null, return false.
		*
		* @hide (just needed internally right now)
		*/
		public boolean sameAs(Bitmap other) {
		return this == other \|\|
		(other != null &&
		nativeSameAs(mNativeBitmap, other.mNativeBitmap));
		}

		/**
		* Rebuilds any caches associated with the bitmap that are used for
		* drawing it. In the case of purgeable bitmaps, this call will attempt to
		@@ -1042,6 +1055,7 @@ public final class Bitmap implements Parcelable {

		private static native void nativePrepareToDraw(int nativeBitmap);
		private static native void nativeSetHasAlpha(int nBitmap, boolean hasAlpha);
		private static native boolean nativeSameAs(int nb0, int nb1);

		/* package */ final int ni() {
		return mNativeBitmap;