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Diffstat (limited to 'framesequence/jni/FrameSequence_gif.cpp')
| -rw-r--r-- | framesequence/jni/FrameSequence_gif.cpp | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/framesequence/jni/FrameSequence_gif.cpp b/framesequence/jni/FrameSequence_gif.cpp new file mode 100644 index 0000000..e9f3ace --- /dev/null +++ b/framesequence/jni/FrameSequence_gif.cpp @@ -0,0 +1,345 @@ +/* + * Copyright (C) 2013 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. + */ + +#include <string.h> +#include "JNIHelpers.h" +#include "utils/log.h" +#include "utils/math.h" + +#include "FrameSequence_gif.h" + +#define GIF_DEBUG 0 + +// These constants are chosen to imitate common browser behavior +// Note that 0 delay is undefined behavior in the gif standard +static const long MIN_DELAY_MS = 20; +static const long DEFAULT_DELAY_MS = 100; + +static int streamReader(GifFileType* fileType, GifByteType* out, int size) { + Stream* stream = (Stream*) fileType->UserData; + return (int) stream->read(out, size); +} + +static Color8888 gifColorToColor8888(const GifColorType& color) { + return ARGB_TO_COLOR8888(0xff, color.Red, color.Green, color.Blue); +} + +static long getDelayMs(GraphicsControlBlock& gcb) { + long delayMs = gcb.DelayTime * 10; + if (delayMs < MIN_DELAY_MS) { + return DEFAULT_DELAY_MS; + } + return delayMs; +} + +static bool willBeCleared(const GraphicsControlBlock& gcb) { + return gcb.DisposalMode == DISPOSE_BACKGROUND || gcb.DisposalMode == DISPOSE_PREVIOUS; +} + +//////////////////////////////////////////////////////////////////////////////// +// Frame sequence +//////////////////////////////////////////////////////////////////////////////// + +FrameSequence_gif::FrameSequence_gif(Stream* stream) : + mBgColor(TRANSPARENT), mPreservedFrames(NULL), mRestoringFrames(NULL) { + mGif = DGifOpen(stream, streamReader, NULL); + if (!mGif) { + ALOGW("Gif load failed"); + return; + } + + if (DGifSlurp(mGif) != GIF_OK) { + ALOGW("Gif slurp failed"); + DGifCloseFile(mGif); + mGif = NULL; + return; + } + + long durationMs = 0; + int lastUnclearedFrame = -1; + mPreservedFrames = new bool[mGif->ImageCount]; + mRestoringFrames = new int[mGif->ImageCount]; + + GraphicsControlBlock gcb; + for (int i = 0; i < mGif->ImageCount; i++) { + const SavedImage& image = mGif->SavedImages[i]; + DGifSavedExtensionToGCB(mGif, i, &gcb); + + // timing + durationMs += getDelayMs(gcb); + + // preserve logic + mPreservedFrames[i] = false; + mRestoringFrames[i] = -1; + if (gcb.DisposalMode == DISPOSE_PREVIOUS && lastUnclearedFrame >= 0) { + mPreservedFrames[lastUnclearedFrame] = true; + mRestoringFrames[i] = lastUnclearedFrame; + } + if (!willBeCleared(gcb)) { + lastUnclearedFrame = i; + } + } + +#if GIF_DEBUG + ALOGD("FrameSequence_gif created with size %d %d, frames %d dur %ld", + mGif->SWidth, mGif->SHeight, mGif->ImageCount, durationMs); + for (int i = 0; i < mGif->ImageCount; i++) { + DGifSavedExtensionToGCB(mGif, i, &gcb); + ALOGD(" Frame %d - must preserve %d, restore point %d, trans color %d", + i, mPreservedFrames[i], mRestoringFrames[i], gcb.TransparentColor); + } +#endif + + if (mGif->SColorMap) { + // calculate bg color + GraphicsControlBlock gcb; + DGifSavedExtensionToGCB(mGif, 0, &gcb); + if (gcb.TransparentColor == NO_TRANSPARENT_COLOR) { + mBgColor = gifColorToColor8888(mGif->SColorMap->Colors[mGif->SBackGroundColor]); + } + } +} + +FrameSequence_gif::~FrameSequence_gif() { + if (mGif) { + DGifCloseFile(mGif); + } + delete[] mPreservedFrames; + delete[] mRestoringFrames; +} + +FrameSequenceState* FrameSequence_gif::createState() const { + return new FrameSequenceState_gif(*this); +} + +//////////////////////////////////////////////////////////////////////////////// +// draw helpers +//////////////////////////////////////////////////////////////////////////////// + +// return true if area of 'target' is completely covers area of 'covered' +static bool checkIfCover(const GifImageDesc& target, const GifImageDesc& covered) { + return target.Left <= covered.Left + && covered.Left + covered.Width <= target.Left + target.Width + && target.Top <= covered.Top + && covered.Top + covered.Height <= target.Top + target.Height; +} + +static void copyLine(Color8888* dst, const unsigned char* src, const ColorMapObject* cmap, + int transparent, int width) { + for (; width > 0; width--, src++, dst++) { + if (*src != transparent) { + *dst = gifColorToColor8888(cmap->Colors[*src]); + } + } +} + +static void setLineColor(Color8888* dst, Color8888 color, int width) { + for (; width > 0; width--, dst++) { + *dst = color; + } +} + +static void getCopySize(const GifImageDesc& imageDesc, int maxWidth, int maxHeight, + GifWord& copyWidth, GifWord& copyHeight) { + copyWidth = imageDesc.Width; + if (imageDesc.Left + copyWidth > maxWidth) { + copyWidth = maxWidth - imageDesc.Left; + } + copyHeight = imageDesc.Height; + if (imageDesc.Top + copyHeight > maxHeight) { + copyHeight = maxHeight - imageDesc.Top; + } +} + +//////////////////////////////////////////////////////////////////////////////// +// Frame sequence state +//////////////////////////////////////////////////////////////////////////////// + +FrameSequenceState_gif::FrameSequenceState_gif(const FrameSequence_gif& frameSequence) : + mFrameSequence(frameSequence), mPreserveBuffer(NULL), mPreserveBufferFrame(-1) { +} + +FrameSequenceState_gif::~FrameSequenceState_gif() { + delete[] mPreserveBuffer; +} + +void FrameSequenceState_gif::savePreserveBuffer(Color8888* outputPtr, int outputPixelStride, int frameNr) { + if (frameNr == mPreserveBufferFrame) return; + + mPreserveBufferFrame = frameNr; + const int width = mFrameSequence.getWidth(); + const int height = mFrameSequence.getHeight(); + if (!mPreserveBuffer) { + mPreserveBuffer = new Color8888[width * height]; + } + for (int y = 0; y < height; y++) { + memcpy(mPreserveBuffer + width * y, + outputPtr + outputPixelStride * y, + width * 4); + } +} + +void FrameSequenceState_gif::restorePreserveBuffer(Color8888* outputPtr, int outputPixelStride) { + const int width = mFrameSequence.getWidth(); + const int height = mFrameSequence.getHeight(); + if (!mPreserveBuffer) { + ALOGD("preserve buffer not allocated! ah!"); + return; + } + for (int y = 0; y < height; y++) { + memcpy(outputPtr + outputPixelStride * y, + mPreserveBuffer + width * y, + width * 4); + } +} + +long FrameSequenceState_gif::drawFrame(int frameNr, + Color8888* outputPtr, int outputPixelStride, int previousFrameNr) { + + GifFileType* gif = mFrameSequence.getGif(); + if (!gif) { + ALOGD("Cannot drawFrame, mGif is NULL"); + return -1; + } + +#if GIF_DEBUG + ALOGD(" drawFrame on %p nr %d on addr %p, previous frame nr %d", + this, frameNr, outputPtr, previousFrameNr); +#endif + + const int height = mFrameSequence.getHeight(); + const int width = mFrameSequence.getWidth(); + + GraphicsControlBlock gcb; + + int start = max(previousFrameNr + 1, 0); + + for (int i = max(start - 1, 0); i < frameNr; i++) { + int neededPreservedFrame = mFrameSequence.getRestoringFrame(i); + if (neededPreservedFrame >= 0 && (mPreserveBufferFrame != neededPreservedFrame)) { +#if GIF_DEBUG + ALOGD("frame %d needs frame %d preserved, but %d is currently, so drawing from scratch", + i, neededPreservedFrame, mPreserveBufferFrame); +#endif + start = 0; + } + } + + for (int i = start; i <= frameNr; i++) { + DGifSavedExtensionToGCB(gif, i, &gcb); + const SavedImage& frame = gif->SavedImages[i]; + +#if GIF_DEBUG + bool frameOpaque = gcb.TransparentColor == NO_TRANSPARENT_COLOR; + ALOGD("producing frame %d, drawing frame %d (opaque %d, disp %d, del %d)", + frameNr, i, frameOpaque, gcb.DisposalMode, gcb.DelayTime); +#endif + if (i == 0) { + //clear bitmap + Color8888 bgColor = mFrameSequence.getBackgroundColor(); + for (int y = 0; y < height; y++) { + for (int x = 0; x < width; x++) { + outputPtr[y * outputPixelStride + x] = bgColor; + } + } + } else { + GraphicsControlBlock prevGcb; + DGifSavedExtensionToGCB(gif, i - 1, &prevGcb); + const SavedImage& prevFrame = gif->SavedImages[i - 1]; + bool prevFrameDisposed = willBeCleared(prevGcb); + + bool newFrameOpaque = gcb.TransparentColor == NO_TRANSPARENT_COLOR; + bool prevFrameCompletelyCovered = newFrameOpaque + && checkIfCover(frame.ImageDesc, prevFrame.ImageDesc); + + if (prevFrameDisposed && !prevFrameCompletelyCovered) { + switch (prevGcb.DisposalMode) { + case DISPOSE_BACKGROUND: { + Color8888* dst = outputPtr + prevFrame.ImageDesc.Left + + prevFrame.ImageDesc.Top * outputPixelStride; + + GifWord copyWidth, copyHeight; + getCopySize(prevFrame.ImageDesc, width, height, copyWidth, copyHeight); + for (; copyHeight > 0; copyHeight--) { + setLineColor(dst, TRANSPARENT, copyWidth); + dst += outputPixelStride; + } + } break; + case DISPOSE_PREVIOUS: { + restorePreserveBuffer(outputPtr, outputPixelStride); + } break; + } + } + + if (mFrameSequence.getPreservedFrame(i - 1)) { + // currently drawn frame will be restored by a following DISPOSE_PREVIOUS draw, so + // we preserve it + savePreserveBuffer(outputPtr, outputPixelStride, i - 1); + } + } + + bool willBeCleared = gcb.DisposalMode == DISPOSE_BACKGROUND + || gcb.DisposalMode == DISPOSE_PREVIOUS; + if (i == frameNr || !willBeCleared) { + const ColorMapObject* cmap = gif->SColorMap; + if (frame.ImageDesc.ColorMap) { + cmap = frame.ImageDesc.ColorMap; + } + + if (cmap == NULL || cmap->ColorCount != (1 << cmap->BitsPerPixel)) { + ALOGW("Warning: potentially corrupt color map"); + } + + const unsigned char* src = (unsigned char*)frame.RasterBits; + Color8888* dst = outputPtr + frame.ImageDesc.Left + + frame.ImageDesc.Top * outputPixelStride; + GifWord copyWidth, copyHeight; + getCopySize(frame.ImageDesc, width, height, copyWidth, copyHeight); + for (; copyHeight > 0; copyHeight--) { + copyLine(dst, src, cmap, gcb.TransparentColor, copyWidth); + src += frame.ImageDesc.Width; + dst += outputPixelStride; + } + } + } + + return getDelayMs(gcb); +} + +//////////////////////////////////////////////////////////////////////////////// +// Registry +//////////////////////////////////////////////////////////////////////////////// + +#include "Registry.h" + +static bool isGif(void* header, int header_size) { + return !memcmp(GIF_STAMP, header, GIF_STAMP_LEN) + || !memcmp(GIF87_STAMP, header, GIF_STAMP_LEN) + || !memcmp(GIF89_STAMP, header, GIF_STAMP_LEN); +} + +static FrameSequence* createFramesequence(Stream* stream) { + return new FrameSequence_gif(stream); +} + +static RegistryEntry gEntry = { + GIF_STAMP_LEN, + isGif, + createFramesequence, + NULL, +}; +static Registry gRegister(gEntry); + |