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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkMovie.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkStream.h"
#include "SkTemplates.h"
#include "SkUtils.h"
#include "gif_lib.h"
class SkGIFMovie : public SkMovie {
public:
SkGIFMovie(SkStream* stream);
virtual ~SkGIFMovie();
protected:
virtual bool onGetInfo(Info*);
virtual bool onSetTime(SkMSec);
virtual bool onGetBitmap(SkBitmap*);
private:
GifFileType* fGIF;
int fCurrIndex;
int fLastDrawIndex;
SkBitmap fBackup;
};
static int Decode(GifFileType* fileType, GifByteType* out, int size) {
SkStream* stream = (SkStream*) fileType->UserData;
return (int) stream->read(out, size);
}
SkGIFMovie::SkGIFMovie(SkStream* stream)
{
fGIF = DGifOpen( stream, Decode );
if (NULL == fGIF)
return;
if (DGifSlurp(fGIF) != GIF_OK)
{
DGifCloseFile(fGIF);
fGIF = NULL;
}
fCurrIndex = -1;
fLastDrawIndex = -1;
}
SkGIFMovie::~SkGIFMovie()
{
if (fGIF)
DGifCloseFile(fGIF);
}
static SkMSec savedimage_duration(const SavedImage* image)
{
for (int j = 0; j < image->ExtensionBlockCount; j++)
{
if (image->ExtensionBlocks[j].Function == GRAPHICS_EXT_FUNC_CODE)
{
int size = image->ExtensionBlocks[j].ByteCount;
SkASSERT(size >= 4);
const uint8_t* b = (const uint8_t*)image->ExtensionBlocks[j].Bytes;
return ((b[2] << 8) | b[1]) * 10;
}
}
return 0;
}
bool SkGIFMovie::onGetInfo(Info* info)
{
if (NULL == fGIF)
return false;
SkMSec dur = 0;
for (int i = 0; i < fGIF->ImageCount; i++)
dur += savedimage_duration(&fGIF->SavedImages[i]);
info->fDuration = dur;
info->fWidth = fGIF->SWidth;
info->fHeight = fGIF->SHeight;
info->fIsOpaque = false; // how to compute?
return true;
}
bool SkGIFMovie::onSetTime(SkMSec time)
{
if (NULL == fGIF)
return false;
SkMSec dur = 0;
for (int i = 0; i < fGIF->ImageCount; i++)
{
dur += savedimage_duration(&fGIF->SavedImages[i]);
if (dur >= time)
{
fCurrIndex = i;
return fLastDrawIndex != fCurrIndex;
}
}
fCurrIndex = fGIF->ImageCount - 1;
return true;
}
static void copyLine(uint32_t* dst, const unsigned char* src, const ColorMapObject* cmap,
int transparent, int width)
{
for (; width > 0; width--, src++, dst++) {
if (*src != transparent) {
const GifColorType& col = cmap->Colors[*src];
*dst = SkPackARGB32(0xFF, col.Red, col.Green, col.Blue);
}
}
}
static void copyInterlaceGroup(SkBitmap* bm, const unsigned char*& src,
const ColorMapObject* cmap, int transparent, int copyWidth,
int copyHeight, const GifImageDesc& imageDesc, int rowStep,
int startRow)
{
int row;
// every 'rowStep'th row, starting with row 'startRow'
for (row = startRow; row < copyHeight; row += rowStep) {
uint32_t* dst = bm->getAddr32(imageDesc.Left, imageDesc.Top + row);
copyLine(dst, src, cmap, transparent, copyWidth);
src += imageDesc.Width;
}
// pad for rest height
src += imageDesc.Width * ((imageDesc.Height - row + rowStep - 1) / rowStep);
}
static void blitInterlace(SkBitmap* bm, const SavedImage* frame, const ColorMapObject* cmap,
int transparent)
{
int width = bm->width();
int height = bm->height();
GifWord copyWidth = frame->ImageDesc.Width;
if (frame->ImageDesc.Left + copyWidth > width) {
copyWidth = width - frame->ImageDesc.Left;
}
GifWord copyHeight = frame->ImageDesc.Height;
if (frame->ImageDesc.Top + copyHeight > height) {
copyHeight = height - frame->ImageDesc.Top;
}
// deinterlace
const unsigned char* src = (unsigned char*)frame->RasterBits;
// group 1 - every 8th row, starting with row 0
copyInterlaceGroup(bm, src, cmap, transparent, copyWidth, copyHeight, frame->ImageDesc, 8, 0);
// group 2 - every 8th row, starting with row 4
copyInterlaceGroup(bm, src, cmap, transparent, copyWidth, copyHeight, frame->ImageDesc, 8, 4);
// group 3 - every 4th row, starting with row 2
copyInterlaceGroup(bm, src, cmap, transparent, copyWidth, copyHeight, frame->ImageDesc, 4, 2);
copyInterlaceGroup(bm, src, cmap, transparent, copyWidth, copyHeight, frame->ImageDesc, 2, 1);
}
static void blitNormal(SkBitmap* bm, const SavedImage* frame, const ColorMapObject* cmap,
int transparent)
{
int width = bm->width();
int height = bm->height();
const unsigned char* src = (unsigned char*)frame->RasterBits;
uint32_t* dst = bm->getAddr32(frame->ImageDesc.Left, frame->ImageDesc.Top);
GifWord copyWidth = frame->ImageDesc.Width;
if (frame->ImageDesc.Left + copyWidth > width) {
copyWidth = width - frame->ImageDesc.Left;
}
GifWord copyHeight = frame->ImageDesc.Height;
if (frame->ImageDesc.Top + copyHeight > height) {
copyHeight = height - frame->ImageDesc.Top;
}
int srcPad, dstPad;
dstPad = width - copyWidth;
srcPad = frame->ImageDesc.Width - copyWidth;
for (; copyHeight > 0; copyHeight--) {
copyLine(dst, src, cmap, transparent, copyWidth);
src += frame->ImageDesc.Width;
dst += width;
}
}
static void fillRect(SkBitmap* bm, GifWord left, GifWord top, GifWord width, GifWord height,
uint32_t col)
{
int bmWidth = bm->width();
int bmHeight = bm->height();
uint32_t* dst = bm->getAddr32(left, top);
GifWord copyWidth = width;
if (left + copyWidth > bmWidth) {
copyWidth = bmWidth - left;
}
GifWord copyHeight = height;
if (top + copyHeight > bmHeight) {
copyHeight = bmHeight - top;
}
for (; copyHeight > 0; copyHeight--) {
sk_memset32(dst, col, copyWidth);
dst += bmWidth;
}
}
static void drawFrame(SkBitmap* bm, const SavedImage* frame, const ColorMapObject* cmap)
{
int transparent = -1;
for (int i = 0; i < frame->ExtensionBlockCount; ++i) {
ExtensionBlock* eb = frame->ExtensionBlocks + i;
if (eb->Function == GRAPHICS_EXT_FUNC_CODE &&
eb->ByteCount == 4) {
bool has_transparency = ((eb->Bytes[0] & 1) == 1);
if (has_transparency) {
transparent = (unsigned char)eb->Bytes[3];
}
}
}
if (frame->ImageDesc.ColorMap != NULL) {
// use local color table
cmap = frame->ImageDesc.ColorMap;
}
if (cmap == NULL || cmap->ColorCount != (1 << cmap->BitsPerPixel)) {
SkDEBUGFAIL("bad colortable setup");
return;
}
if (frame->ImageDesc.Interlace) {
blitInterlace(bm, frame, cmap, transparent);
} else {
blitNormal(bm, frame, cmap, transparent);
}
}
static bool checkIfWillBeCleared(const SavedImage* frame)
{
for (int i = 0; i < frame->ExtensionBlockCount; ++i) {
ExtensionBlock* eb = frame->ExtensionBlocks + i;
if (eb->Function == GRAPHICS_EXT_FUNC_CODE &&
eb->ByteCount == 4) {
// check disposal method
int disposal = ((eb->Bytes[0] >> 2) & 7);
if (disposal == 2 || disposal == 3) {
return true;
}
}
}
return false;
}
static void getTransparencyAndDisposalMethod(const SavedImage* frame, bool* trans, int* disposal)
{
*trans = false;
*disposal = 0;
for (int i = 0; i < frame->ExtensionBlockCount; ++i) {
ExtensionBlock* eb = frame->ExtensionBlocks + i;
if (eb->Function == GRAPHICS_EXT_FUNC_CODE &&
eb->ByteCount == 4) {
*trans = ((eb->Bytes[0] & 1) == 1);
*disposal = ((eb->Bytes[0] >> 2) & 7);
}
}
}
// return true if area of 'target' is completely covers area of 'covered'
static bool checkIfCover(const SavedImage* target, const SavedImage* covered)
{
if (target->ImageDesc.Left <= covered->ImageDesc.Left
&& covered->ImageDesc.Left + covered->ImageDesc.Width <=
target->ImageDesc.Left + target->ImageDesc.Width
&& target->ImageDesc.Top <= covered->ImageDesc.Top
&& covered->ImageDesc.Top + covered->ImageDesc.Height <=
target->ImageDesc.Top + target->ImageDesc.Height) {
return true;
}
return false;
}
static void disposeFrameIfNeeded(SkBitmap* bm, const SavedImage* cur, const SavedImage* next,
SkBitmap* backup, SkColor color)
{
// We can skip disposal process if next frame is not transparent
// and completely covers current area
bool curTrans;
int curDisposal;
getTransparencyAndDisposalMethod(cur, &curTrans, &curDisposal);
bool nextTrans;
int nextDisposal;
getTransparencyAndDisposalMethod(next, &nextTrans, &nextDisposal);
if ((curDisposal == 2 || curDisposal == 3)
&& (nextTrans || !checkIfCover(next, cur))) {
switch (curDisposal) {
// restore to background color
// -> 'background' means background under this image.
case 2:
fillRect(bm, cur->ImageDesc.Left, cur->ImageDesc.Top,
cur->ImageDesc.Width, cur->ImageDesc.Height,
color);
break;
// restore to previous
case 3:
bm->swap(*backup);
break;
}
}
// Save current image if next frame's disposal method == 3
if (nextDisposal == 3) {
const uint32_t* src = bm->getAddr32(0, 0);
uint32_t* dst = backup->getAddr32(0, 0);
int cnt = bm->width() * bm->height();
memcpy(dst, src, cnt*sizeof(uint32_t));
}
}
bool SkGIFMovie::onGetBitmap(SkBitmap* bm)
{
const GifFileType* gif = fGIF;
if (NULL == gif)
return false;
if (gif->ImageCount < 1) {
return false;
}
const int width = gif->SWidth;
const int height = gif->SHeight;
if (width <= 0 || height <= 0) {
return false;
}
// no need to draw
if (fLastDrawIndex >= 0 && fLastDrawIndex == fCurrIndex) {
return true;
}
int startIndex = fLastDrawIndex + 1;
if (fLastDrawIndex < 0 || !bm->readyToDraw()) {
// first time
startIndex = 0;
// create bitmap
bm->setConfig(SkBitmap::kARGB_8888_Config, width, height, 0);
if (!bm->allocPixels(NULL)) {
return false;
}
// create bitmap for backup
fBackup.setConfig(SkBitmap::kARGB_8888_Config, width, height, 0);
if (!fBackup.allocPixels(NULL)) {
return false;
}
} else if (startIndex > fCurrIndex) {
// rewind to 1st frame for repeat
startIndex = 0;
}
int lastIndex = fCurrIndex;
if (lastIndex < 0) {
// first time
lastIndex = 0;
} else if (lastIndex > fGIF->ImageCount - 1) {
// this block must not be reached.
lastIndex = fGIF->ImageCount - 1;
}
SkColor bgColor = SkPackARGB32(0, 0, 0, 0);
if (gif->SColorMap != NULL) {
const GifColorType& col = gif->SColorMap->Colors[fGIF->SBackGroundColor];
bgColor = SkColorSetARGB(0xFF, col.Red, col.Green, col.Blue);
}
static SkColor paintingColor = SkPackARGB32(0, 0, 0, 0);
// draw each frames - not intelligent way
for (int i = startIndex; i <= lastIndex; i++) {
const SavedImage* cur = &fGIF->SavedImages[i];
if (i == 0) {
bool trans;
int disposal;
getTransparencyAndDisposalMethod(cur, &trans, &disposal);
if (!trans && gif->SColorMap != NULL) {
paintingColor = bgColor;
} else {
paintingColor = SkColorSetARGB(0, 0, 0, 0);
}
bm->eraseColor(paintingColor);
fBackup.eraseColor(paintingColor);
} else {
// Dispose previous frame before move to next frame.
const SavedImage* prev = &fGIF->SavedImages[i-1];
disposeFrameIfNeeded(bm, prev, cur, &fBackup, paintingColor);
}
// Draw frame
// We can skip this process if this index is not last and disposal
// method == 2 or method == 3
if (i == lastIndex || !checkIfWillBeCleared(cur)) {
drawFrame(bm, cur, gif->SColorMap);
}
}
// save index
fLastDrawIndex = lastIndex;
return true;
}
///////////////////////////////////////////////////////////////////////////////
#include "SkTRegistry.h"
SkMovie* Factory(SkStream* stream) {
char buf[GIF_STAMP_LEN];
if (stream->read(buf, GIF_STAMP_LEN) == GIF_STAMP_LEN) {
if (memcmp(GIF_STAMP, buf, GIF_STAMP_LEN) == 0 ||
memcmp(GIF87_STAMP, buf, GIF_STAMP_LEN) == 0 ||
memcmp(GIF89_STAMP, buf, GIF_STAMP_LEN) == 0) {
// must rewind here, since our construct wants to re-read the data
stream->rewind();
return SkNEW_ARGS(SkGIFMovie, (stream));
}
}
return NULL;
}
static SkTRegistry<SkMovie*, SkStream*> gReg(Factory);