#include <stdafx.h>

#include "gif89a.h"
#include "gif.h"

LPCGLOBAL_INFO gi;
LPFRAME fm;
BYTE *prevBits;

//將顏色表轉換成調色板
int get_palette(RGBQUAD *lpPalette,BYTE *lpColorTable,int size)
{
	DWORD *p=(DWORD*)lpPalette;	BYTE *q=lpColorTable;
	while (size--)	{*p++=RGB(*(q+2),*(q+1),*q);q+=3;}
	return sizeof(RGBQUAD)*256;
}
//對當前幀進行交錯處理
void interlace()
{
	if (!fm->interlaceFlag) return;

	int w=fm->imageWidth,h=fm->imageHeight,i;
	BYTE *dest,*p,*q;	dest=new BYTE[w*h];

	q=fm->dataBuf;
	for (i=0;i<h;i+=8)	{p=dest+i*w; memcpy(p,q,w);	q+=w;}
	for (i=4;i<h;i+=8)	{p=dest+i*w; memcpy(p,q,w);	q+=w;}
	for (i=2;i<h;i+=4)	{p=dest+i*w; memcpy(p,q,w);	q+=w;}
	for (i=1;i<h;i+=2)	{p=dest+i*w; memcpy(p,q,w);	q+=w;}

	delete []fm->dataBuf;
	fm->dataBuf=dest;
	fm->interlaceFlag=FALSE;
}
//顏色復制函數；不復制前景色
void copycolor(BYTE *p1,BYTE *p2,int len)
{
	while (len--){if(*p2!=fm->ctrlExt.trsColorIndex) *p1=*p2;  p1++;p2++;}
}
//取得當前幀的圖像位數據
int get_bits(BYTE *lpBits)
{
	BYTE *p,*q;
	int bpl=(gi->scrWidth*8+31)/32*4;	//bytes per line
	int i,w=fm->imageWidth,h=fm->imageHeight;
	
	if ((w<gi->scrWidth||h<gi->scrHeight)&&prevBits)
		memcpy(lpBits,prevBits,bpl*gi->scrHeight);

	p=lpBits+(gi->scrHeight-1-fm->imageTPos)*bpl+fm->imageLPos;
	q=(BYTE*)(fm->dataBuf);
	if (!fm->ctrlExt.trsFlag||!prevBits)	//沒有透明色或者是第一幀
		for (i=0;i<h;i++)	{memcpy(p,q,w);	p-=bpl;q+=w;}
	else
		for (i=0;i<h;i++)	{copycolor(p,q,w);	p-=bpl;q+=w;}

	return bpl*gi->scrHeight;
}

HANDLE LoadGif(LPCTSTR fn)
{
	CGif89a gif(fn,FALSE);	if (!gif) return 0;

	int i,len,w,h,bpl,frames;
	HANDLE hResDyn;
	BYTE *lpResDyn,*lpBits;
	RESDYNDATAHEADER *lpHead;
	DISPLAYFRAMEINFO *lpDisp;
	STOREFRAMEINFO *lpStore;

	gi=gif.getGlobalInfo();
	frames=gi->frames;
	w=gi->scrWidth;	h=gi->scrHeight;
	bpl=(w*8+31)/32*4;
	len=sizeof(RESDYNDATAHEADER)
			+sizeof(DISPLAYFRAMEINFO)*frames
			+sizeof(STOREFRAMEINFO)*frames
			+sizeof(RGBQUAD)*256;
	len+=(sizeof(RGBQUAD)*256+bpl*h)*frames;

	hResDyn=GlobalAlloc(GHND,len);
	if (!hResDyn) return 0;
	lpResDyn=(BYTE*)GlobalLock(hResDyn);

	lpHead=(RESDYNDATAHEADER*)lpResDyn;
	lpHead->ContentSize=len;
	lpHead->Width=w;
	lpHead->Height=h;
	lpHead->BitCount=8;
	lpHead->DisplayFrameQuantity=frames;
	lpHead->StroeFrameQuantity=frames;

	lpDisp=(DISPLAYFRAMEINFO*)(lpResDyn+sizeof(RESDYNDATAHEADER));
	lpStore=(STOREFRAMEINFO*)((BYTE*)lpDisp+sizeof(DISPLAYFRAMEINFO)*frames);
	lpBits=(BYTE*)lpStore+sizeof(STOREFRAMEINFO)*frames;
	len=0;
	if (gi->gFlag) 
		len=get_palette((RGBQUAD*)lpBits,gi->gColorTable,gi->gSize);
	lpBits+=len;	prevBits=NULL;
	for(i=0;i<frames;i++)
	{
		fm=(LPFRAME)gif.getNextFrame();
		if (!fm) goto error;
		lpDisp->StoreFrame=i+1;
		lpDisp->DelayTime=fm->ctrlExt.delayTime*10;
		lpStore->Width=w;
		lpStore->Height=h;
		lpStore->BitCount=8;
		lpStore->LocalPalette=fm->lFlag;
		lpStore->XorFlag=0;
		lpStore->Reserved=0;
		lpStore->DataOfset=lpBits-lpResDyn;
		len=0;
		if (fm->lFlag)
			len=get_palette((RGBQUAD*)lpBits,fm->pColorTable,fm->lSize);
		lpBits+=len;
		if (fm->interlaceFlag) interlace();
		len=get_bits(lpBits);
		prevBits=lpBits;	//記下前一幀
		lpBits+=len;
		lpDisp++;lpStore++;
	}
	len=lpBits-lpResDyn;
	if (lpHead->ContentSize>len) lpHead->ContentSize=len;

	gif.close();
	GlobalUnlock(hResDyn);
	hResDyn=GlobalReAlloc(hResDyn,len,GMEM_MOVEABLE);
	return hResDyn;
error:
	gif.close();
	GlobalUnlock(hResDyn);
	GlobalFree(hResDyn);
	return 0;
}
int SaveGif(LPCTSTR fn,HANDLE hResDyn)
{
	return 0;
}