tif_getimage.c

一个国人自己实现图像库的程序（有参考价值）

            {
                ret = 0;
                break;
            }

            pos = ((row+img->row_offset) % th) * TIFFTileRowSize(tif);

    	    if (col + tw > w) 
            {
                /*
                 * Tile is clipped horizontally.  Calculate
                 * visible portion and skewing factors.
                 */
                uint32 npix = w - col;
                fromskew = tw - npix;
                (*put)(img, raster+y*w+col, col, y,
                       npix, nrow, fromskew, toskew + fromskew, buf + pos);
            }
            else 
            {
                (*put)(img, raster+y*w+col, col, y, tw, nrow, 0, toskew, buf + pos);
            }
        }

        y += (orientation == ORIENTATION_TOPLEFT ? -(int32) nrow : (int32) nrow);
    }
    _TIFFfree(buf);
    return (ret);
}

/*
 * Get an tile-organized image that has
 *	 SamplesPerPixel > 1
 *	 PlanarConfiguration separated
 * We assume that all such images are RGB.
 */	
static int
gtTileSeparate(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
{
    TIFF* tif = img->tif;
    tileSeparateRoutine put = img->put.separate;
    uint16 orientation;
    uint32 col, row, y, rowstoread;
    uint32 pos;
    uint32 tw, th;
    u_char* buf;
    u_char* r;
    u_char* g;
    u_char* b;
    u_char* a;
    tsize_t tilesize;
    int32 fromskew, toskew;
    int alpha = img->alpha;
    uint32 nrow;
    int ret = 1;

    tilesize = TIFFTileSize(tif);
    buf = (u_char*) _TIFFmalloc(4*tilesize);
    if (buf == 0) {
	TIFFError(TIFFFileName(tif), "No space for tile buffer");
	return (0);
    }
    r = buf;
    g = r + tilesize;
    b = g + tilesize;
    a = b + tilesize;
    if (!alpha)
	memset(a, 0xff, tilesize);
    TIFFGetField(tif, TIFFTAG_TILEWIDTH, &tw);
    TIFFGetField(tif, TIFFTAG_TILELENGTH, &th);
    y = setorientation(img, h);
    orientation = img->orientation;
    toskew = -(int32) (orientation == ORIENTATION_TOPLEFT ? tw+w : tw-w);
    for (row = 0; row < h; row += nrow) 
    {
        rowstoread = th - (row + img->row_offset) % th;
    	nrow = (row + rowstoread > h ? h - row : rowstoread);
        for (col = 0; col < w; col += tw) 
        {
            if (TIFFReadTile(tif, r, col+img->col_offset,
                             row+img->row_offset,0,0) < 0 && img->stoponerr)
            {
                ret = 0;
                break;
            }
            if (TIFFReadTile(tif, g, col+img->col_offset,
                             row+img->row_offset,0,1) < 0 && img->stoponerr)
            {
                ret = 0;
                break;
            }
            if (TIFFReadTile(tif, b, col+img->col_offset,
                             row+img->row_offset,0,2) < 0 && img->stoponerr)
            {
                ret = 0;
                break;
            }
            if (alpha && TIFFReadTile(tif,a,col+img->col_offset,
                                      row+img->row_offset,0,3) < 0 && img->stoponerr)
            {
                ret = 0;
                break;
            }

            pos = ((row+img->row_offset) % th) * TIFFTileRowSize(tif);

            if (col + tw > w) 
            {
                /*
                 * Tile is clipped horizontally.  Calculate
                 * visible portion and skewing factors.
                 */
                uint32 npix = w - col;
                fromskew = tw - npix;
                (*put)(img, raster+y*w+col, col, y,
                       npix, nrow, fromskew, toskew + fromskew, 
                       r + pos, g + pos, b + pos, a + pos);
            } 
            else 
            {
                (*put)(img, raster+y*w+col, col, y,
                       tw, nrow, 0, toskew, r + pos, g + pos, b + pos, a + pos);
            }
        }

        y += (orientation == ORIENTATION_TOPLEFT ?-(int32) nrow : (int32) nrow);
    }
    _TIFFfree(buf);
    return (ret);
}

/*
 * Get a strip-organized image that has
 *	PlanarConfiguration contiguous if SamplesPerPixel > 1
 * or
 *	SamplesPerPixel == 1
 */	
static int
gtStripContig(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
{
    TIFF* tif = img->tif;
    tileContigRoutine put = img->put.contig;
    uint16 orientation;
    uint32 row, y, nrow, rowstoread;
    uint32 pos;
    u_char* buf;
    uint32 rowsperstrip;
    uint32 imagewidth = img->width;
    tsize_t scanline;
    int32 fromskew, toskew;
    int ret = 1;

    buf = (u_char*) _TIFFmalloc(TIFFStripSize(tif));
    if (buf == 0) {
	TIFFError(TIFFFileName(tif), "No space for strip buffer");
	return (0);
    }
    y = setorientation(img, h);
    orientation = img->orientation;
    toskew = -(int32) (orientation == ORIENTATION_TOPLEFT ? w+w : w-w);
    TIFFGetFieldDefaulted(tif, TIFFTAG_ROWSPERSTRIP, &rowsperstrip);
    scanline = TIFFScanlineSize(tif);
    fromskew = (w < imagewidth ? imagewidth - w : 0);
    for (row = 0; row < h; row += nrow) 
    {
        rowstoread = rowsperstrip - (row + img->row_offset) % rowsperstrip;
        nrow = (row + rowstoread > h ? h - row : rowstoread);
        if (TIFFReadEncodedStrip(tif,
                                 TIFFComputeStrip(tif,row+img->row_offset, 0),
                                 buf, 
                                 ((row + img->row_offset)%rowsperstrip + nrow) * scanline) < 0
            && img->stoponerr)
        {
            ret = 0;
            break;
        }

        pos = ((row + img->row_offset) % rowsperstrip) * scanline;
        (*put)(img, raster+y*w, 0, y, w, nrow, fromskew, toskew, buf + pos);
        y += (orientation == ORIENTATION_TOPLEFT ?-(int32) nrow : (int32) nrow);
    }
    _TIFFfree(buf);
    return (ret);
}

/*
 * Get a strip-organized image with
 *	 SamplesPerPixel > 1
 *	 PlanarConfiguration separated
 * We assume that all such images are RGB.
 */
static int
gtStripSeparate(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
{
    TIFF* tif = img->tif;
    tileSeparateRoutine put = img->put.separate;
    uint16 orientation;
    u_char *buf;
    u_char *r, *g, *b, *a;
    uint32 row, y, nrow, rowstoread;
    uint32 pos;
    tsize_t scanline;
    uint32 rowsperstrip, offset_row;
    uint32 imagewidth = img->width;
    tsize_t stripsize;
    int32 fromskew, toskew;
    int alpha = img->alpha;
    int	ret = 1;

    stripsize = TIFFStripSize(tif);
    r = buf = (u_char *)_TIFFmalloc(4*stripsize);
    if (buf == 0) {
	TIFFError(TIFFFileName(tif), "No space for tile buffer");
	return (0);
    }
    g = r + stripsize;
    b = g + stripsize;
    a = b + stripsize;
    if (!alpha)
	memset(a, 0xff, stripsize);
    y = setorientation(img, h);
    orientation = img->orientation;
    toskew = -(int32) (orientation == ORIENTATION_TOPLEFT ? w+w : w-w);
    TIFFGetFieldDefaulted(tif, TIFFTAG_ROWSPERSTRIP, &rowsperstrip);
    scanline = TIFFScanlineSize(tif);
    fromskew = (w < imagewidth ? imagewidth - w : 0);
    for (row = 0; row < h; row += nrow) 
    {
        rowstoread = rowsperstrip - (row + img->row_offset) % rowsperstrip;    	
        nrow = (row + rowstoread > h ? h - row : rowstoread);
        offset_row = row + img->row_offset;
    	if (TIFFReadEncodedStrip(tif, TIFFComputeStrip(tif, offset_row, 0),
                                 r, ((row + img->row_offset)%rowsperstrip + nrow) * scanline) < 0 
            && img->stoponerr)
        {
            ret = 0;
            break;
        }
        if (TIFFReadEncodedStrip(tif, TIFFComputeStrip(tif, offset_row, 1),
                                 g, ((row + img->row_offset)%rowsperstrip + nrow) * scanline) < 0 
            && img->stoponerr)
        {
            ret = 0;
            break;
        }
        if (TIFFReadEncodedStrip(tif, TIFFComputeStrip(tif, offset_row, 2),
                                 b, ((row + img->row_offset)%rowsperstrip + nrow) * scanline) < 0 
            && img->stoponerr)
        {
            ret = 0;
            break;
        }
        if (alpha &&
            (TIFFReadEncodedStrip(tif, TIFFComputeStrip(tif, offset_row, 3),
                                  a, ((row + img->row_offset)%rowsperstrip + nrow) * scanline) < 0 
             && img->stoponerr))
        {
            ret = 0;
            break;
        }

        pos = ((row + img->row_offset) % rowsperstrip) * scanline;
        (*put)(img, raster+y*w, 0, y, w, nrow, fromskew, toskew, r + pos, g + pos, 
               b + pos, a + pos);
        y += (orientation == ORIENTATION_TOPLEFT ? -(int32) nrow : (int32) nrow);
    }
    _TIFFfree(buf);
    return (ret);
}

/*
 * The following routines move decoded data returned
 * from the TIFF library into rasters filled with packed
 * ABGR pixels (i.e. suitable for passing to lrecwrite.)
 *
 * The routines have been created according to the most
 * important cases and optimized.  pickTileContigCase and
 * pickTileSeparateCase analyze the parameters and select
 * the appropriate "put" routine to use.
 */
#define	REPEAT8(op)	REPEAT4(op); REPEAT4(op)
#define	REPEAT4(op)	REPEAT2(op); REPEAT2(op)
#define	REPEAT2(op)	op; op
#define	CASE8(x,op)			\
    switch (x) {			\
    case 7: op; case 6: op; case 5: op;	\
    case 4: op; case 3: op; case 2: op;	\
    case 1: op;				\
    }
#define	CASE4(x,op)	switch (x) { case 3: op; case 2: op; case 1: op; }
#define	NOP

#define	UNROLL8(w, op1, op2) {		\
    uint32 _x;				\
    for (_x = w; _x >= 8; _x -= 8) {	\
	op1;				\
	REPEAT8(op2);			\
    }					\
    if (_x > 0) {			\
	op1;				\
	CASE8(_x,op2);			\
    }					\
}
#define	UNROLL4(w, op1, op2) {		\
    uint32 _x;				\
    for (_x = w; _x >= 4; _x -= 4) {	\
	op1;				\
	REPEAT4(op2);			\
    }					\
    if (_x > 0) {			\
	op1;				\
	CASE4(_x,op2);			\
    }					\
}
#define	UNROLL2(w, op1, op2) {		\
    uint32 _x;				\
    for (_x = w; _x >= 2; _x -= 2) {	\
	op1;				\
	REPEAT2(op2);			\
    }					\
    if (_x) {				\
	op1;				\
	op2;				\
    }					\
}
    
#define	SKEW(r,g,b,skew)	{ r += skew; g += skew; b += skew; }
#define	SKEW4(r,g,b,a,skew)	{ r += skew; g += skew; b += skew; a+= skew; }

#define A1 ((uint32)(0xffL<<24))
#define	PACK(r,g,b)	\
	((uint32)(r)|((uint32)(g)<<8)|((uint32)(b)<<16)|A1)
#define	PACK4(r,g,b,a)	\
	((uint32)(r)|((uint32)(g)<<8)|((uint32)(b)<<16)|((uint32)(a)<<24))
#define W2B(v) (((v)>>8)&0xff)
#define	PACKW(r,g,b)	\
	((uint32)W2B(r)|((uint32)W2B(g)<<8)|((uint32)W2B(b)<<16)|A1)
#define	PACKW4(r,g,b,a)	\
	((uint32)W2B(r)|((uint32)W2B(g)<<8)|((uint32)W2B(b)<<16)|((uint32)W2B(a)<<24))

#define	DECLAREContigPutFunc(name) \
static void name(\
    TIFFRGBAImage* img, \
    uint32* cp, \
    uint32 x, uint32 y, \
    uint32 w, uint32 h, \
    int32 fromskew, int32 toskew, \
    u_char* pp \
)

/*
 * 8-bit palette => colormap/RGB
 */
DECLAREContigPutFunc(put8bitcmaptile)
{
    uint32** PALmap = img->PALmap;
    int samplesperpixel = img->samplesperpixel;

    (void) y;
    while (h-- > 0) {
	for (x = w; x-- > 0;)
        {
	    *cp++ = PALmap[*pp][0];
            pp += samplesperpixel;
        }
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 4-bit palette => colormap/RGB
 */
DECLAREContigPutFunc(put4bitcmaptile)
{
    uint32** PALmap = img->PALmap;

    (void) x; (void) y;
    fromskew /= 2;
    while (h-- > 0) {
	uint32* bw;
	UNROLL2(w, bw = PALmap[*pp++], *cp++ = *bw++);
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 2-bit palette => colormap/RGB
 */
DECLAREContigPutFunc(put2bitcmaptile)
{
    uint32** PALmap = img->PALmap;

    (void) x; (void) y;
    fromskew /= 4;
    while (h-- > 0) {
	uint32* bw;
	UNROLL4(w, bw = PALmap[*pp++], *cp++ = *bw++);
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 1-bit palette => colormap/RGB
 */
DECLAREContigPutFunc(put1bitcmaptile)
{
    uint32** PALmap = img->PALmap;

    (void) x; (void) y;
    fromskew /= 8;
    while (h-- > 0) {
	uint32* bw;
	UNROLL8(w, bw = PALmap[*pp++], *cp++ = *bw++);
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 8-bit greyscale => colormap/RGB
 */
DECLAREContigPutFunc(putgreytile)
{
    int samplesperpixel = img->samplesperpixel;
    uint32** BWmap = img->BWmap;

    (void) y;
    while (h-- > 0) {
	for (x = w; x-- > 0;)
        {
	    *cp++ = BWmap[*pp][0];
            pp += samplesperpixel;
        }
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 16-bit greyscale => colormap/RGB
 */
DECLAREContigPutFunc(put16bitbwtile)
{
    int samplesperpixel = img->samplesperpixel;
    uint32** BWmap = img->BWmap;

    (void) y;
    while (h-- > 0) {
        uint16 *wp = (uint16 *) pp;

	for (x = w; x-- > 0;)
        {
            /* use high order byte of 16bit value */

	    *cp++ = BWmap[*wp >> 8][0];
            pp += 2 * samplesperpixel;
            wp += samplesperpixel;
        }
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 1-bit bilevel => colormap/RGB
 */
DECLAREContigPutFunc(put1bitbwtile)
{
    uint32** BWmap = img->BWmap;

    (void) x; (void) y;
    fromskew /= 8;
    while (h-- > 0) {
	uint32* bw;
	UNROLL8(w, bw = BWmap[*pp++], *cp++ = *bw++);
	cp += toskew;
	pp += fromskew;
    }
}

/*
 * 2-bit greyscale => colormap/RGB