leptonica write to memory with PNG format
Nereden Yazdırıldığı: Datakent
Kategori: Diğer bölümler
Forum Adı: C, C++, Visual C++
Forum Tanımlaması: C, C++, Visual C++ Örnekleri
URL: http://forum.datakent.com/forum_posts.asp?TID=2466
Tarih: 19.Nisan.2024 Saat 06:34
Konu: leptonica write to memory with PNG format
Mesajı Yazan: aziz.alkurt
Konu: leptonica write to memory with PNG format
Mesaj Tarihi: 09.Aralik.2012 Saat 12:51
insert to leptonica -> pngio.c
//-------------------------------------------------------------------------------
struct mem_encode
{
char *buffer;
size_t size;
};
void
my_png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
/* with libpng15 next line causes pointer deference error; use libpng12 */
struct mem_encode* p=(struct mem_encode*)png_ptr->io_ptr;
size_t nsize = p->size + length;
/* allocate or grow buffer */
if(p->buffer)
p->buffer = (char *)realloc(p->buffer, nsize);
else
p->buffer = (char *)malloc(nsize);
if(!p->buffer)
png_error(png_ptr, "Write Error");
/* copy new bytes to end of buffer */
memcpy(p->buffer + p->size, data, length);
p->size += length;
}
void
my_png_flush(png_structp png_ptr)
{
}
//------------------------------------------------------------------------------------------
change "pixWriteMemPng" function in leptonica -> pngio.c
//------------------------------------------------------------------------------------------
l_int32
pixWriteMemPng(l_uint8 **pdata,
size_t *psize,
PIX *pix,
l_float32 gamma)
{
struct mem_encode state;
char commentstring[] = "Comment";
l_int32 i, j, k;
l_int32 wpl, d, cmflag;
l_int32 ncolors;
l_int32 *rmap, *gmap, *bmap;
l_uint32 *data, *ppixel;
png_byte bit_depth, color_type;
png_uint_32 w, h;
png_uint_32 xres, yres;
png_bytep *row_pointers;
png_bytep rowbuffer;
png_structp png_ptr;
png_infop info_ptr;
png_colorp palette;
PIX *pixt;
PIXCMAP *cmap;
char *text;
PROCNAME("pixWriteMemPng");
if (!pix)
return ERROR_INT("pix not defined", procName, 1);
/* Allocate the 2 data structures */
if ((png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
(png_voidp)NULL, NULL, NULL)) == NULL)
return ERROR_INT("png_ptr not made", procName, 1);
if ((info_ptr = png_create_info_struct(png_ptr)) == NULL) {
png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
return ERROR_INT("info_ptr not made", procName, 1);
}
/* Set up png setjmp error handling */
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return ERROR_INT("internal png error", procName, 1);
}
state.buffer = NULL;
state.size = 0;
png_set_write_fn(png_ptr, &state, my_png_write_data, my_png_flush);
/* With best zlib compression (9), get between 1 and 10% improvement
* over default (5), but the compression is 3 to 10 times slower.
* Our default compression is the zlib default (5). */
png_set_compression_level(png_ptr, var_ZLIB_COMPRESSION);
w = pixGetWidth(pix);
h = pixGetHeight(pix);
d = pixGetDepth(pix);
if ((cmap = pixGetColormap(pix)))
cmflag = 1;
else
cmflag = 0;
/* Set the color type and bit depth. */
if (d == 32 && var_PNG_WRITE_ALPHA == 1) {
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGBA; /* 6 */
cmflag = 0; /* ignore if it exists */
}
else if (d == 24 || d == 32) {
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB; /* 2 */
cmflag = 0; /* ignore if it exists */
}
else {
bit_depth = d;
color_type = PNG_COLOR_TYPE_GRAY; /* 0 */
}
if (cmflag)
color_type = PNG_COLOR_TYPE_PALETTE; /* 3 */
#if DEBUG
fprintf(stderr, "cmflag = %d, bit_depth = %d, color_type = %d\n",
cmflag, bit_depth, color_type);
#endif /* DEBUG */
png_set_IHDR(png_ptr, info_ptr, w, h, bit_depth, color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
PNG_FILTER_TYPE_BASE);
/* Store resolution in ppm, if known */
xres = (png_uint_32)(39.37 * (l_float32)pixGetXRes(pix) + 0.5);
yres = (png_uint_32)(39.37 * (l_float32)pixGetYRes(pix) + 0.5);
if ((xres == 0) || (yres == 0))
png_set_pHYs(png_ptr, info_ptr, 0, 0, PNG_RESOLUTION_UNKNOWN);
else
png_set_pHYs(png_ptr, info_ptr, xres, yres, PNG_RESOLUTION_METER);
if (cmflag) {
pixcmapToArrays(cmap, &rmap, &gmap, &bmap);
ncolors = pixcmapGetCount(cmap);
/* Make and save the palette */
if ((palette = (png_colorp)(CALLOC(ncolors, sizeof(png_color))))
== NULL)
return ERROR_INT("palette not made", procName, 1);
for (i = 0; i < ncolors; i++) {
palette.red = (png_byte)rmap;
palette.green = (png_byte)gmap;
palette.blue = (png_byte)bmap;
}
png_set_PLTE(png_ptr, info_ptr, palette, (int)ncolors);
FREE(rmap);
FREE(gmap);
FREE(bmap);
}
/* 0.4545 is treated as the default by some image
* display programs (not gqview). A value > 0.4545 will
* lighten an image as displayed by xv, display, etc. */
if (gamma > 0.0)
png_set_gAMA(png_ptr, info_ptr, (l_float64)gamma);
if ((text = pixGetText(pix))) {
png_text text_chunk;
text_chunk.compression = PNG_TEXT_COMPRESSION_NONE;
text_chunk.key = commentstring;
text_chunk.text = text;
text_chunk.text_length = strlen(text);
#ifdef PNG_ITXT_SUPPORTED
text_chunk.itxt_length = 0;
text_chunk.lang = NULL;
text_chunk.lang_key = NULL;
#endif
png_set_text(png_ptr, info_ptr, &text_chunk, 1);
}
/* Write header and palette info */
png_write_info(png_ptr, info_ptr);
if ((d != 32) && (d != 24))
{ /* not rgb color */
/* Generate a temporary pix with bytes swapped.
* For a binary image, there are two conditions in
* which you must first invert the data for writing png:
* (a) no colormap
* (b) colormap with BLACK set to 0
* png writes binary with BLACK = 0, unless contradicted
* by a colormap. If the colormap has BLACK = "1"
* (typ. about 255), do not invert the data. If there
* is no colormap, you must invert the data to store
* in default BLACK = 0 state. */
if (d == 1 &&
(!cmap || (cmap && ((l_uint8 *)(cmap->array))[0] == 0x0))) {
pixt = pixInvert(NULL, pix);
pixEndianByteSwap(pixt);
}
else
pixt = pixEndianByteSwapNew(pix);
if (!pixt) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return ERROR_INT("pixt not made", procName, 1);
}
/* Make and assign array of image row pointers */
if ((row_pointers = (png_bytep *)CALLOC(h, sizeof(png_bytep))) == NULL)
return ERROR_INT("row-pointers not made", procName, 1);
wpl = pixGetWpl(pixt);
data = pixGetData(pixt);
for (i = 0; i < h; i++)
row_pointers = (png_bytep)(data + i * wpl);
png_set_rows(png_ptr, info_ptr, row_pointers);
/* Transfer the data */
png_write_image(png_ptr, row_pointers);
png_write_end(png_ptr, info_ptr);
if (cmflag)
FREE(palette);
FREE(row_pointers);
pixDestroy(&pixt);
png_destroy_write_struct(&png_ptr, &info_ptr);
*pdata=(unsigned char *)state.buffer;
*psize=state.size;
return 0;
}
/* For rgb, compose and write a row at a time */
data = pixGetData(pix);
wpl = pixGetWpl(pix);
if (d == 24) { /* See note 7 above: special case of 24 bpp rgb */
for (i = 0; i < h; i++) {
ppixel = data + i * wpl;
png_write_rows(png_ptr, (png_bytepp)&ppixel, 1);
}
}
else { /* 32 bpp rgb and rgba */
if ((rowbuffer = (png_bytep)CALLOC(w, 4)) == NULL)
return ERROR_INT("rowbuffer not made", procName, 1);
for (i = 0; i < h; i++) {
ppixel = data + i * wpl;
for (j = k = 0; j < w; j++) {
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_RED);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_GREEN);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_BLUE);
if (var_PNG_WRITE_ALPHA == 1)
rowbuffer[k++] = GET_DATA_BYTE(ppixel, L_ALPHA_CHANNEL);
ppixel++;
}
png_write_rows(png_ptr, &rowbuffer, 1);
}
FREE(rowbuffer);
}
png_write_end(png_ptr, info_ptr);
if (cmflag)
FREE(palette);
png_destroy_write_struct(&png_ptr, &info_ptr);
*pdata=(unsigned char *)state.buffer;
*psize=state.size;
return 0;
}
TEST
//----------------------------------------------------------------------------------------------------
unsigned char* dstTmp = NULL;
FILE *file;
file =fopen("d:/b.bmp","rb");
fseek (file , 0 , SEEK_END);
size_t length=ftell (file);
rewind (file);
dstTmp = (unsigned char*) malloc (sizeof(unsigned char)*length);
fread (dstTmp,1,length,file);
fclose(file);
Pix *pix = pixReadMem(dstTmp,length);
pixWriteMemPng(&dstTmp,&length,pix,0);
file=fopen("d:/test.png","wb");
fwrite(dstTmp,1,length,file);
fclose(file);
//----------------------------------------------------------------------------------------------------
|
|