/*!
* pixReadRGBAPng()
*
* Input: filename (of png file)
* Return: pix, or null on error
*
* Notes:
* (1) Wrapper to keep the alpha channel of a png, if it exists.
* (2) The default behavior of pix read functions is to ignore
* the alpha channel.
* (3) This always leaves alpha stripping in the same mode as
* when this function begins. So if alpha stripping is in
* default mode, this disables it, reads the file (including
* the alpha channel), and resets back to stripping. Otherwise,
* it leaves stripping disabled.
*/
PIX *
pixReadRGBAPng(const char *filename)
{
l_int32 format;
FILE *fp;
PIX *pix;
PROCNAME("pixReadRGBAPng");
if (!filename)
return (PIX *)ERROR_PTR("filename not defined", procName, NULL);
/* If alpha channel reading is enabled, just read it */
if (var_PNG_STRIP_ALPHA == FALSE)
return pixRead(filename);
/* Make sure it's a png file */
if ((fp = fopenReadStream(filename)) == NULL)
return (PIX *)ERROR_PTR("image file not found", procName, NULL);
findFileFormat(fp, &format);
if (format != IFF_PNG) {
fclose(fp);
L_ERROR_STRING("file format is %s, not png", procName,
ImageFileFormatExtensions[format]);
return NULL;
}
l_pngSetStripAlpha(0);
pix = pixReadStreamPng(fp);
l_pngSetStripAlpha(1); /* reset to default */
fclose(fp);
if (!pix) L_ERROR("pix not read", procName);
return pix;
}
/*!
* pixaReadStream()
*
* Input: stream
* Return: pixa, or null on error
*/
PIXA *
pixaReadStream(FILE *fp)
{
l_int32 n, i, xres, yres, version;
l_int32 ignore;
BOXA *boxa;
PIX *pix;
PIXA *pixa;
PROCNAME("pixaReadStream");
#if !HAVE_LIBPNG /* defined in environ.h */
return (PIXA *)ERROR_PTR("no libpng: can't read data", procName, NULL);
#else
if (!fp)
return (PIXA *)ERROR_PTR("stream not defined", procName, NULL);
if (fscanf(fp, "\nPixa Version %d\n", &version) != 1)
return (PIXA *)ERROR_PTR("not a pixa file", procName, NULL);
if (version != PIXA_VERSION_NUMBER)
return (PIXA *)ERROR_PTR("invalid pixa version", procName, NULL);
if (fscanf(fp, "Number of pix = %d\n", &n) != 1)
return (PIXA *)ERROR_PTR("not a pixa file", procName, NULL);
if ((pixa = pixaCreate(n)) == NULL)
return (PIXA *)ERROR_PTR("pixa not made", procName, NULL);
if ((boxa = boxaReadStream(fp)) == NULL)
return (PIXA *)ERROR_PTR("boxa not made", procName, NULL);
boxaDestroy(&pixa->boxa);
pixa->boxa = boxa;
for (i = 0; i < n; i++) {
if ((fscanf(fp, " pix[%d]: xres = %d, yres = %d\n",
&ignore, &xres, &yres)) != 3)
return (PIXA *)ERROR_PTR("res reading", procName, NULL);
if ((pix = pixReadStreamPng(fp)) == NULL)
return (PIXA *)ERROR_PTR("pix not read", procName, NULL);
pixSetXRes(pix, xres);
pixSetYRes(pix, yres);
pixaAddPix(pixa, pix, L_INSERT);
}
return pixa;
#endif /* !HAVE_LIBPNG */
}
/*!
* pixReadMemPng()
*
* Input: cdata (const; png-encoded)
* size (of data)
* Return: pix, or null on error
*
* Notes:
* (1) The @size byte of @data must be a null character.
*/
PIX *
pixReadMemPng(const l_uint8 *cdata,
size_t size)
{
l_uint8 *data;
FILE *fp;
PIX *pix;
PROCNAME("pixReadMemPng");
if (!cdata)
return (PIX *)ERROR_PTR("cdata not defined", procName, NULL);
data = (l_uint8 *)cdata; /* we're really not going to change this */
if ((fp = fmemopen(data, size, "r")) == NULL)
return (PIX *)ERROR_PTR("stream not opened", procName, NULL);
pix = pixReadStreamPng(fp);
fclose(fp);
return pix;
}
/*!
* pixReadStream()
*
* Input: fp (file stream)
* hint (bitwise OR of L_HINT_* values for jpeg; use 0 for no hint)
* Return: pix if OK; null on error
*
* Notes:
* (1) The hint only applies to jpeg.
*/
PIX *
pixReadStream(FILE *fp,
l_int32 hint)
{
l_int32 format, ret;
l_uint8 *comment;
PIX *pix;
PROCNAME("pixReadStream");
if (!fp)
return (PIX *)ERROR_PTR("stream not defined", procName, NULL);
pix = NULL;
findFileFormatStream(fp, &format);
switch (format)
{
case IFF_BMP:
if ((pix = pixReadStreamBmp(fp)) == NULL )
return (PIX *)ERROR_PTR( "bmp: no pix returned", procName, NULL);
break;
// case IFF_JFIF_JPEG:
// if ((pix = pixReadStreamJpeg(fp, READ_24_BIT_COLOR, 1, NULL, hint))
// == NULL)
// return (PIX *)ERROR_PTR( "jpeg: no pix returned", procName, NULL);
// ret = fgetJpegComment(fp, &comment);
// if (!ret && comment)
// pixSetText(pix, (char *)comment);
// FREE(comment);
// break;
case IFF_PNG:
if ((pix = pixReadStreamPng(fp)) == NULL)
return (PIX *)ERROR_PTR("png: no pix returned", procName, NULL);
break;
case IFF_TIFF:
case IFF_TIFF_PACKBITS:
case IFF_TIFF_RLE:
case IFF_TIFF_G3:
case IFF_TIFF_G4:
case IFF_TIFF_LZW:
case IFF_TIFF_ZIP:
if ((pix = pixReadStreamTiff(fp, 0)) == NULL) /* page 0 by default */
return (PIX *)ERROR_PTR("tiff: no pix returned", procName, NULL);
break;
case IFF_PNM:
if ((pix = pixReadStreamPnm(fp)) == NULL)
return (PIX *)ERROR_PTR("pnm: no pix returned", procName, NULL);
break;
case IFF_GIF:
if ((pix = pixReadStreamGif(fp)) == NULL)
return (PIX *)ERROR_PTR("gif: no pix returned", procName, NULL);
break;
case IFF_JP2:
if ((pix = pixReadStreamJp2k(fp, 1, NULL, 0)) == NULL)
return (PIX *)ERROR_PTR("jp2: no pix returned", procName, NULL);
break;
case IFF_WEBP:
if ((pix = pixReadStreamWebP(fp)) == NULL)
return (PIX *)ERROR_PTR("webp: no pix returned", procName, NULL);
break;
case IFF_SPIX:
if ((pix = pixReadStreamSpix(fp)) == NULL)
return (PIX *)ERROR_PTR("spix: no pix returned", procName, NULL);
break;
case IFF_UNKNOWN:
return (PIX *)ERROR_PTR( "Unknown format: no pix returned",
procName, NULL);
break;
}
if (pix)
pixSetInputFormat(pix, format);
return pix;
}
