Add PNG gAMA and cHRM chunk support.

This commit is contained in:
Michael R Sweet 2021-06-09 17:22:22 -04:00
parent a962b1d069
commit 01184d0bb5
No known key found for this signature in database
GPG Key ID: BE67C75EC81F3244
2 changed files with 61 additions and 10 deletions

View File

@ -1646,6 +1646,11 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
height = 0; // Height
unsigned char bit_depth = 0, // Bit depth
color_type = 0; // Color type
double gamma = 2.2, // Gamma value
wx = 0.0, wy = 0.0, // White point chromacity
rx = 0.0, ry = 0.0, // Red chromacity
gx = 0.0, gy = 0.0, // Green chromacity
bx = 0.0, by = 0.0; // Blue chromacity
// Read the file header...
@ -1671,6 +1676,19 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
if (!st)
{
PDFIO_DEBUG("copy_png: wx=%g, wy=%g, rx=%g, ry=%g, gx=%g, gy=%g, bx=%g, by=%g\n", wx, wy, rx, ry, gx, gy, bx, by);
PDFIO_DEBUG("copy_png: gamma=%g\n", gamma);
if (!pdfioDictGetArray(dict, "ColorSpace"))
{
PDFIO_DEBUG("copy_png: Adding %s ColorSpace value.\n", color_type == _PDFIO_PNG_TYPE_GRAY ? "CalGray" : "CalRGB");
if (wx != 0.0)
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateCalibratedColorFromPrimaries(dict->pdf, color_type == _PDFIO_PNG_TYPE_GRAY ? 1 : 3, gamma, wx, wy, rx, ry, bx, by, gx, gy));
else
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateCalibratedColorFromMatrix(dict->pdf, color_type == _PDFIO_PNG_TYPE_GRAY ? 1 : 3, gamma, pdfioSRGBMatrix, pdfioSRGBWhitePoint));
}
obj = pdfioFileCreateObj(dict->pdf, dict);
if ((st = pdfioObjCreateStream(obj, PDFIO_FILTER_NONE)) == NULL)
@ -1750,10 +1768,6 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
pdfioDictSetNumber(dict, "Width", width);
pdfioDictSetNumber(dict, "Height", height);
pdfioDictSetNumber(dict, "BitsPerComponent", bit_depth);
if (color_type == _PDFIO_PNG_TYPE_GRAY)
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateCalibratedColorFromMatrix(dict->pdf, 1, pdfioSRGBGamma, NULL, pdfioSRGBWhitePoint));
else if (color_type == _PDFIO_PNG_TYPE_RGB)
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateCalibratedColorFromMatrix(dict->pdf, 3, pdfioSRGBGamma, pdfioSRGBMatrix, pdfioSRGBWhitePoint));
pdfioDictSetName(dict, "Filter", "FlateDecode");
if ((decode = pdfioDictCreate(dict->pdf)) == NULL)
@ -1782,16 +1796,55 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
crc = update_png_crc(crc, buffer, length);
PDFIO_DEBUG("copy_png: Adding Indexed ColorSpace value.\n");
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateIndexedColor(dict->pdf, length / 3, buffer));
break;
#if 0
case _PDFIO_PNG_CHUNK_cHRM : // Cromacities and white point
if (length != 32)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
if (read(fd, buffer, length) != length)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
crc = update_png_crc(crc, buffer, length);
wx = 0.00001 * ((buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]);
wy = 0.00001 * ((buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7]);
rx = 0.00001 * ((buffer[8] << 24) | (buffer[9] << 16) | (buffer[10] << 8) | buffer[11]);
ry = 0.00001 * ((buffer[12] << 24) | (buffer[13] << 16) | (buffer[14] << 8) | buffer[15]);
gx = 0.00001 * ((buffer[16] << 24) | (buffer[17] << 16) | (buffer[18] << 8) | buffer[19]);
gy = 0.00001 * ((buffer[20] << 24) | (buffer[21] << 16) | (buffer[22] << 8) | buffer[23]);
bx = 0.00001 * ((buffer[24] << 24) | (buffer[25] << 16) | (buffer[26] << 8) | buffer[27]);
by = 0.00001 * ((buffer[28] << 24) | (buffer[29] << 16) | (buffer[30] << 8) | buffer[31]);
break;
case _PDFIO_PNG_CHUNK_gAMA : // Gamma correction
if (length != 4)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
if (read(fd, buffer, length) != length)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
crc = update_png_crc(crc, buffer, length);
gamma = 10000.0 / ((buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]);
break;
#if 0
case _PDFIO_PNG_CHUNK_tRNS : // Transparency information
break;
#endif // 0

View File

@ -67,12 +67,11 @@
273440DA263D732000FBFD63 /* README.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = "<group>"; };
273440DB263D732000FBFD63 /* NOTICE */ = {isa = PBXFileReference; lastKnownFileType = text; path = NOTICE; sourceTree = "<group>"; };
273440DC263D732000FBFD63 /* Makefile */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.make; path = Makefile; sourceTree = "<group>"; };
273440DD263D732000FBFD63 /* pdfio.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = pdfio.md; sourceTree = "<group>"; };
273440DD263D732000FBFD63 /* pdfio.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = pdfio.md; path = doc/pdfio.md; sourceTree = "<group>"; };
273440DE263D732000FBFD63 /* pdfio.pc.in */ = {isa = PBXFileReference; lastKnownFileType = text; path = pdfio.pc.in; sourceTree = "<group>"; };
273440DF263D732000FBFD63 /* LICENSE */ = {isa = PBXFileReference; lastKnownFileType = text; path = LICENSE; sourceTree = "<group>"; };
273440E0263D732000FBFD63 /* TODO.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = TODO.md; sourceTree = "<group>"; };
273440E1263D73A300FBFD63 /* pdfio.html */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; path = pdfio.html; sourceTree = "<group>"; };
273440E2263D73A300FBFD63 /* pdfio.3 */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = pdfio.3; sourceTree = "<group>"; };
273440E1263D73A300FBFD63 /* pdfio.html */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; name = pdfio.html; path = doc/pdfio.html; sourceTree = "<group>"; };
273440E2263D73A300FBFD63 /* pdfio.3 */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; name = pdfio.3; path = doc/pdfio.3; sourceTree = "<group>"; };
273440E3263DD7EA00FBFD63 /* pdfio-token.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = "pdfio-token.c"; sourceTree = "<group>"; };
/* End PBXFileReference section */
@ -139,7 +138,6 @@
273440E1263D73A300FBFD63 /* pdfio.html */,
273440DD263D732000FBFD63 /* pdfio.md */,
273440DA263D732000FBFD63 /* README.md */,
273440E0263D732000FBFD63 /* TODO.md */,
);
name = Documentation;
sourceTree = "<group>";