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Add tRNS chunk support.

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Michael R Sweet 2021-06-10 10:57:46 -04:00
parent 01184d0bb5
commit d5ceed0694
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1 changed files with 89 additions and 3 deletions
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92
pdfio-content.c
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@ -1638,7 +1638,8 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
pdfio_dict_t *decode = NULL; // Parameters for PNG decode
ssize_t bytes; // Bytes read
unsigned char buffer[16384]; // Read buffer
unsigned length, // Length
unsigned i, // Looping var
length, // Length
type, // Chunk code
crc, // CRC-32
temp, // Temporary value
@ -1651,6 +1652,7 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
rx = 0.0, ry = 0.0, // Red chromacity
gx = 0.0, gy = 0.0, // Green chromacity
bx = 0.0, by = 0.0; // Blue chromacity
pdfio_array_t *mask = NULL; // Color masking array
// Read the file header...
@ -1844,10 +1846,94 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
gamma = 10000.0 / ((buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]);
break;
#if 0
case _PDFIO_PNG_CHUNK_tRNS : // Transparency information
switch (color_type)
{
case _PDFIO_PNG_TYPE_INDEXED :
if (length > 256)
{
_pdfioFileError(dict->pdf, "Bad transparency chunk in image file.");
return (NULL);
}
if (read(fd, buffer, length) != length)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
for (i = 0; i < length; i ++)
{
if (!buffer[i])
break;
}
if (i < length)
{
if ((mask = pdfioArrayCreate(dict->pdf)) == NULL)
return (NULL);
pdfioArrayAppendNumber(mask, i);
for (i ++; i < length; i ++)
{
if (buffer[i])
break;
}
pdfioArrayAppendNumber(mask, i - 1);
}
break;
case _PDFIO_PNG_TYPE_GRAY :
if (length != 2)
{
_pdfioFileError(dict->pdf, "Bad transparency chunk in image file.");
return (NULL);
}
if (read(fd, buffer, length) != length)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
if ((mask = pdfioArrayCreate(dict->pdf)) == NULL)
return (NULL);
pdfioArrayAppendNumber(mask, buffer[1]);
pdfioArrayAppendNumber(mask, buffer[1]);
break;
case _PDFIO_PNG_TYPE_RGB :
if (length != 6)
{
_pdfioFileError(dict->pdf, "Bad transparency chunk in image file.");
return (NULL);
}
if (read(fd, buffer, length) != length)
{
_pdfioFileError(dict->pdf, "Early end-of-file in image file.");
return (NULL);
}
if ((mask = pdfioArrayCreate(dict->pdf)) == NULL)
return (NULL);
pdfioArrayAppendNumber(mask, buffer[1]);
pdfioArrayAppendNumber(mask, buffer[3]);
pdfioArrayAppendNumber(mask, buffer[5]);
pdfioArrayAppendNumber(mask, buffer[1]);
pdfioArrayAppendNumber(mask, buffer[3]);
pdfioArrayAppendNumber(mask, buffer[5]);
break;
}
crc = update_png_crc(crc, buffer, length);
if (mask)
pdfioDictSetArray(dict, "Mask", mask);
break;
#endif // 0
default : // Something else
while (length > 0)