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Toward first png.

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This commit is contained in:
James Grogan 2022-11-24 17:43:31 +00:00
parent 8f97e9b7a1
commit 33369b1775
12 changed files with 190 additions and 102 deletions
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30
src/image/png/PngWriter.cpp
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@ -83,9 +83,9 @@ void PngWriter::writeHeader()
mPngHeader.updateData();
mOutStream->writeBytes(mPngHeader.getData());
std::cout << "Writing header " << mPngHeader.toString() << std::endl;
auto crc = mPngHeader.getCrc();
std::cout << mPngHeader.toString() << "*********" << std::endl;
mOutStream->write(crc);
}
@ -98,7 +98,11 @@ void PngWriter::writeEndChunk()
std::vector<unsigned char> char_data = StringUtils::toBytes("IEND");
CyclicRedundancyChecker crc_check;
auto crc = crc_check.doCrc(char_data.data(), char_data.size());
for (auto c : char_data)
{
crc_check.addValue(c);
}
auto crc = crc_check.getChecksum();
mOutStream->write(crc);
std::cout << "Writing end chunk" << std::endl;
@ -108,11 +112,6 @@ void PngWriter::writeDataChunks(const BufferBitStream& buffer)
{
auto num_bytes = buffer.getBuffer().size();
auto max_bytes{32000};
std::vector<unsigned char> crc_buffer(num_bytes + 4, 0);
crc_buffer[0] = 'I';
crc_buffer[1] = 'D';
crc_buffer[2] = 'A';
crc_buffer[3] = 'T';
unsigned num_dat_chunks = num_bytes/max_bytes + 1;
unsigned offset = 0;
@ -127,18 +126,23 @@ void PngWriter::writeDataChunks(const BufferBitStream& buffer)
std::cout << "Writing idat length " << num_bytes << std::endl;
mOutStream->write(num_bytes);
mOutStream->writeBytes(StringUtils::toBytes("IDAT"));
std::vector<unsigned char> char_data = StringUtils::toBytes("IDAT");
mOutStream->writeBytes(char_data);
CyclicRedundancyChecker crc_check;
for (auto c : char_data)
{
crc_check.addValue(c);
}
for(unsigned jdx=0; jdx<num_bytes; jdx++)
{
auto val = buffer.getBuffer()[idx*max_bytes + jdx];
crc_buffer[jdx + 4] = val;
mOutStream->writeByte(val);
crc_check.addValue(val);
}
CyclicRedundancyChecker crc_check;
auto crc = crc_check.doCrc(crc_buffer.data(), crc_buffer.size());
auto crc = crc_check.getChecksum();
std::cout << "Writing idat crc" << crc << std::endl;
mOutStream->write(crc);
}