sdrangel/sdrbase/util/png.cpp

312 wiersze
7.6 KiB
C++
Czysty Zwykły widok Historia

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Jon Beniston, M7RCE //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#include "png.h"
#include <QDebug>
#include <QString>
#include <QBuffer>
#include <QFile>
PNG::PNG()
{
}
PNG::PNG(QByteArray data) :
m_bytes(data),
m_width(0),
m_height(0)
{
int idx = findChunk("IHDR");
if (idx >= 0)
{
m_width = getInt(idx + 8);
m_height = getInt(idx + 12);
}
else
{
qDebug() << "PNG: No IHDR found";
}
}
void PNG::appendSignature()
{
m_bytes.append(m_signature);
}
void PNG::appendEnd()
{
QByteArray ba;
appendChunk("IEND", ba);
}
void PNG::appendChunk(const char *type, QByteArray chunk)
{
appendInt(chunk.size());
appendInt(typeStringToInt(type));
m_bytes.append(chunk);
appendInt(crc(type, chunk)); // CRC type and data, but not length
}
void PNG::append(QByteArray data)
{
m_bytes.append(data);
}
void PNG::appendInt(QByteArray& ba, quint32 value)
{
// Network byte order
ba.append((value >> 24) & 0xff);
ba.append((value >> 16) & 0xff);
ba.append((value >> 8) & 0xff);
ba.append((value) & 0xff);
}
void PNG::appendShort(QByteArray& ba, quint16 value)
{
// Network byte order
ba.append((value >> 8) & 0xff);
ba.append((value) & 0xff);
}
void PNG::appendInt(quint32 value)
{
appendInt(m_bytes, value);
}
qint32 PNG::getInt(int index)
{
qint32 v = 0;
for (int i = 0; i < 4; i++) {
v |= (m_bytes[index+i] & 0xff) << ((3-i)*8);
}
return v;
}
qint32 PNG::crc(const char *type, const QByteArray data)
{
m_crc.init();
m_crc.calculate((const uint8_t *)type, 4);
m_crc.calculate((const uint8_t *)data.data(), data.size());
return m_crc.get();
}
qint32 PNG::typeStringToInt(const char *header)
{
quint32 v = 0;
for (int i = 0; i < 4; i++) {
v |= header[i] << ((3-i)*8);
}
return v;
}
QString PNG::intToTypeString(quint32 type)
{
QString s;
for (int i = 0; i < 4; i++)
{
char c = (type >> ((3-i)*8)) & 0xff;
s.append(c);
}
return s;
}
// Animation control chunk for APNGs (loops=0 is infinite)
void PNG::appendacTL(int frames, quint32 loops)
{
QByteArray ba;
appendInt(ba, frames);
appendInt(ba, loops);
appendChunk("acTL", ba);
}
// Frame control chunk for APNGs
void PNG::appendfcTL(quint32 seqNo, quint32 width, quint32 height, int fps, quint32 xOffset, quint32 yOffset)
{
QByteArray ba;
appendInt(ba, seqNo);
appendInt(ba, width);
appendInt(ba, height);
appendInt(ba, xOffset);
appendInt(ba, yOffset);
appendShort(ba, 1);
appendShort(ba, fps);
ba.append((char)0); // No disposal
ba.append((char)0); // Overwrite previous image
appendChunk("fcTL", ba);
}
// Animation frame data
void PNG::appendfdAT(quint32 seqNo, const QByteArray& data)
{
QByteArray ba;
appendInt(ba, seqNo);
ba.append(data);
appendChunk("fdAT", ba);
}
QByteArray PNG::data()
{
return m_bytes;
}
bool PNG::checkSignature()
{
return m_bytes.startsWith(m_signature);
}
int PNG::findChunk(const char *type, int startIndex)
{
if ((startIndex == 0) && !checkSignature())
{
qDebug() << "PNG::findChunk - PNG signature not found";
return -1;
}
int i = startIndex == 0 ? m_signature.size() : startIndex;
qint32 typeInt = typeStringToInt(type);
while (i < m_bytes.size())
{
qint32 chunkType = getInt(i+4);
if (typeInt == chunkType) {
return i;
}
qint32 length = getInt(i);
i += 12 + length;
}
return -1;
}
// Get chunk including length, type data and CRC
QByteArray PNG::getChunk(const char *type)
{
int start = findChunk(type);
if (start >= 0)
{
quint32 length = getInt(start);
return m_bytes.mid(start, length + 12);
}
return QByteArray();
}
// Get all chunks with same type
QByteArray PNG::getChunks(const char *type)
{
int start = 0;
QByteArray bytes;
while ((start = findChunk(type, start)) != -1)
{
quint32 length = getInt(start);
QByteArray chunk = m_bytes.mid(start, length + 12);
bytes.append(chunk);
start += chunk.size();
}
return bytes;
}
// Get data from chunk
QList<QByteArray> PNG::getChunkData(const char *type)
{
int start = 0;
QList<QByteArray> chunks;
while ((start = findChunk(type, start)) != -1)
{
quint32 length = getInt(start);
QByteArray chunk = m_bytes.mid(start + 8, length);
chunks.append(chunk);
start += length + 12;
}
return chunks;
}
quint32 PNG::getWidth() const
{
return m_width;
}
quint32 PNG::getHeight() const
{
return m_height;
}
bool APNG::addImage(const QImage& image, int fps)
{
if (!m_ended)
{
QByteArray ba;
QBuffer buffer(&ba);
buffer.open(QIODevice::ReadWrite);
if (image.save(&buffer, "PNG"))
{
PNG pngIn(ba);
if (m_frame == 0)
{
m_png.append(pngIn.getChunk("IHDR"));
m_png.appendacTL(m_frames);
m_png.appendfcTL(m_seqNo++, pngIn.getWidth(), pngIn.getHeight(), fps);
// PNGs can contain multiple IDAT chunks, typically each limited to 8kB
m_png.append(pngIn.getChunks("IDAT"));
}
else
{
m_png.appendfcTL(m_seqNo++, pngIn.getWidth(), pngIn.getHeight(), fps);
QList<QByteArray> data = pngIn.getChunkData("IDAT");
for (int i = 0; i < data.size(); i++) {
m_png.appendfdAT(m_seqNo++, data[i]);
}
}
m_frame++;
return true;
}
else
{
qDebug() << "APNG::addImage - Failed to save image to PNG";
return false;
}
}
else
{
qDebug() << "APNG::addImage - Call to addImage after IEND added";
return false;
}
}
bool APNG::save(const QString& fileName)
{
if (!m_ended)
{
if (m_frame != m_frames) {
qDebug() << "APNG::save - " << m_frame << " frames added out of expected " << m_frames;
}
m_png.appendEnd();
m_ended = true;
}
QFile animFile(fileName);
if (animFile.open(QIODevice::WriteOnly | QIODevice::Truncate))
{
animFile.write(m_png.data());
animFile.close();
return true;
}
else
{
return false;
}
}