QtPBFImagePlugin/src/pbfhandler.cpp

118 lines
2.6 KiB
C++

#include <QImage>
#include <QIODevice>
#include <QtEndian>
#include <QDebug>
#include "gzip.h"
#include "tile.h"
#include "style.h"
#include "pbfhandler.h"
#define TILE_SIZE 512
#define GZIP_MAGIC 0x1F8B
#define GZIP_MAGIC_MASK 0xFFFF
#define PBF_MAGIC 0x1A00
#define PBF_MAGIC_MASK 0xFF00
static bool isMagic(quint16 magic, quint16 mask, quint16 value)
{
return ((qFromBigEndian(value) & mask) == magic);
}
static bool isGZIPPBF(quint16 magic)
{
return isMagic(GZIP_MAGIC, GZIP_MAGIC_MASK, magic);
}
static bool isPlainPBF(quint16 magic)
{
return isMagic(PBF_MAGIC, PBF_MAGIC_MASK, magic);
}
bool PBFHandler::canRead() const
{
if (canRead(device())) {
setFormat("mvt");
return true;
} else
return false;
}
bool PBFHandler::canRead(QIODevice *device)
{
quint16 magic;
qint64 size = device->peek((char*)&magic, sizeof(magic));
if (size != sizeof(magic))
return false;
if (isPlainPBF(magic))
return true;
else if (isGZIPPBF(magic)) {
QByteArray ba(Gzip::uncompress(device, sizeof(magic)));
if (ba.size() < (int)sizeof(magic))
return false;
return isPlainPBF(*((quint16*)ba.constData()));
} else
return false;
}
bool PBFHandler::read(QImage *image)
{
quint16 magic;
if (device()->peek((char*)&magic, sizeof(magic)) != sizeof(magic))
return false;
QByteArray ba;
if (isGZIPPBF(magic)) {
ba = Gzip::uncompress(device());
if (ba.isNull()) {
qCritical() << "Invalid gzip data";
return false;
}
} else if (isPlainPBF(magic))
ba = device()->readAll();
vector_tile::Tile data;
if (!data.ParseFromArray(ba.constData(), ba.size())) {
qCritical() << "Invalid PBF data";
return false;
}
QList<QByteArray> list(format().split(';'));
int zoom = list.size() ? list.first().toInt() : 0;
int overzoom = (list.size() > 1) ? list.at(1).toInt() : 0;
QSize scaledSize(_scaledSize.isValid()
? _scaledSize : QSize(TILE_SIZE, TILE_SIZE));
QSize size(scaledSize.width()<<overzoom,
scaledSize.height()<<overzoom);
QPointF scale((qreal)scaledSize.width() / TILE_SIZE,
(qreal)scaledSize.height() / TILE_SIZE);
*image = QImage(size, QImage::Format_ARGB32_Premultiplied);
Tile tile(image, zoom, scale);
_style->render(data, tile);
return true;
}
bool PBFHandler::supportsOption(ImageOption option) const
{
return (option == Size || option == ScaledSize);
}
void PBFHandler::setOption(QImageIOHandler::ImageOption option,
const QVariant &value)
{
if (option == ScaledSize)
_scaledSize = value.toSize();
}
QVariant PBFHandler::option(ImageOption option) const
{
return (option == Size) ? QSize(TILE_SIZE, TILE_SIZE) : QVariant();
}