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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#include "vtkTGAReader.h"
#include "vtkDataArray.h"
#include "vtkImageData.h"
#include "vtkImageFlip.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include <vtksys/FStream.hxx>
VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkTGAReader);
namespace
{
constexpr int HeaderSize = 18;
enum TGAFormat : unsigned char
{
Uncompressed_RGB = 2,
RLE_RGB = 10
};
}
//----------------------------------------------------------------------------
void vtkTGAReader::ExecuteInformation()
{
char header[::HeaderSize];
if (this->GetMemoryBuffer())
{
const char* memBuffer = static_cast<const char*>(this->GetMemoryBuffer());
std::copy(memBuffer, memBuffer + ::HeaderSize, header);
}
else
{
this->ComputeInternalFileName(0);
vtksys::ifstream file(this->InternalFileName, std::ios::binary);
file.read(header, ::HeaderSize * sizeof(char));
file.close();
}
// tmp char needed to avoid strict anti aliasing warning
char* tmp = &header[8];
this->DataOrigin[0] = static_cast<double>(*reinterpret_cast<short*>(tmp));
tmp = &header[10];
this->DataOrigin[1] = static_cast<double>(*reinterpret_cast<short*>(tmp));
this->DataOrigin[2] = 0.0;
this->DataExtent[0] = 0;
tmp = &header[12];
this->DataExtent[1] = static_cast<int>(*reinterpret_cast<short*>(tmp) - 1);
this->DataExtent[2] = 0;
tmp = &header[14];
this->DataExtent[3] = static_cast<int>(*reinterpret_cast<short*>(tmp) - 1);
bool upperLeft = static_cast<bool>((header[17] >> 5) & 1);
this->SetFileLowerLeft(!upperLeft);
this->SetHeaderSize(::HeaderSize);
this->SetDataScalarTypeToUnsignedChar();
this->SetNumberOfScalarComponents(header[16] / 8);
this->vtkImageReader2::ExecuteInformation();
}
//------------------------------------------------------------------------------
void vtkTGAReader::ExecuteDataWithInformation(vtkDataObject* output, vtkInformation* outInfo)
{
vtkImageData* data = this->AllocateOutputData(output, outInfo);
data->GetPointData()->GetScalars()->SetName("TGAImage");
this->ComputeDataIncrements();
std::vector<unsigned char> content;
if (this->GetMemoryBuffer())
{
const unsigned char* uBuffer = reinterpret_cast<const unsigned char*>(this->GetMemoryBuffer());
content.assign(uBuffer, uBuffer + this->GetMemoryBufferLength());
}
else
{
vtksys::ifstream imageFile(this->InternalFileName, std::ios::binary);
content.assign(std::istreambuf_iterator<char>(imageFile), std::istreambuf_iterator<char>());
}
bool encoded = (content[2] == ::TGAFormat::RLE_RGB);
vtkIdType nComponents = this->GetNumberOfScalarComponents();
// buffer to image data
unsigned char* outPtr = reinterpret_cast<unsigned char*>(data->GetScalarPointer());
unsigned char* endPtr =
outPtr + ((this->DataExtent[3] + 1) * (this->DataExtent[1] + 1) * nComponents);
auto GetColor = [&](size_t& currentIndex, unsigned char*& buffer) {
for (vtkIdType j = 0; j < nComponents; j++)
{
buffer[j] = content[currentIndex + j];
}
if (nComponents >= 3) // swap red and blue
{
std::swap(buffer[0], buffer[2]);
}
currentIndex += nComponents;
buffer += nComponents;
};
size_t skip = ::HeaderSize + static_cast<size_t>(content[0]);
size_t index = skip;
while (outPtr < endPtr && index < content.size())
{
if (encoded)
{
unsigned char packet = content[index++];
if (packet & 0x80) // packet is RLE if highest bit is 1
{
// RLE packet (clear highest bit and add 1)
packet = (packet & 0x7f) + 1;
unsigned char* dupBuffer = outPtr;
GetColor(index, outPtr);
for (unsigned char i = 0; i < packet - 1; i++)
{
for (vtkIdType k = 0; k < nComponents; k++)
{
outPtr[k] = dupBuffer[k];
}
outPtr += nComponents;
}
}
else
{
// raw packet (add 1)
packet += 1;
for (unsigned char i = 0; i < packet; i++)
{
GetColor(index, outPtr);
}
}
}
else
{
GetColor(index, outPtr);
}
}
if (!this->FileLowerLeft)
{
vtkNew<vtkImageFlip> flipY;
flipY->SetFilteredAxis(1);
flipY->SetInputData(data);
flipY->Update();
data->ShallowCopy(flipY->GetOutput());
}
}
//----------------------------------------------------------------------------
int vtkTGAReader::CanReadFile(const char* fname)
{
vtksys::ifstream file(fname, std::ios::binary);
if (!file.is_open())
{
return 0;
}
char header[::HeaderSize];
file.read(header, ::HeaderSize * sizeof(char));
// only uncompressed RGB and RLE encoded RGB formats are supported
if (header[2] != ::TGAFormat::RLE_RGB && header[2] != ::TGAFormat::Uncompressed_RGB)
{
vtkWarningMacro("Only RLE RGB and uncompressed RGB TGA files are supported");
return 0;
}
return 1;
}
//------------------------------------------------------------------------------
void vtkTGAReader::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os, indent);
}
VTK_ABI_NAMESPACE_END
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