This class read data from a png file and store it in an image. More...
#include <png.hpp>
Classes | |
struct | source_manager |
Source manager that allow us to read from a std::istream. More... | |
Public Member Functions | |
reader (image &img) | |
Constructor. | |
reader (image &img, std::istream &f) | |
Constructor. | |
void | load (std::istream &f) |
Load an image from a png file. | |
Private Member Functions | |
void | read_from_file (std::istream &f) |
Load an image from a png file. | |
void | check_if_png (png_structp png_ptr, std::istream &f) const |
Check that the stream contains a PNG file. | |
void | read_image (png_structp png_ptr, png_infop info_ptr) |
Read the image data of the PNG. | |
void | read_sequential_image (png_structp png_ptr, png_infop info_ptr) |
Read the image data of a non interlaced PNG. | |
void | read_interlaced_image (png_structp png_ptr, png_infop info_ptr, unsigned int passes) |
Read the image data of an interlaced PNG. | |
void | copy_pixel_line (png_bytep data, unsigned int y) |
Copy the pixels taken from the PNG to the image. | |
void | create_read_structures (png_structp &png_ptr, png_infop &info_ptr) const |
Initialize the png read structures. | |
Private Attributes | |
image & | m_image |
The image in which we store the data we read. | |
Static Private Attributes | |
static const unsigned int | s_rgba_pixel_size = 4 |
Size, in bytes, of a red/green/blue/alpha pixel in a png file. |
This class read data from a png file and store it in an image.
Definition at line 55 of file png.hpp.
claw::graphic::png::reader::reader | ( | image & | img ) |
Constructor.
img | The image in which the data will be stored. |
Definition at line 90 of file png_reader.cpp.
: m_image( img ) { } // png::reader::reader()
claw::graphic::png::reader::reader | ( | image & | img, |
std::istream & | f | ||
) |
Constructor.
img | The image in which the data will be stored. |
f | The file from which we read the data. |
Definition at line 103 of file png_reader.cpp.
References load().
void claw::graphic::png::reader::check_if_png | ( | png_structp | png_ptr, |
std::istream & | f | ||
) | const [private] |
Check that the stream contains a PNG file.
png_ptr | PNG file description. |
f | The stream to read from. |
Definition at line 183 of file png_reader.cpp.
References CLAW_EXCEPTION, and CLAW_PRECOND.
{ CLAW_PRECOND( !!f ); const unsigned int bytes_to_check = 8; png_byte buffer[bytes_to_check]; /* Read in some of the signature bytes */ f.read( (char*)buffer, bytes_to_check * sizeof(png_byte) ); if ( (png_sig_cmp(buffer, (png_size_t)0, bytes_to_check) != 0) || !f ) throw CLAW_EXCEPTION( "Not a PNG file." ); png_set_sig_bytes(png_ptr, bytes_to_check); } // png::reader::check_if_png()
void claw::graphic::png::reader::copy_pixel_line | ( | png_bytep | data, |
unsigned int | y | ||
) | [private] |
Copy the pixels taken from the PNG to the image.
data | the pixels from the PNG image. |
y | Index of the line of the image in which we copy the pixels. |
Definition at line 312 of file png_reader.cpp.
References CLAW_PRECOND.
{ CLAW_PRECOND( data ); CLAW_PRECOND( y < m_image.height() ); // four bytes for each pixel in the line for (unsigned int x=0; x!=m_image.width(); ++x, data+=s_rgba_pixel_size) { m_image[y][x].components.red = data[0]; m_image[y][x].components.green = data[1]; m_image[y][x].components.blue = data[2]; m_image[y][x].components.alpha = data[3]; } } // png::reader::copy_pixel_line()
void claw::graphic::png::reader::create_read_structures | ( | png_structp & | png_ptr, |
png_infop & | info_ptr | ||
) | const [private] |
Initialize the png read structures.
png_ptr | PNG file description. |
info_ptr | PNG file informations. |
Definition at line 334 of file png_reader.cpp.
References CLAW_EXCEPTION.
{ png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); if (png_ptr) { info_ptr = png_create_info_struct(png_ptr); if (!info_ptr) png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL); } if (!png_ptr || !info_ptr) throw CLAW_EXCEPTION("Can't create PNG read structures."); } // png::reader::create_read_structures()
void claw::graphic::png::reader::load | ( | std::istream & | f ) |
Load an image from a png file.
f | PNG file. |
Definition at line 114 of file png_reader.cpp.
References CLAW_PRECOND.
Referenced by reader().
{ CLAW_PRECOND( !!f ); std::istream::pos_type init_pos = f.tellg(); try { read_from_file(f); } catch(...) { f.clear(); f.seekg( init_pos, std::ios_base::beg ); throw; } } // png::reader::load()
void claw::graphic::png::reader::read_from_file | ( | std::istream & | f ) | [private] |
Load an image from a png file.
f | PNG file. |
Definition at line 137 of file png_reader.cpp.
References claw__graphic__png__source_manager__read(), and CLAW_EXCEPTION.
{ source_manager infile(f); png_structp png_ptr; png_infop info_ptr; create_read_structures(png_ptr, info_ptr); if (setjmp(png_jmpbuf(png_ptr))) { /* If we get here, we had a problem reading the file */ /* Free all of the memory associated with the png_ptr and info_ptr */ png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); throw CLAW_EXCEPTION("Invalid PNG file."); } check_if_png( png_ptr, f ); png_set_read_fn( png_ptr, (void *)&infile, claw__graphic__png__source_manager__read ); png_set_strip_16(png_ptr); png_set_expand_gray_1_2_4_to_8(png_ptr); png_set_packing(png_ptr); // transform palette index into RGB value png_set_palette_to_rgb(png_ptr); // add an alpha value if none png_set_filler( png_ptr, std::numeric_limits<rgba_pixel_8::component_type>::max(), PNG_FILLER_AFTER ); png_read_info(png_ptr, info_ptr); read_image( png_ptr, info_ptr ); png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); } // png::reader::read_from_file()
void claw::graphic::png::reader::read_image | ( | png_structp | png_ptr, |
png_infop | info_ptr | ||
) | [private] |
Read the image data of the PNG.
png_ptr | PNG file description. |
info_ptr | PNG file informations. |
Definition at line 206 of file png_reader.cpp.
References CLAW_PRECOND.
{ CLAW_PRECOND( png_ptr ); CLAW_PRECOND( info_ptr ); m_image.set_size( png_get_image_width(png_ptr, info_ptr), png_get_image_height(png_ptr, info_ptr) ); if ( png_get_interlace_type(png_ptr, info_ptr) == PNG_INTERLACE_NONE ) read_sequential_image(png_ptr, info_ptr); else read_interlaced_image( png_ptr, info_ptr, png_set_interlace_handling(png_ptr) ); } // png::reader::read_image()
void claw::graphic::png::reader::read_interlaced_image | ( | png_structp | png_ptr, |
png_infop | info_ptr, | ||
unsigned int | passes | ||
) | [private] |
Read the image data of an interlaced PNG.
png_ptr | PNG file description. |
info_ptr | PNG file informations. |
passes | Number of passes (for interlaced images). |
Definition at line 261 of file png_reader.cpp.
References CLAW_PRECOND.
{ CLAW_PRECOND( passes > 1 ); CLAW_PRECOND( png_ptr ); CLAW_PRECOND( info_ptr ); const unsigned int row_length = s_rgba_pixel_size * m_image.width(); png_bytepp data = (png_bytepp)png_malloc( png_ptr, sizeof(png_bytep) * m_image.height() ); unsigned int i=0; try { for (i=0; i!=m_image.height(); ++i) { data[i] = (png_bytep)png_malloc( png_ptr, row_length ); if (!data[i]) throw std::bad_alloc(); copy_pixel_line( data[i], i ); } for (unsigned int p=0; p!=passes; ++p) png_read_rows( png_ptr, data, NULL, m_image.height() ); for (unsigned int y=0; y!=m_image.height(); ++y) copy_pixel_line( data[y], y ); } catch(...) { for(unsigned int j=0; j!=i; ++j) png_free(png_ptr, data[j]); png_free(png_ptr, data); throw; } for(i=0; i!=m_image.height(); ++i) png_free(png_ptr, data[i]); png_free(png_ptr, data); } // png::reader::read_interlaced_image()
void claw::graphic::png::reader::read_sequential_image | ( | png_structp | png_ptr, |
png_infop | info_ptr | ||
) | [private] |
Read the image data of a non interlaced PNG.
png_ptr | PNG file description. |
info_ptr | PNG file informations. |
Definition at line 228 of file png_reader.cpp.
References CLAW_PRECOND.
{ CLAW_PRECOND( png_ptr ); CLAW_PRECOND( info_ptr ); png_bytep data = (png_bytep)png_malloc( png_ptr, s_rgba_pixel_size * m_image.width() ); try { for (unsigned int y=0; y!=m_image.height(); ++y) { png_read_row(png_ptr, data, NULL); copy_pixel_line( data, y ); } } catch(...) { png_free(png_ptr, data); throw; } png_free(png_ptr, data); } // png::reader::read_sequential_image()
image& claw::graphic::png::reader::m_image [private] |
const unsigned int claw::graphic::png::reader::s_rgba_pixel_size = 4 [static, private] |