//! returns true if the file maybe is able to be loaded by this class
bool PictureLoaderPng::isALoadableFileFormat( vfs::NFile file) const
{
if( !file.isOpen() )
return false;
png_byte buffer[8];
// Read the first few bytes of the PNG file
if( file.read(buffer, 8) != 8 )
return false;
// Check if it really is a PNG file
return !png_sig_cmp(buffer, 0, 8);
}
// load in the image data
Picture PictureLoaderPng::load(vfs::NFile file , bool streaming) const
{
if(!file.isOpen())
{
Logger::warning( "LOAD PNG: can't open file " + file.path().toString() );
return Picture::getInvalid();
}
png_byte buffer[8];
// Read the first few bytes of the PNG file
if( file.read(buffer, 8) != 8 )
{
Logger::warning( "LOAD PNG: can't read file " + file.path().toString() );
return Picture::getInvalid();
}
// Check if it really is a PNG file
if( png_sig_cmp(buffer, 0, 8) )
{
Logger::warning( "LOAD PNG: not really a png " + file.path().toString() );
return Picture::getInvalid();
}
// Allocate the png read struct
png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
NULL, (png_error_ptr)png_cpexcept_error,
(png_error_ptr)png_cpexcept_warn);
if( !png_ptr )
{
Logger::warning( "LOAD PNG: Internal PNG create read struct failure " + file.path().toString() );
return Picture::getInvalid();
}
// Allocate the png info struct
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
Logger::warning( "LOAD PNG: Couldn't create image information for PNG file " + file.path().toString() );
png_destroy_read_struct(&png_ptr, NULL, NULL);
return Picture::getInvalid();
}
// for proper error handling
if (setjmp(png_jmpbuf(png_ptr)))
{
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
Logger::warning( "LOAD PNG: Error reading the PNG file. " + file.path().toString() );
return Picture::getInvalid();
}
// changed by zola so we don't need to have public FILE pointers
png_set_read_fn(png_ptr, &file, user_read_data_fcn);
png_set_sig_bytes(png_ptr, 8); // Tell png that we read the signature
png_read_info(png_ptr, info_ptr); // Read the info section of the png file
unsigned int Width;
unsigned int Height;
int BitDepth;
int ColorType;
{
// Use temporary variables to avoid passing casted pointers
png_uint_32 w,h;
// Extract info
png_get_IHDR(png_ptr, info_ptr,
&w, &h,
&BitDepth, &ColorType, NULL, NULL, NULL);
Width=w;
Height=h;
}
// Convert palette color to true color
if (ColorType==PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png_ptr);
// Convert low bit colors to 8 bit colors
if (BitDepth < 8)
{
if (ColorType==PNG_COLOR_TYPE_GRAY || ColorType==PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_expand_gray_1_2_4_to_8(png_ptr);
else
png_set_packing(png_ptr);
}
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
png_set_tRNS_to_alpha(png_ptr);
// Convert high bit colors to 8 bit colors
if (BitDepth == 16)
png_set_strip_16(png_ptr);
// Convert gray color to true color
if (ColorType==PNG_COLOR_TYPE_GRAY || ColorType==PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png_ptr);
int intent;
const double screen_gamma = 2.2;
if (png_get_sRGB(png_ptr, info_ptr, &intent))
png_set_gamma(png_ptr, screen_gamma, 0.45455);
else
{
double image_gamma;
if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
png_set_gamma(png_ptr, screen_gamma, image_gamma);
else
png_set_gamma(png_ptr, screen_gamma, 0.45455);
}
// Update the changes in between, as we need to get the new color type
// for proper processing of the RGBA type
png_read_update_info(png_ptr, info_ptr);
{
// Use temporary variables to avoid passing casted pointers
png_uint_32 w,h;
// Extract info
png_get_IHDR(png_ptr, info_ptr,
&w, &h,
&BitDepth, &ColorType, NULL, NULL, NULL);
Width=w;
Height=h;
}
// Convert RGBA to BGRA
if (ColorType==PNG_COLOR_TYPE_RGB_ALPHA)
{
png_set_bgr(png_ptr);
}
if( !Height )
{
Logger::warning( "LOAD PNG: Internal PNG create row pointers failure %s", file.path().toCString() );
png_destroy_read_struct(&png_ptr, NULL, NULL);
return Picture::getInvalid();
}
// Create array of pointers to rows in image data
std::vector<unsigned char> bytes;
int pixelSize = (ColorType==PNG_COLOR_TYPE_RGB_ALPHA ? 4 : 3);
bytes.resize( Width * Height * pixelSize );
ScopedArrayPtr<unsigned char*> RowPointers( (unsigned char**)new png_bytep[ Height ] );
// Fill array of pointers to rows in image data
unsigned char* data = &bytes[0];
for(unsigned int i=0; i<Height; ++i)
{
RowPointers.data()[i] = data;
data += Width * pixelSize;
}
// for proper error handling
if( setjmp( png_jmpbuf( png_ptr ) ) )
{
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return Picture::getInvalid();
}
// Read data using the library function that handles all transformations including interlacing
png_read_image( png_ptr, RowPointers.data() );
png_read_end( png_ptr, NULL );
png_destroy_read_struct( &png_ptr, &info_ptr, 0 ); // Clean up memory
// Create the image structure to be filled by png data
Picture pic;
if( ColorType==PNG_COLOR_TYPE_RGB_ALPHA )
{
pic = Picture( Size( Width, Height ), bytes.data(), streaming );
}
else
{
std::vector<unsigned char> b4;
b4.resize( Width * Height * 4 );
for( unsigned int index=0; index < Width * Height; index++ )
{
b4[ index*4+3 ] = 0xff;
b4[ index*4+0 ] = bytes[index*3+2];
b4[ index*4+1 ] = bytes[index*3+1];
b4[ index*4+2 ] = bytes[index*3+0];
}
pic = Picture( Size( Width, Height ), b4.data(), streaming );
}
return pic;
}