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PNMImageHeader Class Reference

This is the base class of PNMImage, PNMReader, and PNMWriter. More...

#include "pnmImageHeader.h"

Inheritance diagram for PNMImageHeader:
PfmFile PNMImage PNMReader PNMWriter PNMFileTypePfm::Reader PNMFileTypePfm::Writer

Classes

class  Histogram
 
class  PixelSpec
 
class  PixelSpecCount
 

Public Types

enum  ColorType {
  CT_invalid = 0, CT_grayscale = 1, CT_two_channel = 2, CT_color = 3,
  CT_four_channel = 4
}
 
typedef pmap< PixelSpec, int > HistMap
 
typedef pvector< PixelSpecPalette
 
typedef pvector< PixelSpecCountPixelCount
 

Public Member Functions

 PNMImageHeader (const PNMImageHeader &copy)
 
ColorSpace get_color_space () const
 
ColorType get_color_type () const
 Returns the image type of the image, as an enumerated value. More...
 
std::string get_comment () const
 
xelval get_maxval () const
 
int get_num_channels () const
 
LVecBase2i get_size () const
 
PNMFileTypeget_type () const
 
int get_x_size () const
 Returns the number of pixels in the X direction. More...
 
int get_y_size () const
 Returns the number of pixels in the Y direction. More...
 
bool has_alpha () const
 Returns true if the image includes an alpha channel, false otherwise. More...
 
bool has_type () const
 
bool is_grayscale () const
 Returns false if the image is a full-color image, and has red, green, and blue components; true if it is a grayscale image and has only a gray component. More...
 
PNMReadermake_reader (const Filename &filename, PNMFileType *type=nullptr, bool report_unknown_type=true) const
 Returns a newly-allocated PNMReader of the suitable type for reading from the indicated image filename, or NULL if the filename cannot be read for some reason. More...
 
PNMReadermake_reader (std::istream *file, bool owns_file=true, const Filename &filename=Filename(), std::string magic_number=std::string(), PNMFileType *type=nullptr, bool report_unknown_type=true) const
 Returns a newly-allocated PNMReader of the suitable type for reading from the already-opened image file, or NULL if the file cannot be read for some reason. More...
 
PNMWritermake_writer (const Filename &filename, PNMFileType *type=nullptr) const
 Returns a newly-allocated PNMWriter of the suitable type for writing an image to the indicated filename, or NULL if the filename cannot be written for some reason. More...
 
PNMWritermake_writer (std::ostream *file, bool owns_file=true, const Filename &filename=Filename(), PNMFileType *type=nullptr) const
 Returns a newly-allocated PNMWriter of the suitable type for writing to the already-opened image file, or NULL if the file cannot be written for some reason. More...
 
void operator= (const PNMImageHeader &copy)
 
void output (std::ostream &out) const
 
bool read_header (const Filename &filename, PNMFileType *type=nullptr, bool report_unknown_type=true)
 Opens up the image file and tries to read its header information to determine its size, number of channels, etc. More...
 
bool read_header (std::istream &data, const std::string &filename=std::string(), PNMFileType *type=nullptr, bool report_unknown_type=true)
 Reads the image header information only from the indicated stream. More...
 
void set_comment (const std::string &comment)
 
void set_type (PNMFileType *type)
 Sets the file type of this PNMImage. More...
 

Static Public Member Functions

static bool has_alpha (ColorType color_type)
 This static variant of has_alpha() returns true if the indicated image type includes an alpha channel, false otherwise. More...
 
static bool is_grayscale (ColorType color_type)
 This static variant of is_grayscale() returns true if the indicated image type represents a grayscale image, false otherwise. More...
 
static bool read_magic_number (std::istream *file, std::string &magic_number, int num_bytes)
 Ensures that the first n bytes of the file are read into magic_number. More...
 

Public Attributes

 get_color_space
 Returns the color space that the image is encoded in, or CS_unspecified if unknown. More...
 
 get_comment
 Gets the user comment from the file. More...
 
 get_maxval
 Returns the maximum channel value allowable for any pixel in this image; for instance, 255 for a typical 8-bit-per-channel image. More...
 
 get_num_channels
 Returns the number of channels in the image. More...
 
 get_size
 Returns the number of pixels in each direction. More...
 
 get_type
 If the file type is known (e.g. More...
 
 has_type
 Returns true if the PNMImageHeader knows what type it is, false otherwise. More...
 
 set_comment
 Writes a user comment string to the image (header). More...
 

Detailed Description

This is the base class of PNMImage, PNMReader, and PNMWriter.

It encapsulates all the information associated with an image that describes its size, number of channels, etc; that is, all the information about the image except the image data itself. It's the sort of information you typically read from the image file's header.

Definition at line 40 of file pnmImageHeader.h.

Member Function Documentation

◆ get_color_type()

PNMImageHeader::ColorType PNMImageHeader::get_color_type ( ) const
inline

Returns the image type of the image, as an enumerated value.

This is really just the number of channels cast to the enumerated type.

Definition at line 67 of file pnmImageHeader.I.

Referenced by osxGraphicsPipe::create_cg_image(), has_alpha(), and is_grayscale().

◆ get_x_size()

int PNMImageHeader::get_x_size ( ) const
inline

◆ get_y_size()

int PNMImageHeader::get_y_size ( ) const
inline

◆ has_alpha() [1/2]

bool PNMImageHeader::has_alpha ( PNMImageHeader::ColorType  color_type)
inlinestatic

This static variant of has_alpha() returns true if the indicated image type includes an alpha channel, false otherwise.

Definition at line 106 of file pnmImageHeader.I.

Referenced by PNMImage::add_sub_image(), PNMImage::blend_sub_image(), PNMImage::copy_sub_image(), PNMImage::mult_sub_image(), and PNMImage::unfiltered_stretch_from().

◆ has_alpha() [2/2]

bool PNMImageHeader::has_alpha ( ) const
inline

◆ is_grayscale() [1/2]

bool PNMImageHeader::is_grayscale ( PNMImageHeader::ColorType  color_type)
inlinestatic

This static variant of is_grayscale() returns true if the indicated image type represents a grayscale image, false otherwise.

Definition at line 86 of file pnmImageHeader.I.

◆ is_grayscale() [2/2]

bool PNMImageHeader::is_grayscale ( ) const
inline

Returns false if the image is a full-color image, and has red, green, and blue components; true if it is a grayscale image and has only a gray component.

(The gray color is actually stored in the blue channel, and the red and green channels are ignored.)

Definition at line 97 of file pnmImageHeader.I.

References get_color_type().

Referenced by PNMImage::add_alpha(), PNMImage::make_grayscale(), PNMImage::remove_alpha(), and PNMImage::write().

◆ make_reader() [1/2]

PNMReader * PNMImageHeader::make_reader ( const Filename filename,
PNMFileType type = nullptr,
bool  report_unknown_type = true 
) const

Returns a newly-allocated PNMReader of the suitable type for reading from the indicated image filename, or NULL if the filename cannot be read for some reason.

The filename "-" always stands for standard input. If type is specified, it is a suggestion for the file type to use.

The PNMReader should be deleted when it is no longer needed.

Definition at line 80 of file pnmImageHeader.cxx.

Referenced by PfmFile::read(), PNMImage::read(), and read_header().

◆ make_reader() [2/2]

PNMReader * PNMImageHeader::make_reader ( std::istream *  file,
bool  owns_file = true,
const Filename filename = Filename(),
std::string  magic_number = std::string(),
PNMFileType type = nullptr,
bool  report_unknown_type = true 
) const

Returns a newly-allocated PNMReader of the suitable type for reading from the already-opened image file, or NULL if the file cannot be read for some reason.

owns_file should be set true if the PNMReader is to be considered the owner of the stream pointer (in which case the stream will be deleted on completion, whether successful or not), or false if it should not delete it.

The filename parameter is optional here, since the file has already been opened; it is only used to examine the extension and attempt to guess the file type.

If magic_number is nonempty, it is assumed to represent the first few bytes that have already been read from the file. Some file types may have difficulty if this is more than two bytes.

If type is non-NULL, it is a suggestion for the file type to use.

The PNMReader should be deleted when it is no longer needed.

Definition at line 139 of file pnmImageHeader.cxx.

References read_magic_number().

◆ make_writer() [1/2]

PNMWriter * PNMImageHeader::make_writer ( const Filename filename,
PNMFileType type = nullptr 
) const

Returns a newly-allocated PNMWriter of the suitable type for writing an image to the indicated filename, or NULL if the filename cannot be written for some reason.

The filename "-" always stands for standard output. If type is specified, it is a suggestion for the file type to use.

The PNMWriter should be deleted when it is no longer needed.

Definition at line 248 of file pnmImageHeader.cxx.

Referenced by PfmFile::write(), and PNMImage::write().

◆ make_writer() [2/2]

PNMWriter * PNMImageHeader::make_writer ( std::ostream *  file,
bool  owns_file = true,
const Filename filename = Filename(),
PNMFileType type = nullptr 
) const

Returns a newly-allocated PNMWriter of the suitable type for writing to the already-opened image file, or NULL if the file cannot be written for some reason.

owns_file should be set true if the PNMWriter is to be considered the owner of the stream pointer (in which case the stream will be deleted on completion, whether successful or not), or false if it should not delete it.

The filename parameter is optional here, since the file has already been opened; it is only used to examine the extension and attempt to guess the intended file type.

If type is non-NULL, it is a suggestion for the file type to use.

The PNMWriter should be deleted when it is no longer needed.

Definition at line 304 of file pnmImageHeader.cxx.

References PNMFileTypeRegistry::get_global_ptr(), PNMFileTypeRegistry::get_type_from_extension(), PNMWriter::is_valid(), and PNMFileType::make_writer().

◆ read_header() [1/2]

bool PNMImageHeader::read_header ( const Filename filename,
PNMFileType type = nullptr,
bool  report_unknown_type = true 
)

Opens up the image file and tries to read its header information to determine its size, number of channels, etc.

If successful, updates the header information and returns true; otherwise, returns false.

Definition at line 33 of file pnmImageHeader.cxx.

References make_reader().

Referenced by SourceTextureImage::read_header(), and GeoMipTerrain::set_heightfield().

◆ read_header() [2/2]

bool PNMImageHeader::read_header ( std::istream &  data,
const std::string &  filename = std::string(),
PNMFileType type = nullptr,
bool  report_unknown_type = true 
)

Reads the image header information only from the indicated stream.

The filename is advisory only, and may be used to suggest a type if it has a known extension.

If type is non-NULL, it is a suggestion for the type of file it is (and a non-NULL type will override any magic number test or filename extension lookup).

Returns true if successful, false on error.

Definition at line 58 of file pnmImageHeader.cxx.

◆ read_magic_number()

bool PNMImageHeader::read_magic_number ( std::istream *  file,
std::string &  magic_number,
int  num_bytes 
)
static

Ensures that the first n bytes of the file are read into magic_number.

If magic_number is initially nonempty, assumes these represent the first few bytes already extracted. Returns true if successful, false if an end of file or error occurred before num_bytes could be read.

Definition at line 365 of file pnmImageHeader.cxx.

Referenced by make_reader().

◆ set_type()

void PNMImageHeader::set_type ( PNMFileType type)
inline

Sets the file type of this PNMImage.

This will be the default type used when an image is read, if the type cannot be determined by magic number or inferred by extension, or the type used when the image is written, if the type cannot be inferred from the filename extension.

Definition at line 206 of file pnmImageHeader.I.

Member Data Documentation

◆ get_color_space

ColorSpace PNMImageHeader::get_color_space
inline

Returns the color space that the image is encoded in, or CS_unspecified if unknown.

Definition at line 71 of file pnmImageHeader.h.

Referenced by GeoMipTerrain::set_heightfield().

◆ get_comment

std::string PNMImageHeader::get_comment
inline

Gets the user comment from the file.

Definition at line 80 of file pnmImageHeader.h.

◆ get_maxval

xelval PNMImageHeader::get_maxval
inline

Returns the maximum channel value allowable for any pixel in this image; for instance, 255 for a typical 8-bit-per-channel image.

A pixel with this value is full on.

Definition at line 70 of file pnmImageHeader.h.

Referenced by GeoMipTerrain::calc_ambient_occlusion(), PNMImage::clamp_val(), Texture::consider_rescale(), DestTextureImage::copy(), PNMImage::copy_channel(), PNMImage::copy_sub_image(), PNMImage::darken_sub_image(), PNMImage::expand_border(), PNMImage::indirect_1d_lookup(), PNMImage::lighten_sub_image(), PT(), PNMImage::read(), PNMImage::to_alpha_val(), and PNMImage::to_val().

◆ get_num_channels

int PNMImageHeader::get_num_channels
inline

◆ get_size

LVecBase2i PNMImageHeader::get_size
inline

Returns the number of pixels in each direction.

This is one more than the largest allowable coordinates.

Definition at line 76 of file pnmImageHeader.h.

◆ get_type

PNMFileType * PNMImageHeader::get_type
inline

If the file type is known (e.g.

has_type() returns true), returns its PNMFileType pointer; otherwise, returns NULL.

Definition at line 85 of file pnmImageHeader.h.

Referenced by Texture::consider_rescale(), PNMImage::expand_border(), and PNMImage::read().

◆ has_type

bool PNMImageHeader::has_type
inline

Returns true if the PNMImageHeader knows what type it is, false otherwise.

Definition at line 85 of file pnmImageHeader.h.

◆ set_comment

void PNMImageHeader::set_comment
inline

Writes a user comment string to the image (header).

Definition at line 80 of file pnmImageHeader.h.

Referenced by DisplayRegion::save_screenshot().


The documentation for this class was generated from the following files: