Image Class


Summary

Class image stores an image and provides methods for reading, writing, and
manipulating images.  It requires libjpeg, which is installed by default with most
Linux distributions.  More info on libjpeg may be found here <http://www.ijg.org>.
The following formats are supported:

 raw PGM			read/write
 raw PPM			read/write
 JPEG(RGB or gray)		read/write
 raw TARGA(gray, RGB or RGBA)	read
 rle TARGA(gray, RGB or RGBA)	read


State

 uint	width		image width in pixels

 uint	height		image height in pixels

 uint	depth		number of color channels(bytes) per pixel.  Though the I/O
			methods only use depths [1, 4], the image manipulation
			methods handle arbitrary depths.

 ulong	size		total bytes needed to store the image: width by height
			by depth

 byte	*pixmap		pointer to pixel map


Methods

 	image()

		Set numbers to zero, pointer to NULL.

 	~image()

		Free pixel map memory.

 void	dump(FILE *OUT=stdout)

		Dump resolution and size information to the given file pointer.

 image&	operator=(const image &img)

		Allocate a new pixel map and copy all data.
		Return a reference to the current image.

 void	fliph()

		Flip image horizontally.

 void	flipv()

		Flip image vertically.

 image*	conform(uint width, uint height, char crop_align=0)

		Crop and scale to the given width and height.
		Crop alignment may be 'c'(center), 'l'(left), 'r'(right),
		't'(top), or 'b'(bottom), or zero(no cropping).

		Return a pointer to the new image.

 int	read_PNM(FILE *IN)

		Read a raw PGM(P5) or raw PPM(P6) image from the given file
		pointer.

		Return zero upon success, less-than-zero upon failure.

 int	write_PNM(FILE *OUT)

		Write a raw PGM(P5) if depth is 1, or a raw PPM(P6) if depth is
		3, to the given file pointer.

		Return zero upon success, less-than-zero upon failure.

 int	read_JPEG(FILE *IN)

		Read a JPEG file, which may be RGB or grayscale, from the given
		file pointer.

		Return zero upon success, less-than-zero upon failure.

 int	write_JPEG(FILE *OUT, int quality=75)

		Write a JPEG file, which may be RGB or grayscale, at the given
		quality, to the given file pointer.

		Return zero upon success, less-than-zero upon failure.

 int	read_TARGA(FILE *IN)

		Read a TARGA image from the given file pointer.
		The following TARGA types are supported:

		 2	raw	RGB(A)
		 3	raw	grayscale
		 10	rle	RGB(A)
		 11	rle	grayscale

		Return zero upon success, less-than-zero upon failure.

 int	read(char *path)

		Read any type suppored by the above read functions by calling
		the appropriate one, depending on the suffix(pgm, ppm, jpg, tga)
		of the given path.

		Return zero upon success, less-than-zero upon failure.