Visualize file data as a png.  Intended for memory or core dumps.

This tool is an experiment, intended to characterize the memory usage of large
process core dumps.  It does by converting each byte to a colored pixel, and
building an image from these line by line.  For serious core dump analysis,
look for other tools that read the metadata and structure from the dump.

By default, the least significant bit is masked, so that the image can't be
converted back to the input file, to avoid inadvertent privacy leaks.  Use -M
to avoid masking, or increase BYTE_MASK to mask more bits.

1. Build

Using gcc: gcc -O3 -lm -lpng -o dump2png dump2png.c

Requires libpng.  This is a good candidate for optimization (-O3).

2. Usage

$ ./dump2png --help
USAGE: dump2png [-HM] [-w width] [-h height_max]
                [-p palette] [-o outfile.png]
                [-k skip_factor] [-s seek_bytes]
                [-z zoom_factor] file

                [--help]	# for full help

palette types: gray, gray16b, gray16l, gray32b, gray32l,
               hues, hues6, fhues, color, color16, color32, rgb,
               dvi, x86 (default).

	-H            	don't autoscale height
	-M            	don't mask least significant bit
	-k skip_factor	skips horiz lines; eg, 3 means show 1 out of 3
	-s seek_bytes	the byte offset of the infile to begin reading
	-z zoom_factor	averages multiple bytes; eg, 16 avgs 16 as 1
	-z palette	palette type for colorization:

	gray		grayscale, per byte
	gray16b		grayscale, per short (big-endian)
	gray16l		grayscale, per short (little-endian)
	gray32b		grayscale, per long (big-endian)
	gray32l		grayscale, per long (little-endian)
	hues		map to 3 hue ranges (rgb), per byte (zoom safe)
	hues6		map to 6 hue ranges (rgbcmy), per byte
	fhues		map to 3 full hue ranges (rgb), per byte (zoom safe)
	color		full colorized scale, per byte
	color16		full colorized scale, per short (16-bit)
	color32		full colorized scale, per long (32-bit)
	rgb		treat 3 sequential bytes as RGB
	dvi		use RGB to convey differential, value, integral
	x86		grayscale with some (9) color indicators:

	    green = common english chars: 'e', 't', 'a'
	    red = common x86 instructions: movl, call, testl
	    blue = binary values: 0x01, 0x02, 0x03

3. Examples

$ ./dump2png core.node.13562	# by default uses "x86" palette
$ ./dump2png -w 2048 core	# output image 2048 pixels wide
$ ./dump2png -o out.png core	# write to "out.png"
$ ./dump2png -p gray core	# grayscale palette
$ ./dump2png -p color core	# full color palette
$ ./dump2png -p hues core	# RGB hues only (zoom friendly)
$ ./dump2png -z 32 core		# Zoom out by 32x (32 bytes averaged as 1 pixel)
$ ./dump2png -k 10 core		# Include one horiz line out of 10 (skip 9)

You can always open the images up in an image editor (eg, gimp) and apply more
effects.