Block diagram
xwd is a file format written by eponymous X11 screen capture
application (xwd stands for "X Window Dump"). Typically, an average
user transforms xwd format into something more widespread by any of
xwdtopnm and pnmto... utilities right away.
xwd format itself provides a raw uncompressed bitmap with some metainformation, like pixel format, width, height, bit depth, etc. Note that technically format includes machine-dependent fields and thus is probably a poor choice for true cross-platform usage.
This page hosts a formal specification of xwd (X Window Dump) bitmap image using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
meta:
id: xwd
title: xwd (X Window Dump) bitmap image
application: xwd
file-extension: xwd
xref:
justsolve: XWD
pronom: fmt/401
license: CC0-1.0
endian: be
doc: |
xwd is a file format written by eponymous X11 screen capture
application (xwd stands for "X Window Dump"). Typically, an average
user transforms xwd format into something more widespread by any of
`xwdtopnm` and `pnmto...` utilities right away.
xwd format itself provides a raw uncompressed bitmap with some
metainformation, like pixel format, width, height, bit depth,
etc. Note that technically format includes machine-dependent fields
and thus is probably a poor choice for true cross-platform usage.
seq:
- id: len_header
type: u4
doc: Size of the header in bytes
- id: hdr
size: len_header - 4
type: header
- id: color_map
size: 12
type: color_map_entry
repeat: expr
repeat-expr: hdr.color_map_entries
types:
header:
seq:
- id: file_version
type: u4
doc: X11WD file version (always 07h)
- id: pixmap_format
type: u4
doc: Format of the image data
enum: pixmap_format
- id: pixmap_depth
type: u4
doc: Pixmap depth in pixels - in practice, bits per pixel
- id: pixmap_width
type: u4
doc: Pixmap width in pixels
- id: pixmap_height
type: u4
doc: Pixmap height in pixels
- id: x_offset
type: u4
doc: Bitmap X offset (number of pixels to ignore at the beginning of each scan-line)
- id: byte_order
type: u4
doc: Byte order of image data
enum: byte_order
- id: bitmap_unit
type: u4
doc: Bitmap base data size
- id: bitmap_bit_order
type: u4
doc: Bit-order of image data
- id: bitmap_pad
type: u4
doc: Bitmap scan-line pad
- id: bits_per_pixel
type: u4
doc: Bits per pixel
- id: bytes_per_line
type: u4
doc: Bytes per scan-line
- id: visual_class
type: u4
doc: Class of the image
enum: visual_class
- id: red_mask
type: u4
doc: Red mask
- id: green_mask
type: u4
doc: Green mask
- id: blue_mask
type: u4
doc: Blue mask
- id: bits_per_rgb
type: u4
doc: Size of each color mask in bits
- id: number_of_colors
type: u4
doc: Number of colors in image
- id: color_map_entries
type: u4
doc: Number of entries in color map
- id: window_width
type: u4
doc: Window width
- id: window_height
type: u4
doc: Window height
- id: window_x
type: s4
doc: Window upper left X coordinate
- id: window_y
type: s4
doc: Window upper left Y coordinate
- id: window_border_width
type: u4
doc: Window border width
- id: creator
type: strz
encoding: UTF-8
doc: Program that created this xwd file
color_map_entry:
seq:
- id: entry_number
type: u4
doc: Number of the color map entry
- id: red
type: u2
- id: green
type: u2
- id: blue
type: u2
- id: flags
type: u1
- id: padding
type: u1
enums:
pixmap_format:
0: x_y_bitmap
1: x_y_pixmap
2: z_pixmap
byte_order:
0: le
1: be
visual_class:
0: static_gray
1: gray_scale
2: static_color
3: pseudo_color
4: true_color
5: direct_color