GIMP brush format is native to the GIMP image editor for storing a brush or a texture. It can be used in all Paint Tools, for example Pencil and Paintbrush. It works by repeating the brush bitmap as you move the tool. The Spacing parameter sets the distance between the brush marks as a percentage of brush width. Its default value can be set in the brush file.
You can also use GIMP to create new brushes in this format. Custom brushes can be loaded into GIMP for use in the paint tools by copying them into one of the Brush Folders - select Edit > Preferences in the menu bar, expand the Folders section and choose Brushes to see the recognized Brush Folders or to add new ones.
This page hosts a formal specification of GIMP brush file version 2 using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = GimpBrush.from_file("path/to/local/file.gbr")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = GimpBrush(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.len_header # => get len header
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
class GimpBrush(KaitaiStruct):
"""GIMP brush format is native to the GIMP image editor for storing a brush or a texture.
It can be used in all [Paint Tools](https://docs.gimp.org/2.10/en/gimp-tools-paint.html),
for example Pencil and Paintbrush. It works by repeating the brush bitmap as you move
the tool. The Spacing parameter sets the distance between the brush marks as a percentage
of brush width. Its default value can be set in the brush file.
You can also use GIMP to create new brushes in this format. Custom brushes can be loaded
into GIMP for use in the paint tools by copying them into one of the Brush Folders -
select **Edit** > **Preferences** in the menu bar, expand the **Folders** section
and choose **Brushes** to see the recognized Brush Folders or to add new ones.
.. seealso::
Source - https://github.com/GNOME/gimp/blob/441631322b/devel-docs/gbr.txt
"""
class ColorDepth(Enum):
grayscale = 1
rgba = 4
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.len_header = self._io.read_u4be()
self._raw_header = self._io.read_bytes((self.len_header - 4))
_io__raw_header = KaitaiStream(BytesIO(self._raw_header))
self.header = GimpBrush.Header(_io__raw_header, self, self._root)
class Header(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.version = self._io.read_u4be()
if not self.version == 2:
raise kaitaistruct.ValidationNotEqualError(2, self.version, self._io, u"/types/header/seq/0")
self.width = self._io.read_u4be()
if not self.width >= 1:
raise kaitaistruct.ValidationLessThanError(1, self.width, self._io, u"/types/header/seq/1")
if not self.width <= 10000:
raise kaitaistruct.ValidationGreaterThanError(10000, self.width, self._io, u"/types/header/seq/1")
self.height = self._io.read_u4be()
if not self.height >= 1:
raise kaitaistruct.ValidationLessThanError(1, self.height, self._io, u"/types/header/seq/2")
if not self.height <= 10000:
raise kaitaistruct.ValidationGreaterThanError(10000, self.height, self._io, u"/types/header/seq/2")
self.bytes_per_pixel = KaitaiStream.resolve_enum(GimpBrush.ColorDepth, self._io.read_u4be())
self.magic = self._io.read_bytes(4)
if not self.magic == b"\x47\x49\x4D\x50":
raise kaitaistruct.ValidationNotEqualError(b"\x47\x49\x4D\x50", self.magic, self._io, u"/types/header/seq/4")
self.spacing = self._io.read_u4be()
self.brush_name = (KaitaiStream.bytes_terminate(self._io.read_bytes_full(), 0, False)).decode(u"UTF-8")
class Bitmap(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.rows = []
for i in range(self._root.header.height):
self.rows.append(GimpBrush.Row(self._io, self, self._root))
class Row(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.pixels = []
for i in range(self._root.header.width):
_on = self._root.header.bytes_per_pixel
if _on == GimpBrush.ColorDepth.grayscale:
self.pixels.append(GimpBrush.Row.PixelGray(self._io, self, self._root))
elif _on == GimpBrush.ColorDepth.rgba:
self.pixels.append(GimpBrush.Row.PixelRgba(self._io, self, self._root))
class PixelGray(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.gray = self._io.read_u1()
@property
def red(self):
if hasattr(self, '_m_red'):
return self._m_red
self._m_red = 0
return getattr(self, '_m_red', None)
@property
def green(self):
if hasattr(self, '_m_green'):
return self._m_green
self._m_green = 0
return getattr(self, '_m_green', None)
@property
def blue(self):
if hasattr(self, '_m_blue'):
return self._m_blue
self._m_blue = 0
return getattr(self, '_m_blue', None)
@property
def alpha(self):
if hasattr(self, '_m_alpha'):
return self._m_alpha
self._m_alpha = self.gray
return getattr(self, '_m_alpha', None)
class PixelRgba(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.red = self._io.read_u1()
self.green = self._io.read_u1()
self.blue = self._io.read_u1()
self.alpha = self._io.read_u1()
@property
def len_body(self):
if hasattr(self, '_m_len_body'):
return self._m_len_body
self._m_len_body = ((self.header.width * self.header.height) * self.header.bytes_per_pixel.value)
return getattr(self, '_m_len_body', None)
@property
def body(self):
if hasattr(self, '_m_body'):
return self._m_body
_pos = self._io.pos()
self._io.seek(self.len_header)
self._m_body = self._io.read_bytes(self.len_body)
self._io.seek(_pos)
return getattr(self, '_m_body', None)