1#
2# The Python Imaging Library
3#
4# load a GIMP brush file
5#
6# History:
7# 96-03-14 fl Created
8# 16-01-08 es Version 2
9#
10# Copyright (c) Secret Labs AB 1997.
11# Copyright (c) Fredrik Lundh 1996.
12# Copyright (c) Eric Soroos 2016.
13#
14# See the README file for information on usage and redistribution.
15#
16#
17# See https://github.com/GNOME/gimp/blob/mainline/devel-docs/gbr.txt for
18# format documentation.
19#
20# This code Interprets version 1 and 2 .gbr files.
21# Version 1 files are obsolete, and should not be used for new
22# brushes.
23# Version 2 files are saved by GIMP v2.8 (at least)
24# Version 3 files have a format specifier of 18 for 16bit floats in
25# the color depth field. This is currently unsupported by Pillow.
26from __future__ import annotations
27
28from . import Image, ImageFile
29from ._binary import i32be as i32
30
31
32def _accept(prefix: bytes) -> bool:
33 return len(prefix) >= 8 and i32(prefix, 0) >= 20 and i32(prefix, 4) in (1, 2)
34
35
36##
37# Image plugin for the GIMP brush format.
38
39
40class GbrImageFile(ImageFile.ImageFile):
41 format = "GBR"
42 format_description = "GIMP brush file"
43
44 def _open(self) -> None:
45 header_size = i32(self.fp.read(4))
46 if header_size < 20:
47 msg = "not a GIMP brush"
48 raise SyntaxError(msg)
49 version = i32(self.fp.read(4))
50 if version not in (1, 2):
51 msg = f"Unsupported GIMP brush version: {version}"
52 raise SyntaxError(msg)
53
54 width = i32(self.fp.read(4))
55 height = i32(self.fp.read(4))
56 color_depth = i32(self.fp.read(4))
57 if width <= 0 or height <= 0:
58 msg = "not a GIMP brush"
59 raise SyntaxError(msg)
60 if color_depth not in (1, 4):
61 msg = f"Unsupported GIMP brush color depth: {color_depth}"
62 raise SyntaxError(msg)
63
64 if version == 1:
65 comment_length = header_size - 20
66 else:
67 comment_length = header_size - 28
68 magic_number = self.fp.read(4)
69 if magic_number != b"GIMP":
70 msg = "not a GIMP brush, bad magic number"
71 raise SyntaxError(msg)
72 self.info["spacing"] = i32(self.fp.read(4))
73
74 comment = self.fp.read(comment_length)[:-1]
75
76 if color_depth == 1:
77 self._mode = "L"
78 else:
79 self._mode = "RGBA"
80
81 self._size = width, height
82
83 self.info["comment"] = comment
84
85 # Image might not be small
86 Image._decompression_bomb_check(self.size)
87
88 # Data is an uncompressed block of w * h * bytes/pixel
89 self._data_size = width * height * color_depth
90
91 def load(self) -> Image.core.PixelAccess | None:
92 if self._im is None:
93 self.im = Image.core.new(self.mode, self.size)
94 self.frombytes(self.fp.read(self._data_size))
95 return Image.Image.load(self)
96
97
98#
99# registry
100
101
102Image.register_open(GbrImageFile.format, GbrImageFile, _accept)
103Image.register_extension(GbrImageFile.format, ".gbr")