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trezor-firmware/python/src/trezorlib/toif.py

248 lines
7.7 KiB
Python

# This file is part of the Trezor project.
#
# Copyright (C) 2012-2022 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
import struct
import zlib
from dataclasses import dataclass
from enum import Enum
from typing import Sequence, Tuple
import construct as c
from typing_extensions import Literal
from .tools import EnumAdapter
try:
# Explanation of having to use "Image.Image" in typing:
# https://stackoverflow.com/questions/58236138/pil-and-python-static-typing/58236618#58236618
from PIL import Image
PIL_AVAILABLE = True
except ImportError:
PIL_AVAILABLE = False
RGBPixel = Tuple[int, int, int]
class ToifMode(Enum):
full_color = b"f" # big endian
grayscale = b"g" # odd hi
full_color_le = b"F" # little endian
grayscale_eh = b"G" # even hi
ToifStruct = c.Struct(
"magic" / c.Const(b"TOI"),
"format" / EnumAdapter(c.Bytes(1), ToifMode),
"width" / c.Int16ul,
"height" / c.Int16ul,
"data" / c.Prefixed(c.Int32ul, c.GreedyBytes),
)
def _compress(data: bytes) -> bytes:
z = zlib.compressobj(level=9, wbits=-10)
return z.compress(data) + z.flush()
def _decompress(data: bytes) -> bytes:
return zlib.decompress(data, wbits=-10)
def _from_pil_rgb(pixels: Sequence[RGBPixel], little_endian: bool) -> bytes:
data = bytearray()
for r, g, b in pixels:
c = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | ((b & 0xF8) >> 3)
if little_endian:
data += struct.pack("<H", c)
else:
data += struct.pack(">H", c)
return bytes(data)
def _to_rgb(data: bytes, little_endian: bool) -> bytes:
res = bytearray()
for i in range(0, len(data), 2):
if little_endian:
(c,) = struct.unpack("<H", data[i : i + 2])
else:
(c,) = struct.unpack(">H", data[i : i + 2])
r = (c & 0xF800) >> 8
g = (c & 0x07E0) >> 3
b = (c & 0x001F) << 3
res += bytes((r, g, b))
return bytes(res)
def _from_pil_grayscale(pixels: Sequence[int], right_hi: bool) -> bytes:
data = bytearray()
for i in range(0, len(pixels), 2):
left, right = pixels[i], pixels[i + 1]
if right_hi:
c = (right & 0xF0) | ((left & 0xF0) >> 4)
else:
c = (left & 0xF0) | ((right & 0xF0) >> 4)
data += struct.pack(">B", c)
return bytes(data)
def _from_pil_grayscale_alpha(
pixels: Sequence[Tuple[int, int]], right_hi: bool
) -> bytes:
data = bytearray()
for i in range(0, len(pixels), 2):
left_w_alpha, right_w_alpha = pixels[i], pixels[i + 1]
left = int((left_w_alpha[0] * left_w_alpha[1]) / 255)
right = int((right_w_alpha[0] * right_w_alpha[1]) / 255)
if right_hi:
c = (right & 0xF0) | ((left & 0xF0) >> 4)
else:
c = (left & 0xF0) | ((right & 0xF0) >> 4)
data += struct.pack(">B", c)
return bytes(data)
def _to_grayscale(data: bytes, right_hi: bool) -> bytes:
res = bytearray()
for pixel in data:
if right_hi:
right = pixel & 0xF0
left = (pixel & 0x0F) << 4
else:
left = pixel & 0xF0
right = (pixel & 0x0F) << 4
res += bytes((left, right))
return bytes(res)
@dataclass
class Toif:
mode: ToifMode
size: Tuple[int, int]
data: bytes
def __post_init__(self) -> None:
# checking the data size
width, height = self.size
if self.mode is ToifMode.grayscale or self.mode is ToifMode.grayscale_eh:
expected_size = width * height // 2
else:
expected_size = width * height * 2
uncompressed = _decompress(self.data)
if len(uncompressed) != expected_size:
raise ValueError(
f"Uncompressed data is {len(uncompressed)} bytes, expected {expected_size}"
)
def to_image(self) -> "Image.Image":
if not PIL_AVAILABLE:
raise RuntimeError(
"PIL is not available. Please install via 'pip install Pillow'"
)
uncompressed = _decompress(self.data)
pil_mode: Literal["L", "RGB"]
if self.mode is ToifMode.grayscale:
pil_mode = "L"
raw_data = _to_grayscale(uncompressed, right_hi=False)
elif self.mode is ToifMode.grayscale_eh:
pil_mode = "L"
raw_data = _to_grayscale(uncompressed, right_hi=True)
elif self.mode is ToifMode.full_color:
pil_mode = "RGB"
raw_data = _to_rgb(uncompressed, little_endian=False)
else: # self.mode is ToifMode.full_color_le:
pil_mode = "RGB"
raw_data = _to_rgb(uncompressed, little_endian=True)
return Image.frombuffer(pil_mode, self.size, raw_data, "raw", pil_mode, 0, 1)
def to_bytes(self) -> bytes:
width, height = self.size
return ToifStruct.build(
dict(format=self.mode, width=width, height=height, data=self.data)
)
def save(self, filename: str) -> None:
with open(filename, "wb") as out:
out.write(self.to_bytes())
def from_bytes(data: bytes) -> Toif:
return from_struct(ToifStruct.parse(data))
def from_struct(parsed: c.Container) -> Toif:
return Toif(parsed.format, (parsed.width, parsed.height), parsed.data)
def load(filename: str) -> Toif:
with open(filename, "rb") as f:
return from_bytes(f.read())
def from_image(
image: "Image.Image",
background: Tuple[int, int, int, int] = (0, 0, 0, 255),
legacy_format: bool = False,
) -> Toif:
if not PIL_AVAILABLE:
raise RuntimeError(
"PIL is not available. Please install via 'pip install Pillow'"
)
if image.mode == "RGBA":
img_background = Image.new("RGBA", image.size, background)
blend = Image.alpha_composite(img_background, image)
image = blend.convert("RGB")
if image.mode == "1":
image = image.convert("L")
if image.mode == "L":
if image.size[0] % 2 != 0:
raise ValueError("Only even-width grayscale images are supported")
if not legacy_format:
toif_mode = ToifMode.grayscale_eh
toif_data = _from_pil_grayscale(image.getdata(), right_hi=True)
else:
toif_mode = ToifMode.grayscale
toif_data = _from_pil_grayscale(image.getdata(), right_hi=False)
elif image.mode == "LA":
toif_mode = ToifMode.grayscale
if image.size[0] % 2 != 0:
raise ValueError("Only even-width grayscale images are supported")
if not legacy_format:
toif_mode = ToifMode.grayscale_eh
toif_data = _from_pil_grayscale_alpha(image.getdata(), right_hi=True)
else:
toif_mode = ToifMode.grayscale
toif_data = _from_pil_grayscale_alpha(image.getdata(), right_hi=False)
elif image.mode == "RGB":
if not legacy_format:
toif_mode = ToifMode.full_color_le
toif_data = _from_pil_rgb(image.getdata(), little_endian=True)
else:
toif_mode = ToifMode.full_color
toif_data = _from_pil_rgb(image.getdata(), little_endian=False)
else:
raise ValueError(f"Unsupported image mode: {image.mode}")
data = _compress(toif_data)
return Toif(toif_mode, image.size, data)