871 lines
34 KiB
Python
871 lines
34 KiB
Python
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"""Fetch and decode images in various formats."""
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import io
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import math
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import struct
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from hashlib import md5
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from io import BytesIO
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from itertools import cycle
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from math import inf
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from pathlib import Path
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from urllib.parse import urlparse
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from urllib.request import url2pathname
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from xml.etree import ElementTree
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import pydyf
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from PIL import Image, ImageFile, ImageOps
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from . import DEFAULT_OPTIONS
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from .layout.percent import percentage
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from .logger import LOGGER
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from .svg import SVG
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from .urls import URLFetchingError, fetch
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# Don’t crash when converting truncated images
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ImageFile.LOAD_TRUNCATED_IMAGES = True
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class ImageLoadingError(ValueError):
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"""An error occured when loading an image.
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The image data is probably corrupted or in an invalid format.
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"""
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@classmethod
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def from_exception(cls, exception):
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name = type(exception).__name__
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value = str(exception)
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return cls(f'{name}: {value}' if value else name)
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class RasterImage:
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def __init__(self, pillow_image, image_id, image_data, filename=None,
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cache=None, orientation='none', options=DEFAULT_OPTIONS):
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# Transpose image
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original_pillow_image = pillow_image
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pillow_image = rotate_pillow_image(pillow_image, orientation)
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if original_pillow_image is not pillow_image:
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# Keep image format as it is discarded by transposition
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pillow_image.format = original_pillow_image.format
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# Discard original data, as the image has been transformed
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image_data = filename = None
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self.id = image_id
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self._cache = {} if cache is None else cache
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self._jpeg_quality = jpeg_quality = options['jpeg_quality']
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self._dpi = options['dpi']
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if 'transparency' in pillow_image.info:
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pillow_image = pillow_image.convert('RGBA')
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elif pillow_image.mode in ('1', 'P', 'I'):
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pillow_image = pillow_image.convert('RGB')
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self.mode = pillow_image.mode
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self.width = pillow_image.width
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self.height = pillow_image.height
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self.ratio = (self.width / self.height) if self.height != 0 else inf
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self.optimize = optimize = options['optimize_images']
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if pillow_image.format in ('JPEG', 'MPO'):
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self.format = 'JPEG'
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if image_data is None or optimize or jpeg_quality is not None:
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image_file = io.BytesIO()
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options = {'format': 'JPEG', 'optimize': optimize}
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if self._jpeg_quality is not None:
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options['quality'] = self._jpeg_quality
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pillow_image.save(image_file, **options)
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image_data = image_file.getvalue()
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filename = None
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else:
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self.format = 'PNG'
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if image_data is None or optimize or pillow_image.format != 'PNG':
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image_file = io.BytesIO()
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pillow_image.save(image_file, format='PNG', optimize=optimize)
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image_data = image_file.getvalue()
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filename = None
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self.image_data = self.cache_image_data(image_data, filename)
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def get_intrinsic_size(self, resolution, font_size):
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return self.width / resolution, self.height / resolution, self.ratio
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def draw(self, stream, concrete_width, concrete_height, image_rendering):
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if self.width <= 0 or self.height <= 0:
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return
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interpolate = image_rendering == 'auto'
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ratio = 1
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if self._dpi:
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pt_to_in = 4 / 3 / 96
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width_inches = abs(concrete_width * stream.ctm[0][0] * pt_to_in)
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height_inches = abs(concrete_height * stream.ctm[1][1] * pt_to_in)
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dpi = max(self.width / width_inches, self.height / height_inches)
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if dpi > self._dpi:
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ratio = self._dpi / dpi
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image_name = stream.add_image(self, interpolate, ratio)
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stream.transform(
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concrete_width, 0, 0, -concrete_height, 0, concrete_height)
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stream.draw_x_object(image_name)
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def cache_image_data(self, data, filename=None, alpha=False):
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if filename:
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return LazyLocalImage(filename)
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else:
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key = f'{self.id}{int(alpha)}{self._dpi or ""}'
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return LazyImage(self._cache, key, data)
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def get_x_object(self, interpolate, dpi_ratio):
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if dpi_ratio == 1:
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width, height = self.width, self.height
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else:
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thumbnail = Image.open(io.BytesIO(self.image_data.data))
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width = max(1, int(round(self.width * dpi_ratio)))
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height = max(1, int(round(self.height * dpi_ratio)))
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thumbnail.thumbnail((width, height))
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image_file = io.BytesIO()
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thumbnail.save(
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image_file, format=thumbnail.format, optimize=self.optimize)
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width, height = thumbnail.width, thumbnail.height
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self.image_data = self.cache_image_data(image_file.getvalue())
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if self.mode in ('RGB', 'RGBA'):
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color_space = '/DeviceRGB'
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elif self.mode in ('L', 'LA'):
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color_space = '/DeviceGray'
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elif self.mode == 'CMYK':
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color_space = '/DeviceCMYK'
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else:
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LOGGER.warning('Unknown image mode: %s', self.mode)
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color_space = '/DeviceRGB'
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extra = pydyf.Dictionary({
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'Type': '/XObject',
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'Subtype': '/Image',
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'Width': width,
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'Height': height,
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'ColorSpace': color_space,
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'BitsPerComponent': 8,
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'Interpolate': 'true' if interpolate else 'false',
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})
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if self.format == 'JPEG':
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extra['Filter'] = '/DCTDecode'
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return pydyf.Stream([self.image_data], extra)
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extra['Filter'] = '/FlateDecode'
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extra['DecodeParms'] = pydyf.Dictionary({
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# Predictor 15 specifies that we're providing PNG data,
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# ostensibly using an "optimum predictor", but doesn't actually
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# matter as long as the predictor value is 10+ according to the
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# spec. (Other PNG predictor values assert that we're using
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# specific predictors that we don't want to commit to, but
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# "optimum" can vary.)
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'Predictor': 15,
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'Columns': width,
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})
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if self.mode in ('RGB', 'RGBA'):
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# Defaults to 1.
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extra['DecodeParms']['Colors'] = 3
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if self.mode in ('RGBA', 'LA'):
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# Remove alpha channel from image
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pillow_image = Image.open(io.BytesIO(self.image_data.data))
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alpha = pillow_image.getchannel('A')
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pillow_image = pillow_image.convert(self.mode[:-1])
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png_data = self._get_png_data(pillow_image)
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# Save alpha channel as mask
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alpha_data = self._get_png_data(alpha)
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stream = self.cache_image_data(alpha_data, alpha=True)
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extra['SMask'] = pydyf.Stream([stream], extra={
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'Filter': '/FlateDecode',
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'Type': '/XObject',
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'Subtype': '/Image',
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'DecodeParms': pydyf.Dictionary({
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'Predictor': 15,
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'Columns': width,
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}),
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'Width': width,
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'Height': height,
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'ColorSpace': '/DeviceGray',
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'BitsPerComponent': 8,
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'Interpolate': 'true' if interpolate else 'false',
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})
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else:
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png_data = self._get_png_data(
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Image.open(io.BytesIO(self.image_data.data)))
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return pydyf.Stream([self.cache_image_data(png_data)], extra)
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@staticmethod
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def _get_png_data(pillow_image):
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image_file = BytesIO()
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pillow_image.save(image_file, format='PNG')
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# Read the PNG header, then discard it because we know it's a PNG. If
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# this weren't just output from Pillow, we should actually check it.
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image_file.seek(8)
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png_data = []
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raw_chunk_length = image_file.read(4)
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# PNG files consist of a series of chunks.
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while raw_chunk_length:
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# Each chunk begins with its data length (four bytes, may be zero),
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# then its type (four ASCII characters), then the data, then four
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# bytes of a CRC.
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chunk_length, = struct.unpack('!I', raw_chunk_length)
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chunk_type = image_file.read(4)
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if chunk_type == b'IDAT':
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png_data.append(image_file.read(chunk_length))
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else:
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image_file.seek(chunk_length, io.SEEK_CUR)
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# We aren't checking the CRC, we assume this is a valid PNG.
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image_file.seek(4, io.SEEK_CUR)
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raw_chunk_length = image_file.read(4)
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return b''.join(png_data)
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class LazyImage(pydyf.Object):
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def __init__(self, cache, key, data):
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super().__init__()
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self._key = key
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self._cache = cache
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cache[key] = data
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@property
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def data(self):
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return self._cache[self._key]
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class LazyLocalImage(pydyf.Object):
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def __init__(self, filename):
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super().__init__()
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self._filename = filename
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@property
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def data(self):
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return Path(self._filename).read_bytes()
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class SVGImage:
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def __init__(self, tree, base_url, url_fetcher, context):
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self._svg = SVG(tree, base_url)
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self._base_url = base_url
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self._url_fetcher = url_fetcher
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self._context = context
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def get_intrinsic_size(self, image_resolution, font_size):
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width, height = self._svg.get_intrinsic_size(font_size)
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if None in (width, height):
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viewbox = self._svg.get_viewbox()
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if viewbox and viewbox[2] and viewbox[3]:
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ratio = viewbox[2] / viewbox[3]
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if width:
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height = width / ratio
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elif height:
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width = height * ratio
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else:
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ratio = None
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elif width and height:
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ratio = width / height
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else:
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ratio = 1
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return width, height, ratio
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def draw(self, stream, concrete_width, concrete_height, image_rendering):
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try:
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self._svg.draw(
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stream, concrete_width, concrete_height, self._base_url,
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self._url_fetcher, self._context)
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except BaseException:
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LOGGER.error('Failed to render SVG image %s', self._base_url)
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def get_image_from_uri(cache, url_fetcher, options, url, forced_mime_type=None,
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context=None, orientation='from-image'):
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"""Get an Image instance from an image URI."""
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if url in cache:
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return cache[url]
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try:
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with fetch(url_fetcher, url) as result:
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parsed_url = urlparse(result.get('redirected_url'))
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if parsed_url.scheme == 'file':
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filename = url2pathname(parsed_url.path)
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else:
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filename = None
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if 'string' in result:
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string = result['string']
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else:
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string = result['file_obj'].read()
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mime_type = forced_mime_type or result['mime_type']
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image = None
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svg_exceptions = []
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# Try to rely on given mimetype for SVG
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if mime_type == 'image/svg+xml':
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try:
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tree = ElementTree.fromstring(string)
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image = SVGImage(tree, url, url_fetcher, context)
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except Exception as svg_exception:
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svg_exceptions.append(svg_exception)
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# Try pillow for raster images, or for failing SVG
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if image is None:
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try:
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pillow_image = Image.open(BytesIO(string))
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except Exception as raster_exception:
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if mime_type == 'image/svg+xml':
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# Tried SVGImage then Pillow for a SVG, abort
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raise ImageLoadingError.from_exception(svg_exceptions[0])
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try:
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# Last chance, try SVG
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tree = ElementTree.fromstring(string)
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image = SVGImage(tree, url, url_fetcher, context)
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except Exception:
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# Tried Pillow then SVGImage for a raster, abort
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raise ImageLoadingError.from_exception(raster_exception)
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else:
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# Store image id to enable cache in Stream.add_image
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image_id = md5(url.encode()).hexdigest()
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image = RasterImage(
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pillow_image, image_id, string, filename, cache,
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orientation, options)
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except (URLFetchingError, ImageLoadingError) as exception:
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LOGGER.error('Failed to load image at %r: %s', url, exception)
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image = None
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cache[url] = image
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return image
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def rotate_pillow_image(pillow_image, orientation):
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"""Return a copy of a Pillow image with modified orientation.
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If orientation is not changed, return the same image.
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"""
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image_format = pillow_image.format
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|
|
if orientation == 'from-image':
|
|||
|
|
if 'exif' in pillow_image.info:
|
|||
|
|
pillow_image = ImageOps.exif_transpose(pillow_image)
|
|||
|
|
elif orientation != 'none':
|
|||
|
|
angle, flip = orientation
|
|||
|
|
if angle > 0:
|
|||
|
|
rotation = getattr(Image.Transpose, f'ROTATE_{angle}')
|
|||
|
|
pillow_image = pillow_image.transpose(rotation)
|
|||
|
|
if flip:
|
|||
|
|
pillow_image = pillow_image.transpose(
|
|||
|
|
Image.Transpose.FLIP_LEFT_RIGHT)
|
|||
|
|
|
|||
|
|
# Keep image format as it is discarded by transposition
|
|||
|
|
pillow_image.format = image_format
|
|||
|
|
return pillow_image
|
|||
|
|
|
|||
|
|
|
|||
|
|
def process_color_stops(vector_length, positions):
|
|||
|
|
"""Give color stops positions on the gradient vector.
|
|||
|
|
|
|||
|
|
``vector_length`` is the distance between the starting point and ending
|
|||
|
|
point of the vector gradient.
|
|||
|
|
|
|||
|
|
``positions`` is a list of ``None``, or ``Dimension`` in px or %. 0 is the
|
|||
|
|
starting point, 1 the ending point.
|
|||
|
|
|
|||
|
|
See https://drafts.csswg.org/css-images-3/#color-stop-syntax.
|
|||
|
|
|
|||
|
|
Return processed color stops, as a list of floats in px.
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
# Resolve percentages
|
|||
|
|
positions = [percentage(position, vector_length) for position in positions]
|
|||
|
|
|
|||
|
|
# First and last default to 100%
|
|||
|
|
if positions[0] is None:
|
|||
|
|
positions[0] = 0
|
|||
|
|
if positions[-1] is None:
|
|||
|
|
positions[-1] = vector_length
|
|||
|
|
|
|||
|
|
# Make sure positions are increasing
|
|||
|
|
previous_pos = positions[0]
|
|||
|
|
for i, position in enumerate(positions):
|
|||
|
|
if position is not None:
|
|||
|
|
if position < previous_pos:
|
|||
|
|
positions[i] = previous_pos
|
|||
|
|
else:
|
|||
|
|
previous_pos = position
|
|||
|
|
|
|||
|
|
# Assign missing values
|
|||
|
|
previous_i = -1
|
|||
|
|
for i, position in enumerate(positions):
|
|||
|
|
if position is not None:
|
|||
|
|
base = positions[previous_i]
|
|||
|
|
increment = (position - base) / (i - previous_i)
|
|||
|
|
for j in range(previous_i + 1, i):
|
|||
|
|
positions[j] = base + j * increment
|
|||
|
|
previous_i = i
|
|||
|
|
|
|||
|
|
return positions
|
|||
|
|
|
|||
|
|
|
|||
|
|
def normalize_stop_positions(positions):
|
|||
|
|
"""Normalize stop positions between 0 and 1.
|
|||
|
|
|
|||
|
|
Return ``(first, last, positions)``.
|
|||
|
|
|
|||
|
|
first: original position of the first position.
|
|||
|
|
last: original position of the last position.
|
|||
|
|
positions: list of positions between 0 and 1.
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
first, last = positions[0], positions[-1]
|
|||
|
|
total_length = last - first
|
|||
|
|
if total_length == 0:
|
|||
|
|
positions = [0] * len(positions)
|
|||
|
|
else:
|
|||
|
|
positions = [(pos - first) / total_length for pos in positions]
|
|||
|
|
return first, last, positions
|
|||
|
|
|
|||
|
|
|
|||
|
|
def gradient_average_color(colors, positions):
|
|||
|
|
"""
|
|||
|
|
https://drafts.csswg.org/css-images-3/#gradient-average-color
|
|||
|
|
"""
|
|||
|
|
nb_stops = len(positions)
|
|||
|
|
assert nb_stops > 1
|
|||
|
|
assert nb_stops == len(colors)
|
|||
|
|
total_length = positions[-1] - positions[0]
|
|||
|
|
if total_length == 0:
|
|||
|
|
positions = list(range(nb_stops))
|
|||
|
|
total_length = nb_stops - 1
|
|||
|
|
premul_r = [r * a for r, g, b, a in colors]
|
|||
|
|
premul_g = [g * a for r, g, b, a in colors]
|
|||
|
|
premul_b = [b * a for r, g, b, a in colors]
|
|||
|
|
alpha = [a for r, g, b, a in colors]
|
|||
|
|
result_r = result_g = result_b = result_a = 0
|
|||
|
|
total_weight = 2 * total_length
|
|||
|
|
for i, position in enumerate(positions[1:], 1):
|
|||
|
|
weight = (position - positions[i - 1]) / total_weight
|
|||
|
|
for j in (i - 1, i):
|
|||
|
|
result_r += premul_r[j] * weight
|
|||
|
|
result_g += premul_g[j] * weight
|
|||
|
|
result_b += premul_b[j] * weight
|
|||
|
|
result_a += alpha[j] * weight
|
|||
|
|
# Un-premultiply:
|
|||
|
|
return (result_r / result_a, result_g / result_a,
|
|||
|
|
result_b / result_a, result_a) if result_a != 0 else (0, 0, 0, 0)
|
|||
|
|
|
|||
|
|
|
|||
|
|
class Gradient:
|
|||
|
|
def __init__(self, color_stops, repeating):
|
|||
|
|
assert color_stops
|
|||
|
|
# List of (r, g, b, a)
|
|||
|
|
self.colors = tuple(color for color, _ in color_stops)
|
|||
|
|
# List of Dimensions
|
|||
|
|
self.stop_positions = tuple(position for _, position in color_stops)
|
|||
|
|
# Boolean
|
|||
|
|
self.repeating = repeating
|
|||
|
|
|
|||
|
|
def get_intrinsic_size(self, image_resolution, font_size):
|
|||
|
|
return None, None, None
|
|||
|
|
|
|||
|
|
def draw(self, stream, concrete_width, concrete_height, _image_rendering):
|
|||
|
|
# TODO: handle color spaces
|
|||
|
|
scale_y, type_, points, positions, colors = self.layout(
|
|||
|
|
concrete_width, concrete_height)
|
|||
|
|
|
|||
|
|
if type_ == 'solid':
|
|||
|
|
stream.rectangle(0, 0, concrete_width, concrete_height)
|
|||
|
|
red, green, blue, alpha = colors[0]
|
|||
|
|
stream.set_color_rgb(red, green, blue)
|
|||
|
|
if alpha != 1:
|
|||
|
|
stream.set_alpha(alpha, stroke=False)
|
|||
|
|
stream.fill()
|
|||
|
|
return
|
|||
|
|
|
|||
|
|
alphas = [color[3] for color in colors]
|
|||
|
|
alpha_couples = [
|
|||
|
|
(alphas[i], alphas[i + 1])
|
|||
|
|
for i in range(len(alphas) - 1)]
|
|||
|
|
color_couples = [
|
|||
|
|
[colors[i][:3], colors[i + 1][:3], 1]
|
|||
|
|
for i in range(len(colors) - 1)]
|
|||
|
|
|
|||
|
|
# Premultiply colors
|
|||
|
|
for i, alpha in enumerate(alphas):
|
|||
|
|
if alpha == 0:
|
|||
|
|
if i > 0:
|
|||
|
|
color_couples[i - 1][1] = color_couples[i - 1][0]
|
|||
|
|
if i < len(colors) - 1:
|
|||
|
|
color_couples[i][0] = color_couples[i][1]
|
|||
|
|
for i, (a0, a1) in enumerate(alpha_couples):
|
|||
|
|
if 0 not in (a0, a1) and (a0, a1) != (1, 1):
|
|||
|
|
color_couples[i][2] = a0 / a1
|
|||
|
|
|
|||
|
|
shading_type = 2 if type_ == 'linear' else 3
|
|||
|
|
domain = (positions[0], positions[-1])
|
|||
|
|
extend = not self.repeating
|
|||
|
|
encode = (len(colors) - 1) * (0, 1)
|
|||
|
|
bounds = positions[1:-1]
|
|||
|
|
sub_functions = (
|
|||
|
|
stream.create_interpolation_function((0, 1), c0, c1, n)
|
|||
|
|
for c0, c1, n in color_couples)
|
|||
|
|
function = stream.create_stitching_function(
|
|||
|
|
domain, encode, bounds, sub_functions)
|
|||
|
|
shading = stream.add_shading(
|
|||
|
|
shading_type, 'RGB', domain, points, extend, function)
|
|||
|
|
stream.transform(d=scale_y)
|
|||
|
|
|
|||
|
|
if any(alpha != 1 for alpha in alphas):
|
|||
|
|
alpha_stream = stream.set_alpha_state(
|
|||
|
|
0, 0, concrete_width, concrete_height)
|
|||
|
|
|
|||
|
|
shading_type = 2 if type_ == 'linear' else 3
|
|||
|
|
sub_functions = (
|
|||
|
|
stream.create_interpolation_function((0, 1), (c0,), (c1,), 1)
|
|||
|
|
for c0, c1 in alpha_couples)
|
|||
|
|
function = stream.create_stitching_function(
|
|||
|
|
domain, encode, bounds, sub_functions)
|
|||
|
|
alpha_shading = alpha_stream.add_shading(
|
|||
|
|
shading_type, 'Gray', domain, points, extend, function)
|
|||
|
|
alpha_stream.transform(d=scale_y)
|
|||
|
|
alpha_stream.stream = [f'/{alpha_shading.id} sh']
|
|||
|
|
|
|||
|
|
stream.shading(shading.id)
|
|||
|
|
|
|||
|
|
def layout(self, width, height):
|
|||
|
|
"""Get layout information about the gradient.
|
|||
|
|
|
|||
|
|
width, height: Gradient box. Top-left is at coordinates (0, 0).
|
|||
|
|
|
|||
|
|
Returns (scale_y, type_, points, positions, colors).
|
|||
|
|
|
|||
|
|
scale_y: vertical scale of the gradient. float, used for ellipses
|
|||
|
|
radial gradients. 1 otherwise.
|
|||
|
|
type_: gradient type.
|
|||
|
|
points: coordinates of useful points, depending on type_:
|
|||
|
|
'solid': None.
|
|||
|
|
'linear': (x0, y0, x1, y1)
|
|||
|
|
coordinates of the starting and ending points.
|
|||
|
|
'radial': (cx0, cy0, radius0, cx1, cy1, radius1)
|
|||
|
|
coordinates of the starting end ending circles
|
|||
|
|
positions: positions of the color stops. list of floats in between 0
|
|||
|
|
and 1 (0 at the starting point, 1 at the ending point).
|
|||
|
|
colors: list of (r, g, b, a).
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
raise NotImplementedError
|
|||
|
|
|
|||
|
|
|
|||
|
|
class LinearGradient(Gradient):
|
|||
|
|
def __init__(self, color_stops, direction, repeating):
|
|||
|
|
Gradient.__init__(self, color_stops, repeating)
|
|||
|
|
# ('corner', keyword) or ('angle', radians)
|
|||
|
|
self.direction_type, self.direction = direction
|
|||
|
|
|
|||
|
|
def layout(self, width, height):
|
|||
|
|
# Only one color, render the gradient as a solid color
|
|||
|
|
if len(self.colors) == 1:
|
|||
|
|
return 1, 'solid', None, [], [self.colors[0]]
|
|||
|
|
|
|||
|
|
# Define the (dx, dy) unit vector giving the direction of the gradient.
|
|||
|
|
# Positive dx: right, positive dy: down.
|
|||
|
|
if self.direction_type == 'corner':
|
|||
|
|
y, x = self.direction.split('_')
|
|||
|
|
factor_x = -1 if x == 'left' else 1
|
|||
|
|
factor_y = -1 if y == 'top' else 1
|
|||
|
|
diagonal = math.hypot(width, height)
|
|||
|
|
# Note the direction swap: dx based on height, dy based on width
|
|||
|
|
# The gradient line is perpendicular to a diagonal.
|
|||
|
|
dx = factor_x * height / diagonal
|
|||
|
|
dy = factor_y * width / diagonal
|
|||
|
|
else:
|
|||
|
|
assert self.direction_type == 'angle'
|
|||
|
|
angle = self.direction # 0 upwards, then clockwise
|
|||
|
|
dx = math.sin(angle)
|
|||
|
|
dy = -math.cos(angle)
|
|||
|
|
|
|||
|
|
# Round dx and dy to avoid floating points errors caused by
|
|||
|
|
# trigonometry and angle units conversions
|
|||
|
|
dx, dy = round(dx, 9), round(dy, 9)
|
|||
|
|
|
|||
|
|
# Normalize colors positions
|
|||
|
|
colors = list(self.colors)
|
|||
|
|
vector_length = abs(width * dx) + abs(height * dy)
|
|||
|
|
positions = process_color_stops(vector_length, self.stop_positions)
|
|||
|
|
if not self.repeating:
|
|||
|
|
# Add explicit colors at boundaries if needed, because PDF doesn’t
|
|||
|
|
# extend color stops that are not displayed
|
|||
|
|
if positions[0] == positions[1]:
|
|||
|
|
positions.insert(0, positions[0] - 1)
|
|||
|
|
colors.insert(0, colors[0])
|
|||
|
|
if positions[-2] == positions[-1]:
|
|||
|
|
positions.append(positions[-1] + 1)
|
|||
|
|
colors.append(colors[-1])
|
|||
|
|
first, last, positions = normalize_stop_positions(positions)
|
|||
|
|
|
|||
|
|
if self.repeating:
|
|||
|
|
# Render as a solid color if the first and last positions are equal
|
|||
|
|
# See https://drafts.csswg.org/css-images-3/#repeating-gradients
|
|||
|
|
if first == last:
|
|||
|
|
color = gradient_average_color(colors, positions)
|
|||
|
|
return 1, 'solid', None, [], [color]
|
|||
|
|
|
|||
|
|
# Define defined gradient length and steps between positions
|
|||
|
|
stop_length = last - first
|
|||
|
|
assert stop_length > 0
|
|||
|
|
position_steps = [
|
|||
|
|
positions[i + 1] - positions[i]
|
|||
|
|
for i in range(len(positions) - 1)]
|
|||
|
|
|
|||
|
|
# Create cycles used to add colors
|
|||
|
|
next_steps = cycle([0] + position_steps)
|
|||
|
|
next_colors = cycle(colors)
|
|||
|
|
previous_steps = cycle([0] + position_steps[::-1])
|
|||
|
|
previous_colors = cycle(colors[::-1])
|
|||
|
|
|
|||
|
|
# Add colors after last step
|
|||
|
|
while last < vector_length:
|
|||
|
|
step = next(next_steps)
|
|||
|
|
colors.append(next(next_colors))
|
|||
|
|
positions.append(positions[-1] + step)
|
|||
|
|
last += step * stop_length
|
|||
|
|
|
|||
|
|
# Add colors before last step
|
|||
|
|
while first > 0:
|
|||
|
|
step = next(previous_steps)
|
|||
|
|
colors.insert(0, next(previous_colors))
|
|||
|
|
positions.insert(0, positions[0] - step)
|
|||
|
|
first -= step * stop_length
|
|||
|
|
|
|||
|
|
# Define the coordinates of the starting and ending points
|
|||
|
|
start_x = (width - dx * vector_length) / 2
|
|||
|
|
start_y = (height - dy * vector_length) / 2
|
|||
|
|
points = (
|
|||
|
|
start_x + dx * first, start_y + dy * first,
|
|||
|
|
start_x + dx * last, start_y + dy * last)
|
|||
|
|
|
|||
|
|
return 1, 'linear', points, positions, colors
|
|||
|
|
|
|||
|
|
|
|||
|
|
class RadialGradient(Gradient):
|
|||
|
|
def __init__(self, color_stops, shape, size, center, repeating):
|
|||
|
|
Gradient.__init__(self, color_stops, repeating)
|
|||
|
|
# Center of the ending shape. (origin_x, pos_x, origin_y, pos_y)
|
|||
|
|
self.center = center
|
|||
|
|
# Type of ending shape: 'circle' or 'ellipse'
|
|||
|
|
self.shape = shape
|
|||
|
|
# size_type: 'keyword'
|
|||
|
|
# size: 'closest-corner', 'farthest-corner',
|
|||
|
|
# 'closest-side', or 'farthest-side'
|
|||
|
|
# size_type: 'explicit'
|
|||
|
|
# size: (radius_x, radius_y)
|
|||
|
|
self.size_type, self.size = size
|
|||
|
|
|
|||
|
|
def layout(self, width, height):
|
|||
|
|
# Only one color, render the gradient as a solid color
|
|||
|
|
if len(self.colors) == 1:
|
|||
|
|
return 1, 'solid', None, [], [self.colors[0]]
|
|||
|
|
|
|||
|
|
# Define the center of the gradient
|
|||
|
|
origin_x, center_x, origin_y, center_y = self.center
|
|||
|
|
center_x = percentage(center_x, width)
|
|||
|
|
center_y = percentage(center_y, height)
|
|||
|
|
if origin_x == 'right':
|
|||
|
|
center_x = width - center_x
|
|||
|
|
if origin_y == 'bottom':
|
|||
|
|
center_y = height - center_y
|
|||
|
|
|
|||
|
|
# Resolve sizes and vertical scale
|
|||
|
|
size_x, size_y = self._handle_degenerate(
|
|||
|
|
*self._resolve_size(width, height, center_x, center_y))
|
|||
|
|
scale_y = size_y / size_x
|
|||
|
|
|
|||
|
|
# Normalize colors positions
|
|||
|
|
colors = list(self.colors)
|
|||
|
|
positions = process_color_stops(size_x, self.stop_positions)
|
|||
|
|
if not self.repeating:
|
|||
|
|
# Add explicit colors at boundaries if needed, because PDF doesn’t
|
|||
|
|
# extend color stops that are not displayed
|
|||
|
|
if positions[0] > 0 and positions[0] == positions[1]:
|
|||
|
|
positions.insert(0, 0)
|
|||
|
|
colors.insert(0, colors[0])
|
|||
|
|
if positions[-2] == positions[-1]:
|
|||
|
|
positions.append(positions[-1] + 1)
|
|||
|
|
colors.append(colors[-1])
|
|||
|
|
if positions[0] < 0:
|
|||
|
|
# PDF doesn’t like negative radiuses, shift into the positive realm
|
|||
|
|
if self.repeating:
|
|||
|
|
# Add vector lengths to first position until positive
|
|||
|
|
vector_length = positions[-1] - positions[0]
|
|||
|
|
offset = vector_length * (1 + (-positions[0] // vector_length))
|
|||
|
|
positions = [position + offset for position in positions]
|
|||
|
|
else:
|
|||
|
|
# Only keep colors with position >= 0, interpolate if needed
|
|||
|
|
if positions[-1] <= 0:
|
|||
|
|
# All stops are negative, fill with the last color
|
|||
|
|
return 1, 'solid', None, [], [self.colors[-1]]
|
|||
|
|
for i, position in enumerate(positions):
|
|||
|
|
if position == 0:
|
|||
|
|
# Keep colors and positions from this rank
|
|||
|
|
colors, positions = colors[i:], positions[i:]
|
|||
|
|
break
|
|||
|
|
if position > 0:
|
|||
|
|
# Interpolate with previous rank to get color at 0
|
|||
|
|
color = colors[i]
|
|||
|
|
previous_color = colors[i - 1]
|
|||
|
|
previous_position = positions[i - 1]
|
|||
|
|
assert previous_position < 0
|
|||
|
|
intermediate_color = gradient_average_color(
|
|||
|
|
[previous_color, previous_color, color, color],
|
|||
|
|
[previous_position, 0, 0, position])
|
|||
|
|
colors = [intermediate_color] + colors[i:]
|
|||
|
|
positions = [0] + positions[i:]
|
|||
|
|
break
|
|||
|
|
first, last, positions = normalize_stop_positions(positions)
|
|||
|
|
|
|||
|
|
# Render as a solid color if the first and last positions are the same
|
|||
|
|
# See https://drafts.csswg.org/css-images-3/#repeating-gradients
|
|||
|
|
if first == last and self.repeating:
|
|||
|
|
color = gradient_average_color(colors, positions)
|
|||
|
|
return 1, 'solid', None, [], [color]
|
|||
|
|
|
|||
|
|
# Define the coordinates of the gradient circles
|
|||
|
|
points = (
|
|||
|
|
center_x, center_y / scale_y, first,
|
|||
|
|
center_x, center_y / scale_y, last)
|
|||
|
|
|
|||
|
|
if self.repeating:
|
|||
|
|
points, positions, colors = self._repeat(
|
|||
|
|
width, height, scale_y, points, positions, colors)
|
|||
|
|
|
|||
|
|
return scale_y, 'radial', points, positions, colors
|
|||
|
|
|
|||
|
|
def _repeat(self, width, height, scale_y, points, positions, colors):
|
|||
|
|
# Keep original lists and values, they’re useful
|
|||
|
|
original_colors = colors.copy()
|
|||
|
|
original_positions = positions.copy()
|
|||
|
|
gradient_length = points[5] - points[2]
|
|||
|
|
|
|||
|
|
# Get the maximum distance between the center and the corners, to find
|
|||
|
|
# how many times we have to repeat the colors outside
|
|||
|
|
max_distance = max(
|
|||
|
|
math.hypot(width - points[0], height / scale_y - points[1]),
|
|||
|
|
math.hypot(width - points[0], -points[1] * scale_y),
|
|||
|
|
math.hypot(-points[0], height / scale_y - points[1]),
|
|||
|
|
math.hypot(-points[0], -points[1] * scale_y))
|
|||
|
|
repeat_after = math.ceil((max_distance - points[5]) / gradient_length)
|
|||
|
|
if repeat_after > 0:
|
|||
|
|
# Repeat colors and extrapolate positions
|
|||
|
|
repeat = 1 + repeat_after
|
|||
|
|
colors *= repeat
|
|||
|
|
positions = [
|
|||
|
|
i + position for i in range(repeat) for position in positions]
|
|||
|
|
points = points[:5] + (points[5] + gradient_length * repeat_after,)
|
|||
|
|
|
|||
|
|
if points[2] == 0:
|
|||
|
|
# Inner circle has 0 radius, no need to repeat inside, return
|
|||
|
|
return points, positions, colors
|
|||
|
|
|
|||
|
|
# Find how many times we have to repeat the colors inside
|
|||
|
|
repeat_before = points[2] / gradient_length
|
|||
|
|
|
|||
|
|
# Set the inner circle size to 0
|
|||
|
|
points = points[:2] + (0,) + points[3:]
|
|||
|
|
|
|||
|
|
# Find how many times the whole gradient can be repeated
|
|||
|
|
full_repeat = int(repeat_before)
|
|||
|
|
if full_repeat:
|
|||
|
|
# Repeat colors and extrapolate positions
|
|||
|
|
colors += original_colors * full_repeat
|
|||
|
|
positions = [
|
|||
|
|
i - full_repeat + position for i in range(full_repeat)
|
|||
|
|
for position in original_positions] + positions
|
|||
|
|
|
|||
|
|
# Find the ratio of gradient that must be added to reach the center
|
|||
|
|
partial_repeat = repeat_before - full_repeat
|
|||
|
|
if partial_repeat == 0:
|
|||
|
|
# No partial repeat, return
|
|||
|
|
return points, positions, colors
|
|||
|
|
|
|||
|
|
# Iterate through positions in reverse order, from the outer
|
|||
|
|
# circle to the original inner circle, to find positions from
|
|||
|
|
# the inner circle (including full repeats) to the center
|
|||
|
|
assert (original_positions[0], original_positions[-1]) == (0, 1)
|
|||
|
|
assert 0 < partial_repeat < 1
|
|||
|
|
reverse = original_positions[::-1]
|
|||
|
|
ratio = 1 - partial_repeat
|
|||
|
|
for i, position in enumerate(reverse, start=1):
|
|||
|
|
if position == ratio:
|
|||
|
|
# The center is a color of the gradient, truncate original
|
|||
|
|
# colors and positions and prepend them
|
|||
|
|
colors = original_colors[-i:] + colors
|
|||
|
|
new_positions = [
|
|||
|
|
position - full_repeat - 1
|
|||
|
|
for position in original_positions[-i:]]
|
|||
|
|
positions = new_positions + positions
|
|||
|
|
return points, positions, colors
|
|||
|
|
if position < ratio:
|
|||
|
|
# The center is between two colors of the gradient,
|
|||
|
|
# define the center color as the average of these two
|
|||
|
|
# gradient colors
|
|||
|
|
color = original_colors[-i]
|
|||
|
|
next_color = original_colors[-(i - 1)]
|
|||
|
|
next_position = original_positions[-(i - 1)]
|
|||
|
|
average_colors = [color, color, next_color, next_color]
|
|||
|
|
average_positions = [position, ratio, ratio, next_position]
|
|||
|
|
zero_color = gradient_average_color(
|
|||
|
|
average_colors, average_positions)
|
|||
|
|
colors = [zero_color] + original_colors[-(i - 1):] + colors
|
|||
|
|
new_positions = [
|
|||
|
|
position - 1 - full_repeat for position
|
|||
|
|
in original_positions[-(i - 1):]]
|
|||
|
|
positions = (
|
|||
|
|
[ratio - 1 - full_repeat] + new_positions + positions)
|
|||
|
|
return points, positions, colors
|
|||
|
|
|
|||
|
|
def _resolve_size(self, width, height, center_x, center_y):
|
|||
|
|
"""Resolve circle size of the radial gradient."""
|
|||
|
|
if self.size_type == 'explicit':
|
|||
|
|
size_x, size_y = self.size
|
|||
|
|
size_x = percentage(size_x, width)
|
|||
|
|
size_y = percentage(size_y, height)
|
|||
|
|
return size_x, size_y
|
|||
|
|
left = abs(center_x)
|
|||
|
|
right = abs(width - center_x)
|
|||
|
|
top = abs(center_y)
|
|||
|
|
bottom = abs(height - center_y)
|
|||
|
|
pick = min if self.size.startswith('closest') else max
|
|||
|
|
if self.size.endswith('side'):
|
|||
|
|
if self.shape == 'circle':
|
|||
|
|
size_xy = pick(left, right, top, bottom)
|
|||
|
|
return size_xy, size_xy
|
|||
|
|
# else: ellipse
|
|||
|
|
return pick(left, right), pick(top, bottom)
|
|||
|
|
# else: corner
|
|||
|
|
if self.shape == 'circle':
|
|||
|
|
size_xy = pick(math.hypot(left, top), math.hypot(left, bottom),
|
|||
|
|
math.hypot(right, top), math.hypot(right, bottom))
|
|||
|
|
return size_xy, size_xy
|
|||
|
|
# else: ellipse
|
|||
|
|
corner_x, corner_y = pick(
|
|||
|
|
(left, top), (left, bottom), (right, top), (right, bottom),
|
|||
|
|
key=lambda a: math.hypot(*a))
|
|||
|
|
return corner_x * math.sqrt(2), corner_y * math.sqrt(2)
|
|||
|
|
|
|||
|
|
def _handle_degenerate(self, size_x, size_y):
|
|||
|
|
"""Handle degenerate radial gradients.
|
|||
|
|
|
|||
|
|
See https://drafts.csswg.org/css-images-3/#degenerate-radials
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
if size_x == size_y == 0:
|
|||
|
|
size_x = size_y = 1e-7
|
|||
|
|
elif size_x == 0:
|
|||
|
|
size_x = 1e-7
|
|||
|
|
size_y = 1e7
|
|||
|
|
elif size_y == 0:
|
|||
|
|
size_x = 1e7
|
|||
|
|
size_y = 1e-7
|
|||
|
|
return size_x, size_y
|