mirror of
https://github.com/Kozea/WeasyPrint.git
synced 2024-10-05 08:27:22 +03:00
321 lines
10 KiB
Python
321 lines
10 KiB
Python
# coding: utf8
|
||
|
||
# WeasyPrint converts web documents (HTML, CSS, ...) to PDF.
|
||
# Copyright (C) 2011 Simon Sapin
|
||
#
|
||
# This program is free software: you can redistribute it and/or modify
|
||
# it under the terms of the GNU Affero General Public License as
|
||
# published by the Free Software Foundation, either version 3 of the
|
||
# License, or (at your option) any later version.
|
||
#
|
||
# This program 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 Affero General Public License for more details.
|
||
#
|
||
# You should have received a copy of the GNU Affero General Public License
|
||
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||
|
||
|
||
|
||
from __future__ import division
|
||
import urllib
|
||
try:
|
||
from urlparse import urljoin
|
||
except ImportError:
|
||
# Python 3
|
||
from urllib.parse import urljoin
|
||
|
||
|
||
import cairo
|
||
import cssutils.css.value
|
||
|
||
from ..css.utils import (get_single_keyword, get_keyword,
|
||
get_pixel_value, get_percentage_value)
|
||
from ..formatting_structure import boxes
|
||
from .. import text
|
||
from .figures import Point, Line, Trapezoid
|
||
|
||
|
||
def get_image_surface_from_uri(uri):
|
||
try:
|
||
fileimage = urllib.urlopen(uri)
|
||
if fileimage.info().gettype() != 'image/png':
|
||
raise NotImplementedError("Only png images are implemented")
|
||
return cairo.ImageSurface.create_from_png(fileimage)
|
||
except IOError:
|
||
return None
|
||
|
||
|
||
def draw_box(context, box):
|
||
if has_background(box):
|
||
draw_background(context, box)
|
||
|
||
if isinstance(box, boxes.TextBox):
|
||
draw_text(context, box)
|
||
return
|
||
|
||
if isinstance(box, boxes.ReplacedBox):
|
||
draw_replacedbox(context, box)
|
||
|
||
if isinstance(box, boxes.ParentBox):
|
||
for child in box.children:
|
||
draw_box(context, child)
|
||
|
||
draw_border(context, box)
|
||
|
||
|
||
def has_background(box):
|
||
"""
|
||
Return the given box has any background.
|
||
"""
|
||
return box.style['background-color'][0].alpha > 0 or \
|
||
get_single_keyword(box.style['background-image']) != 'none'
|
||
|
||
|
||
def draw_canvas_background(context, page):
|
||
"""
|
||
Draw the canvas’s background, taken from the root element.
|
||
|
||
If the root element is "html" and has no background, the canvas’s
|
||
background is taken from its "body" child.
|
||
|
||
In both cases the background position is the same as if it was drawn on
|
||
the element.
|
||
|
||
See http://www.w3.org/TR/CSS21/colors.html#background
|
||
"""
|
||
if has_background(page.root_box):
|
||
draw_background(context, page.root_box, on_entire_canvas=True)
|
||
elif page.root_box.element.tag.lower() == 'html':
|
||
for child in page.root_box.children:
|
||
if child.element.tag.lower() == 'body':
|
||
# This must be drawn now, before anything on the root element.
|
||
draw_background(context, child, on_entire_canvas=True)
|
||
|
||
|
||
def draw_background(context, box, on_entire_canvas=False):
|
||
"""
|
||
Draw the box background color and image to a Cairo context.
|
||
"""
|
||
if getattr(box, 'background_drawn', False):
|
||
return
|
||
|
||
box.background_drawn = True
|
||
|
||
if not has_background(box):
|
||
return
|
||
|
||
with context.stacked():
|
||
# Change coordinates to make the rest easier.
|
||
context.translate(box.border_box_x(), box.border_box_y())
|
||
bg_width = box.border_width()
|
||
bg_height = box.border_height()
|
||
|
||
if not on_entire_canvas:
|
||
context.rectangle(0, 0, bg_width, bg_height)
|
||
context.clip()
|
||
|
||
# Background color
|
||
bg_color = box.style['background-color'][0]
|
||
if bg_color.alpha > 0:
|
||
context.set_source_colorvalue(bg_color)
|
||
context.paint()
|
||
|
||
# Background image
|
||
bg_image = box.style['background-image'][0]
|
||
if bg_image.type != 'URI':
|
||
return
|
||
|
||
surface = get_image_surface_from_uri(bg_image.absoluteUri)
|
||
if not surface:
|
||
return
|
||
|
||
image_width = surface.get_width()
|
||
image_height = surface.get_height()
|
||
|
||
context.translate(*absolute_background_position(
|
||
box.style['background-position'], bg_width, bg_height,
|
||
image_width, image_height))
|
||
|
||
bg_repeat = get_single_keyword(box.style['background-repeat'])
|
||
if bg_repeat != 'repeat':
|
||
# Get the current clip rectangle
|
||
clip_x1, clip_y1, clip_x2, clip_y2 = context.clip_extents()
|
||
clip_width = clip_x2 - clip_x1
|
||
clip_height = clip_y2 - clip_y1
|
||
|
||
if bg_repeat in ('no-repeat', 'repeat-x'):
|
||
# Limit the drawn area vertically
|
||
clip_y1 = 0
|
||
clip_height = image_height
|
||
|
||
if bg_repeat in ('no-repeat', 'repeat-y'):
|
||
# Limit the drawn area horizontally
|
||
clip_x1 = 0
|
||
clip_width = image_width
|
||
|
||
# Second clip for the background image
|
||
context.rectangle(clip_x1, clip_y1, clip_width, clip_height)
|
||
context.clip()
|
||
|
||
pattern = cairo.SurfacePattern(surface)
|
||
pattern.set_extend(cairo.EXTEND_REPEAT)
|
||
context.set_source(pattern)
|
||
context.paint()
|
||
|
||
|
||
def make_css_value(value):
|
||
return cssutils.css.value.PropertyValue(value)[0]
|
||
|
||
|
||
def absolute_background_position(css_values, bg_width, bg_height,
|
||
image_width, image_height):
|
||
"""
|
||
Parse cssutils Value objects for background-position and return
|
||
(position_x, position_y) relative to the background’s top left corner,
|
||
in pixels.
|
||
|
||
http://www.w3.org/TR/CSS21/colors.html#propdef-background-position
|
||
"""
|
||
if len(css_values) == 1:
|
||
css_values = [css_values[0], make_css_value('center')]
|
||
else:
|
||
assert len(css_values) == 2
|
||
|
||
horizontal = None
|
||
vertical = None
|
||
non_keywords = []
|
||
for value in css_values:
|
||
keyword = get_keyword(value)
|
||
if keyword == 'top':
|
||
assert vertical is None
|
||
vertical = make_css_value('0%')
|
||
elif keyword == 'bottom':
|
||
assert vertical is None
|
||
vertical = make_css_value('100%')
|
||
elif keyword == 'left':
|
||
assert horizontal is None
|
||
horizontal = make_css_value('0%')
|
||
elif keyword == 'right':
|
||
assert horizontal is None
|
||
horizontal = make_css_value('100%')
|
||
elif keyword == 'center':
|
||
if horizontal is None:
|
||
horizontal = make_css_value('50%')
|
||
else:
|
||
vertical = make_css_value('50%')
|
||
else:
|
||
assert keyword is None
|
||
non_keywords.append(value)
|
||
|
||
# In that order. If both value are non-keyword, the first one
|
||
# is horizontal and the second one vertical. list.pop() gives
|
||
# the last value.
|
||
if vertical is None:
|
||
vertical = non_keywords.pop()
|
||
if horizontal is None:
|
||
horizontal = non_keywords.pop()
|
||
|
||
vertical_pixels = background_position_value(
|
||
vertical, bg_height, image_height)
|
||
horizontal_pixels = background_position_value(
|
||
horizontal, bg_width, image_width)
|
||
return horizontal_pixels, vertical_pixels
|
||
|
||
|
||
def background_position_value(value, bg_size, image_size):
|
||
pixels = get_pixel_value(value)
|
||
if pixels is not None:
|
||
return pixels
|
||
|
||
percentage = get_percentage_value(value)
|
||
assert percentage is not None
|
||
return (bg_size - image_size) * percentage / 100.
|
||
|
||
|
||
|
||
def draw_border(context, box):
|
||
"""
|
||
Draw the box border to a Cairo context.
|
||
"""
|
||
# TODO: implement border-spacing, border-collapse and the other border style
|
||
|
||
def get_edge(x, y, width, height):
|
||
return (Point(x,y), Point(x+width,y), Point(x+width, y+height),
|
||
Point(x, y+height))
|
||
|
||
def get_border_area():
|
||
# border area
|
||
x = box.position_x + box.margin_left
|
||
y = box.position_y + box.margin_top
|
||
border_edge = get_edge(x, y, box.border_width(), box.border_height())
|
||
# padding area
|
||
x = x + box.border_left_width
|
||
y = y + box.border_top_width
|
||
padding_edge = get_edge(x, y, box.padding_width(), box.padding_height())
|
||
return border_edge, padding_edge
|
||
|
||
def get_lines(rectangle):
|
||
n = len (rectangle)
|
||
for i, point in enumerate(rectangle):
|
||
yield Line(rectangle[i], rectangle[(i+1) % n])
|
||
|
||
def get_trapezoids():
|
||
border_edge, padding_edge = get_border_area()
|
||
for line1,line2 in zip(get_lines(border_edge), get_lines(padding_edge)):
|
||
yield Trapezoid(line1, line2)
|
||
|
||
def draw_border_side(side, trapezoid):
|
||
width = float(box.style['border-%s-width'%side][0].value)
|
||
if box.style['border-%s-width'%side] == 0:
|
||
return
|
||
color = box.style['border-%s-color'%side][0]
|
||
style = box.style['border-%s-style'%side][0].value
|
||
if color.alpha > 0:
|
||
with context.stacked():
|
||
if not style in ["dotted", "dashed"]:
|
||
trapezoid.draw_path(context)
|
||
context.clip()
|
||
elif style == "dotted":
|
||
#TODO:Find a way to make a real dotted border
|
||
context.set_dash([width], 0)
|
||
elif style == "dashed":
|
||
#TODO:Find a way to make a real dashed border
|
||
context.set_dash([4*width], 0)
|
||
line = trapezoid.get_middle_line()
|
||
line.draw_path(context)
|
||
context.set_source_colorvalue(color)
|
||
context.set_line_width(width)
|
||
context.stroke()
|
||
|
||
trapezoids_side = zip(["top", "right", "bottom", "left"], get_trapezoids())
|
||
|
||
for side, trapezoid in trapezoids_side:
|
||
draw_border_side(side, trapezoid)
|
||
|
||
|
||
def draw_text(context, textbox):
|
||
"""
|
||
Draw the given TextBox to a Cairo context from Pangocairo Context
|
||
"""
|
||
fragment = text.TextLineFragment.from_textbox(textbox)
|
||
context.move_to(textbox.position_x, textbox.position_y)
|
||
context.show_layout(fragment.get_layout())
|
||
|
||
|
||
def draw_replacedbox(context, box):
|
||
"""
|
||
Draw the given ReplacedBox to a Cairo context
|
||
"""
|
||
x, y = box.padding_box_x(), box.padding_box_y()
|
||
width, height = box.width, box.height
|
||
with context.stacked():
|
||
context.translate(x, y)
|
||
context.rectangle(0, 0, width, height)
|
||
context.clip()
|
||
scale_width = width/box.replacement.intrinsic_width()
|
||
scale_height = height/box.replacement.intrinsic_height()
|
||
context.scale(scale_width, scale_height)
|
||
box.replacement.draw(context)
|