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224 | from typing import List, Tuple
import cairocffi as cairo
import pangocairocffi
import pangocffi
from pangocffi import Attribute, AttrList, FontDescription, Layout, Rectangle, ffi
from ....text.textstyle import TextStyle
from ....utils.geom import Rect
from .utils import get_rgb_color
def to_pango_units(size: float) -> int:
return pangocffi.units_from_double(size)
def from_pango_units(size: int) -> float:
return pangocffi.units_to_double(size)
def to_pango_color(color: Tuple[float, float, float]) -> Tuple[int, int, int]:
r, g, b = color
max = 2 ** 16 - 1
return (int(r * max), int(g * max), int(b * max))
def attr_from_scale(scale_factor: float, start_index: int, end_index: int):
scale_factor = ffi.cast("double", scale_factor)
attr = Attribute._init_pointer(
pangocffi.pango.pango_attr_scale_new(scale_factor),
)
attr.start_index = start_index
attr.end_index = end_index
return attr
def style_to_attributes(
style: TextStyle, text_scale: float, start_index: int, end_index: int
) -> List[Attribute]:
kwargs = dict(start_index=start_index, end_index=end_index)
attrs = [
Attribute.from_size_absolute(to_pango_units(style.size), **kwargs),
Attribute.from_family(style.font, **kwargs),
Attribute.from_foreground_color(
*to_pango_color(get_rgb_color(style.color)), **kwargs
),
]
if text_scale is not None:
attrs.append(attr_from_scale(text_scale, **kwargs))
weight = pangocffi.Weight.BOLD if style.bold else pangocffi.Weight.NORMAL
attrs.append(Attribute.from_weight(weight, **kwargs))
style = pangocffi.Style.ITALIC if style.italic else pangocffi.Style.NORMAL
attrs.append(Attribute.from_style(style, **kwargs))
return attrs
INVISIBLE_SPACE = "⠀" # this is not a normal space, but U+2800
def byte_length(text):
return len(text.encode("utf8"))
def get_text_and_attributes(
parsed_text, style: TextStyle, styles, text_scale: float
) -> Tuple[str, AttrList]:
attr_list = AttrList()
base_style = [styles["default"].compose(style)]
start = 0
text = ""
def push_attrs(style, start_index, end_index):
for attr in style_to_attributes(style, text_scale, start_index, end_index):
attr_list.insert(attr)
def active_style():
return [style for style in reversed(base_style) if style is not None][0]
line = ""
for (token, value) in parsed_text:
if token == "text":
line += value
text += value
elif token == "newline":
for _ in range(value):
if not line:
# This fixes the height of empty lines
text += INVISIBLE_SPACE
text += "\n"
line = ""
elif token == "begin":
push_attrs(active_style(), start, byte_length(text))
start = byte_length(text)
if value.startswith("#"):
base_style.append(None)
else:
base_style.append(active_style().compose(styles[value]))
elif token == "end":
push_attrs(active_style(), start, byte_length(text))
start = byte_length(text)
base_style.pop()
if start < byte_length(text):
push_attrs(base_style[0], start, byte_length(text))
assert len(base_style) == 1
assert base_style[0] is not None
return text, attr_list
def get_text_height(pctx: pangocffi.Context, style: TextStyle, resolution_scale: float):
font = FontDescription()
font.set_family(style.font)
font.set_absolute_size(to_pango_units(style.size))
ret = pangocffi.pango.pango_context_get_metrics(
pctx.get_pointer(), font.get_pointer(), pangocffi.ffi.NULL
)
descent = from_pango_units(pangocffi.pango.pango_font_metrics_get_descent(ret))
ascent = from_pango_units(pangocffi.pango.pango_font_metrics_get_ascent(ret))
return (ascent + descent) * resolution_scale
def build_layout(
ctx: cairo.Context,
pctx: pangocffi.Context,
parsed_text,
style: TextStyle,
styles,
resolution_scale: float,
spacing_scale: float = 1.0,
text_scale: float = 1.0,
) -> pangocffi.Layout:
# TODO: fix letter spacing
style = styles["default"].compose(style)
layout = pangocairocffi.create_layout(ctx)
layout.set_ellipsize(pangocffi.EllipsizeMode.NONE)
layout.set_alignment(get_pango_alignment(style))
text, attributes = get_text_and_attributes(parsed_text, style, styles, text_scale)
layout.set_text(text)
layout.set_attributes(attributes)
height = get_text_height(pctx, style, resolution_scale)
assert style.line_spacing >= 1.0
spacing = (style.line_spacing * style.size) - height
layout.set_spacing(to_pango_units(spacing * spacing_scale))
return layout
def from_pango_rect(rect: Rectangle) -> Rect:
return Rect(
x=from_pango_units(rect.x),
y=from_pango_units(rect.y),
width=from_pango_units(rect.width),
height=from_pango_units(rect.height),
)
def get_extents(layout: pangocffi.Layout, ink=True) -> Rect:
rect_logical, rect_ink = layout.get_extents()
return from_pango_rect(rect_ink if ink else rect_logical)
def get_byte_range(parsed_text, id_index) -> Tuple[int, int]:
stack = []
byte_count = 0
start = None
for i, (type, value) in enumerate(parsed_text):
if type == "text":
byte_count += byte_length(value)
elif type == "newline":
assert False
elif type == "begin":
if i == id_index:
start = byte_count
stack.append(value)
elif type == "end":
stack.pop()
if start is not None and not stack:
return (start, byte_count)
assert False
def compute_subtext_extents(
layout: Layout, parsed_text, id_index: int
) -> Tuple[float, float]:
"""
Returns the x coordinate and width of a subtext of a single line.
"""
assert layout.get_line_count() == 1
(start, end) = get_byte_range(parsed_text, id_index)
iter = layout.get_iter()
x = None
width = 0
while True:
byte_offset = iter.get_index()
if start <= byte_offset < end:
extents = from_pango_rect(iter.get_char_extents())
if x is None:
assert start == byte_offset
x = extents.x
width += extents.width
if byte_offset >= end or not iter.next_char():
break
assert x is not None
return (x, width)
PANGO_ALIGNMENTS = {
"middle": pangocffi.Alignment.CENTER,
"left": pangocffi.Alignment.LEFT,
"right": pangocffi.Alignment.RIGHT,
}
def get_pango_alignment(style: TextStyle):
return PANGO_ALIGNMENTS[style.align]
|