def get_resolution(context: Context) -> float:
"""
Returns the resolution for the Pango context.
:param context:
a Pango context
:return:
the resolution in "dots per inch". A negative value will be returned
if no resolution has previously been set.
"""
return pangocairo.pango_cairo_context_get_resolution(context.get_pointer())
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 set_resolution(context: Context, dpi: float) -> None:
"""
Sets the resolution for the context. This is a scale factor between points
specified in a PangoFontDescription and Cairo units. The default value is
96, meaning that a 10 point font will be 13 units high.
(10 * 96. / 72. = 13.3).
:param context:
a Pango context
:param dpi:
the resolution in "dots per inch". (Physical inches aren't actually
involved; the terminology is conventional.) A 0 or negative value
means to use the resolution from the font map.
"""
pangocairo.pango_cairo_context_set_resolution(context.get_pointer(), dpi)
def update_context(cairo_context: cairocffi.Context,
pango_context: pangocffi.Context) -> None:
"""
Updates a PangoContext previously created for use with Cairo to match the
current transformation and target surface of a Cairo context. If any
layouts have been created for the context, it's necessary to call
pango_layout_context_changed() on those layouts.
:param cairo_context:
a Cairo context
:param pango_context:
a Pango context, from a pango-cairo font map
"""
cairo_t_pointer = _get_cairo_t_from_cairo_ctx(cairo_context)
pangocairo.pango_cairo_update_context(cairo_t_pointer,
pango_context.get_pointer())
def set_font_options(
context: Context,
options: Optional[ffi.CData]
) -> None:
"""
Sets the font options used when rendering text with this context.
These options override any options that pango_cairo_update_context()
derives from the target surface.
:param context:
a Pango context
:param options:
a cairo_font_options_t, or ``None`` to unset any previously set
options.
"""
if options is None:
options = ffi.NULL
context_pointer = context.get_pointer()
pangocairo.pango_cairo_context_set_font_options(context_pointer, options)
def get_font_options(context: Context) -> Optional[ffi.CData]:
"""
Retrieves any font rendering options previously set with
pango_cairo_context_set_font_options(). This function does not report
options that are derived from the target surface by
pango_cairo_update_context()
:param context:
a Pango Context
:return:
a cairo_font_options_t pointer previously set on the context,
otherwise ``None``.
"""
context_pointer = context.get_pointer()
font_option_pointer = pangocairo.pango_cairo_context_get_font_options(
context_pointer
)
if font_option_pointer == ffi.NULL:
return None
return font_option_pointer
def test_layout_returns_identical_context():
context = Context()
layout = Layout(context)
identical_context = layout.get_context()
assert identical_context.get_pointer() == context.get_pointer()
def test_context_init_identical_context(self):
context = Context()
identical_context = Context.from_pointer(context.get_pointer())
assert identical_context == context