Struct pango::Layout [−][src]
pub struct Layout(_);
Expand description
The Layout
structure represents an entire paragraph
of text. It is initialized with a Context
, UTF-8 string
and set of attributes for that string. Once that is done, the
set of formatted lines can be extracted from the object,
the layout can be rendered, and conversion between logical
character positions within the layout’s text, and the physical
position of the resulting glyphs can be made.
There are also a number of parameters to adjust the formatting
of a Layout
, which are illustrated in Layout
as a list of lines.
The Layout
structure is opaque, and has no user-visible
fields.
Implementations
Forces recomputation of any state in the Layout
that
might depend on the layout’s context. This function should
be called if you make changes to the context subsequent
to creating the layout.
Gets the alignment for the layout: how partial lines are positioned within the horizontal space available.
Returns
the alignment.
Gets whether to calculate the bidirectional base direction
for the layout according to the contents of the layout.
See set_auto_dir()
.
Returns
true
if the bidirectional base direction
is computed from the layout’s contents, false
otherwise.
Gets the Y position of baseline of the first line in self
.
Returns
baseline of first line, from top of self
.
Returns the number of Unicode characters in the
the text of self
.
Returns
the number of Unicode characters
in the text of self
Given an index within a layout, determines the positions that of the strong and weak cursors if the insertion point is at that index. The position of each cursor is stored as a zero-width rectangle. The strong cursor location is the location where characters of the directionality equal to the base direction of the layout are inserted. The weak cursor location is the location where characters of the directionality opposite to the base direction of the layout are inserted.
index_
the byte index of the cursor
Returns
strong_pos
location to store the strong cursor position
(may be None
)
weak_pos
location to store the weak cursor position (may be None
)
This is supported on crate feature v1_46
only.
v1_46
only.Gets the type of ellipsization being performed for self
.
See set_ellipsize()
Returns
the current ellipsization mode for self
.
Use is_ellipsized()
to query whether any paragraphs
were actually ellipsized.
Computes the logical and ink extents of self
. Logical extents
are usually what you want for positioning things. Note that both extents
may have non-zero x and y. You may want to use those to offset where you
render the layout. Not doing that is a very typical bug that shows up as
right-to-left layouts not being correctly positioned in a layout with
a set width.
The extents are given in layout coordinates and in Pango units; layout coordinates begin at the top left corner of the layout.
Returns
ink_rect
rectangle used to store the extents of the
layout as drawn or None
to indicate that the result is
not needed.
logical_rect
rectangle used to store the logical
extents of the layout or None
to indicate that the
result is not needed.
Gets the height of layout used for ellipsization. See
set_height()
for details.
Returns
the height, in Pango units if positive, or number of lines if negative.
Gets the paragraph indent width in Pango units. A negative value indicates a hanging indentation.
Returns
the indent in Pango units.
Returns an iterator to iterate over the visual extents of the layout.
Returns
the new LayoutIter
that should be freed using
pango_layout_iter_free()
.
Gets whether each complete line should be stretched to fill the entire width of the layout.
Returns
the justify.
Retrieves a particular line from a Layout
.
Use the faster line_readonly()
if you do not plan
to modify the contents of the line (glyphs, glyph widths, etc.).
line
the index of a line, which must be between 0 and
<literal>
pango_layout_get_line_count(layout) - 1</literal>
, inclusive.
Returns
the requested
LayoutLine
, or None
if the index is out of
range. This layout line can be ref’ed and retained,
but will become invalid if changes are made to the
Layout
.
Retrieves a particular line from a Layout
.
This is a faster alternative to line()
,
but the user is not expected
to modify the contents of the line (glyphs, glyph widths, etc.).
line
the index of a line, which must be between 0 and
<literal>
pango_layout_get_line_count(layout) - 1</literal>
, inclusive.
Returns
the requested
LayoutLine
, or None
if the index is out of
range. This layout line can be ref’ed and retained,
but will become invalid if changes are made to the
Layout
. No changes should be made to the line.
This is supported on crate feature v1_44
only.
v1_44
only.Gets the value that has been
set with set_line_spacing()
.
Returns the lines of the self
as a list.
Use the faster lines_readonly()
if you do not plan
to modify the contents of the lines (glyphs, glyph widths, etc.).
Returns
a GSList
containing
the lines in the layout. This points to internal data of the Layout
and must be used with care. It will become invalid on any change to the layout’s
text or properties.
Returns the lines of the self
as a list.
This is a faster alternative to lines()
,
but the user is not expected
to modify the contents of the lines (glyphs, glyph widths, etc.).
Returns
a GSList
containing
the lines in the layout. This points to internal data of the Layout
and
must be used with care. It will become invalid on any change to the layout’s
text or properties. No changes should be made to the lines.
Computes the logical and ink extents of self
in device units.
This function just calls extents()
followed by
two extents_to_pixels()
calls, rounding ink_rect
and logical_rect
such that the rounded rectangles fully contain the unrounded one (that is,
passes them as first argument to extents_to_pixels()
).
Returns
ink_rect
rectangle used to store the extents of the
layout as drawn or None
to indicate that the result is
not needed.
logical_rect
rectangle used to store the logical
extents of the layout or None
to indicate that the
result is not needed.
Determines the logical width and height of a Layout
in device units. (size()
returns the width
and height scaled by PANGO_SCALE
.) This
is simply a convenience function around
pixel_extents()
.
Returns
width
location to store the logical width, or None
height
location to store the logical height, or None
Returns the current serial number of self
. The serial number is
initialized to an small number larger than zero when a new layout
is created and is increased whenever the layout is changed using any
of the setter functions, or the Context
it uses has changed.
The serial may wrap, but will never have the value 0. Since it
can wrap, never compare it with “less than”, always use “not equals”.
This can be used to automatically detect changes to a Layout
, and
is useful for example to decide whether a layout needs redrawing.
To force the serial to be increased, use context_changed()
.
Returns
The current serial number of self
.
Obtains the value set by set_single_paragraph_mode()
.
Returns
true
if the layout does not break paragraphs at
paragraph separator characters, false
otherwise.
Gets the text in the layout. The returned text should not be freed or modified.
Returns
the text in the self
.
Counts the number unknown glyphs in self
. That is, zero if
glyphs for all characters in the layout text were found, or more
than zero otherwise.
This function can be used to determine if there are any fonts
available to render all characters in a certain string, or when
used in combination with AttrType::Fallback
, to check if a
certain font supports all the characters in the string.
Returns
The number of unknown glyphs in self
.
Gets the wrap mode for the layout.
Use is_wrapped()
to query whether any paragraphs
were actually wrapped.
Returns
active wrap mode.
Converts from byte index_
within the self
to line and X position.
(X position is measured from the left edge of the line)
index_
the byte index of a grapheme within the layout.
trailing
an integer indicating the edge of the grapheme to retrieve the position of. If > 0, the trailing edge of the grapheme, if 0, the leading of the grapheme.
Returns
line
location to store resulting line index. (which will
between 0 and pango_layout_get_line_count(layout) - 1), or None
x_pos
location to store resulting position within line
(PANGO_SCALE
units per device unit), or None
Converts from an index within a Layout
to the onscreen position
corresponding to the grapheme at that index, which is represented
as rectangle. Note that <literal>
pos->x</literal>
is always the leading
edge of the grapheme and <literal>
pos->x + pos->width</literal>
the trailing
edge of the grapheme. If the directionality of the grapheme is right-to-left,
then <literal>
pos->width</literal>
will be negative.
index_
byte index within self
Returns
pos
rectangle in which to store the position of the grapheme
Queries whether the layout had to ellipsize any paragraphs.
This returns true
if the ellipsization mode for self
is not EllipsizeMode::None
, a positive width is set on self
,
and there are paragraphs exceeding that width that have to be
ellipsized.
Returns
true
if any paragraphs had to be ellipsized, false
otherwise.
Queries whether the layout had to wrap any paragraphs.
This returns true
if a positive width is set on self
,
ellipsization mode of self
is set to EllipsizeMode::None
,
and there are paragraphs exceeding the layout width that have
to be wrapped.
Returns
Computes a new cursor position from an old position and
a count of positions to move visually. If direction
is positive,
then the new strong cursor position will be one position
to the right of the old cursor position. If direction
is negative,
then the new strong cursor position will be one position
to the left of the old cursor position.
In the presence of bidirectional text, the correspondence between logical and visual order will depend on the direction of the current run, and there may be jumps when the cursor is moved off of the end of a run.
Motion here is in cursor positions, not in characters, so a
single call to move_cursor_visually()
may move the
cursor over multiple characters when multiple characters combine
to form a single grapheme.
strong
whether the moving cursor is the strong cursor or the weak cursor. The strong cursor is the cursor corresponding to text insertion in the base direction for the layout.
old_index
the byte index of the grapheme for the old index
old_trailing
if 0, the cursor was at the leading edge of the
grapheme indicated by old_index
, if > 0, the cursor
was at the trailing edge.
direction
direction to move cursor. A negative value indicates motion to the left.
Returns
new_index
location to store the new cursor byte index. A value of -1
indicates that the cursor has been moved off the beginning
of the layout. A value of G_MAXINT
indicates that
the cursor has been moved off the end of the layout.
new_trailing
number of characters to move forward from the
location returned for new_index
to get the position
where the cursor should be displayed. This allows
distinguishing the position at the beginning of one
line from the position at the end of the preceding
line. new_index
is always on the line where the
cursor should be displayed.
Sets the alignment for the layout: how partial lines are positioned within the horizontal space available.
alignment
the alignment
Sets whether to calculate the bidirectional base direction
for the layout according to the contents of the layout;
when this flag is on (the default), then paragraphs in
self
that begin with strong right-to-left characters
(Arabic and Hebrew principally), will have right-to-left
layout, paragraphs with letters from other scripts will
have left-to-right layout. Paragraphs with only neutral
characters get their direction from the surrounding paragraphs.
When false
, the choice between left-to-right and
right-to-left layout is done according to the base direction
of the layout’s Context
. (See Context::set_base_dir()
).
When the auto-computed direction of a paragraph differs from the
base direction of the context, the interpretation of
Alignment::Left
and Alignment::Right
are swapped.
auto_dir
if true
, compute the bidirectional base direction
from the layout’s contents.
Sets the type of ellipsization being performed for self
.
Depending on the ellipsization mode ellipsize
text is
removed from the start, middle, or end of text so they
fit within the width and height of layout set with
set_width()
and set_height()
.
If the layout contains characters such as newlines that
force it to be layed out in multiple paragraphs, then whether
each paragraph is ellipsized separately or the entire layout
is ellipsized as a whole depends on the set height of the layout.
See set_height()
for details.
ellipsize
the new ellipsization mode for self
Sets the default font description for the layout. If no font description is set on the layout, the font description from the layout’s context is used.
desc
the new FontDescription
, or None
to unset the
current font description
Sets the height to which the Layout
should be ellipsized at. There
are two different behaviors, based on whether height
is positive or
negative.
If height
is positive, it will be the maximum height of the layout. Only
lines would be shown that would fit, and if there is any text omitted,
an ellipsis added. At least one line is included in each paragraph regardless
of how small the height value is. A value of zero will render exactly one
line for the entire layout.
If height
is negative, it will be the (negative of) maximum number of lines per
paragraph. That is, the total number of lines shown may well be more than
this value if the layout contains multiple paragraphs of text.
The default value of -1 means that first line of each paragraph is ellipsized.
This behvaior may be changed in the future to act per layout instead of per
paragraph. File a bug against pango at </ulink>
if your
code relies on this behavior.
Height setting only has effect if a positive width is set on
self
and ellipsization mode of self
is not EllipsizeMode::None
.
The behavior is undefined if a height other than -1 is set and
ellipsization mode is set to EllipsizeMode::None
, and may change in the
future.
height
the desired height of the layout in Pango units if positive, or desired number of lines if negative.
Sets the width in Pango units to indent each paragraph. A negative value
of indent
will produce a hanging indentation. That is, the first line will
have the full width, and subsequent lines will be indented by the
absolute value of indent
.
The indent setting is ignored if layout alignment is set to
Alignment::Center
.
indent
the amount by which to indent.
Sets whether each complete line should be stretched to fill the entire width of the layout. This stretching is typically done by adding whitespace, but for some scripts (such as Arabic), the justification may be done in more complex ways, like extending the characters.
Note that this setting is not implemented and so is ignored in Pango older than 1.18.
justify
whether the lines in the layout should be justified.
This is supported on crate feature v1_44
only.
v1_44
only.Sets a factor for line spacing. Typical values are: 0, 1, 1.5, 2. The default values is 0.
If factor
is non-zero, lines are placed
so that
baseline2 = baseline1 + factor * height2
where height2 is the line height of the
second line (as determined by the font(s)).
In this case, the spacing set with
set_spacing()
is ignored.
If factor
is zero, spacing is applied as
before.
factor
the new line spacing factor
Same as set_markup_with_accel()
, but
the markup text isn’t scanned for accelerators.
markup
marked-up text
length
length of marked-up text in bytes, or -1 if markup
is
null-terminated
Sets the layout text and attribute list from marked-up text (see
markup format``). Replaces the current text and attribute list.If accel_marker
is nonzero, the given character will mark the
character following it as an accelerator. For example, accel_marker
might be an ampersand or underscore. All characters marked
as an accelerator will receive a Underline::Low
attribute,
and the first character so marked will be returned in accel_char
.
Two accel_marker
characters following each other produce a single
literal accel_marker
character.
markup
marked-up text
(see markup format</link>
)
length
length of marked-up text in bytes, or -1 if markup
is
null-terminated
accel_marker
marker for accelerators in the text
Returns
accel_char
return location
for first located accelerator, or None
Sets the amount of spacing in Pango unit between the lines of the layout. When placing lines with spacing, Pango arranges things so that
line2.top = line1.bottom + spacing
Note: Since 1.44, Pango defaults to using the
line height (as determined by the font) for placing
lines. The spacing
set with this function is only
taken into account when the line-height factor is
set to zero with set_line_spacing()
.
spacing
the amount of spacing
Sets the text of the layout.
This function validates text
and renders invalid UTF-8
with a placeholder glyph.
Note that if you have used set_markup()
or
set_markup_with_accel()
on self
before, you may
want to call set_attributes()
to clear the attributes
set on the layout from the markup as this function does not clear
attributes.
text
the text
length
maximum length of text
, in bytes. -1 indicates that
the string is nul-terminated and the length should be
calculated. The text will also be truncated on
encountering a nul-termination even when length
is
positive.
Sets the wrap mode; the wrap mode only has effect if a width
is set on the layout with set_width()
.
To turn off wrapping, set the width to -1.
wrap
the wrap mode
Converts from X and Y position within a layout to the byte
index to the character at that logical position. If the
Y position is not inside the layout, the closest position is chosen
(the position will be clamped inside the layout). If the
X position is not within the layout, then the start or the
end of the line is chosen as described for LayoutLine::x_to_index()
.
If either the X or Y positions were not inside the layout, then the
function returns false
; on an exact hit, it returns true
.
x
the X offset (in Pango units) from the left edge of the layout.
y
the Y offset (in Pango units) from the top edge of the layout
Returns
true
if the coordinates were inside text, false
otherwise.
index_
location to store calculated byte index
trailing
location to store a integer indicating where in the grapheme the user clicked. It will either be zero, or the number of characters in the grapheme. 0 represents the leading edge of the grapheme.
Trait Implementations
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
Returns the type identifier of Self
.
Auto Trait Implementations
impl RefUnwindSafe for Layout
impl UnwindSafe for Layout
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T
. Read more
Upcasts an object to a reference of its superclass or interface T
. Read more
Tries to downcast to a subclass or interface implementor T
. Read more
Tries to downcast to a reference of its subclass or interface implementor T
. Read more
Tries to cast to an object of type T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read more
Casts to T
unconditionally. Read more
Casts to &T
unconditionally. Read more
Returns true
if the object is an instance of (can be cast to) T
.
pub fn set_properties_from_value(
&self,
property_values: &[(&str, Value)]
) -> Result<(), BoolError>
pub fn set_property<'a, N, V>(
&self,
property_name: N,
value: V
) -> Result<(), BoolError> where
V: ToValue,
N: Into<&'a str>,
pub fn set_property_from_value<'a, N>(
&self,
property_name: N,
value: &Value
) -> Result<(), BoolError> where
N: Into<&'a str>,
Safety Read more
Safety Read more
Safety Read more
Safety Read more
pub fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
pub fn connect_notify_local<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec),
pub unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec),
pub fn has_property<'a, N>(&self, property_name: N, type_: Option<Type>) -> bool where
N: Into<&'a str>,
pub fn find_property<'a, N>(&self, property_name: N) -> Option<ParamSpec> where
N: Into<&'a str>,
pub fn connect<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static,
N: Into<&'a str>,
Same as connect
but takes a SignalId
instead of a signal name.
pub fn connect_local<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + 'static,
N: Into<&'a str>,
Same as connect_local
but takes a SignalId
instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value>,
N: Into<&'a str>,
Same as connect_unsafe
but takes a SignalId
instead of a signal name.
Emit signal by signal id.
Emit signal with details by signal id.
Emit signal by it’s name.
pub fn bind_property<'a, O, N, M>(
&'a self,
source_property: N,
target: &'a O,
target_property: M
) -> BindingBuilder<'a> where
O: ObjectType,
N: Into<&'a str>,
M: Into<&'a str>,
Same as emit
but takes Value
for the arguments.
Same as emit_by_name
but takes Value
for the arguments.
Returns a SendValue
clone of self
.
impl<'a, T, C> FromValueOptional<'a> for T where
C: ValueTypeChecker<Error = ValueTypeMismatchOrNoneError>,
T: FromValue<'a, Checker = C>,