rustybuzz/hb/shape.rs
1use super::hb_font_t;
2use super::ot_shape::{shape_internal, ShapeContext};
3use super::ot_shape_plan::hb_ot_shape_plan_t;
4use crate::{script, Feature, GlyphBuffer, UnicodeBuffer};
5
6/// Shapes the buffer content using provided font and features.
7///
8/// Consumes the buffer. You can then run [`GlyphBuffer::clear`] to get the [`UnicodeBuffer`] back
9/// without allocating a new one.
10///
11/// If you plan to shape multiple strings using the same [`Face`] prefer [`shape_with_plan`].
12/// This is because [`ShapePlan`] initialization is pretty slow and should preferably be called
13/// once for each [`Face`].
14pub fn shape(face: &hb_font_t, features: &[Feature], mut buffer: UnicodeBuffer) -> GlyphBuffer {
15 buffer.0.guess_segment_properties();
16 let plan = hb_ot_shape_plan_t::new(
17 face,
18 buffer.0.direction,
19 buffer.0.script,
20 buffer.0.language.as_ref(),
21 features,
22 );
23 shape_with_plan(face, &plan, buffer)
24}
25
26/// Shapes the buffer content using the provided font and plan.
27///
28/// Consumes the buffer. You can then run [`GlyphBuffer::clear`] to get the [`UnicodeBuffer`] back
29/// without allocating a new one.
30///
31/// It is up to the caller to ensure that the shape plan matches the properties of the provided
32/// buffer, otherwise the shaping result will likely be incorrect.
33///
34/// # Panics
35///
36/// Will panic when debugging assertions are enabled if the buffer and plan have mismatched
37/// properties.
38pub fn shape_with_plan(
39 face: &hb_font_t,
40 plan: &hb_ot_shape_plan_t,
41 buffer: UnicodeBuffer,
42) -> GlyphBuffer {
43 let mut buffer = buffer.0;
44 buffer.guess_segment_properties();
45
46 debug_assert_eq!(buffer.direction, plan.direction);
47 debug_assert_eq!(
48 buffer.script.unwrap_or(script::UNKNOWN),
49 plan.script.unwrap_or(script::UNKNOWN)
50 );
51
52 if buffer.len > 0 {
53 // Save the original direction, we use it later.
54 let target_direction = buffer.direction;
55 shape_internal(&mut ShapeContext {
56 plan,
57 face,
58 buffer: &mut buffer,
59 target_direction,
60 });
61 }
62
63 GlyphBuffer(buffer)
64}