Struct GraphicsState

pub struct GraphicsState<'a> {

    pub retained: RetainedGraphicsState,
    pub proj_vector: Point<i32>,
    pub proj_axis: CoordAxis,
    pub dual_proj_vector: Point<i32>,
    pub dual_proj_axis: CoordAxis,
    pub freedom_vector: Point<i32>,
    pub freedom_axis: CoordAxis,
    pub fdotp: i32,
    pub round_state: RoundState,
    pub rp0: usize,
    pub rp1: usize,
    pub rp2: usize,
    pub loop_counter: u32,
    pub zp0: ZonePointer,
    pub zp1: ZonePointer,
    pub zp2: ZonePointer,
    pub zones: [Zone<'a>; 2],
    pub is_composite: bool,
    pub backward_compatibility: bool,
    pub is_pedantic: bool,
    pub did_iup_x: bool,
    pub did_iup_y: bool,
}

Context in which instructions are executed.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html

Fields

retained: RetainedGraphicsState

Fields of the graphics state that persist between calls to the interpreter.

proj_vector: Point<i32>

A unit vector whose direction establishes an axis along which distances are measured.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#projection%20vector

proj_axis: CoordAxis

Current axis for the projection vector.

dual_proj_vector: Point<i32>

A second projection vector set to a line defined by the original outline location of two points. The dual projection vector is used when it is necessary to measure distances from the scaled outline before any instructions were executed.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#dual%20projection%20vector

dual_proj_axis: CoordAxis

Current axis for the dual projection vector.

freedom_vector: Point<i32>

A unit vector that establishes an axis along which points can move.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#freedom%20vector

freedom_axis: CoordAxis

Current axis for point movement.

fdotp: i32

Dot product of freedom and projection vectors.

round_state: RoundState

Determines the manner in which values are rounded.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#round%20state

rp0: usize

First reference point.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#rp0

rp1: usize

Second reference point.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#rp1

rp2: usize

Third reference point.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#rp1

loop_counter: u32

Makes it possible to repeat certain instructions a designated number of times. The default value of one assures that unless the value of loop is altered, these instructions will execute one time.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#loop

zp0: ZonePointer

First zone pointer.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#zp0

zp1: ZonePointer

Second zone pointer.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#zp1

zp2: ZonePointer

Third zone pointer.

See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#zp2

zones: [Zone<'a>; 2]

Outline data for each zone.

This array contains the twilight and glyph zones, in that order.

is_composite: bool

True if the current glyph is a composite.

backward_compatibility: bool

If true, enables a set of backward compatibility heuristics that prevent certain modifications to the outline. The purpose is to support “modern” vertical only hinting that attempts to preserve outline shape and metrics in the horizontal direction. This is enabled by default, but fonts (and specific glyphs) can opt out of this behavior using the INSTCTRL instruction. In practice, opting out is usually only done by “ClearType native” fonts.

See https://learn.microsoft.com/en-us/typography/cleartype/truetypecleartype for more background and some gory details.

Defaults to true.

See https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.h#L344

is_pedantic: bool

If true, enables more strict error checking.

Defaults to false.

See https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.h#L195

did_iup_x: bool

Set to true when IUP has been executed in the horizontal direction.

did_iup_y: bool

Set to true when IUP has been executed in the vertical direction.

Implementations

impl GraphicsState<'_>

pub fn unscaled_to_pixels(&self) -> i32

Returns the factor for scaling unscaled points to pixels.

For composite glyphs, “unscaled” points are already scaled so we return the identity.

pub fn reset(&mut self)

Resets the non-retained portions of the graphics state.

pub fn reset_retained(&mut self)

Resets the retained portion of the graphics state to default values while saving the user instance settings.

impl GraphicsState<'_>

pub fn update_projection_state(&mut self)

Updates cached state that is derived from projection vectors.

pub fn project(&self, v1: Point<F26Dot6>, v2: Point<F26Dot6>) -> F26Dot6

Computes the projection of vector given by (v1 - v2) along the current projection vector.

pub fn dual_project(&self, v1: Point<F26Dot6>, v2: Point<F26Dot6>) -> F26Dot6

Computes the projection of vector given by (v1 - v2) along the current dual projection vector.

pub fn dual_project_unscaled(&self, v1: Point<i32>, v2: Point<i32>) -> i32

Computes the projection of vector given by (v1 - v2) along the current dual projection vector for unscaled points.

impl GraphicsState<'_>

pub fn round(&self, distance: F26Dot6) -> F26Dot6

impl<'a> GraphicsState<'a>

pub fn in_bounds<const N: usize>( &self, pairs: [(ZonePointer, usize); N], ) -> bool

Takes an array of (zone pointer, point index) pairs and returns true if all accesses would be valid.

pub fn zone(&self, pointer: ZonePointer) -> &Zone<'a>

pub fn zone_mut(&mut self, pointer: ZonePointer) -> &mut Zone<'a>

pub fn zp0(&self) -> &Zone<'a>

pub fn zp0_mut(&mut self) -> &mut Zone<'a>

pub fn zp1(&self) -> &Zone<'_>

pub fn zp1_mut(&mut self) -> &mut Zone<'a>

pub fn zp2(&self) -> &Zone<'_>

pub fn zp2_mut(&mut self) -> &mut Zone<'a>

impl GraphicsState<'_>

pub(crate) fn move_original( &mut self, zone: ZonePointer, point_ix: usize, distance: F26Dot6, ) -> Result<(), HintErrorKind>

Moves the requested original point by the given distance.

pub(crate) fn move_point( &mut self, zone: ZonePointer, point_ix: usize, distance: F26Dot6, ) -> Result<(), HintErrorKind>

Moves the requested scaled point by the given distance. See https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.c#L1771

pub(crate) fn move_zp2_point( &mut self, point_ix: usize, dx: F26Dot6, dy: F26Dot6, do_touch: bool, ) -> Result<(), HintErrorKind>

Moves the requested scaled point in the zone referenced by zp2 by the given delta.

This is a helper function for SHP, SHC, SHZ, and SHPIX instructions.

See https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.c#L5170

pub(crate) fn point_displacement( &mut self, opcode: u8, ) -> Result<PointDisplacement, HintErrorKind>

Computes the adjustment made to a point along the current freedom vector. See https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.c#L5126

Trait Implementations

impl<'a> Debug for GraphicsState<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GraphicsState<'_>

fn default() -> Self

Returns the “default value” for a type.

impl Deref for GraphicsState<'_>

type Target = RetainedGraphicsState

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for GraphicsState<'_>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.