Struct ShadowGradeConfig 

pub struct ShadowGradeConfig {
    pub fg_dim_strength: f32,
    pub bg_dim_strength: f32,
    pub fg_desaturate_strength: f32,
    pub bg_desaturate_strength: f32,
    pub fg_tint_strength: f32,
    pub bg_tint_strength: f32,
    pub preserve_fg_alpha: bool,
    pub preserve_bg_alpha: bool,
    pub replacement_char: Option<char>,
}

Color grading parameters for the grade-underlying shadow compositing mode.

Each strength field ranges from 0.0 (no effect) to 1.0 (maximum). Effective per-cell strength is field_value * shadow_coverage, where coverage is derived from the rendered shadow cell’s alpha channels.

Background grading is intentionally stronger than foreground grading in the dramatic preset to preserve text readability while making the shadow region clearly visible.

Example

use tui_vfx_shadow::ShadowGradeConfig;

// Use the recommended dramatic preset
let grade = ShadowGradeConfig::dramatic();
assert!(grade.bg_dim_strength > grade.fg_dim_strength);

// Or configure manually
let custom = ShadowGradeConfig {
    fg_dim_strength: 0.15,
    bg_dim_strength: 0.40,
    ..Default::default()
};

Fields

fg_dim_strength: f32

Foreground dimming strength (0.0–1.0).

bg_dim_strength: f32

Background dimming strength (0.0–1.0).

fg_desaturate_strength: f32

Foreground desaturation strength (0.0–1.0).

bg_desaturate_strength: f32

Background desaturation strength (0.0–1.0).

fg_tint_strength: f32

Foreground tint-toward-shadow-color strength (0.0–1.0).

bg_tint_strength: f32

Background tint-toward-shadow-color strength (0.0–1.0).

preserve_fg_alpha: bool

When true, preserve the destination foreground alpha channel.

preserve_bg_alpha: bool

When true, preserve the destination background alpha channel.

replacement_char: Option<char>

Optional replacement character for color-inert glyphs (emoji, PUA).

When Some, glyphs that ignore ANSI fg color attributes are replaced with this character during grading. This prevents bright bitmap glyphs from creating visual artifacts in dimmed shadow regions.

Set to None to preserve all original glyphs (backward compatible default).

Implementations

impl ShadowGradeConfig

pub const fn dramatic() -> Self

Returns the recommended dramatic grade preset.

This preset is intentionally moderate-to-strong so the shadow region is clearly visible on ordinary RGB terminal cells. Background grading is stronger than foreground grading to maintain text readability.

Numeric values are locked by plan and must not change without a plan update.

Trait Implementations

impl Clone for ShadowGradeConfig

fn clone(&self) -> ShadowGradeConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ShadowGradeConfig

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

Formats the value using the given formatter.

impl Default for ShadowGradeConfig

fn default() -> Self

Returns a neutral (zero-strength) grade configuration.

impl<'de> Deserialize<'de> for ShadowGradeConfig

where ShadowGradeConfig: Default,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ShadowGradeConfig

fn eq(&self, other: &ShadowGradeConfig) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ShadowGradeConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for ShadowGradeConfig

impl StructuralPartialEq for ShadowGradeConfig