Struct TextMetrics 

pub struct TextMetrics {
    pub font_size_px: f64,
    pub letter_spacing_px: f64,
    pub text_transform: TextTransform,
    pub monospace: bool,
}

Text-shaping parameters that influence the rendered width of a label.

TextMetrics is how layout code feeds theme typography into the width estimator so margins, tick spacing, label strategy, legend packing, and truncation all see the same width the SVG renderer will eventually paint.

The default is calibrated to Theme::default(): a 12px sans-serif face with no letter spacing and no text transform. measure_text(text, default) is therefore guaranteed to return exactly the legacy approximate_text_width(text) value — this is the backward-compatibility contract that keeps the pre-theme-hooks golden snapshots byte-identical.

Fields

font_size_px: f64

Rendered font size in pixels.

letter_spacing_px: f64

Extra CSS letter-spacing in pixels applied between glyphs.

text_transform: TextTransform

text-transform that will be applied by the renderer.

monospace: bool

Whether the rendered font is a monospace face. Monospace glyphs are noticeably wider than the sans-serif calibration; this flag lets the measurement apply a per-character width correction.

Implementations

impl TextMetrics

pub fn is_legacy_default(&self) -> bool

True when these metrics exactly match the legacy calibration. When true, measure_text short-circuits to approximate_text_width so layout output is bit-for-bit identical to the pre-3.1 behavior.

pub fn from_theme_tick_value(theme: &Theme) -> Self

Build TextMetrics for numeric tick labels from a theme.

Returns the legacy-default metrics (byte-identical to approximate_text_width) when every relevant field on theme matches Theme::default(). Any divergence flips the layout path to the full measure_text measurement.

pub fn from_theme_axis_label(theme: &Theme) -> Self

Build TextMetrics for axis/category labels from a theme.

pub fn from_theme_legend(theme: &Theme) -> Self

Build TextMetrics for legend labels from a theme.

pub fn from_theme_title(theme: &Theme) -> Self

Build TextMetrics for the chart title from a theme.

Trait Implementations

impl Clone for TextMetrics

fn clone(&self) -> TextMetrics

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TextMetrics

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

Formats the value using the given formatter.

impl Default for TextMetrics

fn default() -> Self

Default metrics match the Theme::default() legacy assumptions (12px sans-serif, no letter spacing, no transform). Feeding default metrics to measure_text produces output byte-identical to the legacy approximate_text_width.

impl PartialEq for TextMetrics

fn eq(&self, other: &TextMetrics) -> 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 StructuralPartialEq for TextMetrics