pulp::canvas::TextShaper Class Reference

Text shaper — the PreText-style measure-once-reflow-forever engine. More...

#include <text_shaper.hpp>

Public Member Functions
	TextShaper ()
	~TextShaper ()
PreparedText	prepare (std::string_view text, std::string_view font_family, float font_size, int font_weight=400, int font_slant=0, float letter_spacing=0.0f, const std::vector< Canvas::FontFeature > &font_features={})
	Prepare text for layout — this is the expensive call.
PreparedText	prepare (const AttributedString &text, const std::vector< Canvas::FontFeature > &font_features={})
	Prepare an attributed string (mixed styles).
ShapedLayout	layout (const PreparedText &prepared, float max_width, float line_height=0, int max_lines=0, BreakMode break_mode=BreakMode::normal) const
	Layout prepared text at a specific width — this is the cheap call.
ShapedLayout	layout_with_lines (const PreparedText &prepared, float max_width, float line_height=0, int max_lines=0, BreakMode break_mode=BreakMode::normal) const
	Layout and materialize line text (slightly more expensive than layout()).
float	measure_height (const PreparedText &prepared, float max_width, float line_height=0) const
	Quick height calculation (fastest path — just returns height, no line details).
int	count_lines (const PreparedText &prepared, float max_width) const
	Quick line count.
void	clear_cache ()
	Clear the segment measurement cache.
bool	uses_real_shaping () const
	Whether this shaper uses real font shaping (SkParagraph) or estimation.

Detailed Description

Text shaper — the PreText-style measure-once-reflow-forever engine.

Usage: auto prepared = shaper.prepare("Hello world", "system", 14); auto layout = shaper.layout(prepared, 200.0f); // Just arithmetic! // On resize: auto new_layout = shaper.layout(prepared, 300.0f); // Still just arithmetic!

Constructor & Destructor Documentation

TextShaper()

pulp::canvas::TextShaper::TextShaper

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~TextShaper()

pulp::canvas::TextShaper::~TextShaper

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Member Function Documentation

clear_cache()

void pulp::canvas::TextShaper::clear_cache

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Clear the segment measurement cache.

count_lines()

int pulp::canvas::TextShaper::count_lines	(	const PreparedText &	prepared,
		float	max_width ) const

Quick line count.

layout()

ShapedLayout pulp::canvas::TextShaper::layout	(	const PreparedText &	prepared,
		float	max_width,
		float	line_height = 0,
		int	max_lines = 0,
		BreakMode	break_mode = BreakMode::normal ) const

Layout prepared text at a specific width — this is the cheap call.

Pure arithmetic over cached segment widths. Call on every resize.

When max_lines > 0, truncate the result to N lines. max_lines == 1 is the canonical CSS white-space: nowrap path — it ignores wrapping at the right edge and emits a single line whose width is the text's full intrinsic width (segments past max_width still count toward the line width so consumers that pair this with ellipsis truncation can see they overflow). 0 = unlimited (default).

layout_with_lines()

ShapedLayout pulp::canvas::TextShaper::layout_with_lines	(	const PreparedText &	prepared,
		float	max_width,
		float	line_height = 0,
		int	max_lines = 0,
		BreakMode	break_mode = BreakMode::normal ) const

Layout and materialize line text (slightly more expensive than layout()).

measure_height()

float pulp::canvas::TextShaper::measure_height	(	const PreparedText &	prepared,
		float	max_width,
		float	line_height = 0 ) const

Quick height calculation (fastest path — just returns height, no line details).

prepare() [1/2]

PreparedText pulp::canvas::TextShaper::prepare	(	const AttributedString &	text,
		const std::vector< Canvas::FontFeature > &	font_features = {} )

Prepare an attributed string (mixed styles).

Paragraph-wide OpenType features still affect every span's advances, just as they do when the attributed string is painted by Label.

prepare() [2/2]

PreparedText pulp::canvas::TextShaper::prepare	(	std::string_view	text,
		std::string_view	font_family,
		float	font_size,
		int	font_weight = 400,
		int	font_slant = 0,
		float	letter_spacing = 0.0f,
		const std::vector< Canvas::FontFeature > &	font_features = {} )

Prepare text for layout — this is the expensive call.

Runs text shaping (HarfBuzz via SkShaper when available) and caches segment widths. Call once per (text, font) pair. Do NOT call on every resize.

font_weight is the CSS numeric weight the text will be PAINTED at, and it belongs here because it changes advances. Measuring a bold run through the regular face reports a narrower line than the one that gets drawn, which shows up as text breaking a word or two late and overflowing its box — a wrap bug in appearance, a measurement bug in fact. A caller that omits it is stating the text is Regular.

uses_real_shaping()

bool pulp::canvas::TextShaper::uses_real_shaping

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const

Whether this shaper uses real font shaping (SkParagraph) or estimation.

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The documentation for this class was generated from the following file:

• /home/runner/work/pulp/pulp/core/canvas/include/pulp/canvas/text_shaper.hpp