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v0.0.10 Latest Latest
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 Go to latest Published: Nov 19, 2024 License: BSD-3-Clause Imports: 18 Imported by: 3

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func CanBreakText 

func CanBreakText(fc FontConfiguration, t []rune) pr.MaybeBool

func CharacterRatio added in v0.0.3 

func CharacterRatio(style_ pr.ElementStyle, cache pr.TextRatioCache, isCh bool, fonts FontConfiguration) pr.Float

CharacterRatio returns the ratio 1ex/font_size or 1ch/font_size, according to given style. It should be used with a valid text context to get accurate result. Otherwise, if context is `nil`, it returns 1 as a default value. It does not query WordSpacing or LetterSpacing from the style.

func GetLangQuotes added in v0.0.10 

func GetLangQuotes(lang string) (open, close pr.Strings)

func GetLastWordEnd 

func GetLastWordEnd(fc FontConfiguration, t []rune) int

GetLastWordEnd returns the index in `t` of the last word, or -1

func PangoUnitsFromFloat 

func PangoUnitsFromFloat(v pr.Fl) int32

func PangoUnitsToFloat 

func PangoUnitsToFloat(v pango.Unit) pr.Fl

func StrutLayout 

func StrutLayout(style_ pr.StyleAccessor, context TextLayoutContext) (result [2]pr.Float)

StrutLayout returns a tuple of the used value of `line-height` and the baseline. The baseline is given from the top edge of line height. context is mandatory for the text layout.

Types

type EngineLayout added in v0.0.8 

type EngineLayout interface {
	// Text returns a readonly slice of the text in the layout
	Text() []rune

	// Metrics may return nil when [TextDecorationLine] is empty
	Metrics() *LineMetrics

	// Justification returns the current justification
	Justification() pr.Float
	// SetJustification add an additional spacing between words
	// to justify text. Depending on the implementation, it
	// may be ignored until [ApplyJustification] is called.
	SetJustification(spacing pr.Float)

	ApplyJustification()
}

EngineLayout stores the text engine dependant version of the laid out text.

Is is only meant to be consumed by the text/draw package.

type Feature added in v0.0.7 

type Feature struct {
	Tag   [4]byte
	Value int
}

type FontConfiguration 

type FontConfiguration interface {
	// FontContent returns the content of the given font, which may be needed
	// in the final output.
	FontContent(font FontOrigin) []byte

	// AddFontFace load a font file from an external source, using
	// the given [urlFetcher], which must be valid.
	//
	// It returns the file name of the loaded file.
	AddFontFace(ruleDescriptors validation.FontFaceDescriptors, urlFetcher utils.UrlFetcher) string
	// contains filtered or unexported methods
}

FontConfiguration holds information about the available fonts on the system. It is used for text layout at various steps of the rendering process.

It is implemented by and totaly tighted to text engines, either pango or go-text.

type FontConfigurationPango added in v0.0.8 

type FontConfigurationPango struct {
	// contains filtered or unexported fields
}

FontConfigurationPango holds information about the available fonts on the system. It is used for text layout at various steps of the process.

func NewFontConfigurationPango added in v0.0.8 

func NewFontConfigurationPango(fontmap *fcfonts.FontMap) *FontConfigurationPango

NewFontConfigurationPango uses a fontconfig database to create a new font configuration

func (*FontConfigurationPango) AddFontFace added in v0.0.8 

func (f *FontConfigurationPango) AddFontFace(ruleDescriptors validation.FontFaceDescriptors, urlFetcher utils.UrlFetcher) string

func (*FontConfigurationPango) FontContent added in v0.0.8 

func (f *FontConfigurationPango) FontContent(font FontOrigin) []byte

FontContent returns the content of the given face, which may be needed in the final output.

func (*FontConfigurationPango) LoadFace added in v0.0.8 

func (f *FontConfigurationPango) LoadFace(key fonts.FaceID, format fc.FontFormat) (fonts.Face, error)

type FontOrigin added in v0.0.8 

type FontOrigin struct {
	File string // The filename or identifier of the font file.

	// The index of the face in a collection. It is always 0 for
	// single font files.
	Index uint16

	// For variable fonts, stores 1 + the instance index.
	// (0 to ignore variations).
	Instance uint16
}

FontOrigin is a reference to a binary font file, either on disk or stored in memory.

type FontStretch added in v0.0.7 

type FontStretch uint8
const (
	FSeUltraCondensed FontStretch = iota // ultra condensed width
	FSeExtraCondensed                    // extra condensed width
	FSeCondensed                         // condensed width
	FSeSemiCondensed                     // semi condensed width
	FSeNormal                            // the normal width
	FSeSemiExpanded                      // semi expanded width
	FSeExpanded                          // expanded width
	FSeExtraExpanded                     // extra expanded width
	FSeUltraExpanded                     // ultra expanded width
)

type FontStyle added in v0.0.7 

type FontStyle uint8
const (
	FSyNormal FontStyle = iota
	FSyOblique
	FSyItalic
)

type HyphenDictKey 

type HyphenDictKey struct {
	// contains filtered or unexported fields
}

type HyphenateZone added in v0.0.7 

type HyphenateZone struct {
	Limit        pr.Fl
	IsPercentage bool
}

type Hyphens added in v0.0.7 

type Hyphens uint8
const (
	HManual Hyphens = iota
	HNone
	HAuto
)

type LineMetrics added in v0.0.7 

type LineMetrics struct {
	// Distance from the baseline to the logical top of a line of text.
	// (The logical top may be above or below the top of the
	// actual drawn ink. It is necessary to lay out the text to figure
	// where the ink will be.)
	Ascent pr.Fl

	// Distance above the baseline of the top of the underline.
	// Since most fonts have underline positions beneath the baseline, this value is typically negative.
	UnderlinePosition pr.Fl

	// Suggested thickness to draw for the underline.
	UnderlineThickness pr.Fl

	// Distance above the baseline of the top of the strikethrough.
	StrikethroughPosition pr.Fl
	// Suggested thickness to draw for the strikethrough.
	StrikethroughThickness pr.Fl
}

type OverflowWrap added in v0.0.7 

type OverflowWrap uint8
const (
	ONormal OverflowWrap = iota
	OAnywhere
	OBreakWord
)

type Splitted 

type Splitted struct {
	// Output layout containing (at least) the first line
	Layout EngineLayout

	// Length in runes of the first line
	Length int

	// ResumeAt is the number of runes to skip for the next line.
	// May be -1 if the whole text fits in one line.
	// This may be greater than [Length] in case of preserved
	// newline characters.
	ResumeAt int

	// Width is the width in pixels of the first line
	Width pr.Float

	// Height is the height in pixels of the first line
	Height pr.Float

	// Baseline is the baseline in pixels of the first line
	Baseline pr.Float

	FirstLineRTL bool // true is the first line direction is RTL
}

Splitted exposes the result of laying out one line of text

func SplitFirstLine 

func SplitFirstLine(text_ string, style_ pr.StyleAccessor, context TextLayoutContext,
	maxWidth pr.MaybeFloat, minimum, isLineStart bool,
) Splitted

SplitFirstLine fit as much text from [text_] as possible in the available width given by [maxWidth] minimum=False

type StrutLayoutKey 

type StrutLayoutKey struct {
	// contains filtered or unexported fields
}

type TabSize added in v0.0.7 

type TabSize struct {
	Width      int
	IsMultiple bool // true to use Width * <space character width>
}

type TextLayoutContext 

type TextLayoutContext interface {
	Fonts() FontConfiguration
	HyphenCache() map[HyphenDictKey]hyphen.Hyphener
	StrutLayoutsCache() map[StrutLayoutKey][2]pr.Float
}

type TextLayoutPango added in v0.0.8 

type TextLayoutPango struct {
	Style *TextStyle

	MaxWidth pr.MaybeFloat

	Layout pango.Layout
	// contains filtered or unexported fields
}

TextLayoutPango wraps a pango.Layout object

func (*TextLayoutPango) ApplyJustification added in v0.0.8 

func (p *TextLayoutPango) ApplyJustification()

ApplyJustification re-layout the text, applying justification.

func (*TextLayoutPango) GetFirstLine added in v0.0.8 

func (p *TextLayoutPango) GetFirstLine() (*pango.LayoutLine, int)

GetFirstLine returns the first line and the index of the second line, or -1.

func (*TextLayoutPango) Justification added in v0.0.8 

func (p *TextLayoutPango) Justification() pr.Float

func (*TextLayoutPango) Metrics added in v0.0.8 

func (p *TextLayoutPango) Metrics() *LineMetrics

func (*TextLayoutPango) SetJustification added in v0.0.8 

func (p *TextLayoutPango) SetJustification(spacing pr.Float)

func (*TextLayoutPango) SetText added in v0.0.8 

func (p *TextLayoutPango) SetText(text string)

func (*TextLayoutPango) Text added in v0.0.8 

func (p *TextLayoutPango) Text() []rune

Text returns a readonly slice of the text used in the layout.

type TextStyle added in v0.0.7 

type TextStyle struct {
	TextDecorationLine pr.Decorations

	// FontFeatures stores the resolved value
	// for all the CSS properties related :
	// 	"font-kerning"
	// 	"font-variant-ligatures"
	// 	"font-variant-position"
	// 	"font-variant-caps"
	// 	"font-variant-numeric"
	// 	"font-variant-alternates"
	// 	"font-variant-east-asian"
	// 	"font-feature-settings"
	FontFeatures []Feature

	FontFamily            []string
	FontStyle             FontStyle
	FontStretch           FontStretch
	FontWeight            int
	FontSize              pr.Fl
	FontVariationSettings []Variation // empty for 'normal'

	FontLanguageOverride fontLanguageOverride
	Lang                 string

	WhiteSpace   Whitespace
	OverflowWrap OverflowWrap
	WordBreak    WordBreak

	Hyphens             Hyphens
	HyphenateCharacter  string
	HyphenateLimitChars pr.Ints3
	HyphenateLimitZone  HyphenateZone

	WordSpacing   pr.Fl
	LetterSpacing pr.Fl // 0 for 'normal'
	TabSize       TabSize
}

TextStyle exposes the subset of a pr.Style required to layout text.

func NewTextStyle added in v0.0.7 

func NewTextStyle(style pr.StyleAccessor, ignoreSpacing bool) *TextStyle

If ignoreSpacing is true, 'word-spacing' and 'letter-spacing' are not queried from [style]

type Variation added in v0.0.7 

type Variation struct {
	Tag   [4]byte
	Value pr.Fl
}

type Whitespace added in v0.0.7 

type Whitespace uint8
const (
	WNormal Whitespace = iota
	WNowrap
	WPre
	WPreWrap
	WPreLine
	WBreakSpaces
)

type WordBreak added in v0.0.7 

type WordBreak uint8
const (
	WBNormal WordBreak = iota
	WBBreakAll
)

Source Files

View all Source files

Directories

Path Synopsis
Package draw use a backend and a layout object to draw glyphs on the ouput.
 Package draw use a backend and a layout object to draw glyphs on the ouput.
Package hyphen hyphenates text using existing Hunspell hyphenation dictionaries.
 Package hyphen hyphenates text using existing Hunspell hyphenation dictionaries.

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