README
¶
Line-breaking
This package provides a Go implementation of two line-breaking algorithms with support for bi-directional texts. However, it abstracts text elements (normally, words) with a Box interface that has a Width and Direction instead of plain strings, for more flexibility.
An example usage would be like the following:
package main
import (
"strings"
lb "github.com/aslrousta/line-breaking"
)
var paragraph = "Alice was beginning ..."
type Word string
func (w Word) Direction() lb.Direction { return lb.LeftToRight }
func (w Word) Width() float32 {
// Compute the extent of the word in a desired font-face.
}
func main() {
// Convert words in the paragraph into boxes.
words := strings.Split(paragraph, " ")
boxes := make([]lb.Box, 0, len(words))
for _, w := range words {
boxes = append(boxes, Word(w))
}
spaceWidth := /* Compute the extent of a `space` character */
// Do the line-breaking using Knuth-Plass algorithm.
lines := lb.KnuthPlass(boxes, &lb.Options{
TextWidth: 60,
TextDirection: lb.LeftToRight,
GlueWidth: spaceWidth,
GlueShrink: spaceWidth / 5, /* 20% shrink */
GlueExpand: spaceWidth / 3, /* 33% expand */
})
renderLines(lines)
...
}
See the example folder for a more practical sample code.
Algorithms
Two Greedy and Knuth-Plass line-breaking algorithms are provided. The greedy approach is a fast algorithm that tries to fit as boxes as possible within a line. On the other hand, the Knuth-Plass algorithm is relatively slow but gives better results
Copyright
This package is distributed under the MIT license. See the LICENSE file for more information.
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Box ¶
type Box interface {
// Direction returns the writing direction of the box.
Direction() Direction
// Width returns the extent of the box within the text.
Width() float32
}
Box is a solid text element (typically, a word).
type Line ¶
type Line struct {
// Boxes is the slice of boxes within the line.
Boxes []Box
// GlueWidth is the extent of the glues between the boxes.
GlueWidth float32
}
Line is a series of boxes that fit in a line of text.
func Greedy ¶
Greedy is a greedy but fast line-breaking algorithm that tries to fit as much boxes as possible in each and every line.
func KnuthPlass ¶
KnuthPlass is a relatively slow line-breaking algorithm but gives the best result aesthetically.
type Options ¶
type Options struct {
// TextWidth is the extent of a line of text.
TextWidth float32
// TextDirection is the writing direction of the text.
TextDirection Direction
// GlueWidth is the normal extent of the glues between the boxes.
GlueWidth float32
// GlueShrink is the extent that a glue can shrink to.
GlueShrink float32
// GlueExpand is the extent that a glue can expand to.
GlueExpand float32
}
Options contains several options passed to the line-breaking algorithm.
Source Files
Directories