ocrpdf

package module
v0.0.0-...-8a85526 Latest Latest
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 Go to latest Published: Jul 23, 2016 License: MIT Imports: 7 Imported by: 0

README

ocrpdf

ocrpdf is a library wrapping around Tesseract, Leptonica and gofpdf, designed to assist in the generation of PDF files from scanned documents.

It is designed primarily for use with the goscan2pdf tool.

Documentation

Index

Constants

View Source 
const (
	// AutoOrientation chooses orientation based on longest edge
	AutoOrientation      Orientation = "auto"
	PortraitOrientation              = "portrait"
	LandscapeOrientation             = "landscape"
)

Different orientation modes.

View Source 
const (
	// NoTextScaling specifies that no text scaling will be performed.
	NoTextScaling TextScaling = "off"
	// ContainTextScaling fits the text to the detected word boundary,
	// whilst maintaining the correct aspect ratio for the font.
	ContainTextScaling = "contain"
	// MatchTextScaling fits the text to the detected word boundary exactly,
	// scaling the font if required.
	MatchTextScaling = "match"
)
View Source 
const DefaultJPEGCompression int = 75

Variables

View Source 
var JPEGCompression int = DefaultJPEGCompression

Functions

This section is empty.

Types

type Document 

type Document struct {
	*gofpdf.Fpdf
	// contains filtered or unexported fields
}

Document is a wrapped version of gofpdf.Fpd which adds additional methods for constructing documents with OCR-generated text.

func NewDocument 

func NewDocument(size string) *Document

NewDocument returns a new Document of the specified size.

func (*Document) AddImageLayer 

func (d *Document) AddImageLayer(image Image, imagename string,
	format string, w, h float64)

AddImageLayer adds the specified image to the page, embedding it using the given format, and appear at the specified size (in page units).

func (*Document) AddPage 

func (d *Document) AddPage(image Image, imagename string,
	words []Word, format string) error

AddPage appends the given image to the document, annotating the document with the detected words. Ensure `name` is unique for each distinct image.

func (*Document) AddWords 

func (d *Document) AddWords(words []Word)

AddWords adds the specified words to the page.

func (*Document) GetPageConfiguration 

func (d *Document) GetPageConfiguration(iw, ih float64) (
	w, h float64, orientation Orientation)

GetPageConfiguration returns a suitable page size and orientation to contain an image of the specified dimensions.

func (*Document) SetDebug 

func (d *Document) SetDebug(enabled bool)

SetDebug enables debug mode, in which detected words are outlined, and the text layer is arranged on top of the image (scan) layer.

func (*Document) SetOrientation 

func (d *Document) SetOrientation(orientation Orientation)

SetOrientation sets the orientation of new pages

func (*Document) SetTextScaling 

func (d *Document) SetTextScaling(mode TextScaling)

SetTextScaling enables the scaling of embedded text such that it matches the same area that the original text was detected.

type Image 

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

func NewImageFromFile 

func NewImageFromFile(filename string) (*Image, error)

NewImageFromFile creates and returns a new image loaded from the given file path.

func (*Image) Adjust 

func (i *Image) Adjust(threshold float32) *Image

Adjust improves the clarity and contrast of the image, generally reducing scanning artifacts.

func (*Image) CPIX 

func (i *Image) CPIX() *C.PIX

func (Image) Dimensions 

func (i Image) Dimensions() (int32, int32, int32)

Dimensions calculates the width, height and colour depth of the image.

func (Image) FormatString 

func (i Image) FormatString() string

FormatString returns the image format as a string, e.g. 'jpg'

func (Image) Reader 

func (i Image) Reader(format string) (*bytes.Buffer, string, error)

Reader returns an io.Reader for the image data. If format is not specified, the reader will produce image data in the original image format. Otherwise, `format` must be either "jpeg" or "png"

func (Image) ReaderJPEG 

func (i Image) ReaderJPEG(quality int, progressive bool) (*bytes.Buffer, error)

ReaderJPEG returns an io.Reader for the image data, returning a compressed JPEG of the specified quality (0-100).

func (Image) ReaderPNG 

func (i Image) ReaderPNG(gamma float32) (*bytes.Buffer, error)

ReaderPNG returns an io.Reader for the image data, in PNG format.

func (*Image) Scale 

func (i *Image) Scale(w, h int32) *Image

Scale resizes the image to the specified dimensions.

func (*Image) ScaleDown 

func (i *Image) ScaleDown(w, h int32) *Image

ScaleDown scales down the image to the specified dimensions, returning the original image if it is already smaller (in terms of pixel count)

type Orientation 

type Orientation string

Orientation defines page orientations

type Tess 

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

func NewTess 

func NewTess(datapath string, language string) (*Tess, error)

func (*Tess) SetImagePix 

func (t *Tess) SetImagePix(pix *C.struct_Pix)

SetImagePix sets the image to perform recognition on

func (*Tess) Words 

func (t *Tess) Words() []Word

Words analyses the document and returns a list of recognised words.

type TextScaling 

type TextScaling string

TextScaling defines text scaling modes

type Word 

type Word struct {
	Text   string
	Left   int
	Right  int
	Top    int
	Bottom int
	Width  int
	Height int
}

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