Text box, as defined in an HOCR file. More...

#include <HOCRTextBox.h>

Public Member Functions
	HOCRTextBox ()
	Constructs an empty text box.

bool	hasText () const
	Decide if the text box contains non-trivial text. More...

qreal	angle () const
	Text angle. More...

QXmlStreamAttributes	attributes () const
	Returns the attributes of the textBox. More...

QVector< qreal >	baselinePolynomial () const
	Base line as a polynomial. More...

QPoint	baselineReferencePoint () const
	Base line reference point. More...

QRect	boundingBox () const
	Bounding box. More...

QString	classType () const
	Class of this textBox. More...

int	confidence () const
	Confidence level. More...

QString	direction () const
	Text flow direction. More...

qreal	fontSize () const
	Font size. More...

QString	imageName () const
	Image associated with content of this text box. More...

QString	language () const
	Language of the content of this text box. More...

void	render (QPainter &painter) const
	Paint the contents of the text box to a painter. More...

QImage	toImage (const QFont &overrideFont, QImage::Format format=QImage::Format_Grayscale8) const
	Export this text box as an image. More...

QByteArray	toRawPDFContentStream (const QFont &font, resolution xRes, resolution yRes, length deltaX=length(), length deltaY=length()) const
	Return raw PDF text rendering commands. More...

QString	toText () const
	Export this text box as text. More...

qint64	estimateFit (const QFont &font) const
	Estimate how well a given font fits the textbox. More...

QFont	suggestFont () const
	Suggest font. More...

QString	text () const
	Text content of the text box. More...

Detailed Description

Text box, as defined in an HOCR file.

This class represents a box that may contain text and also other text boxes. Every text box has a bounding rectagle, text, a type, and a list of attributes. There are several helper functions to interpret the attribules.

Texboxes can be rendered on a QPainter. For users who wish to implement their own rendering routines, there are several helper functions that give suggestions for optimal rendering.

The methods of this class are reentrant, but not thread safe.

Definition at line 44 of file HOCRTextBox.h.

Member Function Documentation

◆ angle()

qreal HOCRTextBox::angle ( ) const

inline

Text angle.

Returns: The text angle, as specified in the HOCR file or inherited from parent. If no angle line was specified, this number is zero.

Definition at line 62 of file HOCRTextBox.h.

◆ attributes()

QXmlStreamAttributes HOCRTextBox::attributes ( ) const

inline

Returns the attributes of the textBox.

Returns: The attributes of the textBox, as stored in the corresponding entity of the HOCR file.

Definition at line 69 of file HOCRTextBox.h.

◆ baselinePolynomial()

QVector<qreal> HOCRTextBox::baselinePolynomial ( ) const

inline

Base line as a polynomial.

Returns: The base line as a polynomial, as specified in the HOCR file or inherited from parent. If no base line was specified, this vector is empty.

Definition at line 77 of file HOCRTextBox.h.

◆ baselineReferencePoint()

QPoint HOCRTextBox::baselineReferencePoint ( ) const

inline

Base line reference point.

Returns: The base line reference point, as specified in the HOCR file or inherited from parent. If no base line polynomial is specified, this member is meaningless.

Definition at line 85 of file HOCRTextBox.h.

◆ boundingBox()

QRect HOCRTextBox::boundingBox ( ) const

inline

Bounding box.

Returns: The bounding box of this textBox. If no bounding box was specified in the HOCR file, an empty box is returned.

Definition at line 92 of file HOCRTextBox.h.

◆ classType()

QString HOCRTextBox::classType ( ) const

Class of this textBox.

Returns: The type of this textBox. Typical types are "ocr_page", "ocr_carea", "ocr_par", "ocr_line" or "ocrx_word". If the HOCR element described by this box is not of OCR-related type, an empty string is returned.

◆ confidence()

int HOCRTextBox::confidence ( ) const

inline

Confidence level.

Returns: The confidence level for the content of this textBox. If no confidence level was specified in the HOCR file, -1 is returned.

Definition at line 108 of file HOCRTextBox.h.

◆ direction()

QString HOCRTextBox::direction ( ) const

inline

Text flow direction.

Returns: The text flow direction of the corresponding element in the HOCR file. Returns 'ltr' for left-to-right, and 'rtl' for right-to-left. Any other return value means 'undefined'.

Definition at line 116 of file HOCRTextBox.h.

◆ estimateFit()

qint64 HOCRTextBox::estimateFit ( const QFont & font ) const

Estimate how well a given font fits the textbox.

For this box, and for each subbox, this method computes the width of the text when rendered with the given font, and compares it to the width of the bounding box. The square of the difference is then computed, and the results are added up.

Parameters

font	Font with which the text is to be rendered. The font's pixelSize will be changed in the process.

Returns: Sum of squares. The lower the number, the better does the font fit the textbox

◆ fontSize()

qreal HOCRTextBox::fontSize ( ) const

inline

Font size.

Returns: The font size for the content of this textBox. If no font size was specified in the HOCR file, 0.0 is returned.

Definition at line 123 of file HOCRTextBox.h.

◆ hasText()

bool HOCRTextBox::hasText ( ) const

Decide if the text box contains non-trivial text.

Returns: True if the text box or any of its subboxes contains text other than white space.

◆ imageName()

QString HOCRTextBox::imageName ( ) const

inline

Image associated with content of this text box.

Returns: The name of an image file associated with the content of this text box. If nothing is specified in the HOCR file, an empty string is returned.

Definition at line 131 of file HOCRTextBox.h.

◆ language()

QString HOCRTextBox::language ( ) const

inline

Language of the content of this text box.

Returns: The name of the language of the content of this text box ('eng'). If nothing is specified in the HOCR file, this string is empty.

Definition at line 138 of file HOCRTextBox.h.

◆ render()

void HOCRTextBox::render ( QPainter & painter ) const

Paint the contents of the text box to a painter.

Paint the contents of the text box to a painter. Coordinates are in pixels. This is convenient if the contents of an HOCR file is drawn onto a bitmap that is meant to resemble the original scanned image as closely as possible. When writing to a PDF, for instance, resolution needs to be taken into account.

Parameters

painter QPainter to be used in the paint job

◆ suggestFont()

QFont HOCRTextBox::suggestFont ( ) const

Suggest font.

Suggests a font for rendering this document. Three standard fonts ("Helvetica", "Times", "Courier") are tried, and the one is chose that fits the text box best.

Returns: The best-fitting font

Warning: This method is expensive

◆ text()

QString HOCRTextBox::text ( ) const

inline

Text content of the text box.

Returns: The text of this text box. If nothing is specified in the HOCR file, an empty string is returned.

Definition at line 232 of file HOCRTextBox.h.

◆ toImage()

QImage HOCRTextBox::toImage	(	const QFont &	overrideFont,
		QImage::Format	format = `QImage::Format_Grayscale8`
	)		const

Export this text box as an image.

Paint the contents of the text box to an image and returns the image. In case of an error, an empty image is returned.

Parameters

overrideFont	If null, a standard font will be taken. If not null, then the specified font will be taken.
format	Format of the returned QImage

Returns: An image

◆ toRawPDFContentStream()

QByteArray HOCRTextBox::toRawPDFContentStream	(	const QFont &	font,
		resolution	xRes,
		resolution	yRes,
		length	deltaX = `length()`,
		length	deltaY = `length()`
	)		const

Return raw PDF text rendering commands.

This method converts the text box into a sequence of raw PDF text rendering command that are suitable for inclusion in a PDF file. The commands refer to the font /F1 and assume that this font exists. The text is encoded using the Windows-1252 encoding. Characters that cannot be represented in this encoding are discarded.

Parameters

font	A reference to a QFont that should match the font "/F1" as closely as possible. The font is used to optimise placement of the text.
xRes	Horizontal resolution. Used to transform the bitmap coordinates found in the HOCR file to physical sizes. Needs to be valid, or else the result is undefined.
yRes	Vertical resolution. Used to transform the bitmap coordinates found in the HOCR file to physical sizes. Needs to be valid, or else the result is undefined.
deltaX	Horizontal offest for text placement
deltaY	Vertical offest for text placement

Returns: A QByteArray containing PDF drawing commands

◆ toText()

QString HOCRTextBox::toText ( ) const

Export this text box as text.

Returns: The contents of this text box, and of all child text boxes, with line breaks added.

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

/home/kebekus/Software/projects/scantools/src/libscantools/HOCRTextBox.h

Public Member Functions

Detailed Description

Member Function Documentation

◆ angle()

◆ attributes()

◆ baselinePolynomial()

◆ baselineReferencePoint()

◆ boundingBox()

◆ classType()

◆ confidence()

◆ direction()

◆ estimateFit()

◆ fontSize()

◆ hasText()

◆ imageName()

◆ language()

◆ render()

◆ suggestFont()

◆ text()

◆ toImage()

◆ toRawPDFContentStream()

◆ toText()