Inkscape::Text::Layout::ScanlineMaker Class Reference

private to Layout. More...

#include <Layout-TNG-Scanline-Maker.h>

Inheritance diagram for Inkscape::Text::Layout::ScanlineMaker:

Classes
struct	ScanRun

Public Member Functions
virtual	~ScanlineMaker ()=default
virtual std::vector< ScanRun >	makeScanline (Layout::FontMetrics const &line_height)=0
	Returns a list of chunks on the current line which can fit text with the given properties.
virtual void	completeLine ()=0
	Indicates that the caller has successfully filled the current line and hence that the next call to makeScanline() should return lines on the next lower line.
virtual double	yCoordinate ()=0
	Returns the y coordinate of the top of the scanline that will be returned by the next call to makeScanline().
virtual void	setNewYCoordinate (double new_y)=0
	Forces an arbitrary change in the stored y coordinate of the object.
virtual bool	canExtendCurrentScanline (Layout::FontMetrics const &line_height)=0
	Tests whether the caller can fit a new line with the given metrics into exactly the space returned by the previous call to makeScanline().
virtual void	setLineHeight (Layout::FontMetrics const &line_height)=0
	Sets current line block height.

Detailed Description

private to Layout.

Generates lists of chunks within a shape.

This is the abstract base class for taking a given shape and scanning through it line-by-line to get the horizontal extents of each chunk for a line of a given height. There are two specialisations: One for real shapes and one that turns off wrapping by simulating an infinite shape. In due course there will be a further specialisation to optimise for the common case where the shape is a rectangle.

Definition at line 33 of file Layout-TNG-Scanline-Maker.h.

Constructor & Destructor Documentation

~ScanlineMaker()

virtual Inkscape::Text::Layout::ScanlineMaker::~ScanlineMaker ( )

virtualdefault

Member Function Documentation

canExtendCurrentScanline()

virtual bool Inkscape::Text::Layout::ScanlineMaker::canExtendCurrentScanline ( Layout::FontMetrics const &  line_height )

pure virtual

Tests whether the caller can fit a new line with the given metrics into exactly the space returned by the previous call to makeScanline().

This saves the caller from having to discard its wrapping solution and starting at the beginning of the line again when a larger font is seen. The metrics given here are considered to be the ones that are being used now, and hence is the line advance height used by completeLine().

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

completeLine()

virtual void Inkscape::Text::Layout::ScanlineMaker::completeLine ( )

pure virtual

Indicates that the caller has successfully filled the current line and hence that the next call to makeScanline() should return lines on the next lower line.

There is no error return, the next call to makeScanline() will give an error if there is no more space.

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

makeScanline()

virtual std::vector< ScanRun > Inkscape::Text::Layout::ScanlineMaker::makeScanline ( Layout::FontMetrics const &  line_height )

pure virtual

Returns a list of chunks on the current line which can fit text with the given properties.

It is up to the caller to discard any chunks which are too narrow for its needs. This function may change the y coordinate between calls if the new height too big to fit in the space remaining in this shape. Returns an empty vector if there is no space left in the current shape.

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

setLineHeight()

virtual void Inkscape::Text::Layout::ScanlineMaker::setLineHeight ( Layout::FontMetrics const &  line_height )

pure virtual

Sets current line block height.

Call before completeLine() to correct for actually used line height (in case some chunks with larger font-size rolled back).

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

setNewYCoordinate()

virtual void Inkscape::Text::Layout::ScanlineMaker::setNewYCoordinate ( double  new_y )

pure virtual

Forces an arbitrary change in the stored y coordinate of the object.

The next call to makeScanline() will return runs whose top is at the new coordinate.

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

yCoordinate()

virtual double Inkscape::Text::Layout::ScanlineMaker::yCoordinate ( )

pure virtual

Returns the y coordinate of the top of the scanline that will be returned by the next call to makeScanline().

Implemented in Inkscape::Text::Layout::InfiniteScanlineMaker, and Inkscape::Text::Layout::ShapeScanlineMaker.

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

• /builds/inkscape/inkscape/src/libnrtype/Layout-TNG-Scanline-Maker.h