CairoArrow Class Reference

#include <CairoArrow.H>

Public Member Functions
	CairoArrow (void)
	CairoArrow (cairo_t *cr, float xBase, float yBase, float xPoint, float yPoint, float headToLengthRatio, float width, bool closed, bool filled)
void	draw (cairo_t *cr, float xBase, float yBase, float xPoint, float yPoint, float headToLengthRatio, float width, bool closed, bool filled)
virtual	~CairoArrow ()

Private Member Functions
void	findArrowHeadPoints (float xBase, float yBase, float xPoint, float yPoint, float headToLengthRatio, float width)

Private Attributes
float	xSide1
float	xSide2
	The arrow head side 1. More...
float	ySide1
float	ySide2
	The arrow head side 2. More...
float	vecX
float	vecY
	The shaft vector transposed to the origin. More...

Detailed Description

Given a Cairo context, draw an arrow. Arrows can be of three types, line arrows, closed head arrows and filled head arrows. The arrows are specified by a base (x,y) and point (x,y). The arrow head is specified by a fraction of the shaft size. The arrow head width is specified in pixels.

Examples:

CairoArrowTest.C.

Definition at line 32 of file CairoArrow.H.

Constructor & Destructor Documentation

CairoArrow() [1/2]

CairoArrow::CairoArrow ( void  )

inline

This constructor does nothing. Allows instantiation and usage like so :

CairoArrow ca;
ca.draw(cr, 200, 200, 250, 350, .2, 20, 0, 0);
ca.draw(cr, 400, 400, 300, 200, .2, 20, 1, 0);

Definition at line 70 of file CairoArrow.H.

CairoArrow() [2/2]

CairoArrow::CairoArrow ( cairo_t *  cr, float  xBase, float  yBase, float  xPoint, float  yPoint, float  headToLengthRatio, float  width, bool  closed, bool  filled  )

inline

Construct an arrow by calculating the head points and then use cairo to stroke or fill. The Cairo context which is passed in should already be configured for line width and colour. This medthod is good if you want to draw one arrow :

CairoArrow ca(cr, 200, 200, 250, 350, .2, 20, 0, 0);

Parameters

cr	The cairo context to draw in
xBase	The x arrow shaft base ordinate
yBase	The y arrow shaft base co-ordinate
xPoint	The x arrow shaft point ordinate
yPoint	The y arrow shaft point co-ordinate
headToLengthRatio	The fraction of the shaft length to be taken up by the arrow head
width	The width of the arrow
closed	Close the arrow head (draw a triangle)
filled	Fill the arrow head

Definition at line 89 of file CairoArrow.H.

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~CairoArrow()

virtual CairoArrow::~CairoArrow ( )

inlinevirtual

Definition at line 127 of file CairoArrow.H.

Member Function Documentation

draw()

void CairoArrow::draw ( cairo_t *  cr, float  xBase, float  yBase, float  xPoint, float  yPoint, float  headToLengthRatio, float  width, bool  closed, bool  filled  )

inline

Construct an arrow by calculating the head points and then use cairo to stroke or fill The Cairo context which is passed in should already be configured for line width and colour

Parameters

cr	The cairo context to draw in
xBase	The x arrow shaft base ordinate
yBase	The y arrow shaft base co-ordinate
xPoint	The x arrow shaft point ordinate
yPoint	The y arrow shaft point co-ordinate
headToLengthRatio	The fraction of the shaft length to be taken up by the arrow head
width	The width of the arrow
closed	Close the arrow head (draw a triangle)
filled	Fill the arrow head

Examples:

CairoArrowTest.C.

Definition at line 105 of file CairoArrow.H.

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findArrowHeadPoints()

void CairoArrow::findArrowHeadPoints ( float  xBase, float  yBase, float  xPoint, float  yPoint, float  headToLengthRatio, float  width  )

inlineprivate

Given an arrow shaft, the width and ratio of the head, find the arrow head points. The ratio is how much as a fraction of the shaft size should be consumed by the arrow head. The arrow head side points are derived using the orthogonal unit vector to the shaft vector.

Parameters

xBase	The x arrow shaft base ordinate
yBase	The y arrow shaft base co-ordinate
xPoint	The x arrow shaft point ordinate
yPoint	The y arrow shaft point co-ordinate
headToLengthRatio	The fraction of the shaft length to be taken up by the arrow head
width	The width of the arrow

Definition at line 47 of file CairoArrow.H.

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Member Data Documentation

vecX

float CairoArrow::vecX

private

Definition at line 35 of file CairoArrow.H.

vecY

float CairoArrow::vecY

private

The shaft vector transposed to the origin.

Definition at line 35 of file CairoArrow.H.

xSide1

float CairoArrow::xSide1

private

Definition at line 33 of file CairoArrow.H.

xSide2

float CairoArrow::xSide2

private

The arrow head side 1.

Definition at line 33 of file CairoArrow.H.

ySide1

float CairoArrow::ySide1

private

Definition at line 34 of file CairoArrow.H.

ySide2

float CairoArrow::ySide2

private

The arrow head side 2.

Definition at line 34 of file CairoArrow.H.

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

• /tmp/gtkiostream/include/CairoArrow.H