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prapi::graphics::Graphics< T > Class Template Reference

#include <Graphics.h>

Inheritance diagram for prapi::graphics::Graphics< T >:

Detailed Description

template<class T>
class prapi::graphics::Graphics< T >

Drawing methods.

This is a superclass for classes that are able to draw on various devices. A graphics device must contain a rectangular area of pixels. The upper left corner of the area is used as an origin by default, with the positive y axis running down and the positive x axis to the right. By default, the Graphics class takes care of high-level drawing primitives, and delegates only the setting of pixels to the actual graphics device. It is however possible the override the drawing functions. This way it is possible to create, for example, PostScript graphics etc.

The template parameter T defines the type of a pixel in the graphics context. In a memory buffer, pixels may be represented as chars or ints. For color graphics, the type may be Color.

Public Methods

void setDrawMode (DrawMode mode)

Set the drawing mode.

DrawMode getDrawMode () const

Get the current drawing mode.

void setColor (T color)

Set the current drawing "color" to a value.

T getColor () const

Get the current drawing color.

void setOpacity (double opacity)

Set the opacity of the drawing operations.

double getOpacity ()

Get the current opacity.

void translate (int x, int y)

Shift the origin of this graphics context to the given coordinates.

Point< int > getOrigin () const

Get the current origin of the coordinate system.

void setClip (const Shape *shape)

Set the clipping region.

void drawPixel (int x, int y)

Set a pixel in a graphics context with no interpolation (anti-aliasing).

virtual void drawPixel (double x, double y)

Draw a pixel in a graphics context.

template<class modifier> void modifyPixel (double x, double y)

Modify a pixel.

template<class modifier> void modifyPixel (int x, int y)

Modify a pixel in an image without interpolation (anti-aliasing).

virtual void drawCircle (double centerX, double centerY, double radius)

Draw an anti-alised circle.

virtual void drawArc (double centerX, double centerY, double radius, double startAngle, double endAngle)

Draw an anti-alised arc.

virtual void drawLine (double startX, double startY, double endX, double endY)

Draw an interpolated (anti-aliased) line.

virtual void drawLine (int startX, int startY, int endX, int endY)

Draw a non-interpolated line.

virtual void drawRect (int x, int y, int width, int height)

Draw a rectangle with non-interpolated borders.

virtual void drawRect (double x, double y, double width, double height)

Draw a rectangle with interpolated (anti-alised) borders.

virtual ~Graphics ()

Protected Methods

Graphics (int width=0, int height=0)

Create a new graphics context.

virtual T getPixel (int x, int y) const=0

Get a pixel in a graphics context.

virtual T & pixel (int x, int y)=0

Get a pixel in a graphics context.

virtual void setPixel (int x, int y, T value)=0

Set a pixel in a graphics context.

Protected Attributes

Dimension< int > _dimBounds

The dimensions of the graphics context.

int _iOriginX

The coordinates of the current origin.

int _iOriginY

The coordinates of the current origin.

const Shape * _pClipShape

The current clipping region.

T _color

The current drawing color.

double _dOpacity

The current opacity.

DrawMode _drawMode

The current drawing mode.

Constructor & Destructor Documentation

template<class T>

prapi::graphics::Graphics< T >::Graphics ( int width = 0,

int height = 0

) [inline, protected]

Create a new graphics context.
Subclasses should provide the bounds of their device/buffer at initialization.
Parameters:

width the width of the graphics buffer

height the height of the graphics buffer

Member Function Documentation

template<class T>

void prapi::graphics::Graphics< T >::drawArc ( double centerX,

double centerY,

double radius,

double startAngle,

double endAngle

) [virtual]

Draw an anti-alised arc.
Angles are represented as radians in counter-clockwise direction. Zero angle is at the direction of the horizontal x-axis.
Parameters:

centerX the x coordinate of the center of the circle

centerY the y coordinate of the center of the circle

radius the radius of the circle

template<class T>

void prapi::graphics::Graphics< T >::drawCircle ( double centerX,

double centerY,

double radius

) [virtual]

Draw an anti-alised circle.

Parameters:

centerX the x coordinate of the center of the circle

centerY the y coordinate of the center of the circle

radius the radius of the circle

template<class T>

void prapi::graphics::Graphics< T >::drawLine ( int startX,

int startY,

int endX,

int endY

) [virtual]

Draw a non-interpolated line.

Parameters:

startX the x coordinate of the starting position

startY the y coordinate of the starting position

endX the x coordinate of the end position

endY the y coordinate of the end position

template<class T>

void prapi::graphics::Graphics< T >::drawLine ( double startX,

double startY,

double endX,

double endY

) [virtual]

Draw an interpolated (anti-aliased) line.

Parameters:

startX the x coordinate of the starting position

startY the y coordinate of the starting position

endX the x coordinate of the end position

endY the y coordinate of the end position

template<class T>

void prapi::graphics::Graphics< T >::drawPixel ( double x,

double y

) [virtual]

Draw a pixel in a graphics context.
This method uses bilinear interpolation to draw anti-aliased pixels. Up to four neighboring pixels closest to the given floating-point image coordinates may be affected.
Parameters:

x the x coordinate

y the y coordinate

template<class T>

void prapi::graphics::Graphics< T >::drawPixel ( int x,

int y

) [inline]

Set a pixel in a graphics context with no interpolation (anti-aliasing).
It is not possible to override this method. Instead, subclasses should override the protected get/setPixel() methods.
Parameters:

x the x coordinate

y the y coordinate

template<class T>

virtual void prapi::graphics::Graphics< T >::drawRect ( double x,

double y,

double width,

double height

) [inline, virtual]

Draw a rectangle with interpolated (anti-alised) borders.

Parameters:

x the x coordinate of the upper left corner

y the y coordinate of the upper left corner

width the width of the rectangle

height the height of the rectangle

template<class T>

virtual void prapi::graphics::Graphics< T >::drawRect ( int x,

int y,

int width,

int height

) [inline, virtual]

Draw a rectangle with non-interpolated borders.

Parameters:

x the x coordinate of the upper left corner

y the y coordinate of the upper left corner

width the width of the rectangle

height the height of the rectangle

template<class T>

virtual T prapi::graphics::Graphics< T >::getPixel ( int x,

int y

) const [protected, pure virtual]

Get a pixel in a graphics context.
Subclasses must implement this method to get the contents of the graphics device/buffer. Boundary checking has been done before calling this method. Thus, assuming _dimBounds has been set correctly, subclasses never need to check whether the given coordinates are within the allowed range.
Implemented in prapi::graphics::MemoryGraphics< T >.

template<class T>

template<class modifier>

void prapi::graphics::Graphics< T >::modifyPixel ( int x,

int y

) [inline]

Modify a pixel in an image without interpolation (anti-aliasing).

See also:
modifyPixel(double,double) , drawPixel(int,int)

template<class T>

template<class modifier>

void prapi::graphics::Graphics< T >::modifyPixel ( double x,

double y

) [inline]

Modify a pixel.
This method works in a similar way as drawPixel(), but instead of overwriting a pixel it modifies the old value. The current opacity is used to control the "strength" of the modification. 0 means no change, and 1 means the old value will be modified with exactly the given value. The current drawing mode does not affect pixel modifications. Therefore, this method allows one to alter the pixel data in many customized ways. The modifier template parameter can be any class with the T operator() (T,T) defined. An example:

class MyModifier { public: int operator() (int a, int b) { return b-a; } }; ... //Subtract the value of the pixel at (2.3, 3.5) from three (with anti-aliasing) graphics.setColor(3); graphics.modifyPixel<MyModifier>(2.3, 3.5); //Subtract the value of the pixel at (3, 4) from two (without anti-aliasing) graphics.setColor(4); graphics.setOpacity(0.5); graphics.modifyPixel<MyModifier>(3,4);

template<class T>

virtual T& prapi::graphics::Graphics< T >::pixel ( int x,

int y

) [protected, pure virtual]

Get a pixel in a graphics context.
Subclasses must implement this method to get the contents of the graphics device/buffer. Boundary checking has been done before calling this method. Thus, assuming _dimBounds has been set correctly, subclasses never need to check whether the given coordinates are within the allowed range.
Implemented in prapi::graphics::MemoryGraphics< T >.

template<class T>

void prapi::graphics::Graphics< T >::setClip ( const Shape * shape ) [inline]

Set the clipping region.
The clipping region determines the drawable area in a graphics context. All graphics primitives that fall outside of the clipping region, as determined by the Shape::contains(x,y) method, are not drawn. The clipping region is always interpreted relative to the current origin of the coordinate system. That is, moving the origin also moves the clipping region.

template<class T>

void prapi::graphics::Graphics< T >::setColor ( T color ) [inline]

Set the current drawing "color" to a value.
All subsequent drawing operations will use this color. For gray-scale graphics, for example integer valued memory buffers, the "color" is actually a scalar.

template<class T>

void prapi::graphics::Graphics< T >::setDrawMode ( DrawMode mode ) [inline]

Set the drawing mode.
All subsequent drawing operations will be performed in the indicated mode.

template<class T>

void prapi::graphics::Graphics< T >::setOpacity ( double opacity ) [inline]

Set the opacity of the drawing operations.
Opacity determines how much newly drawn pixels affect those under it. If opacity is set to one, the old pixel value is totally overwritten. If opacity is set to zero, drawing operations have no visible effect. The default value is one.

template<class T>

virtual void prapi::graphics::Graphics< T >::setPixel ( int x,

int y,

T value

) [protected, pure virtual]

Set a pixel in a graphics context.
Subclasses must implement this method to alter the graphics device/buffer. Boundary checking has been done before calling this method. Thus, assuming _dimBounds has been set correctly, subclasses never need to check whether the given coordinates are within the allowed range.
Implemented in prapi::graphics::MemoryGraphics< T >.

template<class T>

void prapi::graphics::Graphics< T >::translate ( int x,

int y

) [inline]

Shift the origin of this graphics context to the given coordinates.
The coordinates of all subsequent drawing operations will be interpreted relative to this position. The origin can lie outside of the boundaried of the graphics context. An example:

//To move the origin to (30,20): graphics.translate(30,20); //To move the origin back: graphics.translate(-30,-20);

In addition to the origin, this method also moves the current clipping region.

Member Data Documentation

template<class T>

T prapi::graphics::Graphics< T >::_color [protected]

The current drawing color.
Set initially to zero.

template<class T>

Dimension<int> prapi::graphics::Graphics< T >::_dimBounds [protected]

The dimensions of the graphics context.
Subclasses must fill this class with the dimensions of the graphics device/buffer.

template<class T>

double prapi::graphics::Graphics< T >::_dOpacity [protected]

The current opacity.
Initially set to one.

template<class T>

DrawMode prapi::graphics::Graphics< T >::_drawMode [protected]

The current drawing mode.
Set initially to DRAWMODE_NORMAL.

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

Graphics.h

Public Methods
void	setDrawMode (DrawMode mode)
	Set the drawing mode.
DrawMode	getDrawMode () const
	Get the current drawing mode.
void	setColor (T color)
	Set the current drawing "color" to a value.
T	getColor () const
	Get the current drawing color.
void	setOpacity (double opacity)
	Set the opacity of the drawing operations.
double	getOpacity ()
	Get the current opacity.
void	translate (int x, int y)
	Shift the origin of this graphics context to the given coordinates.
Point< int >	getOrigin () const
	Get the current origin of the coordinate system.
void	setClip (const Shape *shape)
	Set the clipping region.
void	drawPixel (int x, int y)
	Set a pixel in a graphics context with no interpolation (anti-aliasing).
virtual void	drawPixel (double x, double y)
	Draw a pixel in a graphics context.
template<class modifier> void	modifyPixel (double x, double y)
	Modify a pixel.
template<class modifier> void	modifyPixel (int x, int y)
	Modify a pixel in an image without interpolation (anti-aliasing).
virtual void	drawCircle (double centerX, double centerY, double radius)
	Draw an anti-alised circle.
virtual void	drawArc (double centerX, double centerY, double radius, double startAngle, double endAngle)
	Draw an anti-alised arc.
virtual void	drawLine (double startX, double startY, double endX, double endY)
	Draw an interpolated (anti-aliased) line.
virtual void	drawLine (int startX, int startY, int endX, int endY)
	Draw a non-interpolated line.
virtual void	drawRect (int x, int y, int width, int height)
	Draw a rectangle with non-interpolated borders.
virtual void	drawRect (double x, double y, double width, double height)
	Draw a rectangle with interpolated (anti-alised) borders.
virtual	~Graphics ()
Protected Methods
	Graphics (int width=0, int height=0)
	Create a new graphics context.
virtual T	getPixel (int x, int y) const=0
	Get a pixel in a graphics context.
virtual T &	pixel (int x, int y)=0
	Get a pixel in a graphics context.
virtual void	setPixel (int x, int y, T value)=0
	Set a pixel in a graphics context.
Protected Attributes
Dimension< int >	_dimBounds
	The dimensions of the graphics context.
int	_iOriginX
	The coordinates of the current origin.
int	_iOriginY
	The coordinates of the current origin.
const Shape *	_pClipShape
	The current clipping region.
T	_color
	The current drawing color.
double	_dOpacity
	The current opacity.
DrawMode	_drawMode
	The current drawing mode.

prapi::graphics::Graphics< T > Class Template Reference

Detailed Description

template<class T> class prapi::graphics::Graphics< T >

Public Methods

Protected Methods

Protected Attributes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<class T>
class prapi::graphics::Graphics< T >