Graphics Class Reference

Provides basic graphics capabilities for drawing into any bitmap, particularly FilterBankGenerators. More...

#include <Graphics.h>

Detailed Description

Provides basic graphics capabilities for drawing into any bitmap, particularly FilterBankGenerators.

Wherever possible, this should try to emulate the graphics API of Java 1 to minimize learning curve. For instance, the pen hangs down and to the right.

Definition at line 12 of file Graphics.h.

List of all members.

Public Member Functions
	Graphics (FilterBankGenerator &fbg, unsigned int layer, unsigned int channel)
	constructor, pass a FilterBankGenerator and layer/channel to draw into
	Graphics (FilterBankGenerator &fbg, unsigned int layer, unsigned int chan1, unsigned int chan2, unsigned int chan3)
	constructor, pass a FilterBankGenerator and layer/channel to draw into
	Graphics (unsigned char *base, unsigned int width, unsigned int height, unsigned int interval, unsigned int stride)
	constructor, directly specify an image buffer
void	updateFBG ()
	If you want to reuse a graphics object across multiple frames from a FilterBankGenerator, call this after each new frame, but before you do any drawing.
void	drawRect (int x, int y, int width, int height)
	Draws a rectange, upper left at x,y and extending right and down by width and height.
void	drawRect (float x, float y, float width, float height)
	Draws a rectange, upper left at x,y and extending right and down by width and height.
void	drawLine (int x1, int y1, int x2, int y2)
	Draws a line from (x1, y1) to (x2, y2).
void	drawLine (float x1, float y1, float x2, float y2)
	Draws a line from (x1, y1) to (x2, y2).
void	drawEllipse (float x, float y, float semimajor, float semiminor, AngPi orientation)
	Draws an ellipse at (x,y) with the specified parameters.
void	drawEllipse (int x, int y, float semimajor, float semiminor, AngPi orientation)
	Draws an ellipse at (x,y) with the specified parameters.
void	drawQuarterEllipse (int x, int y, float semimajor, float semiminor, AngPi orientation)
	Draws a quarter ellipse at (x,y) with the specified parameters; semimajor and/or semiminor may be negative.
void	drawPoint (int x, int y)
	Draws a single point at (x1, y1).
void	drawPoint (float x, float y)
	Draws a single point at (x1, y1).
void	setColor (rgb _color)
	Sets the "color" of the pen.
void	setColor (unsigned char _color)
	Sets the "color" of the pen when drawing into a SegCam buffer.
yuv	getColor () const
	returns the "color" of the pen
void	getPixelCoordinates (unsigned int &px, unsigned int &py, float x, float y) const
	sets the pixel-coordinate px and py parameters to the corresponding value of x and y
void	getRealCoordinates (float &x, float &y, unsigned int px, unsigned int py) const
	sets the x and y parameters from the pixel-coordinates px and py
Protected Attributes
FilterBankGenerator *	gen
	the filter bank generator we are drawing into, or NULL
unsigned int	genLayer
	the layer within gen we are drawing into
unsigned int	genChan1
	the channel within gen we are drawing into
unsigned int	genChan2
	the channel within gen we are drawing into
unsigned int	genChan3
	the channel within gen we are drawing into
unsigned char *	img1
	the image we are currently drawing into (may need to be updated if gen is non-NULL, see updateFBG())
unsigned char *	img2
	the image we are currently drawing into (may need to be updated if gen is non-NULL, see updateFBG())
unsigned char *	img3
	the image we are currently drawing into (may need to be updated if gen is non-NULL, see updateFBG())
unsigned int	w
	the width of img
unsigned int	h
	the height of img
unsigned int	xInc
	the number of bytes to skip to move horizontally one pixel in img
unsigned int	yInc
	the number of bytes to skip to move vertically one pixel in img
yuv	color
	the current pen color
Private Member Functions
	Graphics (const Graphics &)
	don't call (copy constructor)
Graphics &	operator= (const Graphics &)
	don't call (assignment operator)

Constructor & Destructor Documentation

Graphics::Graphics	(	FilterBankGenerator &	fbg,
		unsigned int	layer,
		unsigned int	channel
	)

constructor, pass a FilterBankGenerator and layer/channel to draw into

Definition at line 20 of file Graphics.cc.

Graphics::Graphics	(	FilterBankGenerator &	fbg,
		unsigned int	layer,
		unsigned int	chan1,
		unsigned int	chan2,
		unsigned int	chan3
	)

constructor, pass a FilterBankGenerator and layer/channel to draw into

Definition at line 26 of file Graphics.cc.

Graphics::Graphics	(	unsigned char *	base,
		unsigned int	width,
		unsigned int	height,
		unsigned int	interval,
		unsigned int	stride
	)

constructor, directly specify an image buffer

Definition at line 32 of file Graphics.cc.

Graphics::Graphics ( const Graphics & ) [private]

don't call (copy constructor)

Member Function Documentation

void Graphics::drawEllipse	(	int	x,
		int	y,
		float	semimajor,
		float	semiminor,
		AngPi	orientation
	)

Draws an ellipse at (x,y) with the specified parameters.

This expects direct-pixel coordinates, so make sure you check the width and height of the layer you are drawing into

Definition at line 271 of file Graphics.cc.

void Graphics::drawEllipse	(	float	x,
		float	y,
		float	semimajor,
		float	semiminor,
		AngPi	orientation
	)

Draws an ellipse at (x,y) with the specified parameters.

Definition at line 289 of file Graphics.cc.

void Graphics::drawLine	(	float	x1,
		float	y1,
		float	x2,
		float	y2
	)

Draws a line from (x1, y1) to (x2, y2).

Definition at line 264 of file Graphics.cc.

void Graphics::drawLine	(	int	ix1,
		int	iy1,
		int	ix2,
		int	iy2
	)

Draws a line from (x1, y1) to (x2, y2).

This expects direct-pixel coordinates, so make sure you check the width and height of the layer you are drawing into

Todo:: I think this could be a little faster by writing two cases -- one that handles mostly-vertical lines, and one that handles mostly-horizontal ones. Then the primary loop could be over integer coordinates along that axis, and only the position along the other axis would have to be calculated as floating point

Definition at line 163 of file Graphics.cc.

Referenced by drawLine().

void Graphics::drawPoint	(	float	x,
		float	y
	)

Draws a single point at (x1, y1).

Definition at line 77 of file Graphics.h.

void Graphics::drawPoint	(	int	x,
		int	y
	)

Draws a single point at (x1, y1).

This expects direct-pixel coordinates, so make sure you check the width and height of the layer you are drawing into

Definition at line 67 of file Graphics.h.

Referenced by drawEllipse(), drawPoint(), and drawQuarterEllipse().

void Graphics::drawQuarterEllipse	(	int	x,
		int	y,
		float	semimajor,
		float	semiminor,
		AngPi	orientation
	)

Draws a quarter ellipse at (x,y) with the specified parameters; semimajor and/or semiminor may be negative.

This expects direct-pixel coordinates, so make sure you check the width and height of the layer you are drawing into

Definition at line 295 of file Graphics.cc.

void Graphics::drawRect	(	float	x,
		float	y,
		float	width,
		float	height
	)

Draws a rectange, upper left at x,y and extending right and down by width and height.

Definition at line 151 of file Graphics.cc.

void Graphics::drawRect	(	int	x,
		int	y,
		int	width,
		int	height
	)

Draws a rectange, upper left at x,y and extending right and down by width and height.

This expects direct-pixel coordinates, so make sure you check the width and height of the layer you are drawing into

Definition at line 48 of file Graphics.cc.

Referenced by drawRect().

yuv Graphics::getColor ( ) const

returns the "color" of the pen

Currently we don't support multi-channel drawing, so you have to draw into each channel separately to do real color based drawing, but maybe someday we'll add a color class.
In the mean time, this is just the byte that's going to be used to fill in wherever the pen traces

Definition at line 100 of file Graphics.h.

void Graphics::getPixelCoordinates	(	unsigned int &	px,
		unsigned int &	py,
		float	x,
		float	y
	)			const

sets the pixel-coordinate px and py parameters to the corresponding value of x and y

Parameters:

`[out]`	px	the pixel position, relative to left edge, positive right, ranges 0 through width-1
`[out]`	py	the pixel position, relative to top edge, positive down, ranges 0 through height-1
`[in]`	x	the horizontal position, relative to center of the image, left edge is -1 and right edge is 1; no boundary checking is done
`[in]`	y	the vertical pixel position, relative to center of the image, top edge is the negative aspect ratio, bottom edge is positive aspect ratio; no boundary checking is done

To keep the coordinate system square, the x is defined to range -1,1, but y's range depends on the aspect ratio of the image, height/width. Thus typically y will approx. -.75,.75

Definition at line 311 of file Graphics.cc.

Referenced by drawEllipse(), drawLine(), drawPoint(), and drawRect().

void Graphics::getRealCoordinates	(	float &	x,
		float &	y,
		unsigned int	px,
		unsigned int	py
	)			const

sets the x and y parameters from the pixel-coordinates px and py

Parameters:

`[out]`	x	the horizontal position, relative to center of the image, left edge is -1 and right edge is 1; no boundary checking is done
`[out]`	y	the vertical pixel position, relative to center of the image, top edge is the negative aspect ratio, bottom edge is positive aspect ratio; no boundary checking is done
`[in]`	px	the pixel position, relative to left edge, positive right, ranges 0 through width-1
`[in]`	py	the pixel position, relative to top edge, positive down, ranges 0 through height-1

To keep the coordinate system square, the x is defined to range -1,1, but y's range depends on the aspect ratio of the image, height/width. Thus typically y will approx. -.75,.75

Definition at line 322 of file Graphics.cc.

Graphics& Graphics::operator= ( const Graphics & ) [private]

don't call (assignment operator)

void Graphics::setColor ( unsigned char _color )

Sets the "color" of the pen when drawing into a SegCam buffer.

Definition at line 92 of file Graphics.h.

void Graphics::setColor ( rgb _color )

Sets the "color" of the pen.

Currently we don't support multi-channel drawing, so you have to draw into each channel separately to do real color based drawing, but maybe someday we'll add a color class.
In the mean time, this is just the byte that's going to be used to fill in wherever the pen traces

Definition at line 89 of file Graphics.h.

void Graphics::updateFBG ( )

If you want to reuse a graphics object across multiple frames from a FilterBankGenerator, call this after each new frame, but before you do any drawing.

This is automatically called by the constructor, so you don't need to do it if you constructor a fresh Graphics object for each frame. But otherwise you'll need this to update img, w, h, xInc, and yInc from the current frame available in gen

Definition at line 36 of file Graphics.cc.

Referenced by Graphics().