Detailed Description

This virtual class defines the interface of any object accepting drawing primitives on it.

A number of text fonts can be selected with CCanvas::selectTextFont(). These are the implemented font names:

"6x13"
"6x13B" (bold)
"6x13O" (italic)
"9x15"
"9x15B" (bold)
"10x20"
"18x18ja" (Japanese, UNICODE character values)

For an example of each font check the corresponding wiki page.

See also: CImage

Definition at line 40 of file CCanvas.h.

#include <mrpt/img/CCanvas.h>

Inheritance diagram for mrpt::img::CCanvas:

Public Types
enum	TPenStyle { psSolid = 0, psDash, psDot, psDashDot, psDashDotDot }
	Definition of pen styles. More...

Public Member Functions
	CCanvas ()

virtual	~CCanvas ()
	Dummy virtual destructor: More...

virtual void	setPixel (int x, int y, size_t color)=0
	Changes the value of the pixel (x,y). More...

virtual size_t	getWidth () const =0
	Returns the width of the image in pixels. More...

virtual size_t	getHeight () const =0
	Returns the height of the image in pixels. More...

virtual void	line (int x0, int y0, int x1, int y1, const mrpt::img::TColor color, unsigned int width=1, TPenStyle penStyle=psSolid)
	Draws a line. More...

void	rectangle (int x0, int y0, int x1, int y1, const mrpt::img::TColor color, unsigned int width=1)
	Draws a rectangle (an empty rectangle, without filling) More...

void	triangle (int x0, int y0, int size, const mrpt::img::TColor color, bool inferior=true, unsigned int width=1)
	Draws a triangle. More...

virtual void	filledRectangle (int x0, int y0, int x1, int y1, const mrpt::img::TColor color)
	Draws a filled rectangle. More...

virtual void	textOut (int x0, int y0, const std::string &str, const mrpt::img::TColor color)
	Renders 2D text using bitmap fonts. More...

virtual void	selectTextFont (const std::string &fontName)
	Select the current font used when drawing text. More...

virtual void	drawImage (int x, int y, const mrpt::img::CImage &img)
	Draws an image as a bitmap at a given position. More...

void	cross (int x0, int y0, const mrpt::img::TColor color, char type, unsigned int size=5, unsigned int width=1)
	Draw a cross. More...

virtual void	drawImage (int x, int y, const mrpt::img::CImage &img, float rotation, float scale)
	Draws an image as a bitmap at a given position, with some custom scale and rotation changes. More...

virtual void	drawCircle (int x, int y, int radius, const mrpt::img::TColor &color=mrpt::img::TColor(255, 255, 255), unsigned int width=1)
	Draws a circle of a given radius. More...

template<class MATRIX2X2 >
void	ellipseGaussian (const MATRIX2X2 *cov2D, const double mean_x, const double mean_y, double confIntervalStds=2, const mrpt::img::TColor &color=mrpt::img::TColor(255, 255, 255), unsigned int width=1, int nEllipsePoints=20)
	Draws an ellipse representing a given confidence interval of a 2D Gaussian distribution. More...

template<class FEATURELIST >
void	drawFeaturesSimple (const FEATURELIST &list, const TColor &color=TColor::red(), const int cross_size=5)
	Draws a set of marks onto the image, given a generic container of entities having just "x" and "y" fields. More...

template<class FEATURELIST >
void	drawFeatures (const FEATURELIST &list, const TColor &color=TColor::red(), const bool showIDs=false, const bool showResponse=false)
	Draws a set of marks (or scaled circles for features with scale) onto the image, given a generic container of features. More...

Protected Attributes
std::string	m_selectedFont
	The selected font name. More...

const uint32_t *	m_selectedFontBitmaps
	Direct access to character bitmaps. More...

Member Enumeration Documentation

◆ TPenStyle

enum mrpt::img::CCanvas::TPenStyle

Definition of pen styles.

Enumerator
psSolid
psDash
psDot
psDashDot
psDashDotDot

Definition at line 54 of file CCanvas.h.

Constructor & Destructor Documentation

◆ CCanvas()

CCanvas::CCanvas ( )

Definition at line 118 of file CCanvas.cpp.

◆ ~CCanvas()

virtual mrpt::img::CCanvas::~CCanvas ( )

inlinevirtual

Dummy virtual destructor:

Definition at line 65 of file CCanvas.h.

Member Function Documentation

◆ cross()

void CCanvas::cross	(	int	x0,
		int	y0,
		const mrpt::img::TColor	color,
		char	type,
		unsigned int	size = `5`,
		unsigned int	width = `1`
	)

Draw a cross.

Parameters

x0	The point x coordinate
y0	The point y coordinate
color	The color of the cross
size	The size of the cross
type	The cross type. It could be: 'x', '+' or ':'(like '+' but clear at the center dot)
width	The desired width of the cross (this is IGNORED yet)

Definition at line 305 of file CCanvas.cpp.

References line(), and THROW_EXCEPTION.

Referenced by drawFeatures(), drawFeaturesSimple(), find_chessboard_corners_multiple(), and mrpt::gui::CDisplayWindow::plot().

◆ drawCircle()

void CCanvas::drawCircle	(	int	x,
		int	y,
		int	radius,
		const mrpt::img::TColor &	color = `mrpt::img::TColor(255, 255, 255)`,
		unsigned int	width = `1`
	)

virtual

Draws a circle of a given radius.

Parameters

x	The center - x coordinate in pixels.
y	The center - y coordinate in pixels.
radius	The radius - in pixels.
color	The color of the circle.
width	The desired width of the line (this is IGNORED in this virtual class)

Reimplemented in mrpt::img::CImage.

Definition at line 333 of file CCanvas.cpp.

References line(), M_2PI, and mrpt::round().

Referenced by drawFeatures().

◆ drawFeatures()

template<class FEATURELIST >

void mrpt::img::CCanvas::drawFeatures	(	const FEATURELIST &	list,
		const TColor &	color = `TColor::red()`,
		const bool	showIDs = `false`,
		const bool	showResponse = `false`
	)

inline

Draws a set of marks (or scaled circles for features with scale) onto the image, given a generic container of features.

The class of FEATURELIST can be:

See also: drawFeaturesSimple

Definition at line 321 of file CCanvas.h.

References cross(), drawCircle(), mrpt::format(), mrpt::img::TColor::red(), mrpt::round(), and textOut().

◆ drawFeaturesSimple()

template<class FEATURELIST >

void mrpt::img::CCanvas::drawFeaturesSimple	(	const FEATURELIST &	list,
		const TColor &	color = `TColor::red()`,
		const int	cross_size = `5`
	)

inline

Draws a set of marks onto the image, given a generic container of entities having just "x" and "y" fields.

The class of FEATURELIST can be, for example, std::vector<mrpt::math::TPoint2D>, std::vector<TPixelCoordsf> or mrpt::vision::CFeatureList

See also: drawFeatures

Definition at line 300 of file CCanvas.h.

References cross(), and mrpt::round().

◆ drawImage() [1/2]

void CCanvas::drawImage	(	int	x,
		int	y,
		const mrpt::img::CImage &	img
	)

virtual

Draws an image as a bitmap at a given position.

Parameters

x0	The top-left corner x coordinates on this canvas where the image is to be drawn
y0	The top-left corner y coordinates on this canvas where the image is to be drawn
img	The image to be drawn in this canvas This method may be redefined in some classes implementing this interface in a more appropiate manner.

Reimplemented in mrpt::img::CEnhancedMetaFile.

Definition at line 254 of file CCanvas.cpp.

References MRPT_END, MRPT_START, and setPixel().

Referenced by mrpt::slam::CGridMapAligner::AlignPDF_robustMatch(), mrpt::slam::CMetricMapBuilderRBPF::drawCurrentEstimationToImage(), and mrpt::img::CEnhancedMetaFile::drawImage().

◆ drawImage() [2/2]

void CCanvas::drawImage	(	int	x,
		int	y,
		const mrpt::img::CImage &	img,
		float	rotation,
		float	scale
	)

virtual

Draws an image as a bitmap at a given position, with some custom scale and rotation changes.

Parameters

x0	The top-left corner x coordinates on this canvas where the image is to be drawn
y0	The top-left corner y coordinates on this canvas where the image is to be drawn
rotation	The rotation in radians, positive values being anti-clockwise direction, 0 is the normal position.
scale	The scale factor, e.g. 2 means twice the original size.
img	The image to be drawn in this canvas This method may be redefined in some classes implementing this interface in a more appropiate manner.

Reimplemented in mrpt::img::CEnhancedMetaFile.

Definition at line 286 of file CCanvas.cpp.

References MRPT_END, MRPT_START, MRPT_UNUSED_PARAM, and THROW_EXCEPTION.

◆ ellipseGaussian()

template<class MATRIX2X2 >

void mrpt::img::CCanvas::ellipseGaussian	(	const MATRIX2X2 *	cov2D,
		const double	mean_x,
		const double	mean_y,
		double	confIntervalStds = `2`,
		const mrpt::img::TColor &	color = `mrpt::img::TColor(255, 255, 255)`,
		unsigned int	width = `1`,
		int	nEllipsePoints = `20`
	)

inline

Draws an ellipse representing a given confidence interval of a 2D Gaussian distribution.

Parameters

mean_x	The x coordinate of the center point of the ellipse.
mean_y	The y coordinate of the center point of the ellipse.
cov2D	A 2x2 covariance matrix.
confIntervalStds	How many "sigmas" for the confidence level (i.e. 2->95%, 3=99.97%,...)
color	The color of the ellipse
width	The desired width of the line (this is IGNORED in this virtual class)
nEllipsePoints	The number of points to generate to approximate the ellipse shape.

Exceptions

std::exception On an invalid matrix.

Definition at line 250 of file CCanvas.h.

References line(), M_2PI, MRPT_END_WITH_CLEAN_UP, MRPT_START, and mrpt::round().

◆ filledRectangle()

void CCanvas::filledRectangle	(	int	x0,
		int	y0,
		int	x1,
		int	y1,
		const mrpt::img::TColor	color
	)

virtual

Draws a filled rectangle.

Parameters

x0	The top-left x coordinate
y0	The top-left y coordinate
x1	The right-bottom x coordinate
y1	The right-bottom y coordinate
color	The color of the rectangle fill This method may be redefined in some classes implementing this interface in a more appropiate manner.

See also: rectangle

Definition at line 214 of file CCanvas.cpp.

References getHeight(), getWidth(), min, and setPixel().

Referenced by mrpt::slam::CGridMapAligner::AlignPDF_robustMatch(), mrpt::img::CEnhancedMetaFile::CEnhancedMetaFile(), and mrpt::gui::CDisplayWindow::plot().

◆ getHeight()

virtual size_t mrpt::img::CCanvas::getHeight ( ) const

pure virtual

Returns the height of the image in pixels.

Implemented in mrpt::img::CImage, and mrpt::img::CEnhancedMetaFile.

Referenced by filledRectangle(), and line().

◆ getWidth()

virtual size_t mrpt::img::CCanvas::getWidth ( ) const

pure virtual

Returns the width of the image in pixels.

Implemented in mrpt::img::CImage, and mrpt::img::CEnhancedMetaFile.

Referenced by filledRectangle(), and line().

◆ line()

void CCanvas::line	(	int	x0,
		int	y0,
		int	x1,
		int	y1,
		const mrpt::img::TColor	color,
		unsigned int	width = `1`,
		TPenStyle	penStyle = `psSolid`
	)

virtual

Draws a line.

Parameters

x0	The starting point x coordinate
y0	The starting point y coordinate
x1	The end point x coordinate
y1	The end point y coordinate
color	The color of the line
width	The desired width of the line (this is IGNORED in this virtual class) This method may be redefined in some classes implementing this interface in a more appropiate manner.

Reimplemented in mrpt::img::CImage, and mrpt::img::CEnhancedMetaFile.

Definition at line 122 of file CCanvas.cpp.

References getHeight(), getWidth(), MRPT_UNUSED_PARAM, setPixel(), and mrpt::square().

Referenced by cross(), drawCircle(), ellipseGaussian(), rectangle(), and triangle().

◆ rectangle()

void CCanvas::rectangle	(	int	x0,
		int	y0,
		int	x1,
		int	y1,
		const mrpt::img::TColor	color,
		unsigned int	width = `1`
	)

Draws a rectangle (an empty rectangle, without filling)

Parameters

x0	The top-left x coordinate
y0	The top-left y coordinate
x1	The right-bottom x coordinate
y1	The right-bottom y coordinate
color	The color of the line
width	The desired width of the line.

See also: filledRectangle

Definition at line 170 of file CCanvas.cpp.

References line().

Referenced by mrpt::vision::addFeaturesToImage().

◆ selectTextFont()

void CCanvas::selectTextFont ( const std::string & fontName )

virtual

Select the current font used when drawing text.

Parameters

fontName The name of the font

Valid font names:

5x7
6x13
6x13B
6x13O
9x15 (Default at start-up)
9x15B
10x20
18x18ja (Asian characters for UTF-8 strings - Only available if MRPT is built with MRPT_HAS_ASIAN_FONTS = true)

See also: textOut, The example in this page.

Definition at line 229 of file CCanvas.cpp.

References init_fonts_list(), list_registered_fonts, m_selectedFont, and m_selectedFontBitmaps.

Referenced by mrpt::img::CImage::drawChessboardCorners(), mrpt::img::CEnhancedMetaFile::selectVectorTextFont(), and textOut().

◆ setPixel()

virtual void mrpt::img::CCanvas::setPixel	(	int	x,
		int	y,
		size_t	color
	)

pure virtual

Changes the value of the pixel (x,y).

Pixel coordinates starts at the left-top corner of the image, and start in (0,0). The meaning of the parameter "color" depends on the implementation: it will usually be a 24bit RGB value (0x00RRGGBB), but it can also be just a 8bit gray level.

You can also use a TColor() type as input and it will be automatically converted to size_t.

This method must support (x,y) values OUT of the actual image size without neither raising exceptions, nor leading to memory access errors.

Implemented in mrpt::img::CImage, and mrpt::img::CEnhancedMetaFile.

Referenced by drawImage(), filledRectangle(), line(), and textOut().

◆ textOut()

void CCanvas::textOut	(	int	x0,
		int	y0,
		const std::string &	str,
		const mrpt::img::TColor	color
	)

virtual

Renders 2D text using bitmap fonts.

Parameters

x0	The x coordinates
y0	The y coordinates
str	The string to put. If using UNICODE characters, use UTF-8 encoding.
color	The text color

See also: selectTextFont

Reimplemented in mrpt::img::CEnhancedMetaFile.

Definition at line 369 of file CCanvas.cpp.

References mrpt::system::decodeUTF8(), mrpt::img::CImage::isOriginTopLeft(), m_selectedFontBitmaps, MRPT_END, MRPT_START, selectTextFont(), and setPixel().

Referenced by mrpt::img::CImage::drawChessboardCorners(), drawFeatures(), and mrpt::gui::CDisplayWindow::plot().

◆ triangle()

void CCanvas::triangle	(	int	x0,
		int	y0,
		int	size,
		const mrpt::img::TColor	color,
		bool	inferior = `true`,
		unsigned int	width = `1`
	)

Draws a triangle.

Parameters

x0	The triangle center x coordinate
y0	The triangle center y coordinate
size	The size of the triangle
color	The color of the line
inferior	The position of the triangle
width	The desired width of the line.

See also: triangle

Definition at line 190 of file CCanvas.cpp.

References line(), and mrpt::round().

Member Data Documentation

◆ m_selectedFont

std::string mrpt::img::CCanvas::m_selectedFont

protected

The selected font name.

Definition at line 44 of file CCanvas.h.

Referenced by selectTextFont().

◆ m_selectedFontBitmaps

const uint32_t* mrpt::img::CCanvas::m_selectedFontBitmaps

protected

Direct access to character bitmaps.

Definition at line 47 of file CCanvas.h.

Referenced by selectTextFont(), and textOut().

Detailed Description

Public Types

Public Member Functions

Protected Attributes

Member Enumeration Documentation

◆ TPenStyle

Constructor & Destructor Documentation

◆ CCanvas()

◆ ~CCanvas()

Member Function Documentation

◆ cross()

◆ drawCircle()

◆ drawFeatures()

◆ drawFeaturesSimple()

◆ drawImage() [1/2]

◆ drawImage() [2/2]

◆ ellipseGaussian()

◆ filledRectangle()

◆ getHeight()

◆ getWidth()

◆ line()

◆ rectangle()

◆ selectTextFont()

◆ setPixel()

◆ textOut()

◆ triangle()

Member Data Documentation

◆ m_selectedFont

◆ m_selectedFontBitmaps