A singleton class responsible for writing text to an OpenGL context. More...

#include <TextWriter.h>

Public Types
enum	Alignment { NO_ALIGN = 0x0, VCENTER = 0x1, TOP = 0x2, BOTTOM = 0x4, LEFT = 0x8, LEFT_CENTER = 0x9, LEFT_TOP = 0xA, LEFT_BOTTOM = 0xC, RIGHT = 0x10, RIGHT_CENTER = 0x11, RIGHT_TOP = 0x12, RIGHT_BOTTOM = 0x14, HCENTER = 0x20, CENTERED = 0x21, CENTER_TOP = 0x22, CENTER_BOTTOM = 0x24 }
	Enumeration for controlling text alignment.

Public Member Functions
void	newGLContext ()
	Resets the text writer's context-dependent data Called when the OpenGL context is called.

void	printText (const std::string &text, Alignment alignment, float anchorX, float anchorY, int fontSize, bool currColor=false, bool transparent=true)
	Print the given text with an alignment relative to the given anchor point. More...

void	printText (const std::string &text, float left, float bottom, int fontSize, bool currColor=false, bool transparent=true)
	Print the given text to the screen at the given coordinates. More...

void	printAlignText (const std::string &text, Alignment alignment, int fontSize, float hpad, float vpad, bool currColor=false, bool transparent=true)
	Print the given text to the screen with the specified alignment. More...

void	printAnchorText (const std::string &text, float anchorX, float anchorY, float xWeight, float yWeight, int fontSize, bool currColor=false, bool transparent=true)
	Prints the text anchored to the position. The relationship to the anchor depends on the anchor weights. It interpolates them from bottom left top top right. More...

void	textSize (const std::string &text, int fontSize, float &textWidth, float &textHeight)
	Reports the size, in pixels, the given text will consume on the screen, given current font and indicated font size. More...

void	resize (int w, int h)
	Inform the text writer that the viewport has resized. More...

int	getViewWidth () const
	Reports TextWriter's belief of the viewport width. More...

int	getViewHeight () const
	Reports TextWriter's belief of the viewport width. More...

bool	setFont (const std::string &fontName)
	Changes the font family. More...

void	setDefaultColor (float r, float g, float b, float alpha=1.f)
	Sets the default font color. More...

int	flipY (int y)
	A utility function to map from screen to image coordinates. More...

Static Public Member Functions
static void	setDefaultFont (const std::string &fontName)
	Sets the default font to use. More...

static TextWriter *	Instance ()
	Acquire pointer to a singleton text writer instance.

Protected Member Functions
TTF_Font *	getFont (int size)
	Returns a pointer to a font for the given size. More...

void	closeFonts ()
	Close out the current set of fonts.

	TextWriter ()
	Protected constructor. No instantiation allowed.

	~TextWriter ()
	Protected destructor.

void	makeTextDList ()
	Generate the display list for the quad upon which text is printed.

void	makeGLTexture ()
	Generate the OpenGL texture object for the text.

void	sdlSurfaceToGLTex (SDL_Surface *surf)
	Set the surface upon which the text has been rendered to a texture. More...

void	printLine (TTF_Font font, const char text, float left, float bottom, int lineNum)
	The work necessary to print a single line of text. More...

Protected Attributes
int	_width
	The width of the viewport the TextWriter considers when computing text positions.

int	_height
	The height of the viewport the TextWriter considers when computing text positions.

FontMap	_fonts
	Map of all font sizes for this font face.

std::string	_fontName
	Name of font.

GLuint	_textID
	Texture object for texturing the rendered text.

GLuint	_textQuadID
	Call list for the text surface.

float	_defColor [4]
	The default font color.

Static Protected Attributes
static TextWriter *	_instance = 0x0
	The singleton pointer.

Detailed Description

A singleton class responsible for writing text to an OpenGL context.

It has numerous functions for drawing text. It typically works in screen space, where the upper, left-hand corner is (0, 0).

Member Function Documentation

int Menge::SceneGraph::TextWriter::flipY ( int y )

inline

A utility function to map from screen to image coordinates.

The screen coordiantes have the origin in the top, left corner. Image coordinates have the origin at the bottom, left corner.

Parameters

y	The vertical position in screen coordinates.

Returns: The vertical position in corresponding image coordinates.

TTF_Font * Menge::SceneGraph::TextWriter::getFont ( int size )

protected

Returns a pointer to a font for the given size.

Parameters

size	The desired size of the font.

Returns: A pointer to a font instance at the desired size. If size is negative, NULL is returned.

int Menge::SceneGraph::TextWriter::getViewHeight ( ) const

inline

Reports TextWriter's belief of the viewport width.

Returns: The effective viewport width the TextWrtier is using.

int Menge::SceneGraph::TextWriter::getViewWidth ( ) const

inline

Reports TextWriter's belief of the viewport width.

Returns: The effective viewport width the TextWrtier is using.

void Menge::SceneGraph::TextWriter::printAlignText	(	const std::string &	text,
		Alignment	alignment,
		int	fontSize,
		float	hpad,
		float	vpad,
		bool	currColor = `false`,
		bool	transparent = `true`
	)

Print the given text to the screen with the specified alignment.

Parameters

text	The string to draw.
alignment	The alignment, relative to the screen.
fontSize	The size of the text, in pixels.
hpad	The amount of horizontal padding to apply in the horizontal alignment direction. For example, if left aligned, it goes on the left, if right aligned, the padding is on the right.
vpad	The amount of vertical padding to apply in the vertical direction.
currColor	Indicates if the current opengl color should be used (true) or the text writer's default color should be used (false).
transparent	Indicates if the text is super-imposed over the screen or given a matte. True –> superimposed, false –> matted.

void Menge::SceneGraph::TextWriter::printAnchorText	(	const std::string &	text,
		float	anchorX,
		float	anchorY,
		float	xWeight,
		float	yWeight,
		int	fontSize,
		bool	currColor = `false`,
		bool	transparent = `true`
	)

Prints the text anchored to the position. The relationship to the anchor depends on the anchor weights. It interpolates them from bottom left top top right.

Parameters

text	The string to draw.
anchorX	The x-position of the anchor point (in screen coords).
anchorY	The y-position of the anchor point (in screen coords).
xWeight	The horizontal weight in the range [0, 1]. 0–> left, 1 –> right alignment.
yWeight	The vertical weight in the range [0, 1]. 0–> bottom, 1 –> top alignment.
fontSize	The size of the text, in pixels.
currColor	Indicates if the current opengl color should be used (true) or the text writer's default color should be used (false).
transparent	Indicates if the text is super-imposed over the screen or given a matte. True –> superimposed, false –> matted.

void Menge::SceneGraph::TextWriter::printLine	(	TTF_Font *	font,
		const char *	text,
		float	left,
		float	bottom,
		int	lineNum
	)

protected

The work necessary to print a single line of text.

The text is displayed relative to the anchor point of an entire block of text, (left, bottom), withthe text extending above and to the right of the anchor point.

Parameters

font	The font to render the text.
text	The text to draw.
left	The horizontal value of the anchor point.
bottom	The vertical value of the anchor point.
lineNum	The line number of the given text (zero-indexed). Used to offset this line relative to the anchor point.

scale and translate the quad

void Menge::SceneGraph::TextWriter::printText	(	const std::string &	text,
		Alignment	alignment,
		float	anchorX,
		float	anchorY,
		int	fontSize,
		bool	currColor = `false`,
		bool	transparent = `true`
	)

Print the given text with an alignment relative to the given anchor point.

Parameters

text	The string to draw.
alignment	The alignment, relative to the screen.
anchorX	The x-position of the anchor point (in screen coords).
anchorY	The y-position of the anchor point (in screen coords).
fontSize	The size of the text, in pixels.
currColor	Indicates if the current opengl color should be used (true) or the text writer's default color should be used (false).
transparent	Indicates if the text is super-imposed over the screen or given a matte. True –> superimposed, false –> matted.

void Menge::SceneGraph::TextWriter::printText	(	const std::string &	text,
		float	left,
		float	bottom,
		int	fontSize,
		bool	currColor = `false`,
		bool	transparent = `true`
	)

Print the given text to the screen at the given coordinates.

Parameters

text	The string to draw.
left	The position of the left extent of the text (in screen coords).
bottom	The position of the bottom extent of the text (in screen coords).
fontSize	The size of the text, in pixels.
currColor	Indicates if the current opengl color should be used (true) or the text writer's default color should be used (false).
transparent	Indicates if the text is super-imposed over the screen or given a matte. True –> superimposed, false –> matted.

void Menge::SceneGraph::TextWriter::resize	(	int	w,
		int	h
	)

Inform the text writer that the viewport has resized.

This must be called by the viewer when the viewport resizes. This information is how the TextWriter correctly interprets alignment.

Parameters

w	The viewport width (in pixels).
h	The viewport height (in pixels).

void Menge::SceneGraph::TextWriter::sdlSurfaceToGLTex ( SDL_Surface * surf )

protected

Set the surface upon which the text has been rendered to a texture.

Parameters

surf	The surface upon which the text has been rendered.

void Menge::SceneGraph::TextWriter::setDefaultColor	(	float	r,
		float	g,
		float	b,
		float	alpha = `1.f`
	)

Sets the default font color.

Parameters

r	The red component of the color.
g	The green component of the color.
b	The blue component of the color.
alpha	The alpha component of the color. Default value is 1.0.

void Menge::SceneGraph::TextWriter::setDefaultFont ( const std::string & fontName )

static

Sets the default font to use.

Parameters

fontName The path to the font to use.

bool Menge::SceneGraph::TextWriter::setFont ( const std::string & fontName )

Changes the font family.

The first font is loaded at the default size If it is unable to load the font, the old family is left in place

Parameters

fontName The name of the font family to use.

Returns: True if the font was successfully loaded, false otherwise. If false, it uses the default font.

void Menge::SceneGraph::TextWriter::textSize	(	const std::string &	text,
		int	fontSize,
		float &	textWidth,
		float &	textHeight
	)

Reports the size, in pixels, the given text will consume on the screen, given current font and indicated font size.

Parameters

text	The string to draw.
fontSize	The size of the font (in points).
textWidth	The width of the text will be stored in this value.
textHeight	The height of the text will be stored in this value.

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

src/menge/MengeCore/SceneGraph/TextWriter.h
src/menge/MengeCore/SceneGraph/TextWriter.cpp

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Member Function Documentation