A bridge to the FTGL library that manages font rendering with texture fonts. More...

#include <mlGL2DFont.h>

Inheritance diagram for GL2DFont:

Public Types
enum	{ MAX_FONTS = 32 }

Public Member Functions
	GL2DFont ()

	~GL2DFont () override

bool	init ()
	Initializes with the default system font.

bool	init (const char *fontname)
	Initializes the given font, which is either just a font name without .ttf or an absolute path.

bool	init (const char fontname, int numFonts, const int sizes)
	Initializes the given font, which is either just a font name without .ttf or an absolute path, with the given number of font sizes.

void	drawString (float dx, float dy, float fontSize, const float color[4], const char string, size_t length=0, bool overlay=false, bool shadow=true, const float shadowColor=nullptr)
	This function draws a simple string with no line feeds.

int	getStringWidth (float fontSize, const char *string, int length=-1) const
	Returns the width of the given simple string.

int	getFontHeight (float fontSize) const
	Returns the height of a font (ascender+descender) in pixels.

int	getFontAscender (float fontSize) const
	Returns the ascender of the font in pixels.

int	getFontDescender (float fontSize) const
	Returns the descender of the font in pixels (i.e., the positive distance from the baseline).

bool	isInitialized () const
	Returns `true` if font loaded; otherwise, it returns `false`.

bool	isUnicodeRenderingPossible () const
	Returns `true` if Unicode rendering is possible; otherwise, it returns `false`.

void	contextDestroyed () override
	Forgets the resource, the context was destroyed (called by the GLResourceManager).

bool	debugFontRenderingEnabled ()
	Checks whether debug font rendering is enabled.

Public Member Functions inherited from GLResource
	GLResource ()

virtual	~GLResource ()

Static Public Member Functions
static GL2DFont *	getDefaultSystemFont ()
	Returns the default system font.

static std::string	getDefaultSystemFontName ()
	Returns the default font name for proportional fonts.

Static Public Member Functions inherited from GLResource
static GLenum	getGLError ()
	Checks for OpenGL error (returns GL_INVALID_OPERATION if there is no valid OpenGL context).

Protected Member Functions
int	getFontIndex (float fontSize) const
	Returns the font index that should be used for the given size of the font.

void	cleanup ()
	Cleans up the fonts.

bool	reloadFonts ()
	Frees old fonts and reloads them.

void	preFontDraw (bool overlay)
	Initializes font rendering.

void	doFontDraw (float dx, float dy, float fontSize, const float color[4], bool shadow, const char asciiString, const wchar_t optionalUnicodeString, const float *shadowColor)
	Renders the fonts.

void	postFontDraw (const bool overlay)
	Finalizes the font rendering.

bool	checkUTF8StringForUnicodeChars (const char *string, size_t length=0) const
	Checks whether the string contains unicode chars.

const char *	copyAndConvertString (const char string, size_t length, const wchar_t *optionalUnicodeString) const
	Internal method that copies the string to the internal buffer and generates a Unicode string if it is required.

std::string	findFontFile (const char *fontName)
	Searches for the file name of the given font.

std::string	findFontFileWithFontconfig (const char *fontName)
	Searches the font by using fontconfig (Linux only)

Additional Inherited Members
Protected Attributes inherited from GLResource
GLResource *	_next

GLResource *	_previous

Detailed Description

A bridge to the FTGL library that manages font rendering with texture fonts.

The font is loaded in different sizes to get a good matching between size of the loaded font and the size it is displayed in. The rendering of strings expects UTF-8 Unicode encoding. Typically, strings are obtained from ML or Inventor fields or from DcmTree, which also use UTF-8 encoding, so nothing special needs to be done on those strings. If the strings are generated and are not simple ASCII (e.g., Latin1), the user needs to take care of conversion from, e.g., Latin1 to UTF-8.

It is recommended to use getSystemDefaultFonts() for all code that just wants to render text with the default font. This avoids font allocation on each module that makes use of the default font.

It is essential to initialize objects of this class. The most general method just requires a valid GL context and uses the default system font. The implementations take a font, or the font and a list of font sizes to be used to load the fonts with. In general, this class could provide 3D font rendering, but it has been implemented with 2D rendering in mind. The draw methods allow a parameter overlay that specifies whether GL2DFont should take care of the specification of the 2D context (backing up the old projections, using an orthogonal projection for the actual font rendering, and restoring the old projections) or whether this is done outside its scope.

Definition at line 52 of file mlGL2DFont.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Enumerator
MAX_FONTS

Definition at line 60 of file mlGL2DFont.h.

Constructor & Destructor Documentation

◆ GL2DFont()

GL2DFont::GL2DFont ( )

◆ ~GL2DFont()

GL2DFont::~GL2DFont ( )

override

Member Function Documentation

◆ checkUTF8StringForUnicodeChars()

bool GL2DFont::checkUTF8StringForUnicodeChars	(	const char *	string,
		size_t	length = 0 ) const

protected

Checks whether the string contains unicode chars.

◆ cleanup()

void GL2DFont::cleanup ( )

protected

Cleans up the fonts.

◆ contextDestroyed()

void GL2DFont::contextDestroyed ( )

overridevirtual

Forgets the resource, the context was destroyed (called by the GLResourceManager).

Implements GLResource.

◆ copyAndConvertString()

const char * GL2DFont::copyAndConvertString	(	const char *	string,
		size_t	length,
		const wchar_t **	optionalUnicodeString ) const

protected

Internal method that copies the string to the internal buffer and generates a Unicode string if it is required.

If optionalUnicodeString is set, the caller needs to take care of doing MLFree on the wchar_t pointer

◆ debugFontRenderingEnabled()

bool GL2DFont::debugFontRenderingEnabled ( )

Checks whether debug font rendering is enabled.

◆ doFontDraw()

void GL2DFont::doFontDraw	(	float	dx,
		float	dy,
		float	fontSize,
		const float	color[4],
		bool	shadow,
		const char *	asciiString,
		const wchar_t *	optionalUnicodeString,
		const float *	shadowColor )

protected

Renders the fonts.

◆ drawString()

void GL2DFont::drawString	(	float	dx,
		float	dy,
		float	fontSize,
		const float	color[4],
		const char *	string,
		size_t	length = 0,
		bool	overlay = false,
		bool	shadow = true,
		const float *	shadowColor = nullptr )

This function draws a simple string with no line feeds.

The rendering is started at dx,dy, which is used as the baseline position for the drawing. Processing multiline text has to be done manually (see View2D/View2DFont.h for some examples).

Parameters

dx	The 2D position of the text (either in current coordinate system or in lower-left viewport device coordinate system when overlay is set to true)
dy	The 2D position of the text (either in current coordinate system or in lower-left viewport device coordinate system when overlay is set to true)
color	The color of the text (float[4] RGBA)
string	The string to be drawn. The encoding needs to be UTF-8 Unicode encoding (or plain ASCII)
length	The length of the string that should be rendered (if length is 0, strlen is used and the string is expected to be 0 terminated)
fontSize	Point size of the font.
overlay	GL2DFont takes care of setting a valid 2D environment (lower-left viewport device coordinate system)
shadow	Draw a shadow of the font.
shadowColor	The color of the optional text shadow (float[3] RGB)

Warning: This operation requires a valid GL context!

◆ findFontFile()

std::string GL2DFont::findFontFile ( const char * fontName )

protected

Searches for the file name of the given font.

May return a different font file if it is not found.

◆ findFontFileWithFontconfig()

std::string GL2DFont::findFontFileWithFontconfig ( const char * fontName )

protected

Searches the font by using fontconfig (Linux only)

◆ getDefaultSystemFont()

static GL2DFont * GL2DFont::getDefaultSystemFont ( )

static

Returns the default system font.

This is already initialized, a valid GL context is only required for the draw methods. Note: The font is owned by MLOpenGL, do not delete the returned object!

◆ getDefaultSystemFontName()

static std::string GL2DFont::getDefaultSystemFontName ( )

static

Returns the default font name for proportional fonts.

This can be overridden via the 'GL2DFont_DefaultSystemFont' property of ml::ApplicationProperties, which reads its properties from the MeVisLab .prefs file.

◆ getFontAscender()

int GL2DFont::getFontAscender ( float fontSize ) const

Returns the ascender of the font in pixels.

Warning: This operation requires a valid GL context!

◆ getFontDescender()

int GL2DFont::getFontDescender ( float fontSize ) const

Returns the descender of the font in pixels (i.e., the positive distance from the baseline).

Warning: This operation requires a valid GL context!

◆ getFontHeight()

int GL2DFont::getFontHeight ( float fontSize ) const

Returns the height of a font (ascender+descender) in pixels.

Warning: This operation requires a valid GL context!

◆ getFontIndex()

int GL2DFont::getFontIndex ( float fontSize ) const

protected

Returns the font index that should be used for the given size of the font.

◆ getStringWidth()

int GL2DFont::getStringWidth	(	float	fontSize,
		const char *	string,
		int	length = -1 ) const

Returns the width of the given simple string.

Warning: This operation requires a valid GL context!

◆ init() [1/3]

bool GL2DFont::init ( )

Initializes with the default system font.

Warning: This operation requires a valid GL context!

◆ init() [2/3]

bool GL2DFont::init ( const char * fontname )

Initializes the given font, which is either just a font name without .ttf or an absolute path.

Warning: This operation requires a valid GL context!

◆ init() [3/3]

bool GL2DFont::init	(	const char *	fontname,
		int	numFonts,
		const int *	sizes )

Initializes the given font, which is either just a font name without .ttf or an absolute path, with the given number of font sizes.

The list of font sizes should be ordered ascending for getFontIndex to work properly!

Warning: This operation requires a valid GL context!

◆ isInitialized()

bool GL2DFont::isInitialized ( ) const

inline

Returns true if font loaded; otherwise, it returns false.

Definition at line 133 of file mlGL2DFont.h.

◆ isUnicodeRenderingPossible()

bool GL2DFont::isUnicodeRenderingPossible ( ) const

inline

Returns true if Unicode rendering is possible; otherwise, it returns false.

Definition at line 141 of file mlGL2DFont.h.

◆ postFontDraw()

void GL2DFont::postFontDraw ( const bool overlay )

protected

Finalizes the font rendering.

◆ preFontDraw()

void GL2DFont::preFontDraw ( bool overlay )

protected

Initializes font rendering.

◆ reloadFonts()

bool GL2DFont::reloadFonts ( )

protected

Frees old fonts and reloads them.

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

MeVis/Foundation/Sources/MLOpenGL/mlGL2DFont.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ GL2DFont()

◆ ~GL2DFont()

Member Function Documentation

◆ checkUTF8StringForUnicodeChars()

◆ cleanup()

◆ contextDestroyed()

◆ copyAndConvertString()

◆ debugFontRenderingEnabled()

◆ doFontDraw()

◆ drawString()

◆ findFontFile()

◆ findFontFileWithFontconfig()

◆ getDefaultSystemFont()

◆ getDefaultSystemFontName()

◆ getFontAscender()

◆ getFontDescender()

◆ getFontHeight()

◆ getFontIndex()

◆ getStringWidth()

◆ init() [1/3]

◆ init() [2/3]

◆ init() [3/3]

◆ isInitialized()

◆ isUnicodeRenderingPossible()

◆ postFontDraw()

◆ preFontDraw()

◆ reloadFonts()