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 ()
	Init with the default system font.

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

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

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

int	getStringWidth (const float fontSize, const char *string, const size_t length) const
	Get width of the given simple string.

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

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

int	getFontDescender (const float fontSize) const
	Get the descender of the font in pixels (positive distance from the baseline).

bool	isInitialized () const
	Returns true if font loaded, otherwise false.

bool	isUnicodeRenderingPossible () const
	Returns true if unicode rendering is possible, otherwise false.

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

bool	debugFontRenderingEnabled ()
	check if debug font rendering is enabled

Public Member Functions inherited from GLResource
	GLResource ()

virtual	~GLResource ()

Static Public Member Functions
static GL2DFont *	getDefaultSystemFont ()
	get the default system font (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!

static std::string	getDefaultSystemFontName ()
	returns the default font name for proportional fonts (this can be overwritten via the "GL2DFont_DefaultSystemFont" property of ml::ApplicationProperties, which reads its properties from the MeVisLab prefs file)

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

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

void	cleanup ()
	Cleanup the fonts.

bool	reloadFonts ()
	Free old fonts and reload them.

void	preFontDraw (const bool overlay)
	Initialize font rendering.

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

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

bool	checkUTF8StringForUnicodeChars (const char *string, size_t length=0) const
	Check if 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. The rendering of strings expects UTF8 unicode encoding. Typically strings are obtained from ML or Inventor fields or from DcmTree, which also use UTF8 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 UTF8.

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's 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 fontsizes 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 which specifies if GL2DFont should take care of the specification of the 2D context (backing up the old projections, using an orthorgonal projection for the actual font rendering and restoring the old projections) or if this is done outside of its scope.

Definition at line 52 of file mlGL2DFont.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Enumerator
MAX_FONTS

Definition at line 59 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

Check if the string contains unicode chars.

◆ cleanup()

void GL2DFont::cleanup ( )

protected

Cleanup the fonts.

◆ contextDestroyed()

void GL2DFont::contextDestroyed ( )

overridevirtual

forget 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 ( )

check if debug font rendering is enabled

◆ doFontDraw()

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

protected

Render the fonts.

◆ drawString()

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

This function draws a simple string with no linefeeds.

The rendering is started at dx,dy which is used as the baseline position for the drawing. Processing multi line 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 UTF8 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

get the default system font (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 overwritten via the "GL2DFont_DefaultSystemFont" property of ml::ApplicationProperties, which reads its properties from the MeVisLab prefs file)

◆ getFontAscender()

int GL2DFont::getFontAscender ( const float fontSize ) const

Get the ascender of the font in pixels.

Warning: This operation requires a valid GL context!

◆ getFontDescender()

int GL2DFont::getFontDescender ( const float fontSize ) const

Get the descender of the font in pixels (positive distance from the baseline).

Warning: This operation requires a valid GL context!

◆ getFontHeight()

int GL2DFont::getFontHeight ( const float fontSize ) const

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

Warning: This operation requires a valid GL context!

◆ getFontIndex()

int GL2DFont::getFontIndex ( const float fontSize ) const

protected

Get the font idx that should be used for the given size of the font.

◆ getStringWidth()

int GL2DFont::getStringWidth	(	const float	fontSize,
		const char *	string,
		const size_t	length ) const

Get width of the given simple string.

Warning: This operation requires a valid GL context!

◆ init() [1/3]

bool GL2DFont::init ( )

Init with the default system font.

Warning: This operation requires a valid GL context!

◆ init() [2/3]

bool GL2DFont::init ( const char * fontname )

Init the given font (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,
		const int	numFonts,
		const int *	sizes )

Init the given font (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 false.

Definition at line 134 of file mlGL2DFont.h.

◆ isUnicodeRenderingPossible()

bool GL2DFont::isUnicodeRenderingPossible ( ) const

inline

Returns true if unicode rendering is possible, otherwise false.

Definition at line 139 of file mlGL2DFont.h.

◆ postFontDraw()

void GL2DFont::postFontDraw ( const bool overlay )

protected

Finalize the font rendering.

◆ preFontDraw()

void GL2DFont::preFontDraw ( const bool overlay )

protected

Initialize font rendering.

◆ reloadFonts()

bool GL2DFont::reloadFonts ( )

protected

Free old fonts and reload 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()