pangomm: Pango::Renderer Class Reference

Pango::Renderer is a base class that contains the necessary logic for rendering a Pango::Layout or Pango::LayoutLine. More...

#include <pangomm/renderer.h>

Inheritance diagram for Pango::Renderer:

[legend]

Public Types
enum class	Part { FOREGROUND , BACKGROUND , UNDERLINE , STRIKETHROUGH , OVERLINE }

Public Member Functions
	Renderer (Renderer &&src) noexcept

Renderer &	operator= (Renderer &&src) noexcept

	~Renderer () noexcept override

PangoRenderer *	gobj ()
	Provides access to the underlying C GObject.

const PangoRenderer *	gobj () const
	Provides access to the underlying C GObject.

PangoRenderer *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

void	draw_layout (const Glib::RefPtr< Layout > &layout, int x, int y)
	Draws layout with the specified `Pango::Renderer`.

void	draw_layout_line (const Glib::RefPtr< LayoutLine > &line, int x, int y)
	Draws line with the specified `Pango::Renderer`.

void	draw_glyphs (const Glib::RefPtr< Font > &font, const GlyphString &glyphs, int x, int y)
	Draws the glyphs in glyphs with the specified `Pango::Renderer`.

void	draw_glyph_item (const Glib::ustring &text, const GlyphItem &glyph_item, int x, int y)
	Draws the glyphs in glyph_item with the specified `Pango::Renderer`, embedding the text associated with the glyphs in the output if the output format supports it.

void	draw_rectangle (Part part, int x, int y, int width, int height)
	Draws an axis-aligned rectangle in user space coordinates with the specified `Pango::Renderer`.

void	draw_error_underline (int x, int y, int width, int height)
	Draw a squiggly line that approximately covers the given rectangle in the style of an underline used to indicate a spelling error.

void	draw_trapezoid (Part part, double y1, double x11, double x21, double y2, double x12, double x22)
	Draws a trapezoid with the parallel sides aligned with the X axis using the given `Pango::Renderer`; coordinates are in device space.

void	draw_glyph (const Glib::RefPtr< Font > &font, Glyph glyph, double x, double y)
	Draws a single glyph with coordinates in device space.

void	activate ()
	Does initial setup before rendering operations on renderer.

void	deactivate ()
	Cleans up after rendering operations on renderer.

void	part_changed (Part part)
	Informs Pango that the way that the rendering is done for part has changed.

void	set_color (Part part, const Color &color)
	Sets the color for part of the rendering.

Color	get_color (Part part) const
	Gets the current rendering color for the specified part.

void	set_alpha (Part part, guint16 alpha)
	Sets the alpha for part of the rendering.

guint16	get_alpha (Part part) const
	Gets the current alpha for the specified part.

void	set_matrix (const Matrix &matrix)
	Sets the transformation matrix that will be applied when rendering.

Matrix	get_matrix () const
	Gets the transformation matrix that will be applied when rendering.

Glib::RefPtr< Layout >	get_layout ()
	Gets the layout currently being rendered using renderer.

Glib::RefPtr< const Layout >	get_layout () const
	Gets the layout currently being rendered using renderer.

Glib::RefPtr< LayoutLine >	get_layout_line ()
	Gets the layout line currently being rendered using renderer.

Glib::RefPtr< const LayoutLine >	get_layout_line () const
	Gets the layout line currently being rendered using renderer.

Static Public Member Functions
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system.

Protected Member Functions
virtual void	draw_glyphs_vfunc (const Glib::RefPtr< Font > &font, const GlyphString &glyphs, int x, int y)

virtual void	draw_rectangle_vfunc (Part part, int x, int y, int width, int height)

virtual void	draw_error_underline_vfunc (int x, int y, int width, int height)

virtual void	draw_shape_vfunc (const AttrShape &attr, int x, int y)

virtual void	draw_trapezoid_vfunc (Part part, double y1, double x11, double x21, double y2, double x12, double x22)

virtual void	draw_glyph_vfunc (const Glib::RefPtr< Font > &font, Glyph glyph, double x, double y)

virtual void	part_changed_vfunc (Part part)

virtual void	begin_vfunc ()

virtual void	end_vfunc ()

virtual void	prepare_run_vfunc (const GlyphItem &run)

virtual void	draw_glyph_item_vfunc (const Glib::ustring &text, const GlyphItem &glyph_item, int x, int y)

Related Symbols
(Note that these are not member symbols.)
Glib::RefPtr< Pango::Renderer >	wrap (PangoRenderer *object, bool take_copy=false)
	A Glib::wrap() method for this object.

Detailed Description

Pango::Renderer is a base class that contains the necessary logic for rendering a Pango::Layout or Pango::LayoutLine.

By subclassing Pango::Renderer and overriding operations such as draw_glyphs and draw_rectangle, renderers for particular font backends and destinations can be created.

Member Enumeration Documentation

◆ Part

enum class Pango::Renderer::Part

strong

Enumerator
FOREGROUND	The text itself.
BACKGROUND	The area behind the text.
UNDERLINE	Underlines.
STRIKETHROUGH	Strikethrough lines.
OVERLINE	Overlines.

Constructor & Destructor Documentation

◆ Renderer()

Pango::Renderer::Renderer ( Renderer && src )

noexcept

◆ ~Renderer()

Pango::Renderer::~Renderer ( )

overridenoexcept

Member Function Documentation

◆ activate()

void Pango::Renderer::activate ( )

Does initial setup before rendering operations on renderer.

deactivate() should be called when done drawing. Calls such as draw_layout() automatically activate the layout before drawing on it.

Calls to activate() and deactivate() can be nested and the renderer will only be initialized and deinitialized once.

Since pangomm 1.8:

◆ begin_vfunc()

virtual void Pango::Renderer::begin_vfunc ( )

protectedvirtual

◆ deactivate()

void Pango::Renderer::deactivate ( )

Cleans up after rendering operations on renderer.

See docs for activate().

Since pangomm 1.8:

◆ draw_error_underline()

void Pango::Renderer::draw_error_underline	(	int	x,
		int	y,
		int	width,
		int	height
	)

Draw a squiggly line that approximately covers the given rectangle in the style of an underline used to indicate a spelling error.

The width of the underline is rounded to an integer number of up/down segments and the resulting rectangle is centered in the original rectangle.

This should be called while renderer is already active. Use activate() to activate a renderer.

Since pangomm 1.8:

Parameters

x	X coordinate of underline, in Pango units in user coordinate system.
y	Y coordinate of underline, in Pango units in user coordinate system.
width	Width of underline, in Pango units in user coordinate system.
height	Height of underline, in Pango units in user coordinate system.

◆ draw_error_underline_vfunc()

virtual void Pango::Renderer::draw_error_underline_vfunc	(	int	x,
		int	y,
		int	width,
		int	height
	)

protectedvirtual

◆ draw_glyph()

void Pango::Renderer::draw_glyph	(	const Glib::RefPtr< Font > &	font,
		Glyph	glyph,
		double	x,
		double	y
	)

Draws a single glyph with coordinates in device space.

Since pangomm 1.8:

Parameters

font	A `Pango::Font`.
glyph	The glyph index of a single glyph.
x	X coordinate of left edge of baseline of glyph.
y	Y coordinate of left edge of baseline of glyph.

◆ draw_glyph_item()

void Pango::Renderer::draw_glyph_item	(	const Glib::ustring &	text,
		const GlyphItem &	glyph_item,
		int	x,
		int	y
	)

Draws the glyphs in glyph_item with the specified Pango::Renderer, embedding the text associated with the glyphs in the output if the output format supports it.

This is useful for rendering text in PDF.

Note that this method does not handle attributes in glyph_item. If you want colors, shapes and lines handled automatically according to those attributes, you need to use draw_layout_line() or draw_layout().

Note that text is the start of the text for layout, which is then indexed by glyph_item->item->offset.

If text is nullptr, this simply calls draw_glyphs().

The default implementation of this method simply falls back to draw_glyphs().

Since pangomm 1.22:

Parameters

text	The UTF-8 text that glyph_item refers to.
glyph_item	A `Pango::GlyphItem`.
x	X position of left edge of baseline, in user space coordinates in Pango units.
y	Y position of left edge of baseline, in user space coordinates in Pango units.

◆ draw_glyph_item_vfunc()

virtual void Pango::Renderer::draw_glyph_item_vfunc	(	const Glib::ustring &	text,
		const GlyphItem &	glyph_item,
		int	x,
		int	y
	)

protectedvirtual

◆ draw_glyph_vfunc()

virtual void Pango::Renderer::draw_glyph_vfunc	(	const Glib::RefPtr< Font > &	font,
		Glyph	glyph,
		double	x,
		double	y
	)

protectedvirtual

◆ draw_glyphs()

void Pango::Renderer::draw_glyphs	(	const Glib::RefPtr< Font > &	font,
		const GlyphString &	glyphs,
		int	x,
		int	y
	)

Draws the glyphs in glyphs with the specified Pango::Renderer.

Since pangomm 1.8:

Parameters

font	A `Pango::Font`.
glyphs	A `Pango::GlyphString`.
x	X position of left edge of baseline, in user space coordinates in Pango units.
y	Y position of left edge of baseline, in user space coordinates in Pango units.

◆ draw_glyphs_vfunc()

virtual void Pango::Renderer::draw_glyphs_vfunc	(	const Glib::RefPtr< Font > &	font,
		const GlyphString &	glyphs,
		int	x,
		int	y
	)

protectedvirtual

◆ draw_layout()

void Pango::Renderer::draw_layout	(	const Glib::RefPtr< Layout > &	layout,
		int	x,
		int	y
	)

Draws layout with the specified Pango::Renderer.

This is equivalent to drawing the lines of the layout, at their respective positions relative to x, y.

Since pangomm 1.8:

Parameters

layout	A `Pango::Layout`.
x	X position of left edge of baseline, in user space coordinates in Pango units.
y	Y position of left edge of baseline, in user space coordinates in Pango units.

◆ draw_layout_line()

void Pango::Renderer::draw_layout_line	(	const Glib::RefPtr< LayoutLine > &	line,
		int	x,
		int	y
	)

Draws line with the specified Pango::Renderer.

This draws the glyph items that make up the line, as well as shapes, backgrounds and lines that are specified by the attributes of those items.

Since pangomm 1.8:

Parameters

line	A `Pango::LayoutLine`.
x	X position of left edge of baseline, in user space coordinates in Pango units.
y	Y position of left edge of baseline, in user space coordinates in Pango units.

◆ draw_rectangle()

void Pango::Renderer::draw_rectangle	(	Part	part,
		int	x,
		int	y,
		int	width,
		int	height
	)

Draws an axis-aligned rectangle in user space coordinates with the specified Pango::Renderer.

This should be called while renderer is already active. Use activate() to activate a renderer.

Since pangomm 1.8:

Parameters

part	Type of object this rectangle is part of.
x	X position at which to draw rectangle, in user space coordinates in Pango units.
y	Y position at which to draw rectangle, in user space coordinates in Pango units.
width	Width of rectangle in Pango units.
height	Height of rectangle in Pango units.

◆ draw_rectangle_vfunc()

virtual void Pango::Renderer::draw_rectangle_vfunc	(	Part	part,
		int	x,
		int	y,
		int	width,
		int	height
	)

protectedvirtual

◆ draw_shape_vfunc()

virtual void Pango::Renderer::draw_shape_vfunc	(	const AttrShape &	attr,
		int	x,
		int	y
	)

protectedvirtual

◆ draw_trapezoid()

void Pango::Renderer::draw_trapezoid	(	Part	part,
		double	y1,
		double	x11,
		double	x21,
		double	y2,
		double	x12,
		double	x22
	)

Draws a trapezoid with the parallel sides aligned with the X axis using the given Pango::Renderer; coordinates are in device space.

Since pangomm 1.8:

Parameters

part	Type of object this trapezoid is part of.
y1	Y coordinate of top of trapezoid.
x11	X coordinate of left end of top of trapezoid.
x21	X coordinate of right end of top of trapezoid.
y2	Y coordinate of bottom of trapezoid.
x12	X coordinate of left end of bottom of trapezoid.
x22	X coordinate of right end of bottom of trapezoid.

◆ draw_trapezoid_vfunc()

virtual void Pango::Renderer::draw_trapezoid_vfunc	(	Part	part,
		double	y1,
		double	x11,
		double	x21,
		double	y2,
		double	x12,
		double	x22
	)

protectedvirtual

◆ end_vfunc()

virtual void Pango::Renderer::end_vfunc ( )

protectedvirtual

◆ get_alpha()

guint16 Pango::Renderer::get_alpha ( Part part ) const

Gets the current alpha for the specified part.

Since pangomm 1.38:

Parameters

part	The part to get the alpha for.

Returns: The alpha for the specified part, or 0 if it hasn't been set and should be inherited from the environment.

◆ get_color()

Color Pango::Renderer::get_color ( Part part ) const

Gets the current rendering color for the specified part.

Since pangomm 1.8:

Parameters

part	The part to get the color for.

Returns: The color for the specified part, or nullptr if it hasn't been set and should be inherited from the environment.

◆ get_layout() [1/2]

Glib::RefPtr< Layout > Pango::Renderer::get_layout ( )

Gets the layout currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout should not be modified while still being rendered.

Since pangomm 1.20:

Returns: The layout, or nullptr if no layout is being rendered using renderer at this time.

◆ get_layout() [2/2]

Glib::RefPtr< const Layout > Pango::Renderer::get_layout ( ) const

Gets the layout currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout should not be modified while still being rendered.

Since pangomm 1.20:

Returns: The layout, or nullptr if no layout is being rendered using renderer at this time.

◆ get_layout_line() [1/2]

Glib::RefPtr< LayoutLine > Pango::Renderer::get_layout_line ( )

Gets the layout line currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout line should not be modified while still being rendered.

Since pangomm 1.20:

Returns: The layout line, or nullptr if no layout line is being rendered using renderer at this time.

◆ get_layout_line() [2/2]

Glib::RefPtr< const LayoutLine > Pango::Renderer::get_layout_line ( ) const

Gets the layout line currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout line should not be modified while still being rendered.

Since pangomm 1.20:

Returns: The layout line, or nullptr if no layout line is being rendered using renderer at this time.

◆ get_matrix()

Matrix Pango::Renderer::get_matrix ( ) const

Gets the transformation matrix that will be applied when rendering.

See set_matrix().

Returns: The matrix. If no matrix has been set, an identity matrix is returned.

◆ get_type()

static GType Pango::Renderer::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

◆ gobj() [1/2]

PangoRenderer * Pango::Renderer::gobj ( )

inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

const PangoRenderer * Pango::Renderer::gobj ( ) const

inline

Provides access to the underlying C GObject.

◆ gobj_copy()

PangoRenderer * Pango::Renderer::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ operator=()

Renderer & Pango::Renderer::operator= ( Renderer && src )

noexcept

◆ part_changed()

void Pango::Renderer::part_changed ( Part part )

Informs Pango that the way that the rendering is done for part has changed.

This should be called if the rendering changes in a way that would prevent multiple pieces being joined together into one drawing call. For instance, if a subclass of Pango::Renderer was to add a stipple option for drawing underlines, it needs to call

pango_renderer_part_changed (render, PANGO_RENDER_PART_UNDERLINE);

When the stipple changes or underlines with different stipples might be joined together. Pango automatically calls this for changes to colors. (See set_color())

Since pangomm 1.8:

Parameters

part	The part for which rendering has changed.

◆ part_changed_vfunc()

virtual void Pango::Renderer::part_changed_vfunc ( Part part )

protectedvirtual

◆ prepare_run_vfunc()

virtual void Pango::Renderer::prepare_run_vfunc ( const GlyphItem & run )

protectedvirtual

◆ set_alpha()

void Pango::Renderer::set_alpha	(	Part	part,
		guint16	alpha
	)

Sets the alpha for part of the rendering.

Note that the alpha may only be used if a color is specified for part as well.

Since pangomm 1.38:

Parameters

part	The part to set the alpha for.
alpha	An alpha value between 1 and 65536, or 0 to unset the alpha.

◆ set_color()

void Pango::Renderer::set_color	(	Part	part,
		const Color &	color
	)

Sets the color for part of the rendering.

Also see set_alpha().

Since pangomm 1.8:

Parameters

part	The part to change the color of.
color	The new color or `nullptr` to unset the current color.

◆ set_matrix()

void Pango::Renderer::set_matrix ( const Matrix & matrix )

Sets the transformation matrix that will be applied when rendering.

Since pangomm 1.8:

Parameters

matrix A Pango::Matrix, or nullptr to unset any existing matrix (No matrix set is the same as setting the identity matrix.).

Friends And Related Symbol Documentation

◆ wrap()

Glib::RefPtr< Pango::Renderer > wrap	(	PangoRenderer *	object,
		bool	take_copy = `false`
	)

A Glib::wrap() method for this object.

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Related Symbols

Detailed Description

Member Enumeration Documentation

◆ Part

Constructor & Destructor Documentation

◆ Renderer()

◆ ~Renderer()

Member Function Documentation

◆ activate()

◆ begin_vfunc()

◆ deactivate()

◆ draw_error_underline()

◆ draw_error_underline_vfunc()

◆ draw_glyph()

◆ draw_glyph_item()

◆ draw_glyph_item_vfunc()

◆ draw_glyph_vfunc()

◆ draw_glyphs()

◆ draw_glyphs_vfunc()

◆ draw_layout()

◆ draw_layout_line()

◆ draw_rectangle()

◆ draw_rectangle_vfunc()

◆ draw_shape_vfunc()

◆ draw_trapezoid()

◆ draw_trapezoid_vfunc()

◆ end_vfunc()

◆ get_alpha()

◆ get_color()

◆ get_layout() [1/2]

◆ get_layout() [2/2]

◆ get_layout_line() [1/2]

◆ get_layout_line() [2/2]

◆ get_matrix()

◆ get_type()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ operator=()

◆ part_changed()

◆ part_changed_vfunc()

◆ prepare_run_vfunc()

◆ set_alpha()

◆ set_color()

◆ set_matrix()

Friends And Related Symbol Documentation

◆ wrap()