pangomm: Pango::Renderer Class Reference

pangomm 2.52.0

Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Related Symbols | List of all members
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 { Part::FOREGROUND , Part::BACKGROUND , Part::UNDERLINE , Part::STRIKETHROUGH , Part::OVERLINE }
| `Pango::RenderPart` defines different items to render for such purposes as setting colors. More...

## 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.

## 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 )
| related

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.