Module: PangoCairo

Defined in:
pango/lib/pango.rb

Overview

Version:

  • 1.0

Defined Under Namespace

Modules: Font, FontMap

Instance Method Summary collapse

Instance Method Details

#context_get_font_options(context) ⇒ cairo::FontOptions

Retrieves any font rendering options previously set with pango_cairo_context_set_font_options(). This function does not report options that are derived from the target surface by pango_cairo_update_context()

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

Returns:

  • (cairo::FontOptions) —

    the font options previously set on the context, or nil if no options have been set. This value is owned by the context and must not be modified or freed.

#context_get_resolution(context) ⇒ Float

Gets the resolution for the context. See pango_cairo_context_set_resolution()

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

Returns:

  • (Float) —

    the resolution in “dots per inch”. A negative value will be returned if no resolution has previously been set.

#context_get_shape_renderer(context, data) ⇒ PangoCairo::ShapeRendererFunc

Sets callback function for context to use for rendering attributes of type %PANGO_ATTR_SHAPE. See Pango::CairoShapeRendererFunc for details.

Retrieves callback function and associated user data for rendering attributes of type %PANGO_ATTR_SHAPE as set by pango_cairo_context_set_shape_renderer(), if any.

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

  • data (GObject) —

    Pointer to #gpointer to return user data

Returns:

  • (PangoCairo::ShapeRendererFunc) —

    the shape rendering callback previously set on the context, or nil if no shape rendering callback have been set.

#context_set_font_options(context, options) ⇒ nil

Sets the font options used when rendering text with this context. These options override any options that pango_cairo_update_context() derives from the target surface.

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

  • options (cairo::FontOptions) —

    a #cairo_font_options_t, or nil to unset any previously set options. A copy is made.

Returns:

  • (nil)

#context_set_resolution(context, dpi) ⇒ nil

Sets the resolution for the context. This is a scale factor between points specified in a Pango::FontDescription and Cairo units. The default value is 96, meaning that a 10 point font will be 13 units high. (10 * 96. / 72. = 13.3).

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

  • dpi (Float) —

    the resolution in “dots per inch”. (Physical inches aren’t actually involved; the terminology is conventional.) A 0 or negative value means to use the resolution from the font map.

Returns:

  • (nil)

#context_set_shape_renderer(context, func, data, dnotify) ⇒ nil

Sets callback function for context to use for rendering attributes of type %PANGO_ATTR_SHAPE. See Pango::CairoShapeRendererFunc for details.

Parameters:

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

  • func (PangoCairo::ShapeRendererFunc) —

    Callback function for rendering attributes of type %PANGO_ATTR_SHAPE, or nil to disable shape rendering.

  • data (GObject) —

    User data that will be passed to func.

  • dnotify (GLib::DestroyNotify) —

    Callback that will be called when the context is freed to release data, or nil.

Returns:

  • (nil)

#create_context(cr) ⇒ Pango::Context

Creates a context object set up to match the current transformation and target surface of the Cairo context. This context can then be used to create a layout using pango_layout_new().

This function is a convenience function that creates a context using the default font map, then updates it to cr. If you just need to create a layout for use with cr and do not need to access Pango::Context directly, you can use pango_cairo_create_layout() instead.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

Returns:

  • (Pango::Context) —

    the newly created Pango::Context. Free with g_object_unref().

#create_layout(cr) ⇒ Pango::Layout

Creates a layout object set up to match the current transformation and target surface of the Cairo context. This layout can then be used for text measurement with functions like pango_layout_get_size() or drawing with functions like pango_cairo_show_layout(). If you change the transformation or target surface for cr, you need to call pango_cairo_update_layout()

This function is the most convenient way to use Cairo with Pango, however it is slightly inefficient since it creates a separate Pango::Context object for each layout. This might matter in an application that was laying out large amounts of text.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

Returns:

  • (Pango::Layout) —

    the newly created Pango::Layout. Free with g_object_unref().

#error_underline_path(cr, x, y, width, height) ⇒ nil

Add a squiggly line to the current path in the specified cairo context 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)

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • x (Float) —

    The X coordinate of one corner of the rectangle

  • y (Float) —

    The Y coordinate of one corner of the rectangle

  • width (Float) —

    Non-negative width of the rectangle

  • height (Float) —

    Non-negative height of the rectangle

Returns:

  • (nil)

#font_map_get_default ⇒ Pango::FontMap

Gets a default Pango::CairoFontMap to use with Cairo.

Note that the type of the returned object will depend on the particular font backend Cairo was compiled to use; You generally should only use the Pango::FontMap and Pango::CairoFontMap interfaces on the returned object.

The default Cairo fontmap can be changed by using pango_cairo_font_map_set_default(). This can be used to change the Cairo font backend that the default fontmap uses for example.

Note that since Pango 1.32.6, the default fontmap is per-thread. Each thread gets its own default fontmap. In this way, PangoCairo can be used safely from multiple threads.

Returns:

  • (Pango::FontMap) —

    the default PangoCairo fontmap for the current thread. This object is owned by Pango and must not be freed.

#font_map_new ⇒ Pango::FontMap

Creates a new Pango::CairoFontMap object; a fontmap is used to cache information about available fonts, and holds certain global parameters such as the resolution. In most cases, you can use pango_cairo_font_map_get_default() instead.

Note that the type of the returned object will depend on the particular font backend Cairo was compiled to use; You generally should only use the Pango::FontMap and Pango::CairoFontMap interfaces on the returned object.

You can override the type of backend returned by using an environment variable %PANGOCAIRO_BACKEND. Supported types, based on your build, are fc (fontconfig), win32, and coretext. If requested type is not available, NULL is returned. Ie. this is only useful for testing, when at least two backends are compiled in.

Returns:

  • (Pango::FontMap) —

    the newly allocated Pango::FontMap, which should be freed with g_object_unref().

#font_map_new_for_font_type(fonttype) ⇒ Pango::FontMap

Creates a new Pango::CairoFontMap object of the type suitable to be used with cairo font backend of type fonttype.

In most cases one should simply use pango_cairo_font_map_new(), or in fact in most of those cases, just use pango_cairo_font_map_get_default().

Parameters:

  • fonttype (cairo::FontType) —

    desired #cairo_font_type_t

Returns:

  • (Pango::FontMap) —

    the newly allocated Pango::FontMap of suitable type which should be freed with g_object_unref(), or nil if the requested cairo font backend is not supported / compiled in.

#glyph_string_path(cr, font, glyphs) ⇒ nil

Adds the glyphs in glyphs to the current path in the specified cairo context. The origin of the glyphs (the left edge of the baseline) will be at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • font (Pango::Font) —

    a Pango::Font from a #PangoCairoFontMap

  • glyphs (Pango::GlyphString) —

    a Pango::GlyphString

Returns:

  • (nil)

#layout_line_path(cr, line) ⇒ nil

Adds the text in Pango::LayoutLine to the current path in the specified cairo context. The origin of the glyphs (the left edge of the line) will be at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • line (Pango::LayoutLine) —

    a Pango::LayoutLine

Returns:

  • (nil)

#layout_path(cr, layout) ⇒ nil

Adds the text in a Pango::Layout to the current path in the specified cairo context. The top-left corner of the Pango::Layout will be at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • layout (Pango::Layout) —

    a Pango layout

Returns:

  • (nil)

#show_error_underline(cr, x, y, width, height) ⇒ nil

Draw a squiggly line in the specified cairo context 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)

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • x (Float) —

    The X coordinate of one corner of the rectangle

  • y (Float) —

    The Y coordinate of one corner of the rectangle

  • width (Float) —

    Non-negative width of the rectangle

  • height (Float) —

    Non-negative height of the rectangle

Returns:

  • (nil)

#show_glyph_item(cr, text, glyph_item) ⇒ nil

Draws the glyphs in glyph_item in the specified cairo context, embedding the text associated with the glyphs in the output if the output format supports it (PDF for example), otherwise it acts similar to pango_cairo_show_glyph_string().

The origin of the glyphs (the left edge of the baseline) will be drawn at the current point of the cairo context.

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

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • text (String) —

    the UTF-8 text that glyph_item refers to

  • glyph_item (Pango::GlyphItem) —

    a Pango::GlyphItem

Returns:

  • (nil)

#show_glyph_string(cr, font, glyphs) ⇒ nil

Draws the glyphs in glyphs in the specified cairo context. The origin of the glyphs (the left edge of the baseline) will be drawn at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • font (Pango::Font) —

    a Pango::Font from a #PangoCairoFontMap

  • glyphs (Pango::GlyphString) —

    a Pango::GlyphString

Returns:

  • (nil)

#show_layout(cr, layout) ⇒ nil

Draws a Pango::Layout in the specified cairo context. The top-left corner of the Pango::Layout will be drawn at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • layout (Pango::Layout) —

    a Pango layout

Returns:

  • (nil)

#show_layout_line(cr, line) ⇒ nil

Draws a Pango::LayoutLine in the specified cairo context. The origin of the glyphs (the left edge of the line) will be drawn at the current point of the cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • line (Pango::LayoutLine) —

    a Pango::LayoutLine

Returns:

  • (nil)

#update_context(cr, context) ⇒ nil

Updates a Pango::Context previously created for use with Cairo to match the current transformation and target surface of a Cairo context. If any layouts have been created for the context, it’s necessary to call pango_layout_context_changed() on those layouts.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • context (Pango::Context) —

    a Pango::Context, from a pangocairo font map

Returns:

  • (nil)

#update_layout(cr, layout) ⇒ nil

Updates the private Pango::Context of a #PangoLayout created with pango_cairo_create_layout() to match the current transformation and target surface of a Cairo context.

Parameters:

  • cr (cairo::Context) —

    a Cairo context

  • layout (Pango::Layout) —

    a Pango::Layout, from pango_cairo_create_layout()

Returns:

  • (nil)