Package ch.bailu.gtk.pango

Class Context

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.pango.Context
All Implemented Interfaces:
PointerInterface
public class Context extends Object
A `PangoContext` stores global information used to control the
itemization process.

The information stored by `PangoContext` includes the fontmap used
to look up fonts, and default values such as the default language,
default gravity, or default font.

To obtain a `PangoContext`, use [method@Pango.FontMap.create_context].

https://docs.gtk.org/Pango/class.Context.html

  • Constructor Details

    • Context

      public Context(PointerContainer pointer)

    • Context

      public Context()
      Creates a new `PangoContext` initialized to default values.

      This function is not particularly useful as it should always
      be followed by a [method@Pango.Context.set_font_map] call, and the
      function [method@Pango.FontMap.create_context] does these two steps
      together and hence users are recommended to use that.

      If you are using Pango as part of a higher-level system,
      that system may have it's own way of create a `PangoContext`.
      For instance, the GTK toolkit has, among others,
      `gtk_widget_get_pango_context()`. Use those instead.

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • changed

      public void changed()
      Forces a change in the context, which will cause any `PangoLayout`
      using this context to re-layout.

      This function is only useful when implementing a new backend
      for Pango, something applications won't do. Backends should
      call this function if they have attached extra data to the context
      and such data is changed.

    • getBaseDir

      public int getBaseDir()
      Retrieves the base direction for the context.

      See [method@Pango.Context.set_base_dir].
      Returns:
      the base direction for the context.

    • getBaseGravity

      public int getBaseGravity()
      Retrieves the base gravity for the context.

      See [method@Pango.Context.set_base_gravity].
      Returns:
      the base gravity for the context.

    • getFontDescription

      public FontDescription getFontDescription()
      Retrieve the default font description for the context.
      Returns:
      a pointer to the context's default font description. This value must not be modified or freed.

    • getFontMap

      public FontMap getFontMap()
      Gets the `PangoFontMap` used to look up fonts for this context.
      Returns:
      the font map for the. `PangoContext` This value is owned by Pango and should not be unreferenced.

    • getGravity

      public int getGravity()
      Retrieves the gravity for the context.

      This is similar to [method@Pango.Context.get_base_gravity],
      except for when the base gravity is %PANGO_GRAVITY_AUTO for
      which [func@Pango.Gravity.get_for_matrix] is used to return the
      gravity from the current context matrix.
      Returns:
      the resolved gravity for the context.

    • getGravityHint

      public int getGravityHint()
      Retrieves the gravity hint for the context.

      See [method@Pango.Context.set_gravity_hint] for details.
      Returns:
      the gravity hint for the context.

    • getLanguage

      public Language getLanguage()
      Retrieves the global language tag for the context.
      Returns:
      the global language tag.

    • getMatrix

      public Matrix getMatrix()
      Gets the transformation matrix that will be applied when
      rendering with this context.

      See [method@Pango.Context.set_matrix].
      Returns:
      the matrix, or %NULL if no matrix has been set (which is the same as the identity matrix). The returned matrix is owned by Pango and must not be modified or freed.

    • getMetrics

      public FontMetrics getMetrics(@Nullable FontDescription desc, @Nullable Language language)
      Get overall metric information for a particular font description.

      Since the metrics may be substantially different for different scripts,
      a language tag can be provided to indicate that the metrics should be
      retrieved that correspond to the script(s) used by that language.

      The `PangoFontDescription` is interpreted in the same way as by [func@itemize],
      and the family name may be a comma separated list of names. If characters
      from multiple of these families would be used to render the string, then
      the returned fonts would be a composite of the metrics for the fonts loaded
      for the individual families.
      Parameters:
      desc - a `PangoFontDescription` structure. %NULL means that the font description from the context will be used.
      language - language tag used to determine which script to get the metrics for. %NULL means that the language tag from the context will be used. If no language tag is set on the context, metrics for the default language (as determined by [func@Pango.Language.get_default] will be returned.
      Returns:
      a `PangoFontMetrics` object. The caller must call [method@Pango.FontMetrics.unref] when finished using the object.

    • getRoundGlyphPositions

      public boolean getRoundGlyphPositions()
      Returns whether font rendering with this context should
      round glyph positions and widths.
      Returns:

    • getSerial

      public int getSerial()
      Returns the current serial number of @context.

      The serial number is initialized to an small number larger than zero
      when a new context is created and is increased whenever the context
      is changed using any of the setter functions, or the `PangoFontMap` it
      uses to find fonts has changed. The serial may wrap, but will never
      have the value 0. Since it can wrap, never compare it with "less than",
      always use "not equals".

      This can be used to automatically detect changes to a `PangoContext`,
      and is only useful when implementing objects that need update when their
      `PangoContext` changes, like `PangoLayout`.
      Returns:
      The current serial number of @context.

    • loadFont

      public Font loadFont(@Nonnull FontDescription desc)
      Loads the font in one of the fontmaps in the context
      that is the closest match for @desc.
      Parameters:
      desc - a `PangoFontDescription` describing the font to load
      Returns:
      the newly allocated `PangoFont` that was loaded, or %NULL if no font matched.

    • loadFontset

      public Fontset loadFontset(@Nonnull FontDescription desc, @Nonnull Language language)
      Load a set of fonts in the context that can be used to render
      a font matching @desc.
      Parameters:
      desc - a `PangoFontDescription` describing the fonts to load
      language - a `PangoLanguage` the fonts will be used for
      Returns:
      the newly allocated `PangoFontset` loaded, or %NULL if no font matched.

    • setBaseDir

      public void setBaseDir(int direction)
      Sets the base direction for the context.

      The base direction is used in applying the Unicode bidirectional
      algorithm; if the @direction is %PANGO_DIRECTION_LTR or
      %PANGO_DIRECTION_RTL, then the value will be used as the paragraph
      direction in the Unicode bidirectional algorithm. A value of
      %PANGO_DIRECTION_WEAK_LTR or %PANGO_DIRECTION_WEAK_RTL is used only
      for paragraphs that do not contain any strong characters themselves.
      Parameters:
      direction - the new base direction

    • setBaseGravity

      public void setBaseGravity(int gravity)
      Sets the base gravity for the context.

      The base gravity is used in laying vertical text out.
      Parameters:
      gravity - the new base gravity

    • setFontDescription

      public void setFontDescription(@Nullable FontDescription desc)
      Set the default font description for the context
      Parameters:
      desc - the new pango font description

    • setFontMap

      public void setFontMap(@Nullable FontMap font_map)
      Sets the font map to be searched when fonts are looked-up
      in this context.

      This is only for internal use by Pango backends, a `PangoContext`
      obtained via one of the recommended methods should already have a
      suitable font map.
      Parameters:
      font_map - the `PangoFontMap` to set.

    • setGravityHint

      public void setGravityHint(int hint)
      Sets the gravity hint for the context.

      The gravity hint is used in laying vertical text out, and
      is only relevant if gravity of the context as returned by
      [method@Pango.Context.get_gravity] is set to %PANGO_GRAVITY_EAST
      or %PANGO_GRAVITY_WEST.
      Parameters:
      hint - the new gravity hint

    • setLanguage

      public void setLanguage(@Nullable Language language)
      Sets the global language tag for the context.

      The default language for the locale of the running process
      can be found using [func@Pango.Language.get_default].
      Parameters:
      language - the new language tag.

    • setMatrix

      public void setMatrix(@Nullable Matrix matrix)
      Sets the transformation matrix that will be applied when rendering
      with this context.

      Note that reported metrics are in the user space coordinates before
      the application of the matrix, not device-space coordinates after the
      application of the matrix. So, they don't scale with the matrix, though
      they may change slightly for different matrices, depending on how the
      text is fit to the pixel grid.
      Parameters:
      matrix - a `PangoMatrix`, or %NULL to unset any existing matrix. (No matrix set is the same as setting the identity matrix.)

    • setRoundGlyphPositions

      public void setRoundGlyphPositions(boolean round_positions)
      Sets whether font rendering with this context should
      round glyph positions and widths to integral positions,
      in device units.

      This is useful when the renderer can't handle subpixel
      positioning of glyphs.

      The default value is to round glyph positions, to remain
      compatible with previous Pango behavior.
      Parameters:
      round_positions - whether to round glyph positions

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()