cairo-Scaled-Fonts           package:RGtk2           R Documentation

_c_a_i_r_o__s_c_a_l_e_d__f_o_n_t__t

_D_e_s_c_r_i_p_t_i_o_n:

     Font face at particular size and options

_M_e_t_h_o_d_s _a_n_d _F_u_n_c_t_i_o_n_s:

     'cairoScaledFontCreate(font.face, font.matrix, ctm, option)'
      'cairoScaledFontStatus(scaled.font)'
      'cairoScaledFontExtents(scaled.font)'
      'cairoScaledFontTextExtents(scaled.font, utf8)'
      'cairoScaledFontGlyphExtents(scaled.font, glyphs, num.glyphs)'
      'cairoScaledFontGetFontFace(scaled.font)'
      'cairoScaledFontGetFontOptions(scaled.font)'
      'cairoScaledFontGetFontMatrix(scaled.font)'
      'cairoScaledFontGetCtm(scaled.font)'
      'cairoScaledFontGetType(scaled.font)'
      'cairoScaledFontSetUserData(scaled.font, key, user.data)'
      'cairoScaledFontGetUserData(scaled.font, key)'
      'cairoScaledFont(font.face, font.matrix, ctm, option)'

_D_e_t_a_i_l_e_d _D_e_s_c_r_i_p_t_i_o_n:

     'CairoScaledFont' represents a realization of a font face at a
     particular size and transformation and a certain set of font
     options.

_S_t_r_u_c_t_u_r_e_s:


     '_C_a_i_r_o_S_c_a_l_e_d_F_o_n_t' A 'CairoScaledFont' is a font scaled to a
          particular size and device resolution. A 'CairoScaledFont' is
          most useful for low-level font usage where a library or
          application wants to cache a reference to a scaled font to
          speed up the computation of metrics.

          There are various types of scaled fonts, depending on the
          font backend they use. The type of a scaled font can be
          queried using 'cairoScaledFontGetType'.

          Memory management of 'CairoScaledFont' is done with
          'cairoScaledFontReference()' and 'cairoScaledFontDestroy()'.  


     '_C_a_i_r_o_F_o_n_t_E_x_t_e_n_t_s' The 'CairoFontExtents' structure stores metric
          information for a font. Values are given in the current
          user-space coordinate system.

          Because font metrics are in user-space coordinates, they are
          mostly, but not entirely, independent of the current
          transformation matrix. If you call 'cairo_scale(cr, 2.0,
          2.0)', text will be drawn twice as big, but the reported text
          extents will not be doubled. They will change slightly due to
          hinting (so you can't assume that metrics are independent of
          the transformation matrix), but otherwise will remain
          unchanged.  

          '_a_s_c_e_n_t' [numeric]  the distance that the font extends above
               the baseline. Note that this is not always exactly equal
               to the maximum of the extents of all the glyphs in the
               font, but rather is picked to express the font
               designer's intent as to how the font should align with
               elements above it.

          '_d_e_s_c_e_n_t' [numeric]  the distance that the font extends below
               the baseline. This value is positive for typical fonts
               that include portions below the baseline. Note that this
               is not always exactly equal to the maximum of the
               extents of all the glyphs in the font, but rather is
               picked to express the font designer's intent as to how
               the the font should align with elements below it.

          '_h_e_i_g_h_t' [numeric]  the recommended vertical distance between
               baselines when setting consecutive lines of text with
               the font. This is greater than 'ascent'+'descent' by a
               quantity known as the line spacing or external leading.
               When space is at a premium, most fonts can be set with
               only a distance of 'ascent'+'descent' between lines.

          '_m_a_x_X_A_d_v_a_n_c_e' [numeric]  the maximum distance in the X
               direction that the the origin is advanced for any glyph
               in the font.

          '_m_a_x_Y_A_d_v_a_n_c_e' [numeric]  the maximum distance in the Y
               direction that the the origin is advanced for any glyph
               in the font. this will be zero for normal fonts used for
               horizontal writing. (The scripts of East Asia are
               sometimes written vertically.)


     '_C_a_i_r_o_T_e_x_t_E_x_t_e_n_t_s' The 'CairoTextExtents' structure stores the
          extents of a single glyph or a string of glyphs in user-space
          coordinates. Because text extents are in user-space
          coordinates, they are mostly, but not entirely, independent
          of the current transformation matrix. If you call
          'cairo_scale(cr, 2.0, 2.0)', text will be drawn twice as big,
          but the reported text extents will not be doubled. They will
          change slightly due to hinting (so you can't assume that
          metrics are independent of the transformation matrix), but
          otherwise will remain unchanged.  

          '_x_B_e_a_r_i_n_g' [numeric]  the horizontal distance from the origin
               to the leftmost part of the glyphs as drawn. Positive if
               the glyphs lie entirely to the right of the origin.

          '_y_B_e_a_r_i_n_g' [numeric]  the vertical distance from the origin
               to the topmost part of the glyphs as drawn. Positive
               only if the glyphs lie completely below the origin; will
               usually be negative.

          '_w_i_d_t_h' [numeric]  width of the glyphs as drawn

          '_h_e_i_g_h_t' [numeric]  height of the glyphs as drawn

          '_x_A_d_v_a_n_c_e' [numeric] distance to advance in the X direction
               after drawing these glyphs

          '_y_A_d_v_a_n_c_e' [numeric]  distance to advance in the Y direction
               after drawing these glyphs. Will typically be zero
               except for vertical text layout as found in East-Asian
               languages.


_C_o_n_v_e_n_i_e_n_t _C_o_n_s_t_r_u_c_t_i_o_n:

     'cairoScaledFont' is the equivalent of 'cairoScaledFontCreate'.

_A_u_t_h_o_r(_s):

     Derived by RGtkGen from GTK+ documentation

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://www.cairographics.org/manual/cairo-Scaled-Fonts.html>

