cairo-cairo-t             package:RGtk2             R Documentation

_c_a_i_r_o__t

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

     The cairo drawing context

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

     'cairoCreate(target)'
      'cairoStatus(cr)'
      'cairoSave(cr)'
      'cairoRestore(cr)'
      'cairoGetTarget(cr)'
      'cairoPushGroup(cr)'
      'cairoPushGroupWithContent(cr, content)'
      'cairoPopGroup(cr)'
      'cairoPopGroupToSource(cr)'
      'cairoGetGroupTarget(cr)'
      'cairoSetSourceRgb(cr, red, green, blue)'
      'cairoSetSourceRgba(cr, red, green, blue, alpha)'
      'cairoSetSource(cr, source)'
      'cairoSetSourceSurface(cr, surface, x, y)'
      'cairoGetSource(cr)'
      'cairoSetAntialias(cr, antialias)'
      'cairoGetAntialias(cr)'
      'cairoSetDash(cr, dashes, offset)'
      'cairoGetDashCount(cr)'
      'cairoGetDash(cr)'
      'cairoSetFillRule(cr, fill.rule)'
      'cairoGetFillRule(cr)'
      'cairoSetLineCap(cr, line.cap)'
      'cairoGetLineCap(cr)'
      'cairoSetLineJoin(cr, line.join)'
      'cairoGetLineJoin(cr)'
      'cairoSetLineWidth(cr, width)'
      'cairoGetLineWidth(cr)'
      'cairoSetMiterLimit(cr, limit)'
      'cairoGetMiterLimit(cr)'
      'cairoSetOperator(cr, op)'
      'cairoGetOperator(cr)'
      'cairoSetTolerance(cr, tolerance)'
      'cairoGetTolerance(cr)'
      'cairoClip(cr)'
      'cairoClipPreserve(cr)'
      'cairoClipExtents(cr)'
      'cairoResetClip(cr)'
      'cairoCopyClipRectangleList(cr)'
      'cairoFill(cr)'
      'cairoFillPreserve(cr)'
      'cairoFillExtents(cr)'
      'cairoInFill(cr, x, y)'
      'cairoMask(cr, pattern)'
      'cairoMaskSurface(cr, surface, surface.x, surface.y)'
      'cairoPaint(cr)'
      'cairoPaintWithAlpha(cr, alpha)'
      'cairoStroke(cr)'
      'cairoStrokePreserve(cr)'
      'cairoStrokeExtents(cr)'
      'cairoInStroke(cr, x, y)'
      'cairoCopyPage(cr)'
      'cairoShowPage(cr)'
      'cairoSetUserData(cr, key, user.data)'
      'cairoGetUserData(cr, key)'
      'cairo(target)'

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

     'Cairo' is the main object used when drawing with cairo. To draw
     with cairo, you create a 'Cairo', set the target surface, and
     drawing options for the 'Cairo', create shapes with functions like
     'cairoMoveTo' and 'cairoLineTo', and then draw shapes with
     'cairoStroke' or 'cairoFill'. 'Cairo''s can be pushed to a stack
     via 'cairoSave'. They may then safely be changed, without loosing
     the current state. Use 'cairoRestore' to restore to the saved
     state.

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


     '_C_a_i_r_o' A 'Cairo' contains the current state of the rendering
          device, including coordinates of yet to be drawn shapes.

          Cairo contexts, as 'Cairo' objects are named, are central to
          cairo and all drawing with cairo is always done to a 'Cairo'
          object.

          Memory management of 'Cairo' is done with 'cairoReference()'
          and 'cairoDestroy()'.  


     '_C_a_i_r_o_R_e_c_t_a_n_g_l_e' A data structure for holding a rectangle.  

          Since  1.4 *'CairoRectangle' is a transparent-type.*

          '_x' [numeric]  X coordinate of the left side of the rectangle

          '_y' [numeric]  Y coordinate of the the top side of the
               rectangle

          '_w_i_d_t_h' [numeric]  width of the rectangle

          '_h_e_i_g_h_t' [numeric]  height of the rectangle


     '_C_a_i_r_o_R_e_c_t_a_n_g_l_e_L_i_s_t' A data structure for holding a dynamically
          allocated array of rectangles.  

          Since  1.4 *'CairoRectangleList' is a transparent-type.*

          '_s_t_a_t_u_s' ['CairoStatus']  Error status of the rectangle list

          '_r_e_c_t_a_n_g_l_e_s' ['CairoRectangle']  list containing the
               rectangles

          '_n_u_m__r_e_c_t_a_n_g_l_e_s' [integer]  Number of rectangles in this list


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

     'cairo' is the equivalent of 'cairoCreate'.

_E_n_u_m_s _a_n_d _F_l_a_g_s:


     '_C_a_i_r_o_A_n_t_i_a_l_i_a_s' Specifies the type of antialiasing to do when
          rendering text or shapes.  

          '_d_e_f_a_u_l_t' Use the default antialiasing for the subsystem and
               target device

          '_n_o_n_e' Use a bilevel alpha mask

          '_g_r_a_y' Perform single-color antialiasing (using shades of
               gray for black text on a white background, for example).

          '_s_u_b_p_i_x_e_l' Perform antialiasing by taking advantage of the
               order of subpixel elements on devices such as LCD panels


     '_C_a_i_r_o_F_i_l_l_R_u_l_e' 'CairoFillRule' is used to select how paths are
          filled. For both fill rules, whether or not a point is
          included in the fill is determined by taking a ray from that
          point to infinity and looking at intersections with the path.
          The ray can be in any direction, as long as it doesn't pass
          through the end point of a segment or have a tricky
          intersection such as intersecting tangent to the path. (Note
          that filling is not actually implemented in this way. This is
          just a description of the rule that is applied.)

          New entries may be added in future versions.  

          '_w_i_n_d_i_n_g' If the path crosses the ray from left-to-right,
               counts +1. If the path crosses the ray from right to
               left, counts -1. (Left and right are determined from the
               perspective of looking along the ray from the starting
               point.) If the total count is non-zero, the point will
               be filled.

          '_e_v_e_n-_o_d_d' Counts the total number of intersections, without
               regard to the orientation of the contour. If the total
               number of intersections is odd, the point will be
               filled.


     '_C_a_i_r_o_L_i_n_e_C_a_p' Specifies how to render the endpoint of a line when
          stroking.  

          '_b_u_t_t' start(stop) the line exactly at the start(end) point

          '_r_o_u_n_d' use a round ending, the center of the circle is the
               end point

          '_s_q_u_a_r_e' use squared ending, the center of the square is the
               end point


     '_C_a_i_r_o_L_i_n_e_J_o_i_n' Specifies how to render the junction of two lines
          when stroking.  

          '_m_i_t_e_r' use a sharp (angled) corner, see 'cairoSetMiterLimit'

          '_r_o_u_n_d' use a rounded join, the center of the circle is the
               joint point

          '_b_e_v_e_l' use a cut-off join, the join is cut off at half the
               line width from the joint point


     '_C_a_i_r_o_O_p_e_r_a_t_o_r' 'CairoOperator' is used to set the compositing
          operator for all cairo drawing operations.

          The operators marked as unbounded modify their destination
          even outside of the mask layer (that is, their effect is not
          bound by the mask layer).  However, their effect can still be
          limited by way of clipping.

          To keep things simple, the operator descriptions here
          document the behavior for when both source and destination
          are either fully transparent or fully opaque.  The actual
          implementation works for translucent layers too. For a more
          detailed explanation of the effects of each operator,
          including the mathematical definitions, see
          http://cairographics.org/operators/ (<URL:
          http://cairographics.org/operators/>).  

          '_c_l_e_a_r' clear destination layer (bounded)

          '_s_o_u_r_c_e' replace destination layer (bounded)

          '_o_v_e_r' draw source layer on top of destination layer
               (bounded)

          '_i_n' draw source where there was destination content
               (unbounded)

          '_o_u_t' draw source where there was no destination content
               (unbounded)

          '_a_t_o_p' draw source on top of destination content and only
               there

          '_d_e_s_t' ignore the source

          '_d_e_s_t-_o_v_e_r' draw destination on top of source

          '_d_e_s_t-_i_n' leave destination only where there was source
               content (unbounded)

          '_d_e_s_t-_o_u_t' leave destination only where there was no source
               content

          '_d_e_s_t-_a_t_o_p' leave destination on top of source content and
               only there (unbounded)

          '_x_o_r' source and destination are shown where there is only
               one of them

          '_a_d_d' source and destination layers are accumulated

          '_s_a_t_u_r_a_t_e' like over, but assuming source and dest are
               disjoint geometries


_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-cairo-t.html>

