• NAME
• SYNOPSIS
• ABSTRACT
• API DOCUMENTATION
  • Cairo::Context -- The cairo drawing context
  • Paths -- Creating paths and manipulating path data
  • Patterns -- Gradients and filtered sources
  • Transformations -- Manipulating the current transformation matrix
  • Text -- Rendering text and sets of glyphs
• SEE ALSO
• AUTHORS
• COPYRIGHT

NAME

Cairo - Perl interface to the cairo library

SYNOPSIS

  use Cairo;

  my $surface = Cairo::ImageSurface->create ('argb32', 100, 100);
  my $cr = Cairo::Context->create ($surface);

  $cr->rectangle (10, 10, 40, 40);
  $cr->set_source_rgb (0, 0, 0);
  $cr->fill;

  $cr->rectangle (50, 50, 40, 40);
  $cr->set_source_rgb (1, 1, 1);
  $cr->fill;

  $cr->show_page;

  $surface->write_to_png ("output.png");

ABSTRACT

Cairo provides Perl bindings for the vector graphics library cairo. It supports multiple output targets, including the X Window Systems, PDF, and PNG. Cairo produces identical output on all those targets and makes use of hardware acceleration wherever possible.

API DOCUMENTATION

Cairo::Context -- The cairo drawing context

Cairo::Context is the main object used when drawing with Cairo. To draw with Cairo, you create a Cairo::Context, set the target surface, and drawing options for the Cairo::Context, create shapes with methods like $cr-move_to> and $cr->line_to, and then draw shapes with $cr->stroke or $cr->fill.

Cairo::Context's can be pushed to a stack via $cr->save. They may then safely be changed, without loosing the current state. Use $cr->restore to restore to the saved state.

$cr = Cairo::Context->create ($surface)

$surface: Cairo::Surface

$cr->save

$cr->restore

$status = $cr->status

$surface = $cr->get_target

$cr->set_source_rgb ($red, $green, $blue)

$red: double

$green: double

$blue: double

$cr->set_source_rgba ($red, $green, $blue, $alpha)

$red: double

$green: double

$blue: double

$alpha: double

$cr->set_source ($source)

$source: Cairo::Pattern

$cr->set_source_surface ($surface, $x, $y)

$surface: Cairo::Surface

$x: double

$y: double

$source = $cr->get_source ()

$cr->set_antialias ($antialias)

$antialias: Cairo::Antialias

$antialias = $cr->get_antialias

$cr->set_dash ($offset, ...)

$offset: double

...: list of doubles

$cr->set_fill_rule ($fill_rule)

$fill_rule: Cairo::FillRule

$cr->fill_rule_t $cr->get_fill_rule

$cr->set_line_cap ($line_cap)

$line_cap: Cairo::LineCap

$line_cap = $cr->get_line_cap

$cr->set_line_join ($line_join)

$line_join: Cairo::LineJoin

$line_join = $cr->get_line_join

$cr->set_line_width ($width)

$width: double

$width = $cr->get_line_width

$cr->set_miter_limit ($ limit)

$limit: double

$limit = $cr->get_miter_limit

$cr->set_operator ($op)

$op: Cairo::Operator

$op = $cr->get_operator

$cr->set_tolerance ($tolerance)

$tolerance: double

$tolerance = $cr->get_tolerance

$cr->clip

$cr->clip_preserve

$cr->reset_clip

$cr->fill

$cr->fill_preserve

($x1, $y1, $x2, $y2) = $cr->fill_extents

$bool = $cr->in_fill ($x, $y)

$x: double

$y: double

$cr->mask ($pattern)

$pattern: Cairo::Pattern

$cr->mask_surface ($surface, $surface_x, $surface_y)

$surface: Cairo::Surface

$surface_x: double

$surface_y: double

$cr->paint

$cr->paint_with_alpha ($alpha)

$alpha: double

$cr->stroke

$cr->stroke_preserve

($x1, $y1, $x2, $y2) = $cr->stroke_extents

$bool = $cr->in_stroke ($x, $y)

$x: double

$y: double

$cr->copy_page

$cr->show_page

Paths -- Creating paths and manipulating path data

  $path = [
    { type => "move-to", points => [[1, 2]] },
    { type => "line-to", points => [[3, 4]] },
    { type => "curve-to", points => [[5, 6], [7, 8], [9, 10]] },
    ...
    { type => "close-path", points => [] },
  ];

Cairo::Path is a data structure for holding a path. This data structure serves as the return value for $cr->copy_path_data and $cr->copy_path_data_flat as well the input value for $cr->append_path.

Cairo::Path is represented as an array reference that contains path elements, represented by hash references with two keys: type and points. The value for type can be either of the following:

move-to

line-to

curve-to

close-path

The value for points is an array reference which contains zero or more points. Points are represented as array references that contain two doubles: x and y. The necessary number of points depends on the type of the path element:

move-to: 1 point

line_to: 1 point

curve-to: 3 points

close-path: 0 points

The semantics and ordering of the coordinate values are consistent with $cr->move_to, $cr->line_to, $cr->curve_to, and $cr->close_path.

$path = $cr->copy_path

$path = $cr->copy_path_flat

$cr->append_path ($path)

$path: Cairo::Path

($x, $y) = $cr->get_current_point

$cr->new_path

$cr->close_path

$cr->arc ($xc, $yc, $radius, $angle1, $angle2)

$xc: double

$yc: double

$radius: double

$angle1: double

$angle2: double

$cr->arc_negative ($xc, $yc, $radius, $angle1, $angle2)

$xc: double

$yc: double

$radius: double

$angle1: double

$angle2: double

$cr->curve_to ($x1, $y1, $x2, $y2, $x3, $y3)

$x1: double

$y1: double

$x2: double

$y2: double

$x3: double

$y3: double

$cr->line_to ($x, $y)

$x: double

$y: double

$cr->move_to ($x, $y)

$x: double

$y: double

$cr->rectangle ($x, $y, $width, $height)

$x: double

$y: double

$width: double

$height: double

$cr->glyph_path (...)

...: list of Cairo::Glyph's

$cr->text_path ($utf8)

$utf8: string in utf8 encoding

$cr->rel_curve_to ($dx1, $dy1, $dx2, $dy2, $dx3, $dy3)

$dx1: double

$dy1: double

$dx2: double

$dy2: double

$dx3: double

$dy3: double

$cr->rel_line_to ($dx, $dy)

$dx: double

$dy: double

$cr->rel_move_to ($dx, $dy)

$dx: double

$dy: double

Patterns -- Gradients and filtered sources

$status = $pattern->status

$pattern->set_matrix ($matrix)

$matrix: Cairo::Matrix

$matrix = $pattern->get_matrix

$pattern = Cairo::SolidPattern->create_rgb ($red, $green, $blue)

$red: double

$green: double

$blue: double

$pattern = Cairo::SolidPattern->create_rgba ($red, $green, $blue, $alpha)

$red: double

$green: double

$blue: double

$alpha: double

$matrix = $pattern->get_matrix

$pattern = Cairo::SurfacePattern->create ($surface)

$surface: Cairo::Surface

$pattern->set_extend ($extend)

$extend: Cairo::Extend

$extend = $pattern->get_extend

$pattern->set_filter ($filter)

$filter: Cairo::Filter

$filter = $pattern->get_filter

$pattern = Cairo::LinearGradient->create ($x0, $y0, $x1, $y1)

$x0: double

$y0: double

$x1: double

$y1: double

$pattern = Cairo::RadialGradient->create ($cx0, $cy0, $radius0, $cx1, $cy1, $radius1)

$cx0: double

$cy0: double

$radius0: double

$cx1: double

$cy1: double

$radius1: double

$pattern->add_color_stop_rgb (double offset, double red, double green, double blue)

$offset: double

$red: double

$green: double

$blue: double

$pattern->add_color_stop_rgba (double offset, double red, double green, double blue, double alpha)

$offset: double

$red: double

$green: double

$blue: double

$alpha: double

Transformations -- Manipulating the current transformation matrix

$cr->translate ($tx, $ty)

$tx: double

$ty: double

$cr->scale ($sx, $sy)

$sx: double

$sy: double

$cr->rotate ($angle)

$angle: double

$cr->transform ($matrix)

$matrix: Cairo::Matrix

$cr->set_matrix ($matrix)

$matrix: Cairo::Matrix

$matrix = $cr->get_matrix

$cr->identity_matrix

($x, $y) = $cr->user_to_device ($x, $y)

$x: double

$y: double

($dx, $dy) = $cr->user_to_device_distance ($dx, $dy)

$dx: double

$dy: double

($x, $y) = $cr->device_to_user ($x, $y)

$x: double

$y: double

($dx, $dy) = $cr->device_to_user_distance ($dx, $dy)

$dx: double

$dy: double

Text -- Rendering text and sets of glyphs

Glyphs are represented as anonymous hash references with three keys: index, x and y. Example:

  my @glyphs = ({ index => 1, x => 2, y => 3 },
                { index => 2, x => 3, y => 4 },
                { index => 3, x => 4, y => 5 });

$cr->select_font_face ($family, $slant, $weight)

$family: string

$slant: Cairo::FontSlant

$weight: Cairo::FontWeight

$cr->set_font_size ($size)

$size: double

$cr->set_font_matrix ($matrix)

$matrix: Cairo::Matrix

$matrix = $cr->get_font_matrix

$cr->set_font_options ($options)

$options: Cairo::FontOptions

$options = $cr->get_font_options

$cr->show_text ($utf8)

$utf8: string

$cr->show_glyphs (...)

...: list of glyphs

$face = $cr->get_font_face

$extents = $cr->font_extents

$cr->set_font_face ($font_face)

$font_face: Cairo::FontFace

$extents = $cr->text_extents ($utf8)

$utf8: string

$extents = $cr->glyph_extents (...)

...: list of glyphs

SEE ALSO

http://cairographics.org/documentation

Lists many available resources including tutorials and examples

http://cairographics.org/manual/

Contains the reference manual

AUTHORS

Ross McFarland <rwmcfa1 at neces dot com>

Torsten Schoenfeld <kaffeetisch at gmx dot de>

COPYRIGHT

Copyright (C) 2005 by the cairo perl team