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Cairo(3pm) |
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Cairo − Perl interface to the cairo library
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;
$surface−>write_to_png ('output.png');
Cairo provides Perl bindings for the vector graphics library cairo. It supports multiple output targets, including PNG , PDF and SVG . Cairo produces identical output on all those targets.
This is a listing of the API Cairo provides. For more verbose information, refer to the cairo manual at <http://cairographics.org/manual/>.
Drawing
Cairo::Context -- The cairo drawing context
Cairo::Context is the main object used when drawing with Cairo. To draw with Cairo, you create a Cairo::Context, set the target surface, and drawing options for the Cairo::Context, create shapes with methods like "$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−>push_group [1.2]
$cr−>push_group_with_content ($content) [1.2]
$content: Cairo::Content
$pattern =
$cr−>pop_group [1.2]
$cr−>pop_group_to_source [1.2]
$surface = $cr−>get_group_target [1.2]
$cr−>set_source_rgb ($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
$fill_rule =
$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)
$limit: double
($offset, @dashes) =
$cr−>get_dash [1.4]
$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
$cr−>clip_preserve
($x1, $y1, $x2, $y2) = $cr−>clip_extents [1.4]
@rectangles = $cr−>copy_clip_rectangle_list [1.4]
$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
$bool =
$cr−>has_current_point [1.6]
($x, $y) = $cr−>get_current_point
$cr−>new_path
$cr−>new_sub_path [1.2]
$cr−>close_path
($x1, $y1, $x2, $y2) = $cr−>path_extents [1.6]
$cr−>arc ($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
$type = $pattern−>get_type [1.2]
$pattern−>set_extend ($extend)
$extend: Cairo::Extend
$extend =
$pattern−>get_extend
$pattern−>set_filter ($filter)
$filter: Cairo::Filter
$filter =
$pattern−>get_filter
$pattern−>set_matrix ($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
$alpha: double
($r, $g, $b, $a) =
$pattern−>get_rgba [1.4]
$pattern = Cairo::SurfacePattern−>create
($surface)
$surface: Cairo::Surface
$surface =
$pattern−>get_surface [1.4]
$pattern = Cairo::LinearGradient−>create ($x0, $y0,
$x1, $y1)
$x0: double
$y0: double
$x1: double
$y1: double
($x0, $y0, $x1, $y1) =
$pattern−>get_points [1.4]
$pattern = Cairo::RadialGradient−>create ($cx0,
$cy0, $radius0, $cx1,
$cy1, $radius1)
$cx0: double
$cy0: double
$radius0: double
$cx1: double
$cy1: double
$radius1: double
($x0, $y0, $r0, $x1, $y1, $r1)
= $pattern−>get_circles [1.4]
$pattern−>add_color_stop_rgb ($offset, $red,
$green, $blue)
$offset: double
$red: double
$green: double
$blue: double
$pattern−>add_color_stop_rgba ($offset, $red, $green, $blue, $alpha)
$offset: double
$red: double
$green: double
$blue: double
$alpha: double
@stops = $pattern−>get_color_stops [1.4]
A color stop is represented as an array reference with five elements: offset, red, green, blue, and alpha.
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
$cr−>set_scaled_font ($scaled_font) [1.2]
$scaled_font: Cairo::ScaledFont
$scaled_font =
$cr−>get_scaled_font [1.4]
$cr−>show_text ($utf8)
$utf8: string
$cr−>show_glyphs (...)
...: list of glyphs
$cr−>show_text_glyphs ($utf8, $glyphs, $clusters, $cluster_flags) [1.8]
$utf8: string
$glyphs: array ref of glyphs
$clusters: array ref of clusters
$cluster_flags: Cairo::TextClusterFlags
$face =
$cr−>get_font_face
$extents = $cr−>font_extents
$cr−>set_font_face ($font_face)
$font_face: Cairo::FontFace
$cr−>set_scaled_font ($scaled_font)
$scaled_font: Cairo::ScaledFont
$extents = $cr−>text_extents ($utf8)
$utf8: string
$extents = $cr−>glyph_extents (...)
...: list of glyphs
Fonts
Cairo::FontFace -- Base class for fonts
$status = $font_face−>status
$type = $font_face−>get_type [1.2]
Scaled Fonts
-- Caching metrics for a particular font size
$scaled_font = Cairo::ScaledFont−>create
($font_face, $font_matrix,
$ctm, $options)
$font_face:
Cairo::FontFace
$font_matrix: Cairo::Matrix
$ctm: Cairo::Matrix
$options: Cairo::FontOptions
$status =
$scaled_font−>status
$extents = $scaled_font−>extents
$extents = $scaled_font−>text_extents ($utf8)
[1.2]
$utf8: string
$extents = $scaled_font−>glyph_extents (...)
...: list of glyphs
($status, $glyphs, $clusters,
$cluster_flags) =
$scaled_font−>text_to_glyphs ($x, $y, $utf8)
[1.8]
$x: double
$y: double
$utf8: string
$font_face =
$scaled_font−>get_font_face [1.2]
$options = $scaled_font−>get_font_options [1.2]
$font_matrix = $scaled_font−>get_font_matrix [1.2]
$ctm = $scaled_font−>get_ctm [1.2]
$scale_matrix = $scaled_font−>get_scale_matrix
[1.8]
$type = $scaled_font−>get_type [1.2]
Font Options
-- How a font should be rendered
$font_options = Cairo::FontOptions−>create
$status = $font_options−>status
$font_options−>merge ($other)
$other: Cairo::FontOptions
$hash =
$font_options−>hash
$bools = $font_options−>equal ($other)
$other: Cairo::FontOptions
$font_options−>set_antialias ($antialias)
$antialias: Cairo::AntiAlias
$antialias =
$font_options−>get_antialias
$font_options−>set_subpixel_order
($subpixel_order)
$subpixel_order: Cairo::SubpixelOrder
$subpixel_order =
$font_options−>get_subpixel_order
$font_options−>set_hint_style ($hint_style)
$hint_style: Cairo::HintStyle
$hint_style =
$font_options−>get_hint_style
$font_options−>set_hint_metrics ($hint_metrics)
$hint_metrics: Cairo::HintMetrics
$hint_metrics = $font_options−>get_hint_metrics
FreeType Fonts -- Font support for FreeType
If your cairo
library supports it, the FreeType integration allows you to
load font faces from font files. You can query for this
capability with "Cairo::HAS_FT_FONT". To
actually use this, you’ll need the Font::FreeType
module.
my $face = Cairo::FtFontFace−>create ($ft_face,
$load_flags=0)
$ft_face:
Font::FreeType::Face
$load_flags: integer
This method allows you to create a Cairo::FontFace from a Font::FreeType::Face. To obtain the latter, you can for example load it from a file:
my $file = '/usr/share/fonts/truetype/ttf−bitstream−vera/Vera.ttf'; my $ft_face = Font::FreeType−>new−>face ($file); my $face = Cairo::FtFontFace−>create ($ft_face);
Surfaces
Cairo::Surface -- Base class for surfaces
$new = $old−>create_similar ($content, $width,
$height)
$content: Cairo::Content
$width: integer
$height: integer
$status =
$surface−>status
$surface−>finish
$surface−>flush
$font_options = $surface−>get_font_options
$content = $surface−>get_content [1.2]
$surface−>mark_dirty
$surface−>mark_dirty_rectangle ($x, $y, $width,
$height)
$x: integer
$y: integer
$width: integer
$height: integer
$surface−>set_device_offset ($x_offset, $y_offset)
$x_offset: integer
$y_offset: integer
($x_offset, $y_offset) =
$surface−>get_device_offset [1.2]
$surface−>set_fallback_resolution
($x_pixels_per_inch,
$y_pixels_per_inch) [1.2]
$x_pixels_per_inch: double
$y_pixels_per_inch: double
($x_pixels_per_inch,
$y_pixels_per_inch) =
$surface−>get_fallback_resolution [1.8]
$type = $surface−>get_type [1.2]
$status = $surface−>copy_page [1.6]
$status: Cairo::Status
$status = $surface−>show_page [1.6]
$status: Cairo::Status
$boolean = $surface−>has_show_text_glyphs [1.8]
Image
Surfaces -- Rendering to memory buffers
$surface = Cairo::ImageSurface−>create ($format,
$width, $height)
$format: Cairo::Format
$width: integer
$height: integer
$surface =
Cairo::ImageSurface−>create_for_data ($data,
$format,
$width, $height, $stride)
$data: image data
$format: Cairo::Format
$width: integer
$height: integer
$stride: integer
$data =
$surface−>get_data [1.2]
$format = $surface−>get_format [1.2]
$width = $surface−>get_width
$height = $surface−>get_height
$stride = $surface−>get_stride [1.2]
PDF
Surfaces -- Rendering PDF documents
$surface = Cairo::PdfSurface−>create ($filename,
$width_in_points,
$height_in_points) [1.2]
$filename: string
$width_in_points: double
$height_in_points: double
$surface =
Cairo::PdfSurface−>create_for_stream ($callback,
$callback_data, $width_in_points, $height_in_points)
[1.2]
$callback: Cairo::WriteFunc
$callback_data: scalar
$width_in_points: double
$height_in_points: double
$surface−>set_size ($width_in_points, $height_in_points) [1.2]
$width_in_points: double
$height_in_points: double
PNG
Support -- Reading and writing PNG images
$surface = Cairo::ImageSurface−>create_from_png
($filename)
$filename: string
Cairo::ReadFunc: $data = sub { my ($callback_data, $length) = @_; }
$data: binary image data, of
length $length
$callback_data: scalar, user data
$length: integer, bytes to read
$surface =
Cairo::ImageSurface−>create_from_png_stream
($callback,
$callback_data)
$callback: Cairo::ReadFunc
$callback_data: scalar
$status = $surface−>write_to_png ($filename)
$filename: string
Cairo::WriteFunc: sub { my ($callback_data, $data) = @_; }
$callback_data: scalar, user
data
$data: binary image data, to be written
$status = $surface−>write_to_png_stream ($callback, $callback_data)
$callback: Cairo::WriteFunc
$callback_data: scalar
PostScript
Surfaces -- Rendering PostScript documents
$surface = Cairo::PsSurface−>create ($filename,
$width_in_points,
$height_in_points) [1.2]
$filename: string
$width_in_points: double
$height_in_points: double
$surface =
Cairo::PsSurface−>create_for_stream ($callback,
$callback_data, $width_in_points, $height_in_points)
[1.2]
$callback: Cairo::WriteFunc
$callback_data: scalar
$width_in_points: double
$height_in_points: double
$surface−>set_size ($width_in_points, $height_in_points) [1.2]
$width_in_points: double
$height_in_points: double
$surface−>dsc_begin_setup
[1.2]
$surface−>dsc_begin_page_setup [1.2]
$surface−>dsc_comment ($comment) [1.2]
$comment: string
$surface−>restrict_to_level ($level) [1.6]
$level: Cairo::PsLevel
@levels =
Cairo::PsSurface::get_levels [1.6]
$string = Cairo::PsSurface::level_to_string ($level)
[1.6]
$level: Cairo::PsLevel
$surface−>set_eps ($eps) [1.6]
$eps: boolean
$eps = $surface−>get_eps [1.6]
SVG
Surfaces -- Rendering SVG documents
$surface = Cairo::SvgSurface−>create ($filename,
$width_in_points,
$height_in_points) [1.2]
$filename: string
$width_in_points: double
$height_in_points: double
$surface =
Cairo::SvgSurface−>create_for_stream ($callback,
$callback_data, $width_in_points, $height_in_points)
[1.2]
$callback: Cairo::WriteFunc
$callback_data: scalar
$width_in_points: double
$height_in_points: double
$surface−>restrict_to_version ($version) [1.2]
$version: Cairo::SvgVersion
@versions =
Cairo::SvgSurface::get_versions [1.2]
$string = Cairo::SvgSurface::version_to_string ($version)
[1.2]
$version: Cairo::SvgVersion
Utilities
Version Information -- Run-time and compile-time version
checks.
$version = Cairo−>version
$string = Cairo−>version_string
$version_code = Cairo−> VERSION
$version_code = Cairo−>
VERSION_ENCODE ($major, $minor, $micro)
$major: integer
$minor: integer
$micro: integer
$stride = Cairo::Format::stride_for_width ($format, $width) [1.6]
$format: Cairo::Format
$width: integer
<http://cairographics.org/documentation>
Lists many available resources including tutorials and examples
<http://cairographics.org/manual/>
Contains the reference manual
Ross McFarland
<rwmcfa1 at neces dot com>
Torsten Schoenfeld <kaffeetisch at gmx dot de>
Copyright (C) 2004−2009 by the cairo perl team
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Cairo(3pm) | |