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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;
$surface−>write_to_png ('output.png');
Cairo provides Perl bindings for the vector graphics library cairo. It supports multiple output targets, including PNG , PDF and SVG . Cairo produces identical output on all those targets.
Note that this listing still lacks entries for Cairo::Surfaces and some utility methods.
Drawing
Cairo::Context -- The cairo drawing context
Cairo::Context is the main object used when drawing with Cairo. To draw with Cairo, you create a Cairo::Context, set the target surface, and drawing options for the Cairo::Context, create shapes with methods like "$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. =over
$cr =
Cairo::Context−>create ($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]
$pattern−>set_matrix
($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
$pattern−>set_extend
($extend)
$extend: Cairo::Extend
$extend = $pattern−>get_extend
$pattern−>set_filter
($filter)
$filter: Cairo::Filter
$filter = $pattern−>get_filter
$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
(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
@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
$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
$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]
$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
$type = $surface−>get_type [1.2]
$status
= $surface−>copy_page [1.6]
$status: Cairo::Status
$status
= $surface−>show_page [1.6]
$status: Cairo::Status
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) 2004−2008 by the cairo perl team
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Cairo(3pm) | |