Module Functions and Constants

Module Functions

cairo.cairo_version()
Returns:the encoded version
Return type:int

Returns the version of the underlying C cairo library, encoded in a single integer.

cairo.cairo_version_string()
Returns:the encoded version
Return type:str

Returns the version of the underlying C cairo library as a human-readable string of the form “X.Y.Z”.

Module Constants

cairo.version
the pycairo version, as a string
cairo.version_info
the pycairo version, as a tuple

cairo.HAS

cairo.HAS_ATSUI_FONT
cairo.HAS_FT_FONT
cairo.HAS_GLITZ_SURFACE
cairo.HAS_IMAGE_SURFACE
cairo.HAS_PDF_SURFACE
cairo.HAS_PNG_FUNCTIONS
cairo.HAS_PS_SURFACE
cairo.HAS_SVG_SURFACE
cairo.HAS_USER_FONT
cairo.HAS_QUARTZ_SURFACE
cairo.HAS_WIN32_FONT
cairo.HAS_WIN32_SURFACE
cairo.HAS_XCB_SURFACE
cairo.HAS_XLIB_SURFACE
1 if the feature is present in the underlying C cairo library, 0 otherwise

cairo.ANTIALIAS

ANTIALIAS specifies the type of antialiasing to do when rendering text or shapes.

cairo.ANTIALIAS_DEFAULT
Use the default antialiasing for the subsystem and target device
cairo.ANTIALIAS_NONE
Use a bilevel alpha mask
cairo.ANTIALIAS_GRAY
Perform single-color antialiasing (using shades of gray for black text on a white background, for example).
cairo.ANTIALIAS_SUBPIXEL
Perform antialiasing by taking advantage of the order of subpixel elements on devices such as LCD panels.

cairo.CONTENT

These constants are used to describe the content that a Surface will contain, whether color information, alpha information (translucence vs. opacity), or both.

cairo.CONTENT_COLOR
The surface will hold color content only.
cairo.CONTENT_ALPHA
The surface will hold alpha content only.
cairo.CONTENT_COLOR_ALPHA
The surface will hold color and alpha content.

cairo.EXTEND

These constants are used to describe how Pattern color/alpha will be determined for areas “outside” the pattern’s natural area, (for example, outside the surface bounds or outside the gradient geometry).

The default extend mode is EXTEND_NONE for SurfacePattern and EXTEND_PAD for Gradient patterns.

cairo.EXTEND_NONE
pixels outside of the source pattern are fully transparent
cairo.EXTEND_REPEAT
the pattern is tiled by repeating
cairo.EXTEND_REFLECT
the pattern is tiled by reflecting at the edges (Implemented for surface patterns since 1.6)
cairo.EXTEND_PAD
pixels outside of the pattern copy the closest pixel from the source (Since 1.2; but only implemented for surface patterns since 1.6)

New entries may be added in future versions.

cairo.FILL_RULE

These constants are 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.)

The default fill rule is FILL_RULE_WINDING.

cairo.FILL_RULE_WINDING
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.
cairo.FILL_RULE_EVEN_ODD
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.

New entries may be added in future versions.

cairo.FILTER

These constants are used to indicate what filtering should be applied when reading pixel values from patterns. See SurfacePattern.set_filter() for indicating the desired filter to be used with a particular pattern.

cairo.FILTER_FAST
A high-performance filter, with quality similar FILTER_NEAREST
cairo.FILTER_GOOD
A reasonable-performance filter, with quality similar to FILTER_BILINEAR
cairo.FILTER_BEST
The highest-quality available, performance may not be suitable for interactive use.
cairo.FILTER_NEAREST
Nearest-neighbor filtering
cairo.FILTER_BILINEAR
Linear interpolation in two dimensions
cairo.FILTER_GAUSSIAN
This filter value is currently unimplemented, and should not be used in current code.

cairo.FONT_SLANT

These constants specify variants of a FontFace based on their slant.

cairo.FONT_SLANT_NORMAL
Upright font style
cairo.FONT_SLANT_ITALIC
Italic font style
cairo.FONT_SLANT_OBLIQUE
Oblique font style

cairo.FONT_WEIGHT

These constants specify variants of a FontFace based on their weight.

cairo.FONT_WEIGHT_NORMAL
Normal font weight
cairo.FONT_WEIGHT_BOLD
Bold font weight

cairo.FORMAT

These constants are used to identify the memory format of ImageSurface data.

cairo.FORMAT_ARGB32
each pixel is a 32-bit quantity, with alpha in the upper 8 bits, then red, then green, then blue. The 32-bit quantities are stored native-endian. Pre-multiplied alpha is used. (That is, 50% transparent red is 0x80800000, not 0x80ff0000.)
cairo.FORMAT_RGB24
each pixel is a 32-bit quantity, with the upper 8 bits unused. Red, Green, and Blue are stored in the remaining 24 bits in that order.
cairo.FORMAT_A8
each pixel is a 8-bit quantity holding an alpha value.
cairo.FORMAT_A1
each pixel is a 1-bit quantity holding an alpha value. Pixels are packed together into 32-bit quantities. The ordering of the bits matches the endianess of the platform. On a big-endian machine, the first pixel is in the uppermost bit, on a little-endian machine the first pixel is in the least-significant bit.

New entries may be added in future versions.

cairo.HINT_METRICS

These constants specify whether to hint font metrics; hinting font metrics means quantizing them so that they are integer values in device space. Doing this improves the consistency of letter and line spacing, however it also means that text will be laid out differently at different zoom factors.

cairo.HINT_METRICS_DEFAULT
Hint metrics in the default manner for the font backend and target device
cairo.HINT_METRICS_OFF
Do not hint font metrics
cairo.HINT_METRICS_ON
Hint font metrics

cairo.HINT_STYLE

These constants specify the type of hinting to do on font outlines. Hinting is the process of fitting outlines to the pixel grid in order to improve the appearance of the result. Since hinting outlines involves distorting them, it also reduces the faithfulness to the original outline shapes. Not all of the outline hinting styles are supported by all font backends.

cairo.HINT_STYLE_DEFAULT
Use the default hint style for font backend and target device
cairo.HINT_STYLE_NONE
Do not hint outlines
cairo.HINT_STYLE_SLIGHT
Hint outlines slightly to improve contrast while retaining good fidelity to the original shapes.
cairo.HINT_STYLE_MEDIUM
Hint outlines with medium strength giving a compromise between fidelity to the original shapes and contrast
cairo.HINT_STYLE_FULL
Hint outlines to maximize contrast

New entries may be added in future versions.

cairo.LINE_CAP

These constants specify how to render the endpoints of the path when stroking.

The default line cap style is LINE_CAP_BUTT

cairo.LINE_CAP_BUTT
start(stop) the line exactly at the start(end) point
cairo.LINE_CAP_ROUND
use a round ending, the center of the circle is the end point
cairo.LINE_CAP_SQUARE
use squared ending, the center of the square is the end point

cairo.LINE_JOIN

These constants specify how to render the junction of two lines when stroking.

The default line join style is LINE_JOIN_MITER

cairo.LINE_JOIN_MITER
use a sharp (angled) corner, see Context.set_miter_limit()
cairo.LINE_JOIN_ROUND
use a rounded join, the center of the circle is the joint point
cairo.LINE_JOIN_BEVEL
use a cut-off join, the join is cut off at half the line width from the joint point

cairo.OPERATOR

These constants are used to set the compositing operator for all cairo drawing operations.

The default operator is OPERATOR_OVER.

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.

cairo.OPERATOR_CLEAR
clear destination layer (bounded)
cairo.OPERATOR_SOURCE
replace destination layer (bounded)
cairo.OPERATOR_OVER
draw source layer on top of destination layer (bounded)
cairo.OPERATOR_IN
draw source where there was destination content (unbounded)
cairo.OPERATOR_OUT
draw source where there was no destination content (unbounded)
cairo.OPERATOR_ATOP
draw source on top of destination content and only there
cairo.OPERATOR_DEST
ignore the source
cairo.OPERATOR_DEST_OVER
draw destination on top of source
cairo.OPERATOR_DEST_IN
leave destination only where there was source content (unbounded)
cairo.OPERATOR_DEST_OUT
leave destination only where there was no source content
cairo.OPERATOR_DEST_ATOP
leave destination on top of source content and only there (unbounded)
cairo.OPERATOR_XOR
source and destination are shown where there is only one of them
cairo.OPERATOR_ADD
source and destination layers are accumulated
cairo.OPERATOR_SATURATE
like over, but assuming source and dest are disjoint geometries

cairo.PATH

These constants are used to describe the type of one portion of a path when represented as a Path.

cairo.PATH_MOVE_TO
A move-to operation
cairo.PATH_LINE_TO
A line-to operation
cairo.PATH_CURVE_TO
A curve-to operation
cairo.PATH_CLOSE_PATH
A close-path operation

cairo.PS_LEVEL

These constants are used to describe the language level of the PostScript Language Reference that a generated PostScript file will conform to. Note: the constants are only defined when cairo has been compiled with PS support enabled.

cairo.PS_LEVEL_2
The language level 2 of the PostScript specification.
cairo.PS_LEVEL_3
The language level 3 of the PostScript specification.

cairo.SUBPIXEL_ORDER

The subpixel order specifies the order of color elements within each pixel on the display device when rendering with an antialiasing mode of ANTIALIAS_SUBPIXEL.

cairo.SUBPIXEL_ORDER_DEFAULT
Use the default subpixel order for for the target device
cairo.SUBPIXEL_ORDER_RGB
Subpixel elements are arranged horizontally with red at the left
cairo.SUBPIXEL_ORDER_BGR
Subpixel elements are arranged horizontally with blue at the left
cairo.SUBPIXEL_ORDER_VRGB
Subpixel elements are arranged vertically with red at the top
cairo.SUBPIXEL_ORDER_VBGR
Subpixel elements are arranged vertically with blue at the top