cairo-pattern: cairo_pattern_t
In RGtk2: R Bindings for Gtk 2.8.0 and Above

Description Methods and Functions Detailed Description Structures Convenient Construction Enums and Flags Author(s) References

Sources for drawing

cairoPatternAddColorStopRgb(pattern, offset, red, green, blue)
cairoPatternAddColorStopRgba(pattern, offset, red, green, blue, alpha)
cairoPatternGetColorStopCount(pattern)
cairoPatternGetColorStopRgba(pattern, index)
cairoPatternCreateRgb(red, green, blue)
cairoPatternCreateRgba(red, green, blue, alpha)
cairoPatternGetRgba(pattern)
cairoPatternCreateForSurface(surface)
cairoPatternGetSurface(pattern)
cairoPatternCreateLinear(x0, y0, x1, y1)
cairoPatternGetLinearPoints(pattern)
cairoPatternCreateRadial(cx0, cy0, radius0, cx1, cy1, radius1)
cairoPatternGetRadialCircles(pattern)
cairoPatternStatus(pattern)
cairoPatternSetExtend(pattern, extend)
cairoPatternGetExtend(pattern)
cairoPatternSetFilter(pattern, filter)
cairoPatternGetFilter(pattern)
cairoPatternSetMatrix(pattern, matrix)
cairoPatternGetMatrix(pattern, matrix)
cairoPatternGetType(pattern)
cairoPatternSetUserData(pattern, key, user.data)
cairoPatternGetUserData(pattern, key)
cairoPattern(red, green, blue, alpha, surface, x0, y0, x1, y1, cx0, cy0, radius0, cx1, cy1, radius1)

CairoPattern is the paint with which cairo draws. The primary use of patterns is as the source for all cairo drawing operations, although they can also be used as masks, that is, as the brush too.

A cairo pattern is created by using one of the many constructors, of the form cairo_pattern_create_type() or implicitly through cairo_set_source_type() functions.

CairoPattern

A CairoPattern represents a source when drawing onto a surface. There are different subtypes of CairoPattern, for different types of sources; for example, cairoPatternCreateRgb creates a pattern for a solid opaque color.

Other than various cairo_pattern_create_type() functions, some of the pattern types can be implicitly created using various cairo_set_source_type() functions; for example cairoSetSourceRgb.

The type of a pattern can be queried with cairoPatternGetType.

Memory management of CairoPattern is done with cairoPatternReference() and cairoPatternDestroy().

cairoPattern is the result of collapsing the constructors of cairo_pattern_t (cairoPatternCreateRgb, cairoPatternCreateRgba, cairoPatternCreateForSurface, cairoPatternCreateLinear, cairoPatternCreateRadial) and accepts a subset of its arguments matching the required arguments of one of its delegate constructors.

CairoExtend

CairoExtend is 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 CAIRO_EXTEND_NONE for surface patterns and CAIRO_EXTEND_PAD for gradient patterns.

New entries may be added in future versions.

none: pixels outside of the source pattern are fully transparent
repeat: the pattern is tiled by repeating
reflect: the pattern is tiled by reflecting at the edges (Implemented for surface patterns since 1.6)

CairoFilter

CairoFilter is used to indicate what filtering should be applied when reading pixel values from patterns. See cairoPatternSetSource() for indicating the desired filter to be used with a particular pattern.

fast: A high-performance filter, with quality similar to CAIRO_FILTER_NEAREST
good: A reasonable-performance filter, with quality similar to CAIRO_FILTER_BILINEAR
best: The highest-quality available, performance may not be suitable for interactive use.
nearest: Nearest-neighbor filtering
bilinear: Linear interpolation in two dimensions
gaussian: This filter value is currently unimplemented, and should not be used in current code.

CairoPatternType

CairoPatternType is used to describe the type of a given pattern.

The type of a pattern is determined by the function used to create it. The cairoPatternCreateRgb and cairoPatternCreateRgba functions create SOLID patterns. The remaining cairo_pattern_create functions map to pattern types in obvious ways.

The pattern type can be queried with cairoPatternGetType

Most CairoPattern functions can be called with a pattern of any type, (though trying to change the extend or filter for a solid pattern will have no effect). A notable exception is cairoPatternAddColorStopRgb and cairoPatternAddColorStopRgba which must only be called with gradient patterns (either LINEAR or RADIAL). Otherwise the pattern will be shutdown and put into an error state.

New entries may be added in future versions. Since 1.2

solid: The pattern is a solid (uniform) color. It may be opaque or translucent.
surface: The pattern is a based on a surface (an image).
linear: The pattern is a linear gradient.
radial: The pattern is a radial gradient.