Image layers

Fractalshades graphical export is based on the concept of layers. Each layer is linked to a postprocessing field, it can be directly plotted or can be used to modify another layer.

class fractalshades.colors.layers.Virtual_layer(postname, func, output=True)

__init__(postname, func, output=True)

Base class for all layer objects.

Parameters:

postnamestr

Unique identifier key for this layer. When added to a fractalshades.Fractal_plotter plotter (see fractalshades.Fractal_plotter.add_layer) the layer can then be accessed through this key :

layer = plotter[“postname”]

The postname must match a fractalshades.postproc.Postproc associated with this plotter.

funcNone | callable

mapping applied during the post-processing initial step

outputbool

If True : an image will be saved when fractalshades.Fractal_plotter.add_layer directive issued.

set_mask(layer, mask_color=None)

Masks the base-layer

Parameters:

layerBool_layer | Grey_layer

The layer mask

mask_colorNone | 3-uplet or 4_uplet of floats belonging to [0., 1.]

If None, a default value will be provided depending on the masked array subclass If a n-uplet is provided, it shall be with RGB or RGBA values for a colored layer

class fractalshades.colors.layers.Bool_layer(postname, output=True)

__init__(postname, output=True)

Defines a boolean mask array. Where is 1 or True, the attached masked layer values are considered masked.

class fractalshades.colors.layers.Color_layer(postname, func, colormap, probes_z=[0, 1], output=True)

__init__(postname, func, colormap, probes_z=[0, 1], output=True)

A colored layer.

Parameters:

postnamestr

passed to Virtual_layer constructor

func

passed to Virtual_layer constructor

colormapfractalshades.colors.Fractal_colormap

a colormap

probes_z2-floats list

probes_z = (z_min, zmax) ; the z_min value of the field will be mapped to 0. and zmax to 1.

outputbool

passed to Virtual_layer constructor

overlay(layer, overlay_mode)

Combine the output of current layer with an overlayed layer after color-mapping.

Parameters:

layerColor_layer | Grey_layer

The layer to overlay. See Overlay_mode documentation for the options and restrictions.

overlay_modeOverlay_mode

Object describing the kind of overlay used.

set_mask(layer, mask_color=None)

Masks the base-layer

Parameters:

layerBool_layer | Grey_layer

The layer mask

mask_colorNone | 3-uplet or 4_uplet of floats belonging to [0., 1.]

If None, a default value will be provided depending on the masked array subclass If a n-uplet is provided, it shall be with RGB or RGBA values for a colored layer

set_twin_field(layer, scale)

Combine two postprocessing fields in one layer.

Combine the current layer with another layer before color-mapping. (i.e. add directly the underlying float fractalshades.postproc.Postproc arrays), tuning the intensity of the effect with a scaling coefficient.

Parameters:

layerVirtual_Layer instance

The combined layer

scalefloat

A scaling coefficient which will be applied to the twin layer field before adding it to the base field

Notes

Note

Note : The mask of the current layer will be applied.

shade(layer, lighting)

Adds scene lighting to the layer through a normal map effect.

Parameters:

layerNormal_map_layer

The layer holding the normal vector field.

lightingBlinn_lighting

Object describing the scene lighting.

class fractalshades.colors.layers.Normal_map_layer(postname, max_slope=70, output=True)

__init__(postname, max_slope=70, output=True)

Defines a normal map layer

This layer can be either:

• plotted directly (OpenGL normal map format) and used in a post-processing Workflow - e.g. Blender

• or used to apply shading to a Color_layer.shade

Parameters:

postnamestr

passed to Virtual_layer constructor

max_slopefloat

maximal angle (in degree) of the normal map, will be used for re-normalisation

outputbool

passed to Virtual_layer constructor

set_mask(layer, mask_color=None)

Masks the base-layer

Parameters:

layerBool_layer | Grey_layer

The layer mask

mask_colorNone | 3-uplet or 4_uplet of floats belonging to [0., 1.]

If None, a default value will be provided depending on the masked array subclass If a n-uplet is provided, it shall be with RGB or RGBA values for a colored layer

class fractalshades.colors.layers.Grey_layer(postname, func, curve=None, probes_z=[0.0, 1.0], output=True)

__init__(postname, func, curve=None, probes_z=[0.0, 1.0], output=True)

A grey layer.

Parameters:

postnamestr

passed to Virtual_layer constructor

func

passed to Virtual_layer constructor

curveNone | callable

A mapping from [0, 1] to [0, 1] applied after rescaling (this is the equivalent of a colormap in greyscale)

probes_z2-floats list

The preprocessing affine rescaling. If [min, max] the minimum value of the field will be mapped to 0. and the maximum to 1.

outputbool

passed to Virtual_layer constructor

set_mask(layer, mask_color=None)

Masks the base-layer

Parameters:

layerBool_layer | Grey_layer

The layer mask

mask_colorNone | float belonging to [0., 1.]

If None, a default value will be provided depending on the masked array subclass If a value is provided, it shall be with : a float belonging to [0. (black) ; 1. (white)] interval

class fractalshades.colors.layers.Disp_layer(postname, func, curve=None, probes_z=[0.0, 1.0], output=True)

Grey layer with 16-bits precision.

Same functionnality as a Grey_layer but the image export is with 16-bits precision (useful when used as an height map for 3d processing like Blender)

__init__(postname, func, curve=None, probes_z=[0.0, 1.0], output=True)

A grey layer.

Parameters:

postnamestr

passed to Virtual_layer constructor

func

passed to Virtual_layer constructor

curveNone | callable

A mapping from [0, 1] to [0, 1] applied after rescaling (this is the equivalent of a colormap in greyscale)

probes_z2-floats list

The preprocessing affine rescaling. If [min, max] the minimum value of the field will be mapped to 0. and the maximum to 1.

outputbool

passed to Virtual_layer constructor

set_mask(layer, mask_color=None)

Masks the base-layer

Parameters:

layerBool_layer | Grey_layer

The layer mask

mask_colorNone | float belonging to [0., 1.]

If None, a default value will be provided depending on the masked array subclass If a value is provided, it shall be with : a float belonging to [0. (black) ; 1. (white)] interval

class fractalshades.colors.layers.Blinn_lighting(k_ambient, color_ambient, **light_sources)

__init__(k_ambient, color_ambient, **light_sources)

This class holds the properties for the scene lightsources. Its instances can be passed as a parameter to Color_layer.shade.

Parameters:

k_Ambient

ambient lighting coefficient. A typical value is 0.2

color_ambient: 3-uplet float

a RGB 3-tuple, channels values in [0, 1] : the ambient lighting color. Usually white (1., 1., 1.)

add_light_source(k_diffuse, k_specular, shininess, polar_angle, azimuth_angle, color=array([1., 1., 1.]), material_specular_color=None)

Adds a lightsource to the scene

Parameters:

k_diffuse: 3-uplet float

diffuse lighting coefficients, as RGB

k_specular: 3-uplet float

diffuse lighting pourcentage, as RGB

shininess: float

Phong exponent for specular model

polar_angle: float

angle (theta) of light source direction, in degree theta = 0 if incoming light is in xOz plane

azimuth_angle: float

angle (phi) of light source direction, in degree phi = 0 if incoming light is in xOy plane

class fractalshades.colors.layers.Overlay_mode(mode, **mode_options)

__init__(mode, **mode_options)

This class holds the properties for overlaying. Its instances can be passed as a parameter to Color_layer.overlay method.

Parameters:

mode: “alpha_composite” | “tint_or_shade”

the kind of overlay applied

• alpha_composite :

  alpha-compositing of 2 color layers (a Bool_layer may be provided as optionnal parameter, otherwise its is the mask of the upper layer which will be considered for compositing)

• tint_or_shade

  the color of the lower layer will be adjusted (tinted of shaded) depending of the upper layer value (tinted above 0.5, shaded below 0.5). The upper layer in this case shall be a Grey_layer instance.

Other Parameters:

ref_white: 3-uplet float, Optionnal

reference white light RGB coeff for mode “tint_or_shade”

Default to CIE LAB constants Illuminant D65

alpha_mask: `Bool_layer`, Optionnal

Boolean array used for compositing, for alpha_composite mode Defaults to the mask of the upper layer

inverse_mask: bool, Optionnal

if True, inverse the mask