Package 'RGraphSpace'

Map numeric values to a color raster

Description

Helper function that converts numeric values to colors and returns a raster image. Useful for visualizing numeric matrices as color backgrounds.

Usage

as_colorraster(x, palette = hcl.colors(30), na.color = "white")

Arguments

x	A numeric vector or matrix containing values to be mapped to colors.
palette	A vector of colors used as the palette. By default, hcl.colors(30) is used.
na.color	Color used for NA values. Defaults to white.

Details

Values in x are rescaled to the range of the palette using scales::rescale(), and each value is mapped to a corresponding color. If x is a matrix, the resulting raster preserves the same dimensions.

Value

A raster object as produced by as.raster().

Examples

library(RGraphSpace)

# Convert the volcano matrix to a color raster
img <- as_colorraster(volcano)
plot(img)

---

Convert objects to GraphSpace

Description

S3 generic function for coercing objects into a GraphSpace object.

Usage

as.GraphSpace(x, ...)

## Default S3 method:
as.GraphSpace(x, ...)

## S3 method for class 'igraph'
as.GraphSpace(x, ...)

## S3 method for class 'tbl_graph'
as.GraphSpace(x, ...)

## S3 method for class 'data.frame'
as.GraphSpace(x, ...)

## S3 method for class 'Seurat'
as.GraphSpace(x, space = c("embedding", "spatial"), layer = NULL, ...)

Arguments

x	An object to be converted.
...	Additional arguments passed to methods associated with the selected space.
space	Character specifying the coordinate space used for node geometry. Either "embedding" or "spatial". See details.
layer	Name of the layer from which node data should be retrieved (see LayerData).

Details

Unified entry point for converting graph, spatial, and high-dimensional data into a GraphSpace object.

Graph objects are imported either through native methods or via as_tbl_graph when available.

For Seurat objects, coordinate extraction depends on the selected space:

• space = "embedding" uses the first two dimensions returned by Embeddings.

• space = "spatial" uses tissue coordinates returned by GetTissueCoordinates.

Assay data are stored in the data slot of the resulting GraphSpace object. Node metadata from [email protected] are appended to the node table.

Value

A GraphSpace object.

See Also

GraphSpace

---

Draw edge elements in a 2D graph layout

Description

Constructor for GeomEdgeSpace ggproto objects.

A wrapper around geom_segment that enables direct use of edge attributes stored in GraphSpace objects as aesthetics.

This geom is designed to create edge-level aesthetics such as colour and linewidth, or any custom aesthetics defined in GeomEdgeSpace.

Usage

geom_edgespace(
  mapping = NULL,
  data = NULL,
  stat = StatEdgeSpace,
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = FALSE,
  arrow_size = 0.5,
  arrow_offset = 0.01,
  curve = 0,
  parallel_spread = 1,
  loop_direction = "adaptive",
  lineend = "butt",
  linejoin = "mitre",
  raster = FALSE,
  dpi = NULL,
  dev = "cairo",
  scale = 1
)

edgespace_handler()

Arguments

mapping	Set of aesthetic mappings created by ggplot2::aes(). These mappings override global aesthetics and are not inherited from the top-level plot.
data	The data to be displayed in this layer. It can be a GraphSpace object, an igraph object, or the edgespace_handler() closure. When NULL (default), a handler is created internally.
stat	The statistical transformation to use on the data. Defaults to identity.
position	Position adjustment, either as a string or the result of a call to a position adjustment function.
...	Additional parameters passed to the underlying drawing function in GeomEdgeSpace.
na.rm	Logical. Should missing values be removed? Defaults to FALSE.
show.legend	Logical or a named logical vector indicating whether this layer should be included in legends.
inherit.aes	Logical. If FALSE (default), the layer will use aesthetics defined in mapping.
arrow_size	Numeric scaling factor controlling arrowhead geometry (see 'details').
arrow_offset	Numeric value controlling the base offset of arrows at edge endpoints (see 'details').
curve	Numeric. Controls edge curvature, as a fraction of edge length. Non-zero values bow the edge into a smooth curve, and the sign controls which side it bows toward. Ignored for loops and parallel edges (see 'details').
parallel_spread	Controls the lateral spread of parallel edges and self-loops. Ignored for simple non-loop edges (see 'details').
loop_direction	Controls how self-loops are oriented around their node. Options: 'adaptive' (default), 'opposite', and an angle in degrees (see 'details').
lineend	Line end style ('round', 'butt', 'square'). Supplied for compatibility with geom_segment.
linejoin	Line join style ('round', 'mitre', 'bevel'). Supplied for compatibility with geom_segment.
raster	Logical. Should node glyphs be rasterized? Rasterization support is based on rasterise.
dpi	Numeric. Rasterization resolution.
dev	Character. Rasterization backend. One of 'cairo', 'ragg', 'ragg_png', or 'cairo_png'.
scale	Numeric. Rasterization scaling factor (see rasterise).

Details

arrow_size is a numeric scaling factor controlling arrowhead geometry. The value is interpreted in the same numeric space as line width (lwd).

arrow_offset is an additive term that offsets arrow endpoints uniformly in graph space and is bounded by the edge length, in NPC units.

Arrowhead types are specified in the GraphSpace constructor.

curve bows an edge through a control point displaced perpendicular to the edge, by curve times the edge length. curve = 0 (default) renders a straight edge. Typical visible values range from about 0.1 to 0.4; sign sets which side the edge bows toward.

parallel_spread controls the fan opening for parallel edges, reciprocal A->B/B->A pairs, and self-loops – anything where multiple edges share the same vertex pair. curve has no effect on these edges; parallel_spread governs both their curvature magnitude and how far apart they fan. A value of 0 collapses all edges in a group onto the same position; increasing values progressively open the fan. Self-loops behave the same way: a single loop uses parallel_spread to set its own size, and multiple loops at the same node fan out accordingly. A built-in minimum, tied to arrow_size and node size, keeps small parallel_spread values from producing a loop whose arrowhead looks skewed against its own curvature.

loop_direction determines where self-loops sit relative to their node. "adaptive" (default) points each loop in the direction that faces away from the graph's centroid. "opposite" is a two-sided arrangement: loops are split into two groups placed above and below the node. A numeric angle (in degrees) places all loops at a fixed direction regardless of their node's position in the layout. When node position data is unavailable, "adaptive" silently falls back to "opposite".

Value

A ggplot2 layer that renders edge segments defined by GeomEdgeSpace.

Aesthetics

geom_edgespace() understands geom_segment aesthetics.

If these aesthetics are not explicitly provided in aes(), they are automatically retrieved from the GraphSpace object.

x, y, xend, yend	Required; automatically supplied.
colour	Edge colour (see aes_colour_fill_alpha).
alpha	Transparency (see aes_colour_fill_alpha).
linetype	Edge line type (see aes_linetype_size_shape).
linewidth	Edge line width (see aes_linetype_size_shape).

All required aesthetics are supplied from the GraphSpace object and do not need to be manually mapped.

Additional parameters can be passed to control fixed values for the layer. For example: colour = "grey", linetype = 2, linewidth = 1.

Arrows can be further adjusted by arrow_size and arrow_offset arguments (see details).

Label aesthetics

When label is mapped via aes(), a text label is drawn at the visual midpoint of each edge. Labels follow the rendered edge geometry: the chord midpoint for straight edges, the Bezier midpoint for curved edges, and the loop apex for self-loops. Edges with NA labels are silently skipped.

The label_colour aesthetic defaults to the edge colour, and label_alpha defaults to the edge alpha. All other label_* aesthetics default to geom_label when not set.

label	Required to activate label rendering.
label_colour	Label text colour (see geom_label).
label_alpha	Transparency (see geom_label).
label_fill	Background colour (see geom_label).
label_size	Font size (see geom_label).
label_angle	Rotation angle (see geom_label).
label_hjust	Horizontal justification (see geom_label).
label_vjust	Vertical justification (see geom_label).
label_lwd	Border linewidth (see geom_label).
label_lty	Border linetype (see geom_label).
label_family	Font family (see geom_label).
label_fontface	Font face (see geom_label).
label_lineheight	Line height (see geom_label).

See Also

GraphSpace, geom_nodespace, geom_graphspace, geom_segment, geom_label

Examples

library(RGraphSpace)
library(igraph)
library(ggplot2)

# Load a demo igraph
data('gtoy1', package = 'RGraphSpace')

# Create a GraphSpace object
gs <- GraphSpace(gtoy1)

## Not run: 

ggplot(gs) +
  geom_edgespace() +
  geom_nodespace() +
  theme(aspect.ratio = 1)


## End(Not run)

---

Convenience wrapper for node and edge geoms

Description

geom_graphspace() adds both node and edge layers to a ggplot2 plot by calling geom_nodespace and geom_edgespace in sequence. It is a convenience wrapper with no logic of its own; any argument accepted by either underlying geom can be passed via node.params or edge.params.

For independent control of node and edge layers, use geom_nodespace and geom_edgespace directly.

Usage

geom_graphspace(mapping = NULL, node.params = list(), edge.params = list())

Arguments

mapping	An optional aes call passed to geom_nodespace. The most common use is supplying node label aesthetics, e.g. aes(label = nodeLabel).
node.params	A named list of additional arguments forwarded to geom_nodespace.
edge.params	A named list of additional arguments forwarded to geom_edgespace.

Value

A list of two ggplot2 layers, which ggplot2 flattens automatically when added to a plot with +.

See Also

geom_nodespace, geom_edgespace, plotGraphSpace

Examples

library(ggplot2)
data("gtoy1", package = "RGraphSpace")
gs <- GraphSpace(gtoy1)

# Simplest use
ggplot(gs) + geom_graphspace()

# With node labels
ggplot(gs) + geom_graphspace(aes(label = nodeLabel))

# With independent node and edge customization
ggplot(gs) + geom_graphspace(
  node.params = list(aes(label = nodeLabel)),
  edge.params = list(curve = 0.3)
)

---

Draw node elements in a 2D graph layout

Description

Constructor for GeomNodeSpace ggproto objects.

A wrapper around geom_point that enables direct use of node attributes stored in GraphSpace objects as aesthetics.

This geom is designed to map node-level attributes (e.g., fill, size) or any aesthetics supported by GeomPoint.

Usage

geom_nodespace(
  mapping = NULL,
  data = NULL,
  stat = StatNodeSpace,
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = FALSE,
  raster = FALSE,
  dpi = NULL,
  dev = "cairo",
  scale = 1
)

nodespace_handler(mapping = NULL)

Arguments

mapping	Set of aesthetic mappings created by ggplot2::aes(). These mappings override global aesthetics and are not inherited from the top-level plot.
data	The data to be displayed in this layer. It can be a GraphSpace object, an igraph object, or the nodespace_handler() closure. When NULL (default), a handler is created internally from the mapping argument.
stat	The statistical transformation to use on the data. Defaults to identity.
position	Position adjustment, either as a string or the result of a call to a position adjustment function.
...	Additional parameters passed to the underlying drawing function in GeomNodeSpace.
na.rm	Logical. Should missing values be removed? Defaults to FALSE.
show.legend	Logical or a named logical vector indicating whether this layer should be included in legends.
inherit.aes	Logical. If FALSE (default), the layer will use aesthetics defined in mapping.
raster	Logical. Should node glyphs be rasterized? Rasterization support is based on rasterise.
dpi	Numeric. Rasterization resolution.
dev	Character. Rasterization backend. One of 'cairo', 'ragg', 'ragg_png', or 'cairo_png'.
scale	Numeric. Rasterization scaling factor (see rasterise).

Details

The interpretation of size depends on how it is provided:

• As an aesthetic: When mapped within aes(), size follows the behavior of geom_point, using absolute units to ensure consistency with the plot legends.

• As a parameter: When set outside aes(), size is treated as a percentage of the viewport ([0, 100]), scaling in npc units. This allows nodes to resize dynamically with viewport changes.

Value

A ggplot2 layer that renders node glyphs defined by GeomNodeSpace.

Aesthetics

geom_nodespace() understands geom_point aesthetics.

If these aesthetics are not explicitly provided in aes(), they are automatically retrieved from the GraphSpace object.

x, y	Node coordinates (required; automatically supplied).
fill	Node interior colour (see aes_colour_fill_alpha).
colour	Node border colour (see aes_colour_fill_alpha).
alpha	Transparency (see aes_colour_fill_alpha).
shape	Node shape (see points and aes_linetype_size_shape).
size	Node size (see drawing section and aes_linetype_size_shape).
stroke	Node line width (see gg_par and aes_linetype_size_shape).

Required aesthetics are supplied from the GraphSpace object and do not need to be manually mapped.

Additional parameters can be passed to control fixed values for the layer. For example: fill = "red", stroke = 3, alpha = 0.5, or shape = 21.

Label aesthetics

When label is mapped via aes(), a text label is drawn at each node's position using geom_text, rendered on top of the node glyph. Nodes with NA labels are silently skipped.

The label_size and label_colour aesthetics are automatically retrieved from the GraphSpace object when not explicitly provided in aes(). All other label_* aesthetics default to geom_text when not set.

label	Required to activate label rendering.
label_size	Font size (see geom_text).
label_colour	Label colour (see geom_text).
label_alpha	Label transparency (see geom_text).
label_angle	Rotation angle (see geom_text).
label_hjust	Horizontal justification (see geom_text).
label_vjust	Vertical justification (see geom_text).
label_family	Font family (see geom_text).
label_fontface	Font face (see geom_text).
label_lineheight	Line height (see geom_text).

See Also

GraphSpace, geom_edgespace, geom_graphspace, geom_point, geom_text

Examples

library(RGraphSpace)
library(igraph)
library(ggplot2)

# Make a demo igraph
gtoy1 <- make_star(15, mode="out")

# Set some node attributes
V(gtoy1)$nodeSize <- runif(vcount(gtoy1), 1, 20)
V(gtoy1)$nodeColor <- rainbow(vcount(gtoy1))

# Set some variables
V(gtoy1)$user_var1 <- runif(vcount(gtoy1), 1, 3)^3
V(gtoy1)$user_var2 <-  rep(c(1, 2, 3), each = 5)

# Create a GraphSpace object
gs <- GraphSpace(gtoy1, layout = layout_in_circle(gtoy1))

## Not run: 

# Example 1: Nodes scaling with the legend
# When 'size' is mapped inside aes(), it follows
# ggplot2 default behavior: size is translated 
# to absolute units (mm) via 'scale_size()'.

ggplot(gs) + 
geom_edgespace(arrow_offset = 0.01) +
geom_nodespace(mapping = aes(size = nodeSize, fill = user_var2)) + 
scale_size(range = c(1, 12)) + 
theme(aspect.ratio = 1)
  
# Example 2: Nodes scaling with the viewport
# When 'size' is passed as a node attribute, 
# inherited from the igraph object, it is 
# interpreted as a percentage of the plotting 
# area and translated to NPC units.

ggplot(gs) + 
geom_edgespace(arrow_offset = 0.01) +
geom_nodespace(mapping = aes(fill = user_var2)) +
theme(aspect.ratio = 1)
  
# Example 3: Node labels
ggplot(gs) +
  geom_edgespace() +
  geom_nodespace(aes(label = nodeLabel)) +
  theme(aspect.ratio = 1)
  

## End(Not run)

---

GeomEdgeSpace: a ggplot2 prototype for GraphSpace-class methods

Description

GeomEdgeSpace is the underlying ggproto object used by geom_edgespace to draw edge elements in a graph layout.

This geom is designed for network diagrams, where graph attributes are often already in their final form (e.g., hex colors).

Usage

GeomEdgeSpace

Aesthetics

GeomEdgeSpace understands ggplot2's conventions for segment-like geoms.

See Also

geom_edgespace, geom_segment

---

GeomNodeSpace: a ggplot2 prototype for GraphSpace-class methods

Description

GeomNodeSpace is the underlying ggproto object used by geom_nodespace to draw node elements in a graph layout.

This geom is designed for network diagrams, where graph attributes are often already in their final form (e.g., hex colors).

Usage

GeomNodeSpace

Aesthetics

GeomNodeSpace understands ggplot2's conventions for point-like geoms.

See Also

geom_nodespace, geom_point

---

Accessors for fetching slots from a GraphSpace object

Description

getGraphSpace retrieves information from individual slots available in a GraphSpace object.

Usage

## S4 method for signature 'GraphSpace'
getGraphSpace(gs, what = "graph")

Arguments

gs	A preprocessed GraphSpace class object
what	A single character value specifying which slot to retrieve from a 'GraphSpace' object. Options: "graph", "nodes", "edges", "pars", "misc", "image", "canvas", and "fdata".

Value

Content from slots in the GraphSpace object.

Examples

library(RGraphSpace)
library(igraph)

# Load a demo igraph
data('gtoy1', package = 'RGraphSpace')

# Create a new GraphSpace object
gs <- GraphSpace(gtoy1)

# Get the 'graph' slot in gs
getGraphSpace(gs, what = 'graph')

---

Using ggplot2 with GraphSpace objects

Description

GraphSpace objects can be used directly with ggplot2, allowing node attributes and high-dimensional feature data to be mapped through standard aesthetic mappings without manual data extraction. This integration enables:

• Lazy evaluation of node attributes and feature data.

• Automatic synchronization of node metadata for standard ggplot2 geoms such as geom_point.

• Automatic propagation of node metadata required for edge clipping and arrow placement in GraphSpace-native geoms.

Usage

## S3 method for class 'GraphSpace'
ggplot(data, mapping = NULL, ...)

Arguments

data	A GraphSpace object.
mapping	Set of aesthetic mappings created by aes. Passed to ggplot.
...	Additional arguments passed to ggplot.

Details

When a GraphSpace object is supplied to ggplot(), RGraphSpace extends the standard ggplot2 build process to automatically resolve GraphSpace variables and synchronize node metadata required for edge rendering.

When using ggplot(), neither nodespace_handler nor inject_nodespace need to be called explicitly.

Value

A gspace_plot object extending ggplot.

See Also

GraphSpace, geom_nodespace, geom_edgespace, inject_nodespace, nodespace_handler, edgespace_handler

Examples

library(RGraphSpace)
library(igraph)
library(ggplot2)

# Generate a toy star graph
gtoy1 <- make_star(15, mode = "out")
V(gtoy1)$my_node_var <- runif(vcount(gtoy1), 1, 20)

# Create a GraphSpace object
gs <- GraphSpace(gtoy1, layout = layout_in_circle(gtoy1))

## Not run: 

# Example 1: Using RGraphSpace-native geoms
# Edge clipping metadata are injected automatically
ggplot(gs) +
  geom_edgespace(colour = "red") +
  geom_nodespace(aes(size = my_node_var), 
  fill = "steelblue", stroke = 2) +
  scale_size(range = c(2, 15))

# Example 2: Mixing native and general geoms
# Note possible clipping mismatch when combining
# geom_edgespace() with generic ggplot2 node geoms.
# Since geom_point() does not expose the final rendered
# node radius to RGraphSpace, edge clipping is estimated
# from layer parameters and may not exactly match the
# displayed node geometry.
ggplot(gs) +
  geom_edgespace(colour = "red") +
  geom_point(aes(x, y, size = my_node_var), 
  fill = "steelblue", stroke = 2, shape = 21) +
  scale_size(range = c(2, 15))


## End(Not run)

---

Accessors and attribute utilities for GraphSpace objects

Description

Access and modify individual components of a GraphSpace object. Selected igraph methods are applied to the internal graph representation and propagated to downstream node and edge components.

Usage

## S4 method for signature 'GraphSpace'
names(x)

## S4 method for signature 'GraphSpace'
gs_names(x)

## S4 method for signature 'GraphSpace'
gs_nodes(x, ...)

## S4 method for signature 'GraphSpace'
gs_edges(x, ...)

## S4 method for signature 'GraphSpace'
gs_image(x)

## S4 replacement method for signature 'GraphSpace'
gs_image(x) <- value

## S4 method for signature 'GraphSpace'
gs_graph(x)

## S4 method for signature 'GraphSpace'
gs_fdata(x)

## S4 replacement method for signature 'GraphSpace'
gs_fdata(x) <- value

## S4 method for signature 'GraphSpace'
gs_nfeatures(x)

## S4 method for signature 'GraphSpace'
gs_features(x)

## S4 method for signature 'GraphSpace'
gs_vcount(x)

## S4 method for signature 'GraphSpace'
gs_ecount(x)

## S4 method for signature 'GraphSpace'
gs_vertex_attr(x, name, ..., value)

## S4 replacement method for signature 'GraphSpace'
gs_vertex_attr(x, name, ...) <- value

## S4 method for signature 'GraphSpace'
gs_edge_attr(x, name, ..., value)

## S4 replacement method for signature 'GraphSpace'
gs_edge_attr(x, name, ...) <- value

## S4 method for signature 'GraphSpace'
x$name

## S4 replacement method for signature 'GraphSpace'
x$name <- value

## S3 method for class 'GraphSpace'
as.igraph(x, ...)

Arguments

x	A GraphSpace class object
...	Additional arguments passed to extraction methods.
value	Replacement value for the selected slot or attribute.
name	Name of the attribute.

Details

For gs_nodes(), the optional vars argument specifies node-associated features retrieved from the fdata container. See also gs_fetch_features.

Value

Updated GraphSpace object.

See Also

vertex_attr, edge_attr, gs_fetch_features

Examples

library(RGraphSpace)
library(igraph)

# Load a demo igraph
data('gtoy1', package = 'RGraphSpace')

# Create a new GraphSpace object
gs <- GraphSpace(gtoy1)

#--- Usage of GraphSpace attribute accessors:

# Vertex names
names(gs)

# Vertex attribute names
gs_names(gs)

# Get a data frame with nodes
gs_nodes(gs)

# Get a data frame with edges
gs_edges(gs)

# Get vertex count
gs_vcount(gs)

# Get edge count
gs_ecount(gs)

# Access all vertex attributes
gs_vertex_attr(gs)

# Access a specific vertex attribute
gs_vertex_attr(gs, "nodeLabel")

# Modify a single value within a vertex attribute
gs_vertex_attr(gs, "nodeSize")["n1"] <- 10

# Replace an entire vertex attribute
gs_vertex_attr(gs, "nodeSize") <- 10

# Access a specific edge attribute
gs_edge_attr(gs, "edgeColor")

# Replace an entire edge attribute
gs_edge_attr(gs, "edgeLineWidth") <- 1

# Add an image and rescale graph coordinates to image space
# Images may be provided as a raster or numeric matrix
gs_image(gs) <- as_colorraster(volcano)
gs <- normalizeGraphSpace(gs, image.space = FALSE)

---

GraphSpace: An S4 class for igraph objects

Description

GraphSpace: An S4 class for igraph objects

Value

An S4 class object.

Slots

nodes

A data frame containing node coordinates, attributes, and metadata.

edges

A data frame containing edge relationships and attributes.

graph

An igraph object representing the graph structure.

image

A raster object (see as.raster) holding the original background image as supplied by the user. Never modified after construction; always serves as the stable source for normalizeGraphSpace().

canvas

A raster object holding the processed, render-ready image produced by normalizeGraphSpace(). Receives all centering, flipping, and margin adjustments. When this slot contains only the empty sentinel, downstream accessors fall back to @image automatically; see gs_image.

fdata

A Matrix object storing high-dimensional feature data associated with graph nodes.

pars

A list with parameters.

misc

A list with intermediate objects for downstream methods.

uuid

A Universally Unique Identifier (UUID) for the object instance.

Constructor

see GraphSpace constructor.

---

Create a GraphSpace object

Description

GraphSpace is the main constructor for GraphSpace objects, designed to store graph data and metadata for optimized rendering in RGraphSpace.

Usage

## S4 method for signature 'ANY'
GraphSpace(g, layout = NULL, simplify = TRUE, verbose = TRUE, ...)

## S4 method for signature 'data.frame'
GraphSpace(g, verbose = TRUE, ...)

Arguments

g	A graph object inheriting from the igraph class (such as igraph and tbl_graph) or a data.frame used to initialize a GraphSpace object. If a graph is provided, it should include vertex coordinates in x and y attributes, and vertex labels in the name attribute. If a data.frame is provided, it must contain at least x and y columns representing the node coordinates; additional columns will be treated as vertex attributes. For graphs requiring edge definitions, use the igraph initialization.
layout	An optional numeric matrix with two columns for x and y vertex coordinates. If provided, it overrides coordinates in g.
simplify	A logical value. If TRUE (default), removes loops and multiple edges (see simplify).
verbose	A logical value. If TRUE (default), displays detailed messages.
...	Additional arguments passed to the GraphSpace constructor.

Details

GraphSpace objects are designed to bridge the gap between network analysis (via igraph) and high-quality visualization (via ggplot2). The constructor ensures that all necessary aesthetics for geom_graphspace are pre-processed and validated.

Coordinate System and Normalization: By default, the constructor expects coordinates in the x and y vertex attributes, along with unique IDs in the name vertex attribute. If these are not provided, the constructor will generate sequential IDs and assign a layout using the layout_nicely function. These coordinates define the relative positioning of nodes. For optimal rendering, it is recommended to pass the object through normalizeGraphSpace after construction. This converts vertex positions to Normalized Parent Coordinates (NPC), ensuring the graph remains centered and scaled relative to the plotting area.

Data Structure: The resulting object stores nodes and edges in separate internal slots, preserving metadata such as nodeSize and edgeColor. If an igraph object is provided without specific styling attributes, GraphSpace will assign the default values defined in the geom_graphspace aesthetics. Users can also specify custom variables in the input graph to be used as aesthetics within the ggplot2 grammar.

Arrowhead Mapping: The arrowType attribute (see Arrowhead types section) allows for a mapping between symbolic aliases (such as "-->") and internal integer codes. This is useful for assigning interaction types in directed or undirected graphs (e.g., activation vs. inhibition).

Value

A GraphSpace class object.

Vertex attributes

The following attributes in g are evaluated by the constructor:

nodeSize	Numeric [0, 100], representing % of the plotting space.
nodeShape	Integer code [0-25]; see points.
nodeColor	A valid color name or hexadecimal code.
nodeLineWidth	Border thickness; see gpar.
nodeLineColor	A valid color name or hexadecimal code.
nodeLabel	Character string (NA will omit labels).
nodeLabelSize	Font size in pts; see gpar.
nodeLabelColor	A valid color name or hexadecimal code.

Edge attributes

The following attributes in g are evaluated by the constructor:

edgeLineWidth	Edge thickness; see gpar.
edgeColor	A valid color name or hexadecimal code.
edgeLineType	Line style (e.g., "solid", "dashed"); see gpar.
arrowType	Arrowhead style (see Arrowhead types section).

Arrowhead types

Arrowheads are controlled via the arrowType attribute using integer or character codes (see examples in the RGraphSpace vignette).

In directed graphs, arrows follow the edge list orientation by default, representing forward directions (e.g., A -> B). While undirected graphs do not show arrows by default, specific styles can be manually assigned for detailed visualization, including forward, backward, or bidirectional arrowheads.

Directed graphs (A -> B):

Code	Alias	Description
0	"---"	No arrow
1	"-->"	Forward arrow
-1	"--|"	Forward bar

Undirected graphs (A – B):

Code	Alias	Description
0	"---"	No arrow
1	"-->"	Forward arrow
2	"<--"	Backward arrow
3	"<->"	Bidirectional arrow
4	"|->"	Forward arrow / backward bar
-1	"--|"	Forward bar
-2	"|--"	Backward bar
-3	"|-|"	Bidirectional bar
-4	"<-|"	Backward arrow / forward bar

Author(s)

Sysbiolab.

See Also

geom_graphspace, plotGraphSpace

Examples

library(RGraphSpace)
library(igraph)

# Create a star graph
gtoy1 <- make_full_graph(15)

# Custom attributes
V(gtoy1)$nodeSize <- 5
E(gtoy1)$edgeColor <- "red"
E(gtoy1)$arrowType <- "-->"

# Create a GraphSpace
gs <- GraphSpace(gtoy1)

---

Manipulate node features in a GraphSpace object

Description

Utilities for extracting and adding node-associated features stored in the fdata container of a GraphSpace object.

Usage

gs_fetch_features(x, vars = NULL, as_df = FALSE)

gs_add_features(x, data)

Arguments

x	A GraphSpace object.
vars	Character vector specifying feature names to extract. If NULL, all features are returned.
as_df	Logical. If TRUE, returns a data.frame. Otherwise returns the original backend representation.
data	A matrix-like or data.frame object containing node features. Rows must correspond to node identifiers.

Value

• gs_fetch_features() returns a matrix-like object or data.frame containing the selected node features.

• gs_add_features() returns a modified GraphSpace object.

---

Toy 'igraph' objects

Description

Small 'igraph' objects used for workflow demonstrations. All graphs include 'x', 'y', and 'name' vertex attributes.

Usage

data(gtoy1)
data(gtoy2)

Format

igraph

Value

A pre-processed igraph object.

Source

This package.

Examples

library(RGraphSpace)
data(gtoy1)
data(gtoy2)

---

Dynamic Scale Injection for Edge Clipping

Description

Utility function for RGraphSpace that enables edge layers to scan adjacent nodes and determine their dimensions. This information is used to compute arrow clipping offsets, preventing edge geometry from overlapping node symbols.

Usage

inject_nodespace(...)

Arguments

...	Additional parameters passed to other methods (currently ignored).

Details

This function operates in two stages within the ggplot2 workflow:

1. Capture: It scans the plot layers for a GeomNodeSpace to extract both mapping variables (from aes()) and static parameters (specifically size and stroke).

2. Injection: It locates GeomEdgeSpace layers and injects scale rules, captured mappings, and fixed parameters into the geometry parameters.

This "lazy injection" calculates edge clipping based on the actual scales used by the nodes, even if scales are defined after the layers.

Note: inject_nodespace() must be called last in the ggplot chain to allow the function to correctly scan all previously added layers and scales.

Value

An object of class inject_nodespace, which interacts with the ggplot2 + operator.

See Also

geom_edgespace, geom_nodespace

Examples

library(RGraphSpace)
library(igraph)
library(ggplot2)

# Generate a toy star graph
gtoy1 <- make_star(15, mode="out")

# Set node and edge attributes
V(gtoy1)$my_node_var <- runif(vcount(gtoy1), 1, 20)
E(gtoy1)$my_edge_var <-  runif(ecount(gtoy1), 1, 20)

# Create a GraphSpace object with a circular layout
gs <- GraphSpace(gtoy1, layout = layout_in_circle(gtoy1))

## Not run: 
# Build the plot
# Note that inject_nodespace() is called at the end to
# synchronize node sizes with edge clipping.
ggplot() +
  geom_edgespace(aes(colour = my_edge_var), data = gs) +
  geom_nodespace(aes(size = my_node_var), data = gs) +
  scale_size(range = c(2, 15)) +
  inject_nodespace()

## End(Not run)

---

Normalize node coordinates to graph and image spaces

Description

Accessory functions to normalize node coordinates in GraphSpace, either by centering them within the graph boundaries or by mapping them to pixel coordinates of a background image.

Usage

## S4 method for signature 'GraphSpace'
normalizeGraphSpace(
  gs,
  mar = 0.1,
  image.space = .has_image(gs),
  flip.x = FALSE,
  flip.y = image.space,
  flip.v = FALSE,
  flip.h = FALSE,
  swap.xy = FALSE,
  verbose = TRUE,
  rotate.xy = deprecated(),
  use_image = deprecated()
)

## S4 method for signature 'GraphSpace'
cropGraphSpace(gs, crop.coord = c(0, 1, 0, 1), verbose = TRUE)

Arguments

gs	A GraphSpace object to be normalized.
mar	A single numeric value in [0, 0.5] controlling the size of the outer margins around the graph. Without an image, mar specifies symmetric margins as a fraction of the graph space. With an image, mar is interpreted as a fraction of the available image margins surrounding the graph.
image.space	Logical; if an image is available, whether to use it as a background reference map. When enabled, x and y graph coordinates are interpreted as pixel coordinates in the image matrix. Images can be inspected and assigned with gs_image.
flip.x	Logical; whether to flip the node coordinates along the x-axis.
flip.y	Logical; whether to flip the node coordinates along the y-axis. Useful for aligning nodes with image backgrounds, which often use an inverted coordinate system. Defaults to image.space.
flip.v	Logical; whether to vertically flip the background image matrix (top-to-bottom) to align with the graph coordinate system.
flip.h	Logical; whether to horizontally flip the background image matrix (left-to-right) to align with the graph coordinate system.
swap.xy	Logical; whether to swap x and y node coordinates. Useful when the graph coordinate system is transposed relative to the image or reference map.
verbose	A single logical value specifying to display detailed messages (when verbose=TRUE) or not (when verbose=FALSE).
rotate.xy	Deprecated from RGraphSpace 1.4.3; use swap.xy instead.
use_image	Deprecated from RGraphSpace 1.4.0; use image.space instead.
crop.coord	An optional numeric vector of length four specifying a cropping region (xmin, xmax, ymin, ymax), with values in normalized coordinates [0,1].

Details

These functions provide different strategies for coordinate transformation:

• normalizeGraphSpace: Re-scales node coordinates to a [0, 1] unit square based on the graph's bounding box (when image.space = FALSE) or maps them to pixel coordinates (when image.space = TRUE and an image is provided; see gs_image). It handles image-to-graph alignment via flip.\* and swap.\* arguments, used to adjust the graph origin with the image matrix layout. Users should be aware of the potential discrepancy between image matrix orientation (top-down) and graph coordinates (bottom-up). The function attempts to automatically adjust the y-axis to align the graph's bottom-up coordinates with the image's top-down layout, but further manual adjustments might be required.

• cropGraphSpace: Subsets the normalized graph space into a specific region defined by crop.coord. It recalculates node positions and background image boundaries to maintain spatial consistency after cropping. This function requires a previously normalized GraphSpace object.

Value

A GraphSpace object with updated nodes and image slots.

Note

This is an accessory function typically called during the preprocessing of GraphSpace objects before rendering.

See Also

gs_image

Examples

library(RGraphSpace)
library(igraph)

# Create a star graph
gtoy1 <- make_full_graph(30)

# Create a GraphSpace
gs <- GraphSpace(gtoy1)

gs <- normalizeGraphSpace(gs)

gs_crop <- cropGraphSpace(gs, crop.coord = c(0, 1, 0, 0.5))

plotGraphSpace(gs, add.labels = TRUE)

plotGraphSpace(gs_crop, add.labels = TRUE)

---

Plot GraphSpace objects

Description

Plot GraphSpace objects

Usage

## S3 method for class 'GraphSpace'
plot(x, ...)

Arguments

x	A GraphSpace class object.
...	Additional arguments passed to the plotGraphSpace function.

See Also

plotGraphSpace

---

Wrapper function to plot GraphSpace objects in ggplot2

Description

plotGraphSpace() is a High-level plotting interface that translates igraph and GraphSpace data objects into ggplot2 layers.

Usage

## S4 method for signature 'GraphSpace'
plotGraphSpace(
  gs,
  theme = "th0",
  xlab = "Graph coordinates 1",
  ylab = "Graph coordinates 2",
  node.labels = FALSE,
  label.size = 3,
  label.color = "grey20",
  add.image = TRUE,
  raster = FALSE,
  dpi = 300,
  dev = "cairo_png",
  add.labels = deprecated(),
  font.size = deprecated(),
  bg.color = deprecated()
)

## S4 method for signature 'igraph'
plotGraphSpace(gs, ...)

## S4 method for signature 'tbl_graph'
plotGraphSpace(gs, ...)

## S4 method for signature 'gs_graph'
plotGraphSpace(gs, ...)

Arguments

gs	Either an igraph or GraphSpace class object. If gs is an igraph, then it must include x, y, and name vertex attributes (see GraphSpace).
theme	Name of a custom RGraphSpace theme. These themes (from 'th0' to 'th3') consist of preconfigured ggplot settings, which can be subsequently refine using theme.
xlab	The title for the 'x' axis of a 2D-image space.
ylab	The title for the 'y' axis of a 2D-image space.
node.labels	Optional specification of node labels to display. If FALSE (default), no labels are shown. If TRUE, labels are displayed for all nodes. Otherwise, a character vector may be supplied to display labels only for the specified nodes. Character values are matched against the nodeLabel attribute.
label.size	Font size passed to geom_text.
label.color	Color passed to geom_text.
add.image	A logical value indicating whether to add a background image, when one is available (see GraphSpace).
raster	A logical value indicating whether to rasterize the main plot. See rasterise for further specifications.
dpi	Raster resolution, in dots per inch.
dev	Device used in the rasterise call.
add.labels	Deprecated. Use node.labels instead.
font.size	Deprecated. Use theme customization instead.
bg.color	Deprecated. Use theme customization instead.
...	Additional arguments passed to the plotGraphSpace function.

Value

A ggplot-class object.

Author(s)

Sysbiolab.

See Also

GraphSpace

Examples

library(RGraphSpace)
library(igraph)

# Load a demo igraph
data('gtoy1', package = 'RGraphSpace')

# Generate a ggplot for gtoy1
plotGraphSpace(gtoy1, node.labels = TRUE)


# Create a star graph
gtoy_star <- make_full_graph(15)

# Example of setting node and edge attributes
V(gtoy_star)$nodeSize <- 5
E(gtoy_star)$edgeColor <- "red"
E(gtoy_star)$arrowType <- "<->"

# Create a GraphSpace object
gs_star <- GraphSpace(gtoy_star)

# Normalize graph coordinates
gs_star <- normalizeGraphSpace(gs_star)

# Generate a ggplot for gs_star
plotGraphSpace(gs_star)

---

Attribute Processing for GeomEdgeSpace

Description

Manage visual attribute precedence (colour, size, shape) for GeomEdgeSpace objects.

Usage

StatEdgeSpace

Format

A ggproto object.

Attribute Priority

1. Explicit aes() mappings.

2. Fixed geom_edgespace() arguments.

3. Original graph attributes (via optional_aes).

During the setup_data stage, the Stat invokes internal functions to resolve value priority:

1. Explicit Mapping: Values defined by the user inside aes().

2. Fixed Parameters: Constant values passed as arguments in the geom_edgespace() call.

3. Graph Attributes: Original attributes stored within the GraphSpace object, retrieved from the data columns.

See Also

geom_edgespace

---

Attribute Processing for GeomNodeSpace

Description

Manage visual attribute precedence (color, size, shape) for GeomNodeSpace objects.

Usage

StatNodeSpace

Format

A ggproto object.

Attribute Priority

1. Explicit aes() mappings.

2. Fixed geom_nodespace() arguments.

3. Original graph attributes (via optional_aes).

During the setup_data stage, the Stat invokes internal functions to resolve value priority:

1. Explicit Mapping: Values defined by the user inside aes().

2. Fixed Parameters: Constant values passed as arguments in the geom_nodespace() call.

3. Graph Attributes: Original attributes stored within the GraphSpace object, retrieved from the data columns.

See Also

geom_nodespace

---

RGraphSpace ggplot2 themes

Description

A set of ggplot2 themes used by RGraphSpace plots.

Usage

theme_gspace_th0(
  txt_size = 1,
  leg_size = 1,
  bg_colour = "grey95",
  discrete_fill = FALSE,
  discrete_colour = FALSE,
  ...
)

theme_gspace_th1(
  txt_size = 1,
  leg_size = 1,
  bg_colour = "grey95",
  discrete_fill = FALSE,
  discrete_colour = FALSE,
  ...
)

theme_gspace_th2(
  txt_size = 1,
  leg_size = 1,
  bg_colour = "grey95",
  discrete_fill = FALSE,
  discrete_colour = FALSE,
  ...
)

theme_gspace_th3(
  txt_size = 1,
  leg_size = 1,
  bg_colour = "grey95",
  discrete_fill = FALSE,
  discrete_colour = FALSE,
  ...
)

theme_gspace_coords(
  theme = "th0",
  is_norm = FALSE,
  xlab = "Graph coordinates 1",
  ylab = "Graph coordinates 2",
  expand = NULL,
  ...
)

theme_gspace_legend(
  leg_size = 1,
  discrete_fill = FALSE,
  discrete_colour = FALSE,
  ...
)

Arguments

txt_size	Numeric value to scale plot- and axis-related text elements.
leg_size	Numeric value to scale legend-related elements.
bg_colour	A colour name or hex code specifying the panel background.
discrete_fill	Logical; if TRUE, treats the fill legend as discrete to adjust key size.
discrete_colour	Logical; if TRUE, treats the colour legend as discrete to adjust key size.
...	Additional arguments passed to theme_gspace_th* and ggtheme.
theme	Character string specifying the GraphSpace theme variant. Options: th0, th1, th2, and th3.
is_norm	Logical; if TRUE, assumes plot coordinates are already normalized in [0, 1].
xlab	The title for the 'x' axis.
ylab	The title for the 'y' axis.
expand	A range expansion factor applied to both the lower and upper limits of the 'x' and 'y' scales.

Details

theme_gspace_th0() is a minimal wrapper around theme_gray that simplifies axis and legend scaling. The txt_size and leg_size arguments aggregate related theme parameters for quick thematic overrides.

theme_gspace_th1() builds on theme_gspace_th0() and modifies grid lines, axis appearance, and panel borders.

theme_gspace_th2() is similar to theme_gspace_th1() with simplified grid elements and a customizable panel background.

theme_gspace_th3() is similar to theme_gspace_th2() but with slightly adjusted margins, tick appearance, and legend formatting.

The theme_gspace_coords() is a helper function that also adds axes scales for normalized coordinates. It configures axis breaks, limits, and expansion for graph layouts. Plot coordinates are ideally normalized to the interval [0, 1].

theme_gspace_legend() is helper function that adjusts legend text, title, and key sizes by a single scaling factor.

Value

theme_gspace_th*() return a ggplot2 theme object.

theme_gspace_coords() returns a list containing scale and theme components that can be added to a ggplot2 plot.

theme_gspace_legend() returns a list of theme and guide components.

See Also

ggtheme, theme

Examples

library(RGraphSpace)
library(ggplot2)

ggplot(mtcars, aes(wt, mpg)) +
  geom_point() +
  theme_gspace_th0()
  
ggplot(mtcars, 
  aes(scales::rescale(wt), 
      scales::rescale(mpg))) +
  geom_point() +
  theme_gspace_coords("th2", is_norm = TRUE)
  
# Reduce legend element sizes
ggplot(mtcars, aes(wt, mpg, fill = factor(cyl))) + 
  geom_point(shape = 21) + 
  theme_gspace_legend(0.8)

---