getBoundingBox: Functions for finding rectangles associated with SVG objects

In duncantl/SVGAnnotation: Tools for post-processing SVG plots created in R

Description

These functions process the path specifications in an SVG node, i.e. the d attribute.

The most general is getGeneralPath which breaks the path string into a list with as many elements as there are path operations (i.e. M, L, Z, C, S, H, V, ...) and each element containing the numbers for that operation. From this, we can determine the shape, the bounding box, etc.

The other functions compute the rectangle enclosing or associated with an SVG object such as an axis label or any text, a plotting region and so on.

This is useful when creating a link or a mouse over event for an SVG element which is just a path. Ordinarily, the action will only be active when the mouse is on the path rather than "in" the object. By putting a rectangle behind the object and placing the action on that rectangle, the action is active when the mouse is "within" the object, not just on the path.

See addLink and addToolTips and their addArea parameter.

Usage

getBoundingBox(gnode, doc = as(gnode, "XMLInternalDocument"))

Arguments

gnode	the SVG node whose bounding box is to be computed
doc	the XML document in which the SVG node an element

Value

Currently, this returns either a Circle object (a numeric vector with 3 elements giving the x and y coordinates of the center and the radius), a Polyline, Polygon, Line, VerticalLine, HorizontalLine object or a or a 2 x 2 matrix. The columns correspond to the horizontal (x) and vertical (y) coordiantes and the rows give the minimum and maximum of the these dimensions for the rectangle.

Author(s)

Duncan Temple Lang

See Also

addLink

Examples

 doc =  svgPlot({
            plot(c(1:13, 13:1), pch = 0:25)
            abline(h = c(2, 5, 9) + .5, col = 'lightgray', lty = 3)
            lines(1:13, col = 'lightgray', lty = 2)
          })

      # 2 "plot regions" corresponding to the points and 
  rr = getPlotRegionNodes(doc)

  getBoundingBox(rr[[1]])

  xmlSize(rr[[1]])
  groupByPch(xmlChildren(rr[[1]]), 0:25)
  xmlSize(rr[[1]])


  getBoundingBox(rr[[1]][[1]])

  table(xmlSApply(rr[[1]], function(x) class(getBoundingBox(x))))
  table(xmlSApply(rr[[2]], function(x) class(getBoundingBox(x))))

duncantl/SVGAnnotation documentation built on May 15, 2019, 5:57 p.m.