Click Me

\name{imageMap-methods} \docType{methods} \alias{imageMap} \alias{imageMap-methods} \alias{imageMap,Ragraph-method} \alias{imageMap,graph-method} \alias{imageMap,Ragraph,connection,list,character-method} \alias{imageMap,graph,connection,list,character-method} \title{Write an HTML IMG tag together with a MAP image map.} \description{Write an HTML IMG tag together with a MAP image map.} \usage{ \S4method{imageMap}{Ragraph,connection,list,character}(object, con, tags, imgname, width, height, usr = par("usr")) \S4method{imageMap}{graph,connection,list,character}(object, con, tags, imgname, width, height) } \arguments{ \item{object}{The graph layout for which we want to create an image map.} \item{con}{Connection to which the image map is written.} \item{tags}{Named list whose elements are named character vectors. Names must correspond to node names in \code{object}. See details.} \item{imgname}{Character. Name of the image file (for example PNG file) that contains the plot.} \item{width}{Width of the image.} \item{height}{Height of the image.} \item{usr}{Numeric vector of length 4. The user coordinates in the plot window that \code{object} was plotted into.} } \details{The most important tags are \code{TITLE}, \code{HREF}, and \code{TARGET}. If the list \code{tags} contains an element with name \code{TITLE}, then this must be a named character vector containing the tooltips that are to be displayed when the mouse moves over a node. The names of the nodes are specified in the \code{names} attribute of the character vector and must match those of \code{object}. Similarly, \code{HREF} may be used to specify hyperlinks that the browser can follow when the mouse clicks on a node, and \code{TARGET} to specify the target browser window. Currently, only rectangular regions are implemented; the actual shape of the nodes as specified in \code{object} is ignored. Also, tags for edges of the graph are currently not supported. This function is typically used with the following sequence of steps: \enumerate{ \item Create a graph layout with \code{\link[Rgraphviz:agopen]{agopen}} \item Plot it into a bitmap device, e.g. \code{\link{jpeg}} or \code{\link{png}}. \item Write HTML header. \item Call the \code{\link{imageMap}} function. \item Optionally, write further text into the HTML connection. \item Close HTML file. } The new API for plotting of graphs now also allows for this alternative procedure: \enumerate{ \item Lay out the graph object \code{foo} using \code{\link[Rgraphviz]{layoutGraph}} \item render the graph on a bitmap device using \code{\link[Rgraphviz]{renderGraph}} like this: \code{foo <- renderGraph(foo)} \item Write HTML header. \item Call the \code{\link{imageMap}} on the graph object \code{foo}. \item Optionally, write further text into the HTML connection. \item Close HTML file. } } \value{The function is called for its side effect, which is writing text into the connection \code{con}.} \seealso{\code{\link[Rgraphviz]{agopen}} %-does not exist \code{\link[prada:openHTMLpage]{openHTMLpage}} } \author{Wolfgang Huber \url{http://www.ebi.ac.uk/huber}} \keyword{iplot} \examples{ fhtml = paste(tempfile(), ".html", sep="") fpng =paste(tempfile(), ".png", sep="") if(capabilities()["png"] && interactive()) { ## Create a random graph, make tooltips and hyperlinks set.seed(123) g = randomEGraph(letters[14:22], 0.2) tooltip = paste("This is node", nodes(g)) url = paste("This could be a link for node", nodes(g)) names(url) = names(tooltip) = nodes(g) ## Open plot device width = height = 512 png(fpng, width=width, height=height) par(mai=rep(0,4)) ## Layout and render lg = agopen(g, name="My layout") plot(lg) ## Write an HTML file with the image map con = file(fhtml, open="wt") writeLines("Click Me\n", con) imageMap(lg, con, fpng, tags=list(HREF=url, TITLE=tooltip), width=width, height=height) writeLines("", con) close(con) dev.off() cat("Now have a look at file", fhtml, "with your browser.\n") browseURL(fhtml) } }