hwriteImage: Insert an HTML image

Description

Inserts one or several images in an HTML document. The images can be either external ones specified by URL or file path, or captured from the current graphic device.

Usage

hwriteImage(image.url, page=NULL, ..., image.border=0, width=NULL,
height=NULL, capture=FALSE)

Arguments

image.url

a character vector or matrix containing the URL or the file path of images.

page

an optional connection, a character string naming the file to write to or a page object returned by openPage.

image.border

an optional numeric value specifiying the width of the image border. Default is 0.

width, height

an optional HTML length unit (in pixels) specifiying the width (resp. height) at which the image should be rendered. If missing, the default image width (resp. height) will be used.

capture

a logical. If TRUE the image from the current graphic device is captured and written as a PNG file to the filename specified by image.url. Capture resolution is controlled by width and height, which have a default value of 400 pixels. Default is FALSE.

...

optional arguments that will be dispatched to the underlying hwrite call.

Value

A character vector containing the output HTML code.

Details

hwriteImage constructs an HTML <img> tag to insert one or several images. This function can be seamlessly in conjuction with hwrite to position an image. The capture argument enables to capture easily a current plot and to insert it in a web page.

By default, if image.url is a vector the output value will be a character string containing the HTML code of a table containing the images. This behaviour is dictated by the underlying hwrite call made by hwriteImage. The argument table can be set to TRUE to obtain a vector of HTML image tags instead.

Examples

Run this code

# NOT RUN {
## Creates a new web page 'test.html'
tmpdir <- tempdir()
p <- openPage('test.html', dirname=tmpdir)

## Insert an external image
img <- hwriteImage('http://www.ebi.ac.uk/~gpau/hwriter/iris1.jpg', center=TRUE)
hwrite(c(img,caption='Iris'), p, dim=c(2,1),
row.style=list(caption='text-align:center;background-color:#fac'),
row.names=FALSE, br=TRUE)

## Closes the web page
closePage(p)

## Opens a web browser to see the result
if (interactive()) try(browseURL(file.path(tmpdir, 'test.html')))
# }