webview

<h1>Web View API</h1>

<h3><tt><nowiki>
  (import webview)
</nowiki></tt></h3>

This multi-platform library for [https://www.call-cc.org/|CHICKEN]
allows you to show HTML user interfaces in a window, inject JavaScript
code and HTML content into the page and receive messages from JavaScript
on the page.

<h2>Web View</h2>

<h3><tt><nowiki>
  (webview? VALUE) ⇒ BOOLEAN
</nowiki></tt></h3>

Predicate for the tagged pointer type representing a web view window.

<h3><tt><nowiki>
  (webview TITLE PROC [#:url URL] [#:width WIDTH] [#:height HEIGHT] [#:resizable? RESIZABLE] [#:debug? DEBUG]) ⇒ VOID
</nowiki></tt></h3>

Creates a web view window with the given <tt>TITLE</tt> and runs an
event loop until the user closes the window or termination is requested
using <tt>webview-terminate!</tt>.

The message callback is invoked as <tt>(PROC WEBVIEW STRING)</tt>
whenever a script on the web page calls <tt>window.external.invoke(STRING)</tt>.

If you specify a <tt>URL</tt> that is not <tt>#f</tt>, the page at that
location is loaded into the web view. Otherwise, a blank page is loaded
which sends a <tt>"load"</tt> message when ready and contains a
<tt>&lt;div id="app"&gt;</tt> element that you can fill with custom
content, for example using <tt>webview-inject</tt>.

Window properties may be specified using the <tt>WIDTH</tt>,
<tt>HEIGHT</tt> and <tt>RESIZABLE</tt> keyword arguments. When the
<tt>DEBUG</tt> keyword argument is not <tt>#f</tt>, the web view will
allow access to debugging tools, if the platform supports it.

<h3><tt><nowiki>
  (webview-terminate! WEBVIEW) ⇒ VOID
</nowiki></tt></h3>

Requests termination of the event loop for the given <tt>WEBVIEW</tt>.

<h3><tt><nowiki>
  (webview-title-set! WEBVIEW TITLE) ⇒ VOID
</nowiki></tt></h3>

Sets the <tt>TITLE</tt> of the given <tt>WEBVIEW</tt> window.

<h3><tt><nowiki>
  (webview-fullscreen-set! WEBVIEW FULLSCREEN) ⇒ VOID
</nowiki></tt></h3>

Changes the <tt>FULLSCREEN</tt> state of the given <tt>WEBVIEW</tt>
window.

<h3><tt><nowiki>
  (webview-eval WEBVIEW SCRIPT) ⇒ VOID
</nowiki></tt></h3>

Asynchronously triggers evaluation of the given <tt>SCRIPT</tt> code in
the context of the page displayed by the given <tt>WEBVIEW</tt>.

<h3><tt><nowiki>
  (webview-inject WEBVIEW ID HTML) ⇒ VOID
</nowiki></tt></h3>

Asynchronously triggers replacement of the DOM element with the given
<tt>ID</tt> on the page displayed by the given <tt>WEBVIEW</tt> with the
given <tt>HTML</tt> content.

<tt>HTML</tt> content is specified in the form accepted by
<tt>write-html</tt>.

<h2>Dialogs</h2>

<h3><tt><nowiki>
  (webview-dialog WEBVIEW TITLE [VALUE] [#:open | #:save | #:error | #:warning] [#:directory]) ⇒ VALUE
</nowiki></tt></h3>

Shows a modal dialog with the given <tt>TITLE</tt> in the context of the
given <tt>WEBVIEW</tt>.

If the <tt>#:open</tt> or <tt>#:save</tt> flags are given, a file
selection dialog is shown and <tt>VALUE</tt> may be the path to a file
that will be pre-selected. The <tt>#:directory</tt> flag indicates that
directories rather than regular files should be selected. The procedure
will return the path to a selected file or <tt>#f</tt> in case the
dialog is cancelled.

Otherwise, a message dialog is shown and the <tt>#:error</tt> or
<tt>#:warning</tt> flags may be used to switch from an information icon
to a different look. In this case, <tt>VALUE</tt> is the message to
display in the dialog and the procedure will not return a meaningful
result.

<h2>Logging</h2>

<h3><tt><nowiki>
  (webview-log MESSAGE) ⇒ VOID
</nowiki></tt></h3>

Outputs a message using a platform-specific logging mechanism.

<h2>Content Generation</h2>

<h3><tt><nowiki>
  char-set:no-js-escape
</nowiki></tt></h3>

A SRFI-14 set of characters that do not need to be escaped inside a
JavaScript string.

<h3><tt><nowiki>
  (write-js STRING [PORT] [QUOTES]) ⇒ VOID
</nowiki></tt></h3>

Writes a <tt>STRING</tt> to the given <tt>PORT</tt> or the current
output port using JavaScript escaping rules. If <tt>QUOTES</tt> is given
and not <tt>#f</tt>, its content is printed before and after the
<tt>STRING</tt> contents. If <tt>QUOTES</tt> is not given, double quotes
are put around the string.

<h3><tt><nowiki>
  (html-tag-rule TAG) ⇒ RULE
</nowiki></tt></h3>
<h3><tt><nowiki>
  (html-tag-rule TAG RULE) ⇒ VOID
</nowiki></tt></h3>

Retrieves or sets the content rule for HTML elements named <tt>TAG</tt>.
The <tt>RULE</tt> can be one of the symbols <tt>normal</tt>,
<tt>raw</tt> or <tt>void</tt>.

<h3><tt><nowiki>
  (write-html ELEMENT [PORT]) ⇒ VOID
</nowiki></tt></h3>

Writes an HTML5 rendering of the X-expression <tt>ELEMENT</tt> to the
given <tt>PORT</tt> or the current output port.

<tt>ELEMENT</tt> must conform to the following grammar:
<verbatim>
  X-EXPR  = ELEMENT
          | CONTENT
  ELEMENT = (SYMBOL ((SYMBOL CONTENT ...) ...) X-EXPR ...) ;; element with optional attributes
          | (SYMBOL X-EXPR ...)                            ;; element without attributes
  CONTENT = STRING                                         ;; character data
          | SYMBOL                                         ;; symbolic entity reference
          | INTEGER                                        ;; numeric entity reference
</verbatim>

If the tag symbol of the element is <tt>html</tt>, an HTML5 document
type declaration is written before the element itself.