# (lispkit draw web) Library `(lispkit draw web)` provides web page snapshotting capabilities through a WebKit-based web client. The library enables capturing images and generating PDFs from HTML content, local files, data streams, and remote URLs with configurable viewport settings and cropping options. This is a minimalistic example showcasing how to snapshot a web page at a given URL and saving the snapshot in a JPEG file. ```scheme (import (lispkit base) (lispkit draw) ; For using `save-image` (lispkit draw web) ; For web client functionality (lispkit thread future)) ; For handling futures (save-image "~/Downloads/objecthub.jpeg" ; Filename (future-get ; Wait for snapshot generation to finish (web-client-snapshot-url ; Generate snapshot for given URL (make-web-client 1200) ; Create simple web client with 1200 points width "http://objecthub.com")) ; URL to snapshot 'jpg) ; Save image as JPEG ``` Here is an example for creating an HTML document containing a reports table on the fly and then snapshotting the rendered document both as bitmap and PDF. ```scheme (import (lispkit base) (lispkit draw) (lispkit draw web) (lispkit thread future)) (define (generate-web-report data-source path) ;; Create web client optimized for documents (define client (make-web-client 600 '() #f "Report Generator" 1.5)) ;; Generate report in HTML form (define html (string-append "" "Report" "" "" "

Data Report

" "" (apply string-append (map (lambda (item) (string-append "" "")) data-source)) "

Item	Value
" (car item) "	" (cdr item) "

")) ;; Render and snapshot the report both as bitmap and PDF. (define img-snapshot (web-client-snapshot-html client html 'all)) (define pdf-snapshot (web-client-pdf-snapshot-html client html 'all)) ;; Wait for completion and save the snapshots (save-image (string-append path ".png") (future-get img-snapshot) 'png) (write-binary-file (string-append path ".pdf") (future-get pdf-snapshot))) ;; Use the report generator (define sample-data '(("Revenue" . "$125,000") ("Expenses" . "$89,500") ("Profit" . "$35,500") ("Growth" . "12.5%"))) (generate-web-report sample-data "~/Downloads/report") ``` ## Web clients **(make-web-client *****width*****)**

\ \&#xNAN;**(make-web-client *****width scripts*****)**\ \&#xNAN;**(make-web-client *****width scripts viewport*****)**\ \&#xNAN;**(make-web-client *****width scripts viewport name*****)**\ \&#xNAN;**(make-web-client *****width scripts viewport name delay*****)** Returns a new web client object representing a web view of the given *width* with specified optional configuration parameters. Web clients are used to load and snapshot web pages. *scripts* is a list of JavaScript strings to inject into documents rendered via the web client. Supported are the following ways to specify a JavaScript string: * `"..."`: The string contains the JavaScript code. It is injected at the end of the document. * `("...")`: The string wrapped in a pair contains the JavaScript code. It is injected at the end of the document. * `("..."` *start* `)`: The string contains the JavaScript code which is injected at the end of the document if *start* is `#f`. Otherwise, the JavaScript code is injected at the beginning of the document. * `("..."` *start main* `)`: The string contains the JavaScript code which is injected at the end of the document if *start* is `#f`. Otherwise, the JavaScript code is injected at the beginning of the document. Boolean *main* specifies if the code is injected only into the main frame or all frames. Argument *viewport* specifies the view port of rendered documents. Supported are the following values: * `()`: No view port is being defined explicitly. * `#t`: The view port is constraint by the width of the client with a transparent background. * `#f`: The view port is constraint by the width of the client, setting the following other parameters: `initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no`. This is the default. * `"..."`: The view port is defined via the following meta tag: `` Argument *name* defines the name of the application that appears in the user agent string. *delay* specifies the delay in seconds before taking snapshots to allow dynamic content loading (default: 0.0). **(web-client? *****obj*****)**

Returns `#t` if *obj* is a web client object, `#f` otherwise. **(web-client-busy? *****web-client*****)**

Returns `#t` if the web client is currently processing a request, `#f` if it's available for new snapshotting requests. Web clients process requests sequentially to avoid conflicts. ## Crop Modes The various snapshot procedures support six different *crop modes* for controlling what portion of the web page to capture: * **all**: Capture the entire web view bounds, including any empty space. * **trim**: Automatically detect and capture only the content area, trimming empty margins. * **(inset *****top right bottom left*****)**: Crop by insetting the specified amounts from the web view edges. * **(inset-trimmed *****top right bottom left*****)**: Crop by insetting the specified amounts from the automatically detected content area. * **(rect *****x y width height*****)**: Capture a specific rectangular region (standard representation of rectangles). * **((*****x***** . *****y*****) . (*****width***** . *****height*****))**: Alternative rectangle form. * **(rect-trimmed *****x y width height*****)**: Rectangle relative to the trimmed content area. ## Image snapshots **(web-client-snapshot-html *****client html crop-mode*****)**

\ \&#xNAN;**(web-client-snapshot-html *****client html crop-mode width*****)**\ \&#xNAN;**(web-client-snapshot-html *****client html url crop-mode*****)**\ \&#xNAN;**(web-client-snapshot-html *****client html url crop-mode width*****)** Captures an image snapshot of HTML content provided by the string *html* to the web client *client* and returns a future referring to the captured image. *url* is the base URL used for resolving relative resources. It is optional and can be set to `#f`. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`. For details, see section on *Crop Modes*. *width* defines a width for the rendered document and overrides, if provided, the width defined by web client *client*; default is `#f`. **(web-client-snapshot-data *****client data mime*****)**

\ \&#xNAN;**(web-client-snapshot-data *****client data mime encoding*****)**\ \&#xNAN;**(web-client-snapshot-data *****client data mime encoding url*****)**\ \&#xNAN;**(web-client-snapshot-data *****client data mime encoding url crop-mode*****)**\ \&#xNAN;**(web-client-snapshot-data *****client data mime encoding url crop-mode width*****)** Captures an image snapshot of content provided by the bytevector *data* of mime type *mime* to the web client *client* and returns a future referring to the captured image. *encoding* is a string specifying the encoding of the data; default is `"UTF-8"`. *url* is the base URL used for resolving relative resources; default is `"http://localhost"`. *crop-mode* defines what portion of the document is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. *width* defines a width for the rendered document and overrides, if provided, the width defined by web client *client*; default is `#f`. **(web-client-snapshot-file *****client path dir*****)**

\ \&#xNAN;**(web-client-snapshot-file *****client path dir crop-mode*****)**\ \&#xNAN;**(web-client-snapshot-file *****client path dir crop-mode width*****)** Captures an image snapshot of HTML content provided by the file at *path* to the web client *client* and returns a future referring to the captured image. *dir* is the base directory used for resolving relative file resources. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. *width* defines a width for the rendered document and overrides, if provided, the width defined by web client *client*; default is `#f`. **(web-client-snapshot-url *****client req*****)**

\ \&#xNAN;**(web-client-snapshot-url *****client req crop-mode*****)**\ \&#xNAN;**(web-client-snapshot-url *****client req crop-mode width*****)** Captures an image snapshot of HTML content by *req* to the web client *client* and returns a future referring to the captured image. *req* is either a URL or an HTTP request created with library `(lispkit http)`. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. *width* defines a width for the rendered document and overrides, if provided, the width defined by web client *client*; default is `#f`. ## PDF snapshots **(web-client-pdf-snapshot-html *****client html*****)**

\ \&#xNAN;**(web-client-pdf-snapshot-html *****client html crop-mode*****)**\ \&#xNAN;**(web-client-pdf-snapshot-html *****client html url*****)**\ \&#xNAN;**(web-client-pdf-snapshot-html *****client html url crop-mode*****)** Captures a snapshot of HTML content provided by the string *html* to the web client *client* and returns a future referring to a PDF document containing the captured snapshot serialized into a bytevector. *url* is the base URL used for resolving relative resources. It is optional and can be set to `#f`. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`. For details, see section on *Crop Modes*. **(web-client-pdf-snapshot-data *****client data mime*****)**

\ \&#xNAN;**(web-client-pdf-snapshot-data *****client data mime encoding*****)**\ \&#xNAN;**(web-client-pdf-snapshot-data *****client data mime encoding url*****)**\ \&#xNAN;**(web-client-pdf-snapshot-data *****client data mime encoding url crop-mode*****)** Captures a snapshot of content provided by the bytevector *data* of mime type *mime* to the web client *client* and returns a future referring to a PDF document containing the captured snapshot serialized into a bytevector. *encoding* is a string specifying the encoding of the data; default is `"UTF-8"`. *url* is the base URL used for resolving relative resources; default is `"http://localhost"`. *crop-mode* defines what portion of the document is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. **(web-client-pdf-snapshot-file *****client path dir*****)**

\ \&#xNAN;**(web-client-pdf-snapshot-file *****client path dir crop-mode*****)** Captures a snapshot of HTML content provided by the file at *path* to the web client *client* and returns a future referring to a PDF document containing the captured snapshot serialized into a bytevector. *dir* is the base directory used for resolving relative file resources. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. **(web-client-pdf-snapshot-url *****client req*****)**

\ \&#xNAN;**(web-client-pdf-snapshot-url *****client req crop-mode*****)** Captures a snapshot of HTML content by *req* to the web client *client* and returns a future referring to a PDF document containing the captured snapshot serialized into a bytevector. *req* is either a URL or an HTTP request created with library `(lispkit http)`. *crop-mode* defines what portion of the web page is being captured. It is either a rectangular object or has one of the following forms: `all`, `trim`, `(inset top right bottom left)`, `(inset-trimmed top right bottom left)`, `(rect _x y width height_)`, or `(rect-trimmed x y width height)`; default is `all`. For details, see section on *Crop Modes*. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://www.lisppad.app/libraries/lispkit/lispkit-draw-web.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.