# (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*.