FR2796479A1 - Creation of a hypertext document depending on another in a client terminal using client software to create visual effects - Google Patents

Abstract

The first hypertext document (D1) is received by the client from the server. The client extracts (E3) graphical presentation data (ZI1) from the first hypertext document. The presentation of the second hypertext document (D2) is determined (E4) dependent on local parameters (BP,BM). The first document is then erased and the second document processed to display the graphic image.

Description

<B> Creating a <B> hypertext <B> document in dependence on <B> another in a <B> client <B> </ B> terminal. general the creation of hypertext documents, for example the modification of these. It is directed more particularly towards the creation of an image contained in a second hypertext document and to be displayed in a client terminal, hereinafter called "client", in dependence on an initial image contained in a first hypertext document transmitted by a client. server to the customer through a high speed transmission network, such as the Internet. The Internet is based on a client-server structure that uses the Hypertext Transfer Protocol (HTTP). If a client asks the server for a hypertext document, also known as a Web document, the client connects to the Internet, the document is transferred from the server to the client, and the client disconnects from the network. Hypertext documents are most often expressed in Hypertext Markup Language (HTML). Tags in this language define the logical structure of a hypertext document.

Hypertext documents are identified by an addressing system. Each hypertext document, as well as the elements included in the document, are identified by a URL (Uniform Resource Locator). The hypertext document can exist statically on the server or can be dynamically created in the server at the time of the request of the document by the client. This technique is transparent to the customer. The types of documents a client loads and how the client interacts with a document depend on the functionality of the programs used in the browser installed in the client.

Web applications are divided into two categories depending on where they are running the server-side applications and the client-side applications. Applications in the server are responsible for creating and making data available. Applications in the client are responsible for data visualization and user interaction management. The SER server has the ability to edit an existing document before sending it to the client who requested it. The server consults the document, looks for instructions embedded in the document and replaces them with objects requested in instructions by the client. For example, objects are lines of text, images, or other interactive dynamic objects that are created when the document is viewed. This technique is transparent to the user of the client terminal which only displays the result of such a modification.

According to a first SSI (Server Side Includes) technique, pieces of a first document are added in a second document. These songs can be created by an external program. This technique makes it easy to maintain a large number of documents that are available on an HTTP server. The number of statements is constrained, but these instructions support command line calls from the server operating system.

A second technique is based on a server-side software platform, the Active Server Pages (ASP), which uses instructions embedded in a first HTML document and also small programs, scripts expressed for example in the language of VisualBasicScript programming (trademark). The scripts are interpreted by, an interpreter that is integrated into the server. This type of Web application depends on the server's operating system and is developed for access to at least one database. The client then receives a second standard HTML document resulting from modification of the first document, or even a substitution of the first document.

These techniques have the disadvantage of increasing the tasks of the server, so that the analysis of a document in the server lowers the power of the server. On the CL client side, the browser - a graphical interface in the terminal to view a hypertext document - interprets HTML tags and performs graphic presentation. Hypertext documents may contain images and other non-textual elements. If the browser finds such an element in a hypertext document, it automatically loads the corresponding data using the HTTP communication protocol. The presentation of different types of media such as text, images, video, sounds, etc., requires specific software. The media type is identified by the Multipurpose Internet Mail Extensions (MIME) standard format that contains the media type and file extension: type / extension. The SER server adds, in the header of a response to an HTTP request, the specification of the type of the document sent. The browser recognizes the type of document and selects in a table the correct presentation of the document. The basic types of media are, for example, text / html commands, or image / gif graphic images that can be displayed directly by the browser. For other types, the browser uses auxiliary programs in correspondence with the type of document.

The browser uses an object model to view elements of a hypertext document. All items displayed on the client terminal screen are treated as objects. Such an object has attributes, either with values defined in the HTML code, or with default values if there is nothing to specify. Values are attributes at the time of viewing HTML documents. These values could be modified using a script, applying another value to the attribute. But some attributes are read-only and the script is unable to modify the values of these attributes.

For example, the image inclusion HTML <IMG> tag always contains the SRC attribute whose value is the URL of the file containing an image stored in the server. The <IMG> tag can contain the following optional attributes - NAME whose value is a name identifying the image in the object model of the hypertext document - ALT whose value is an alternative name displayed in place of the image if especially the source is not available; - HEIGHT whose value in pixels indicates the height of the image on the screen; - WIDTH whose value in pixels indicates the width of the image on the screen. If the height and width of the image on the screen are not specified in the attributes of the <IMG> tag, the browser views the image in its original size. By taking other values for the height and width imposed by the server, the size of the image to be viewed in the client can be increased or decreased.

The display area reserved for an image on the screen of the client terminal is set proportionally by the server before the hypertext document is viewed by the browser. For this reason, the height and width attributes of the image are read-only. Changing the values of these two attributes involves updating the graphical presentation of the rest of the document by the server. Thus, according to the prior art, an online image that automatically appears in a window determined by the server under the control of the browser in the client terminal in response to a hypertext document transmitted from the server to the client can not be directly modified in size. in the client terminal, for example to zoom in on the image. The object of the invention is that a hypertext document transmitted by the server can be modified in the client terminal, which will relieve the server if it were to make such a modification and which increases the speed of transmission. execution of the modification. In other words, the invention aims at creating in the client terminal a second graphic presentation which depends on a first graphic presentation which is defined in a first hypertext document initially transmitted by the server.

To achieve this objective, the invention proposes a method for creating a second hypertext document in dependence on a first hypertext document provided by a server connected to a client terminal through a transmission network, characterized in that it comprises the steps in the client terminal after receiving the first hypertext document and displaying the graphic presentation corresponding thereto - retrieving data from at least the graphic presentation of the first hypertext document - determining the graphical presentation of the second hypertext document in dependence on the data recovered and local parameters; - delete the first hypertext document so that the graphic presentation of it is no longer visible; and - write the second hypertext document to display the graphic presentation thereof. Despite the impossibility of reading and therefore modifying size attributes of the graphic presentation, such as image, of the first hypertext document, as will be seen in the detailed description, the invention succeeds in replacing in the client terminal the first hypertext document by a second hypertext document whose graphic presentation depends on that of the first document.

In practice, the erase step consists in overwriting the first hypertext document by means of a script written in a third hypertext document transmitted by the server to the client terminal. Since it is not possible to overwrite a hypertext document containing a script, the invention makes use of the notion of zones (FRAMES). More precisely, the invention provides two hypertext documents whose graphic presentations are zones juxtaposed on the screen of the terminal and put together in a common document, so that one of the two hypertext documents containing the script is not deleted, while the other document is the first document to be replaced by the second document.

Thus, according to features of the invention, the first hypertext document may have a graphic presentation which is an area included in the graphic presentation of a hypertext page displayed in the client terminal. In particular, the local parameters may comprise at least one variable having a value selected locally in the client terminal by a user, and said variable may have its value selected by at least one button included in the graphic presentation of a third hypertext document which is linked to the first and second hypertext documents by at least one function for the determining step, said function being integrated in the third document. In general, several functions are written in the script contained in the third document.

The step of determining may comprise, for example, a modification of the content of the first hypertext document.

Prior to the determining step, the method preferably comprises a step of calling at least one function with said local parameters integrated in a third hypertext document transmitted with the first hypertext document by the server, said function being used for the step of determining . According to a preferred embodiment, the calling function is an enlargement or an image reduction with an enlargement or reduction ratio as a local parameter. Other features and advantages of the present invention will emerge more clearly on reading the following description of several preferred embodiments of the invention with reference to the corresponding appended single figure <B> 1 </ B> which is an algorithm of a method of creating a hypertext document according to the invention in a client terminal. As schematically shown in the upper part of FIG. 1, a client terminal CL and a server SER are connected in particular via a high-speed data transmission network, the WWW Internet network to which reference will be made, or an intranet network. The messages exchanged between the client and the server are requests according to the Hypertext Transfer Protocol (HTTP). A request is a URL (Universal Resource Locator) specifying, in particular, following the HTTP protocol name, the name of the server and the name of a document (directory and page) to be displayed in the client terminal CL or the name of the client. a library of functions to be processed in the SER server.

The client terminal is called in the "client" CL to designate the software and hardware resources in the terminal.

The server and the client present the software and hardware features already presented in the preamble of the description. In particular, a browser in the client can interpret the hypertext document description language (page) of HTML screen to display text or image in browser windows that are possibly enriched with elements multimedia and which are generally interactive by means of inserted hyperlinks.

In addition to specific software that helps to present different types of media, the CL client supports a scripting language, such as the JavaScript language (registered trademark), which supplements the HTML language in order to animate HTML pages and open windows. .

The scripts of a Web application executable in the client are either integrated directly into the hypertext HTML document whose graphic presentation, such as an image, is for example to be displayed, or transmitted separately in another hypertext document linked to several hypertext documents. The browser launches a script either when loading the hypertext document, or after an event or an interaction defined in the hypertext document. Events, such as mouse interactions, are directly applied to HTML tags. Scripts are often used to validate data entered into a form as a hypertext document.

Each element of a hypertext document, as well as the browser itself, is treated as an object with a number of properties. With methods that are applied by the script and additional functions provided by the script, certain properties, also called attributes, of objects are modifiable so as to modify the structure and layout of a web document dynamically. This technique is based on the Document Object Mode 1 (DOM) object model.

The fusion between the scripting languages and the DOM model, called the DHTML dynamic language (Dynamic HTML), allows, thanks to the dynamic object processing, the realization of simple animations directly in an HTML page. JavaScript uses a hierarchical object model. To access an object, you must navigate the hierarchy from the level where a function was performed. Below the browser object, we have the window object "WINDOW". The window object groups together "DOCUMENT" objects, "FRAME" fields, "HISTORY" history and "LOCATION" position. The document object includes objects such as anchors "ANCHORS", "DOCUMENTS", "FRAMES" fields, "HISTORY" history and "LOCATION" position. A "FORM" form object can contain objects of the "BUTTON" button type, "CHECKBOX" option group, "TEXTAREA" editable text box, and so on. As already stated in the preamble of the description, an image object "IMG" has attributes "SRC", "NAME", "ALT", "HEIGHT" and "WIDTH".

The height and width attributes of a graphic layout, such as image, are read-only and can not be changed by a script in the client. In this context, the invention aims to overcome this obstacle to the change in size of a first graphic presentation to create from it a second graphic presentation. With reference to FIG. 1, it is assumed at the beginning of an exchange session between the client CL and the server SER that, at a step EO, the client CL has requested a composite hypertext document DC, for example by having filled in a field or selected an option from a list on a server home page and then triggering an HTTP request to the SER server by requesting a SUBMIT submit button. The server then establishes an HTTP response containing the HTML hypertext document in HTML and sending it to the CL client.

Upon receipt of the HTTP response, the PG graphical presentation of the hypertext document DC, as an HTML page, is immediately displayed by the browser in the client CL, at a step E1. As shown in FIG. 1 by way of example, the graphical presentation PG of the composite document DC is an image divided into several zones (frames), here at the numbers of three a background zone ZB presenting for example instructions, a zone ZI1 containing an image, in this case a map of France , and a function zone ZF. The latter has two BP and BM control buttons to "zoom" on the image in the area ZI1, that is to say respectively to zoom in by zooming the image and to zoom out the image, after having placed the cursor of a mouse of the client terminal CL on the respective one of the buttons BP and BM.

The following process steps E2 to E6 executed only in the client CL relate only to a modification of the image area ZI1. Indeed, each zone ZB, ZI1 and ZF is a graphic presentation of a respective HTML hypertext document DB, D1, DF in its own right and therefore these zones have evolutions relatively independent of each other if no link is provided. between them. In this case, the image zone ZI1 is modifiable although during this image modification the other two zones ZB and ZF can be kept without modification. The composite document DC is thus a "parent" vis-à-vis "son" constituted by hypertext documents whose graphic presentations ZB, ZI1 and ZF are perfectly delimited between them. The window constituted by all the zones is indicated by a <FRAMESET> tag in HTML language whose "ROWS" and "COLS" attributes indicate the horizontal and vertical divisions in zones. Each zone is indicated by a respective <FRAME> tag constituting an "HTML object" including in particular the SRC address of the corresponding hypertext document, the name of the document and the margins between the limits of the zone and the document actually to be displayed.

In the illustrated example, a "parent.display" link exists between the ZF function area and the ZI1 image area to enlarge or reduce the image in zone ZI1, locally in the CL client.

As already stated, it is not possible to directly modify at the client level the size, height or width of the image ZI1, since the height attributes "HEIGHT" and width "WIDTH" of the corresponding hypertext document are accessible only read-only in the CL client.

In step E2, a script expressed in JavaScript language and integrated into the hypertext document DF is launched by clicking on one of the BP and BM command buttons contained in the ZF function area. According to the invention, the zones ZF and ZI1 constitute a set of two graphic presentations of two hypertext documents DF and D1 indicated by a <FRAMESET> tag in HTML language.

The script offers two features that are respectively sensitive to the BP and BM control buttons. Each feature, when called, includes analogous steps E3 to E6 presented below. With the help of the script, all the values of the attributes of the object model of the hypertext document D1 relating to the zone ZI1 can be consulted, although this model of object relates to another document not containing the script but simply linked to the hypertext document DF containing the script since the two documents D1 and DF are parts of a common set indicated by a <FRAMESET> tag.

The functionality of the script linked to the button BP or BM having been called, the script retrieves in step E3 the data of the hypertext document D1, that is to say at least the data relating to the image area ZI1, necessary to later create a second hypertext document D2 whose graphic presentation Z12 is reduced or enlarged with respect to the image ZI1. These data are combined with local variables of the functions called to determine in step E4 the new size of the graphic presentation Z12, in this case that of the map of France, which is an enlarged or reduced size according to the button BP or BM has been solicited. In this case, the data are the size, height and width of the "first" image ZI1 defined in the first document D1 transmitted by the server and loaded in the client, as well as the graphic characteristics according to the encoding format of the image, for example the Graphics Interchange Format (GIF) format. This data is included in particular in the values of the attributes SRC, HEIGHT and WIDTH of the tag <IMG> corresponding to the hypertext document D1 of the first image ZI1.

For example, the first document D1 corresponds to the smallest image to be displayed inscribed in a screen window of width W and height H, so that image enlargements, or zoom in, can be deduced by copying each pixel of the smallest image according to the percentage selected by the button BP, then in subsequent cycles indifferently by the button BP or BM. All the images resulting from solicitation of the BP and BM buttons thus contain the pixels of the initial image ZII and can be deduced each from the previous one. At the bottom of FIG. 1, part of a second image Z12 of size (2W.2H) deduced from the image ZI1 by a magnification of ratio 2 is written in the window W.H.

At the end of step E4, the client contains in memory the graphic characteristics of the second image Z12 whose size may be larger or smaller than the fixed size W.H of the display window. A second image embedding tag <IMG> is constructed on the basis of the second determined image Z12, and the second hypertext document D2 is created with for graphic presentation the second image Z12 which differs in size with the graphic presentation ZI1 of the first hypertext document D1.

The second hypertext document D2 being established, the first hypertext document D1 is then erased in the client CL, by a command "CLEAR" overwriting the script, in step E5.

The second document D2 is then written in step E6 in the set of function area and image area, in substitution of the first document D1, using the "WRITELN" method of the script. In the second D2 document, the values of the HEIGHT and WIDTH attributes have changed. The user of the client terminal displays the second image, generally enlarged relative to the first image, by scrolling it in the image area window WH by means of horizontal scroll bars BH and vertical BV along the zone image.

After step E6, the user can decide in step E7 to choose another modification, enlargement or reduction, by requesting the execution of another cycle of steps E1 to E6 starting with another solicitation of one BP and BM buttons. During this other cycle, a third image determined in step E4 is created according to the previous image, said second image Z12, and so on.

However, after step E6, the user may wish to return to the current exchange session between the CL client and the SER server, as indicated in E8. The second hypertext document D2 created in the previous steps is an HTML document that is capable of being transmitted in an HTTP request by the client to the server.

Claims (1)

CLAIMS 1 - Process for creating a second hypertext document in dependence on a first hypertext document provided by a server (SER) connected to a client terminal (CL) through a transmission network (WWW), characterized in that it comprises the following steps performed in the client terminal after reception (E1) of the first hypertext document (D1) and display of the graphic presentation (ZI1) corresponding to it - retrieving (E3) data at least from the graphic presentation (ZI1) the first hypertext document (D1); - determining (E4) the graphical presentation (Z12) of the second hypertext document (D2) in dependence on the recovered data and local parameters (BP, BM); - erase (E5) the first hypertext document (D1) so that the graphic presentation (ZI1) thereof is no longer visible; and - writing (E6) the second hypertext document (D2) to display the graphic presentation (Z12) thereof. 2 - Process according to claim 1, wherein the first hypertext document (D1) has a graphic presentation (ZI1) which is an area included in the graphic presentation of a hypertext page (DC) displayed in the client terminal. 3 - Process according to claim 1 or 2, wherein the local parameters comprise at least one variable (BP, BM) having a value selected locally in the client terminal (CL) by a user. 4 - Process according to claims 2 and 3, wherein said variable has its value selected by at least one button (BP, BM) included in the graphical presentation (ZF) of a third hypertext document (DF) which is linked to the first and second hypertext documents (D1, D2) by at least one function for the determining step (E4), said function being integrated in the third document. 5 - Process according to any one of claims 1 to 4, wherein the step of determining (E4) comprises a modification of the graphical presentation (ZI1) of the first hypertext document (D1). 6 - Process according to any one of claims 1 to 4, comprising before the step of determining (E4), a step of calling (E2) at least one function with said local parameters integrated in a third hypertext document (DF ) transmitted with the first hypertext document (D1) by the server (SER), said function serving for the step of determining (E4). The method of claim 6, wherein the calling function is an enlargement or reduction of an image with an enlargement or reduction ratio as a local parameter.