What’s new in 4D v20

Meet QUIC

As the number of simultaneous connections to the biggest production servers running on 4D continues to grow, ensuring optimal performance has become a top priority for development teams. The QUIC protocol has emerged as a promising solution to address this challenge.

QUIC is a protocol designed to enhance speed and performance in server-side networks. Developed by Google over the last decade, QUIC leverages the benefits of UDP instead of TCP to enable faster recovery in case of packet loss, congestion, and other issues. QUIC is today heavily used, for example, in HTTP/3 as “HTTP over QUIC” and supported by all major browsers, already used in more than half of all connections to Google’s servers. Facebook handles more than 75% of its internet traffic using QUIC, and many apps, such as YouTube, Gmail, or Uber, are using QUIC to communicate with their servers.

We encourage you to try QUIC and provide us with your feedback to help us improve and refine this exciting new technology, paving the way for its inclusion in future releases of 4Dv20. And keep in mind that QUIC can improve the resilience of the 4D infrastructure, making it better equipped to handle bad connections and other network challenges.

Built-in Websocket Server

WebSocket protocol provides a persistent, full-duplex communication channel between a client and a server. It enables real-time data transfer between the two parties and allows faster and more efficient communication.

4D v20 now includes a built-in WebSocket server, allowing developers to build real-time web applications that can handle large volumes of data and provide a seamless user experience.

This opens up a world of possibilities for real-time data visualization, collaborative applications, and IoT applications that require instant updates.

Object and collection literal initializer 

Objects and collections can be initialized in your code using New object and New collection commands.

4D v20 introduced a new and more readable syntax to initializing large or complex objects and collections in your code – the object literal and collection literal.

With object literals, you can initialize an object with its properties and values enclosed in curly braces {}. For example, instead of using the New object command, you can create a new object and initialize its properties in a single line of code like this $object1 := {a : “foo”; b : 42+26; c : {}; d : [“coucou”; “rien”]}.

Similarly, with collection literals, you can initialize a collection with its elements enclosed in square brackets [].

New commands to lock the datastore 

4D provides you with multiple built-in ways to back up your data: 4D backup and the use of a mirror server. With 4D v20, 4D exposes internal commands to lock the datastore, allowing you to copy your data while 4D is running. Say hello to ds.flushAndLock(), ds.locked(), and ds.unlock().

Declaring Class Properties 

4Dv20 brings you a new feature that will ease the use of your classes: declared class properties. Declaring your class properties will significantly improve autocomplete and give you meaningful errors when compiling. Declaring a class property is easy; it uses the same syntax as declaring variables but with the keyword property: property myProperty : text.

Automatic integration of multiple journals 

4D v20 introduces a powerful new feature that can greatly improve your productivity during database maintenance operations. You can focus on developing your application by automatically integrating multiple journals at database startup rather than spending time on manual database management tasks.

To take advantage of this feature, simply ensure that the “Integrate last logs if the database is incomplete” setting is activated, which is the default. Then, place the journal files you wish to integrate next to the current one. 4D will automatically detect any missing operations in the startup database and check all journal files to determine if recovery is possible. If there are no problems, it will integrate the operations from all of the journals without any intervention required on your part.

Build an application with 4D commands 

4D has continuously added new features to help developers create their own build chain, providing greater flexibility and customization options for their applications. These features include the ability to create a “.zip” folder, add additional information such as the copyright on an executable or a “dll”, and create an “info.plist” file.

With the release of 4D v20, two new features have been added to make the process of creating standalone or client/server applications even easier:

1. Adding an Icon to an Executable.
2. Generation of Deployment License File.

A tool for 4D code execution in CLI 

4D v20 brings a new application called tool4d. This application is a subset of 4D designed for your build chain to automate the build process and is dedicated to headless script execution through Command Line Interface. But it also provides the LSP server, which is in communication with the VS Code extension.

4D-Analyzer extension 

This extension got much attention from our 4D developers, and we couldn’t be happier!

4D brought Visual Studio Code code editor support, allowing it to handle 4D code and provide it with standard functionalities such as syntax highlighting, Go To Definition, Signature Help, and code completion.

4D v20 brings new capabilities to the Visual Studio Code editor through the 4D-Analyzer extension: Say hello to code folding & indentation, and syntax checking.

Meet the Improved Distinct Function

The distinct function of the Collection and Entity selection classes allows retrieving a list of unique values.

With 4D v20, you can also retrieve the number of occurrences of each distinct value. Additionally, it allows retrieving all attributes path used in an object field. This functionality can be beneficial when working with large datasets and needing to analyze the frequency of specific values.

Comparison with an Undefined Value

With the introduction of ORDA and other objects in 4D, developers often work with undefined values, sometimes leading to errors when comparing them with different values.

Starting with 4D v20, a new improvement was introduced that allows developers to compare any type of value with an undefined value without throwing an error. This means you can now safely compare undefined values with others without worrying about causing an error in your code.

Introducing the Latest Find and Replace Features

The “Find and Replace” feature in the code editor has existed for many years. Developers can quickly and efficiently search and replace code, especially when dealing with large codebases. 4D v20 is bringing improvements that are sure to be appreciated by developers who rely on this functionality to streamline their coding workflows:

• knowing the number of occurrences to replace,
• knowing the position of the current occurrence,
• having permanent access to the Next and Previous navigation options,
• display a palette instead of a modal window to limit the number of clicks.

Passing form object to Print Form and FORM LOAD commands

With 4D v20, the Form command is supported with Print form and FORM LOAD. Form, with previous versions available for DIALOG or subforms, allows drastically reducing the need for process variables and writing more portable and isolated code. This a welcome improvement to 4D that will undoubtedly make developers’ lives easier and more productive.

Create your own Help Menu

With 4D v20, you can create a custom “Help” menu for your application by passing a collection describing the menu items. This, for instance, allows you to provide your users with easy access to documentation, support, and other helpful resources.

New handy functions for collections 

4Dv20 provides a set of functions to manipulate collections. Besides the over 40 methods we already provided in the previous version, this release gives you:

• first() and last(), as their names indicate, allow access to the first and the last element of a collection.
• The at() function is also an alternative to square brackets (col[x]) with a benefit; the value can be negative to get the items from the end.
• The flat() function is more innovative and will be very useful in some cases. It allows the flattening of collections that can contain collections (that can also include collections, etc.).
• The includes() function is handy because it allows knowing if a collection contains this or that element of almost any type… text, numeric, date… and even references of objects or collections.
• The new reduceRight() that is the optimized equivalent of reverse().reduce()
• The flatMap() function allows us to perform, in a single operation, a map() followed by a flat() – a function that we mentioned before.

PDF format for Print Previewing on Windows

PDF format has now become a viable alternative to XPS for print previewing on Windows, providing users with a new and more accessible option. Microsoft’s decision to make the XPS Viewer an optional Windows feature has caused issues for many users when deploying applications, resulting in end-users being unable to preview their printings. Although installing the free XPS Viewer is a straightforward process, some administrators are hesitant to install additional features, particularly on Remote Desktop environments.
Fortunately, 4D v20 now offers the option of using the PDF format for print previewing. Since almost all current Windows versions have either XPS or PDF pre-installed, end-users should no longer encounter issues with print previewing. This new option offers a more flexible and efficient solution that meets the needs of both end-users and administrators.

Return. Continue. Break. And more

We listened to and followed your feature requests in 4D Forum with several 4D language improvements!

• Starting with statements that allow you to jump out of a block of code:
  • The return keyword terminates the execution of the method or function in which it appears and returns control to the calling method. It can also return an optional value.
  • The break keyword terminates the loop containing it. The following statement executed is the one immediately after the loop’s body.
  • The continue statement terminates the statements’ execution in the current loop’s current iteration and continues the execution of the loop with the next iteration.
• Followed by short-circuit evaluation: In an expression that uses an AND or OR operator, a short-circuit evaluation means that the second argument is executed or evaluated only if the first argument does not suffice to determine the value of the expression. We add two new operators to do it:
  • && for the AND operator
  • || for the OR operator
• And then there is a ternary operator, which is a condition followed by a question mark ( ? ), an expression to evaluate if the condition is truthy followed by a colon (:), and finally, the expression to evaluate if the condition is false: condition? value If True: value If False.

Error Handling

4D v20 is bringing new possibilities to error handling. From now on, you can define a global error handler that will be efficient for all execution contexts (processes, workers, ORDA computed attributes, ORDA functions, etc.). If you miss defining a local error handler in a new process/worker, the global error handler will be invoked automatically. This means no more error dialog displayed on the server or uncaught errors.

Visualize your classes components in the method explorer

4D already allows applications still running in binary mode to take advantage of class features by using a component (in project mode) to create and use your own classes from your (binary mode-based) application. This feature included tips and code completion support to smooth your code writing.

To make your coding experience even easier, 4D v20 is bringing a new feature. From now on, you can visualize a list of all the available component classes in the method explorer, so you decide in a glimpse of an eye which functions you need to use in your code.

Support of larger integers than integer32

So you need larger numbers than 2 Billion (32 bits) with high accuracy for counters or similar? We enhanced reals and the way they’re handled to allow that. While reals are known to be imprecise, they are 100% accurate even for very large numbers, as long as they do not use a decimal point (=integers). This lets you use numbers up to 53 bits, or more exactly, [-(2^53)+1, (2^53)-1]. So a range from −9,007,199,254,740,992 to 9,007,199,254,740,992 will be exactly represented.

Converting to or from the text was limited to using 12-digit scientific notation, resulting in a loss of precision. With 4D v20, we have improved the accuracy and conversion of any Real number (presenting an integer) into a Text. The improvement of the conversion to string concerns the String() command and the JSON and XML commands returning numbers in string form.

Support of Formulas in Collections & Callback Commands

To give a simpler way to use collections with a member method that needs a callback method, 4D allows you to use a formula to define a callback in:

• the collection member functions: every(), .filter(), .find(), .findIndex(), .map(), .orderByMethod(), .reduce(), .some(), .sort()
• the EXECUTE METHOD IN SUBFORM, 
• CALL FORM,
• and CALL WORKER commands.

Allow components to publish classes

Suppose your application is still running in binary mode. In that case, this feature will enable you to benefit from classes and object-oriented development by using a component (in project mode) to create and use your own classes from your (binary mode-based) application. So starting with 4D v20, a new Component section is added to Structure settings -› General allowing you to configure how your component classes and functions will be exposed in the 4D method editor once the component is installed.

Forward parameters from a function or method to another

With 4D v20, developers don’t have to handle complex parameter checks (count parameters, value types) when calling a function and passing parameters.

A new command is provided, Copy parameters, allowing to easily pass parameters used for a function or method call to another function/method. This results in lighter, more elegant, and easier-to-read code. 

Form and subform communication

Starting with 4D v20, associating a variable with a subform has enriched the possibilities of interfaces and communication between forms and subforms. The means of communication are now simplified by two new commands: OBJECT Get subform container value and OBJECT SET SUBFORM CONTAINER VALUE. 

New command to get detailed information about licenses

4D v20 is shipped with a new command that gives all the information about your license usage: Get License Usage. We have also expanded our diagnostic logs. Thanks to getting this feature, you’ll be able to follow the license consumption on your server, optimize your usage and plan ahead for your future needs.

More options for OBJECT SET enterable command

The OBJECT SET ENTERABLE command has been enhanced, enabling you to better manage a field that is not editable. As a third parameter, the command supports a boolean or an integer. 

• So, you can use the command as before without changing your code by passing a boolean. Only the enterable property is modified (False or True).

• Or you can pass an integer. Thus, you can set the enterable and focusable property for your field.

Accessing method parameters that don’t exist

4D v20 allows access to all the method parameters without error, even if some were not passed by a caller. The code is more straightforward and readable without the repeated “if” keyword.

Create a blob attribute in an object

With the introduction of classes, the need for storing data in objects has increased, especially data in the form of blobs. For this reason, 4D v20 supports the encapsulation of blobs in objects.

Beyond the storage aspect, since the blob object is a reference type, your memory usage will be lower, and your speed performance will be greatly enhanced.

Byte Order Mark (BOM) and End of Line (EOL) management

4D has evolved smoothly to follow best practices regarding managing certain invisible characters in text files. That’s why from now on, 4D writes text files without a BOM. And on macOS, 4D uses LF as an EOL character. This is completely automatic for all files written by 4D, such as 4DSettings, 4dm, 4DForm, etc.

As for compatibility settings, new options are available allowing TEXT TO DOCUMENT and File.setText() to generate files without a BOM and use LF as an EOL character on macOS when the optional “charSet” and “breakMode” parameters are missing. For more details, check out the documentation.

Default .gitignore file in new projects

Project mode allows you to easily track changes with Git (version control system), but often you don’t want to track your project files in the Git repository. 4D v20 lets you define what not to track in a new project by automatically adding a default .gitignore file in the project folder with a list of default files and folders to exclude.

Automatic components Signing on Mac

With 4D v20 and on Mac, 4D automatically signs built components using the certificates defined by the user or an Adhoc signature if no certificate is specified. This allows component developers to distribute signed components so end users don’t have to sign them before using them.

Show online documentation directly from the code editor

You can access the details of a class function without having to search on the documentation site. Simply press the F1 key or click the Goto definition… item in the contextual menu.

POP3: Download the Mail Header Only

When retrieving email messages using POP3, it’s possible to retrieve just the message headers (which include information such as the sender, subject, and date) without downloading the entire message body.

Retrieving just the message headers can be helpful when you want to quickly scan the list of messages in your mailbox to decide which ones to download and read in full.

Starting with 4D v20, a new parameter is added to the POP3Transporter.getMail() function to receive your emails without the body. 

IMAP: Mailbox Id and mail keywords

4D v20 brings two handy features to IMAP Transporters:

The first feature is the ability to manage custom email keywords when interacting with specific IMAP mail servers and clients. Custom keywords allow you to tag emails with particular labels or categories, making it easier to organize and find them later. With this new feature in 4D v20, you can add, remove, or list custom email keywords using the IMAP Transporter.

The second feature is mailbox ID support in the IMAP Transporter. When you work with IMAP mailboxes, they can be renamed or moved, making tracking difficult over time. With the mailbox ID support in 4D v20, you can identify a specific mailbox even if it has been renamed or moved. This can be useful for keeping track of essential mailboxes, such as ones that contain archived messages or messages from specific senders.

Microsoft 365 native support

As more customers move to Microsoft 365 for their email needs, 4D v20 offers a solution to simplify email management.

The latest automation features allow for easy automation of Microsoft 365 email operations using built-in commands. These operations include:

• send, receive emails, and list your mailbox folders
• move an email from one folder to another,
• reply to an email and create a conversation,
• create a draft email and save it in the folder of your choice,
• and delete an email.

Microsoft365: folders management

Microsoft is deprecating Basic authentication for IMAP and POP3, which means that users will need to use a more secure authentication method to access their email data. The Graph API is a more secure and modern way to access data in Microsoft 365, including email data.

With the new functions in 4D NetKit, you can now manage (create, delete, rename, and get information) by programming your mailboxes using the Microsoft Graph API.

Get user information from Azure

Besides providing access to Office applications, Microsoft provides an Azure-based Active Directory, allowing users to log in to access services such as Microsoft Sharepoint or OneDrive using a Web Browser. All Microsoft services use the same Single Sign-On, based on the email address. From 4D v20, 4D NetKit allows you to be part of this concept, enabling users to log in to your application using their usual company credentials.

Besides allowing Single Sign-On, it will enable retrieving information on an authenticated user, such as email, department, and phone number. If the administrator permits, you can retrieve details about the user’s colleagues within the same company.

Bcrypt support for passwords

Starting with 4D v20, all passwords are hashed with the bcrypt algorithm. An algorithm takes much longer to compute, enough to prevent brute-force algorithms from recovering the original password.
To put it in place, everything is automatic. You don’t need to touch any setting or any line of code. When the password is changed in the toolbox or using the CHANGE PASSWORD or Set user properties commands, the bcrypt hash is stored. And during authentication, 4D recognizes automatically if the password is stored with legacy or bcrypt hash so that users continue to connect without changing their password. 

Quickly jump to different functions of a class

Classes are composed of several functions of varying lengths. So it is not always easy to find the function to modify or move from one function to another. It is possible to use explorer, which displays the classes and functions, but when you are coding in the editor window, you don’t want to waste time changing windows.

With 4D v20, the list of functions in your class is displayed in the code editor toolbar, allowing you to quickly jump to a specific function. 

Comment Tags

4D v20 takes comments to a new level with comment tags to better organize your comments. Tags are used to classify comments by simply putting the tag at the beginning of the comment line. We have put three tags at your disposal:

• MARK
• TODO
• FIXME

The MARK tag allows you to split your code into sections. You can write it in three different ways. The other two tags TODO and FIXME, are written similarly. The interest is that they have different icons in the list, which allows you to organize your code to prioritize your future actions.

Object Check Syntax 

Auto-completion simplifies code writing and limits errors in function names. But it doesn’t avoid them entirely; it’s easy to reverse two letters, to forget a capital letter. And then spend time looking for why your code doesn’t work. So what better way than to ask 4D to check if the classes or functions already exist? Starting with 4D v20, a warning is displayed in the code editor if you call a function that does not exist.

Code Editor Customization

In addition to customizing the window and the code area, 4D v20 brings two new customization options:

• Show or hide the ten clipboards. 
• The “show/hide lists” icon has been moved to the bottom right next to the lists.

Simplified navigation between code, documentation, and explorer

When creating a form or writing a new function or method, you usually need to:

• access the explorer to fill the form in its folder
• access the explorer to write the documentation for the method
• to see the documentation of a command on the 4D online site
• to see the documentation of a method of a component
• access the code of the function we want to use in our method to make some modifications
• navigate easily between the different functions of a class

In 4D v20, we’ve added menu items and a new list in the code editor, allowing you to better navigate a project’s different elements.

Show online documentation directly from the code editor

With 4D v20, you can access the details of a class function without having to search on the documentation site. Simply press the F1 key or click the Goto definition… item in the contextual menu.

Debugging on the server with scalable web sessions

Scalable web sessions were a significant improvement. They allow you to use 4D tags, 4D actions, and the REST API in preemptive processes, even in interpreted mode, on a 4D server. However, for debugging, you needed to open your development environment on the server to make it switch to cooperative mode, as the debugger window cannot be opened with preemptive processes. Starting with 4D v20, we simplified debugging on the server side by simply attaching the debugger to it.

New Windows System Rendering Engine

Starting with 4D v20, if you use the system rendering engine, 4D uses Microsoft Edge WebView2. This change allows you to benefit from a modern browser with the latest features and security updates. For example, Microsoft Edge can be used to display PDFs.

File Handles

When it comes to writing and reading, the setText and getText functions are at your disposal to read or write the entire content. 4D v20 brings file handles in case you want to read or add one or more lines to an existing document.

File handles are objects created based on “File” objects and have functions to access any part of documents and, from there, to read or write their content sequentially.

SUPPORT OF LZMA, THE NEW COMPRESSION ALGORITHM

With 4D V20, the Zip Create Archive command supports a new compression algorithm: LZMA. The advantage of this algorithm is that it creates smaller archives than the standard zip compression algorithm. You can pass a “zipArchive” object to the command to customize your zip. This allows you to choose the compression algorithm, the encryption algorithm, and other options.

Automatic Row Heights in Collection Based List Boxes

Automatic row heights were already possible for array-based list boxes, allowing them to automatically adapt the height of each row to its content. 4D v20 is bringing this possibility to list boxes based on collections and entity selections.

Say Goodbye to the ALT key

Regarding list boxes and the Drag and Drop action, starting with 4D v20, there is no need to hold the Alt key to move several items simultaneously.

Horizontal & Vertical Cell Padding

The power of list boxes is extended with 4D v20 thanks to two new properties: horizontal and vertical padding (the inner margins or the space between an element’s content and its border). They will give your list boxes new presentation possibilities, and your interface will have an even more professional look.

These properties can be set globally for the whole list box or for each element, like columns, headers, or footers. Once defined for the list box, they will be applied to every sub-object of the list box by inheritance. But of course, each sub-object can have its own settings.

Setting the padding can be done either:

• via design mode from the list of properties under “Coordinates and sizing.”
• or by programming using the LISTBOX SET PROPERTY command thanks to two new constants, lk cell horizontal padding, and lk cell vertical padding.

System Workers: Launch an external process asynchronously

4D v20 continues to bring enhancements to ORDA. Object Relational Data Access is an innovative way of accessing data that combines the advantages of object-oriented programming with those of relational databases, allowing developers to focus on solving business problems rather than managing data access. 

4D v20 brings: 

Users permissions management (REST Server) 

Optimization of performance with complete control over REST requests 

Compare two entity selections

You need robust and optimized functions to work efficiently with object-oriented programming and write as few lines of code as possible. That’s why, with 4D v20, we’re shipping a new function available on the entitySelection object: the selected() function. Thanks to it, you can inspect and compare two entity selections.

4D Write Pro has dramatically improved over the last few versions. In fact, we, the 4D team, are invested in making 4D Write Pro a potent template-based document generator, eliminating the need for manual document creation and reducing the risk of errors.

With 4D Write Pro, you can automatically feed and generate pre-filled documents with contextual information, pulling data directly from the 4D database. This includes information such as names, dates, address information, and numbers, among other types of data. 4D Write Pro then merges this information with your templates, providing a streamlined and efficient document creation process.

4D v20 introduces powerful features such as headers, datasources, and carry-over rows, to name just a few.  Whether you are a business professional or a developer, you will find these features to be extremely useful in improving your workflow and productivity.

4D Write Pro & Text Boxes: docx Import/Export Options

Text boxes allow you to insert a floating container, including text, tables, images, formulas, and other elements anywhere in your document. This feature has been improved in v20 to include exporting and importing these elements from and to docx documents.

Define data contexts

4D v20 opens the world of ORDA and object-oriented development to 4D Write Pro documents. 4D Write Pro documents often contain formulas returning data or calculations depending on the database. Thanks to contexts, associating that data with documents is as straightforward as using the This keyword. A perfect way to create templates and personalized documents with 4D Write Pro.

Dynamically fill tables with entity selections & collections

Manually filling the tables with data every time is a laborious task. And that’s where data context comes as an invaluable option, opening the world of ORDA and object-oriented development to 4D Write Pro templates.

It is now possible to define a “datasource” for the tables of 4D Write Pro. Whether it is an entity selection or a collection, this “datasource” will automatically feed the rows of these tables. The tables will automatically be enlarged based on the selection, even adding additional pages when needed. This allows the end-user of your application to design or modify templates that will be filled automatically with data.

Bottom Carry-Over Rows (subtotals)

Imagine having a big sales table potentially spanning several pages. At the end of one page, you’d like to calculate the subtotal, carry it over to the next page, and include it on the calculations on that page. This is often necessary, sometimes even legally required, when editing long invoices, for example.

4D v20 allows inserting a “subtotal” line at the bottom of each part of the respective tables that can be filled automatically.

This can be done either:

• Via both interfaces (toolbar and sidebar). The table menu contains a new item, “Bottom carry over row.”
• Or by programming, thanks to the new attribute wk bottom carry over row.

And to define the content of the cells in this carry-over row, the new attribute previousItems can be used with all available functions (min/max/sum/etc.) for collections or entity selections.

Tables’ Break Rows

When you have a list of data, for example, a list of people with their continents, countries, and cities, you may want to group them by continent, then by country, and then by city. This will make it easier to understand and analyze the data.

When a table is populated with data from a sorted data source, 4D Write Pro can insert a break row whenever the value of the sorting criteria changes. This allows the user to group the data according to their desired criteria.

In another scenario, this feature can also be used to create reports based on company relations, where a list of employees can be grouped by the company on each continent. By specifying the appropriate sorting criteria, 4D Write Pro can create separate groups for each company on each continent.

4D v20 is shipped with new attributes to define the tables’ layout better. Enabling you to create complex 4D Write Pro documents with ease, but most importantly, visually appealing documents: say hello to page breaks inside table rows. This is useful when the cells have longer text (or several paragraphs). It may be interesting to define that a cell (and therefore a line of the table) can also be split in two to fill the available space on the pages of the documents:

• wk page break inside paragraph can, of course, be applied to paragraphs, but also to any target such as the document itself, a particular section, a range of text, etc. In all cases, the attribute will be assigned to the paragraphs inside the target. This is simply a programming facility.
• wk page break inside table allows a table to be split into two (or more) parts, the separation is done between two lines of the table (as usual)
   
• wk page break inside row also allows to split a table, but this time inside rows. Note that this option is dependent on the previous one. If a table cannot be split, neither can its rows.

Please note that the page break inside table rows option is available in the toolbar and sidebar widgets.

Table headers 

This feature brings another useful table display option, available by programming or through the 4D Write Pro interface widgets. Starting with 4D v20, you can define headers in tables and automatically repeat them after a column or page breaks. 

Document change Detection

When a 4D Write Pro document is in edit mode, it’s often helpful to know if it has actually been modified by the end user. This information allows actions or interfaces to be adjusted for a more user-friendly experience.

The new document.modified property allows 4D Developers to detect changes inside a document and perform actions accordingly. Either transparently (making automatic saves when a document remains open, for example) or modifying their interface intelligently according to conditions.

User-friendly Display of Formulas

Everyone loves formulas; they are integral to 4D Write Pro documents. They allow the integration of a lot of information coming from the database, making document creation more intuitive and automatic.

However, some formulas can sometimes be long from a layout point of view and hard to read for end-users.

That’s why 4D v20 allows you to display formulas as a symbol ⓕ, indicating their presence to make documents more precise and transparent.

This can be done:

• Via the property list, thanks to the new “Display formula source as a symbol” property.
• A new element in the interface.
• Or via programming thanks to the new wk display formula as symbol attribute.

Disable Visibility of Empty Images

4D Write Pro documents can contain images from different sources and in various formats. These images may, in some cases, not be displayed for totally reasonable reasons — such as invalid URLs, formulas returning empty images, formats not supported by the platform, etc.

However, they are always represented by a small empty rectangle showing their theoretical location. 4D v20 is shipped with a new view option enabling you to make empty images completely invisible. This can be done in 3 different ways:

• • The first and most straightforward way is to use the property list, which offers a new entry in the appearance theme. 
  • Or via the user interface in which a new element appears. Either in the toolbar or in the sidebar.
  • Or by programming using the new wk visible empty images parameter.

New image display options

Starting with 4D v20, inline as well as anchored images inside 4D Write Pro documents benefit from seven new formatting types thanks to the new wk image display mode attribute:

• Scaled to fit (by default)
• Truncated
• Truncated centered
• Proportional
• Proportional centered
• Replicated
• Replicated centered

We’ve also made it easier to format the images used as background documents, sections, paragraphs, etc., thanks to the new attribute: wk background display mode.