Add documentation for Bootstrap 5

Author: ker0x

form/bootstrap5.rst

@@ -0,0 +1,172 @@
+Bootstrap 5 Form Theme
+======================
+
+Symfony provides several ways of integrating Bootstrap into your application. The
+most straightforward way is to add the required ``<link>`` and ``<script>``
+elements in your templates (usually you only include them in the main layout
+template which other templates extend from):
+
+.. code-block:: html+twig
+
+    {# templates/base.html.twig #}
+
+    {# beware that the blocks in your template may be named different #}
+    {% block stylesheets %}
+        <!-- Copy CSS from https://getbootstrap.com/docs/5.0/getting-started/introduction/#css -->
+    {% endblock %}
+    {% block javascripts %}
+        <!-- Copy JavaScript from https://getbootstrap.com/docs/5.0/getting-started/introduction/#js -->
+    {% endblock %}
+
+If your application uses modern front-end practices, it's better to use
+:doc:`Webpack Encore </frontend>` and follow :doc:`this tutorial </frontend/encore/bootstrap>`
+to import Bootstrap's sources into your SCSS and JavaScript files.
+
+The next step is to configure the Symfony application to use Bootstrap 5 styles
+when rendering forms. If you want to apply them to all forms, define this
+configuration:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # config/packages/twig.yaml
+        twig:
+            form_themes: ['bootstrap_5_layout.html.twig']
+
+    .. code-block:: xml
+
+        <!-- config/packages/twig.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xmlns:twig="http://symfony.com/schema/dic/twig"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                https://symfony.com/schema/dic/services/services-1.0.xsd
+                http://symfony.com/schema/dic/twig
+                https://symfony.com/schema/dic/twig/twig-1.0.xsd">
+
+            <twig:config>
+                <twig:form-theme>bootstrap_5_layout.html.twig</twig:form-theme>
+                <!-- ... -->
+            </twig:config>
+        </container>
+
+    .. code-block:: php
+
+        // config/packages/twig.php
+        $container->loadFromExtension('twig', [
+            'form_themes' => [
+                'bootstrap_5_layout.html.twig',
+            ],
+
+            // ...
+        ]);
+
+If you prefer to apply the Bootstrap styles on a form to form basis, include the
+``form_theme`` tag in the templates where those forms are used:
+
+.. code-block:: html+twig
+
+    {# ... #}
+    {# this tag only applies to the forms defined in this template #}
+    {% form_theme form 'bootstrap_5_layout.html.twig' %}
+
+    {% block body %}
+        <h1>User Sign Up:</h1>
+        {{ form(form) }}
+    {% endblock %}
+
+.. _reference-forms-bootstrap-error-messages:
+
+General
+-------
+
+By default, all inputs are rendered with the ``mb-3`` class on their container.
+
+Error Messages
+--------------
+
+Form errors are rendered **inside** the ``<label>`` element to make sure there
+is a strong connection between the error and its ``<input>``, as required by the
+`WCAG 2.0 standard`_. To achieve this, ``form_errors()`` is called by
+``form_label()`` internally. If you call to ``form_errors()`` in your template,
+you'll get the error messages displayed *twice*.
+
+Checkboxes and Radios
+---------------------
+
+For a checkbox/radio field, calling ``form_label()`` doesn't render anything.
+Due to Bootstrap internals, the label is already rendered by ``form_widget()``.
+
+Switches
+________
+
+Bootstrap 5 allow to render checkboxes as "`switches`_". You can enable that on your
+Symfony Form ``CheckboxType`` by adding the ``checkbox-switch`` class to the label:
+
+.. configuration-block::
+
+    .. code-block:: php
+
+        $builder->add('myCheckbox', CheckboxType::class, [
+            'label_attr' => [
+                'class' => 'checkbox-switch',
+            ],
+        ]);
+
+    .. code-block:: twig
+
+        {{ form_row(form.myCheckbox, {
+            label_attr: {
+                class: 'checkbox-switch'
+            }
+        }) }}
+
+Floating labels
+---------------
+
+To render an input field with a `floating label`_, you must add a ``label``,
+a ``placeholder`` and the ``form-floating`` class to the ``row_attr`` option
+of your form type.
+
+.. configuration-block::
+
+    .. code-block:: php
+
+        $builder->add('name', TextType::class, [
+            'label' => 'Name',
+            'attr' => [
+                'placeholder' => 'Name',
+            ],
+            'row_attr' => [
+                'class' => 'form-floating',
+            ],
+        ]);
+
+    .. code-block:: twig
+
+        {{ form_row(form.name, {
+            label: 'Name',
+            attr: {
+                placeholder: 'Name'
+            },
+            row_attr: {
+                class: 'form-floating'
+            }
+        }) }}
+
+Accessibility
+-------------
+
+The Bootstrap 5 framework has done a good job making it accessible for functional
+variations like impaired vision and cognitive ability. Symfony has taken this one
+step further to make sure the form theme complies with the `WCAG 2.0 standard`_.
+
+This does not mean that your entire website automatically complies with the full
+standard, but it does mean that you have come far in your work to create a design
+for **all** users.
+
+.. _`WCAG 2.0 standard`: https://www.w3.org/TR/WCAG20/
+.. _`switches`: https://getbootstrap.com/docs/5.0/forms/checks-radios/#switches
+.. _`floating label`: https://getbootstrap.com/docs/5.0/forms/floating-labels/

forms.rst

@@ -1043,6 +1043,7 @@ Form Themes and Customization:
     :maxdepth: 1
 
     /form/bootstrap4
+    /form/bootstrap5
     /form/form_customization
     /form/form_themes