Support for dynamic generation of target zones and image.

Instead of providing a custom image, the author can now specify the
number of columns and rows and a single zone size and zones arranged
in a grid of chosen size will be automatically generated, as well as
the background image.

drag_and_drop_v2/drag_and_drop_v2.py

@@ -335,12 +335,12 @@ class DragAndDropBlock(
         """
 
         js_templates = loader.load_unicode('/templates/html/js_templates.html')
-        # Get a 'html_id' string that is unique for this block.
+        # Get an 'id_suffix' string that is unique for this block.
         # We append it to HTML element ID attributes to ensure multiple instances of the DnDv2 block
         # on the same page don't share the same ID value.
         # We avoid using ID attributes in preference to classes, but sometimes we still need IDs to
         # connect 'for' and 'aria-describedby' attributes to the associated elements.
-        id_suffix = self.location.html_id()  # pylint: disable=no-member
+        id_suffix = self._get_block_id()
         js_templates = js_templates.replace('{{id_suffix}}', id_suffix)
         context = {
             'js_templates': js_templates,
@@ -407,6 +407,18 @@ class DragAndDropBlock(
             'result': 'success',
         }
 
+    def _get_block_id(self):
+        """
+        Return unique ID of this block. Useful for HTML ID attributes.
+        Works both in LMS/Studio and workbench runtimes:
+        - In LMS/Studio, use the location.html_id method.
+        - In the workbench, use the usage_id.
+        """
+        if hasattr(self, 'location'):
+            return self.location.html_id()  # pylint: disable=no-member
+        else:
+            return unicode(self.scope_ids.usage_id)
+
     @staticmethod
     def _get_max_items_per_zone(submissions):
         """

drag_and_drop_v2/public/css/drag_and_drop.css

@@ -286,13 +286,20 @@
 }
 
 .xblock--drag-and-drop .drag-container .target .zone p {
-    width: 100%;
     font-family: Arial;
     font-size: 16px;
     font-weight: bold;
+    position: absolute;
+    left: 0;
+    right: 0;
+    top: 0;
+    bottom: 0;
+    padding: 10px;
+    margin: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
     text-align: center;
-    margin-top: auto;
-    margin-bottom: auto;
 }
 
 /*** FEEDBACK ***/

drag_and_drop_v2/public/css/drag_and_drop_edit.css

@@ -93,7 +93,16 @@
     margin: 10px 0 0 0;
 }
 
-.xblock--drag-and-drop--editor .target-image-form input {
+.xblock--drag-and-drop--editor .target-image-form .background-image-type {
+    display: block;
+    margin-bottom: 8px;
+}
+
+.xblock--drag-and-drop--editor .target-image-form .background-auto {
+    margin-top: 20px;
+}
+
+.xblock--drag-and-drop--editor .target-image-form input[type="text"] {
     width: 50%;
 }
 .xblock--drag-and-drop--editor .target-image-form textarea {
@@ -104,6 +113,11 @@
     display: block;
 }
 
+.xblock--drag-and-drop--editor .target-image-form .background-auto .autozone-layout,
+.xblock--drag-and-drop--editor .target-image-form .background-auto .autozone-size {
+    width: 4em;
+}
+
 .xblock--drag-and-drop--editor input,
 .xblock--drag-and-drop--editor textarea {
     box-sizing: border-box;

drag_and_drop_v2/public/js/drag_and_drop_edit.js

@@ -33,6 +33,7 @@ function DragAndDropEditBlock(runtime, element, params) {
                         zoneElement: Handlebars.compile($(".zone-element-tpl", element).html()),
                         zoneCheckbox: Handlebars.compile($(".zone-checkbox-tpl", element).html()),
                         itemInput: Handlebars.compile($(".item-input-tpl", element).html()),
+                        autozoneSvg: Handlebars.compile($(".autozone-tpl", element).html())
                     };
                 }
             },
@@ -68,6 +69,9 @@ function DragAndDropEditBlock(runtime, element, params) {
                     // Hide settings that are specific to assessment mode
                     _fn.build.$el.feedback.form.find('.problem-mode').trigger('change');
 
+                    // Check whether we're using an autogenerated image and fill related input values accordingly.
+                    _fn.build.initAutozoneInputs();
+
                     // Set focus on first input field.
                     $element.find('input:first').select();
                 },
@@ -93,6 +97,53 @@ function DragAndDropEditBlock(runtime, element, params) {
                     return success
                 },
 
+                initAutozoneInputs: function() {
+                    var image_params = _fn.build.parseDataUriParams(params.target_img_expanded_url);
+                    var image_type = image_params.producer === 'dndv2' ? 'auto' : 'manual';
+                    var zone_tab = _fn.build.$el.zones.tab;
+                    var radio_selector = '.background-image-type input[value=' + image_type + ']';
+                    zone_tab.find(radio_selector).prop('checked', true).trigger('change');
+                    zone_tab.find('.autozone-layout-cols').val(image_params.cols || 3);
+                    zone_tab.find('.autozone-layout-rows').val(image_params.rows || 1);
+                    zone_tab.find('.autozone-size-width').val(image_params.zone_width || 200);
+                    zone_tab.find('.autozone-size-height').val(image_params.zone_height || 200);
+                },
+
+                // Examine the image src to determine whether the background image has been auto generated.
+                isAutogeneratedImage: function(src) {
+                    if (src && src.match(/^data:image\/svg\+xml/)) {
+                        if (_fn.build.parseDataUriParams(src).producer === 'dndv2') {
+                            return true;
+                        }
+                    }
+                    return false;
+                },
+
+                // When we auto generate a background image, we embed some parameters such as zone size and position
+                // into the generated data URI.
+                encodeDataUriParams: function(params) {
+                    var encoded = [];
+                    Object.keys(params).forEach(function(key) {
+                        var json = JSON.stringify(params[key]);
+                        encoded.push(encodeURIComponent(key) + '=' + encodeURIComponent(json));
+                    });
+                    return encoded.join(';');
+                },
+
+                parseDataUriParams: function(data_uri) {
+                    var params = {};
+                    var match = data_uri.match(/^data:image\/svg\+xml;([^,]+),/);
+                    if (match) {
+                        match[1].split(';').forEach(function(str) {
+                            var pair = str.split('=');
+                            if (pair.length === 2) {
+                                params[decodeURIComponent(pair[0])] = JSON.parse(decodeURIComponent(pair[1]));
+                            }
+                        });
+                    }
+                    return params;
+                },
+
                 scrollToTop: function() {
                     $('.drag-builder', element).scrollTop(0);
                 },
@@ -123,7 +174,9 @@ function DragAndDropEditBlock(runtime, element, params) {
                         }
 
                         // Set the target image and bind its event handler:
+                        if (!_fn.build.isAutogeneratedImage(_fn.data.targetImg)) {
                             $('.target-image-form .background-url', element).val(_fn.data.targetImg);
+                        }
                         $('.target-image-form .background-description', element).val(_fn.data.targetImgDescription);
                         _fn.build.$el.targetImage.load(_fn.build.form.zone.imageLoaded);
                         _fn.build.$el.targetImage.attr('src', params.target_img_expanded_url);
@@ -179,6 +232,7 @@ function DragAndDropEditBlock(runtime, element, params) {
                         .on('change', '.problem-mode', _fn.build.form.problem.toggleAssessmentSettings);
 
                     $zoneTab
+                        .on('change', '.background-image-type input', _fn.build.form.zone.toggleAutozoneSettings)
                         .on('click', '.add-zone', function(e) {
                             _fn.build.form.zone.add();
                             // Set focus to first field of the new zone.
@@ -187,7 +241,7 @@ function DragAndDropEditBlock(runtime, element, params) {
                         .on('click', '.remove-zone', _fn.build.form.zone.remove)
                         .on('input', '.zone-row input', _fn.build.form.zone.changedInputHandler)
                         .on('change', '.zone-align-select', _fn.build.form.zone.changedInputHandler)
-                        .on('click', '.target-image-form button', function(e) {
+                        .on('click', '.target-image-form .background-manual button', function(e) {
                             var new_img_url = $.trim($('.target-image-form .background-url', element).val());
                             if (new_img_url) {
                                 // We may need to 'expand' the URL before it will be valid.
@@ -202,6 +256,11 @@ function DragAndDropEditBlock(runtime, element, params) {
                             }
                             _fn.data.targetImg = new_img_url;
                         })
+                        .on(
+                            'click',
+                            '.target-image-form .background-auto button',
+                            _fn.build.form.zone.generateBackgroundAndZones
+                        )
                         .on('input', '.target-image-form .background-description', function(e) {
                             var new_description = $.trim(
                                 $('.target-image-form .background-description', element).val()
@@ -243,6 +302,17 @@ function DragAndDropEditBlock(runtime, element, params) {
                     zone: {
                         totalZonesCreated: 0, // This counter is used for HTML IDs. Never decremented.
                         zoneObjects: [],
+                        toggleAutozoneSettings: function(e) {
+                            var element = _fn.build.$el.zones.tab;
+                            var value = element.find('.background-image-type input:checked').val();
+                            if (value === 'manual') {
+                                element.find('.background-manual').show();
+                                element.find('.background-auto').hide();
+                            } else {
+                                element.find('.background-auto').show();
+                                element.find('.background-manual').hide();
+                            }
+                        },
                         getZoneObjByUID: function(uid) {
                             for (var i = 0; i < _fn.build.form.zone.zoneObjects.length; i++) {
                                 if (_fn.build.form.zone.zoneObjects[i].uid == uid) {
@@ -348,7 +418,6 @@ function DragAndDropEditBlock(runtime, element, params) {
                                 );
                             });
                         },
-
                         changedInputHandler: function(ev) {
                             // Called when any of the inputs have changed.
                             var $changedInput = $(ev.currentTarget);
@@ -375,6 +444,115 @@ function DragAndDropEditBlock(runtime, element, params) {
                             // The target background image has loaded (or reloaded, if changed).
                             _fn.build.form.zone.renderZonesPreview();
                         },
+                        getAutozoneParams: function() {
+                            var element = _fn.build.$el.zones.tab.find('.background-auto');
+                            return {
+                                rows: parseInt(element.find('.autozone-layout-rows').val(), 10),
+                                cols: parseInt(element.find('.autozone-layout-cols').val(), 10),
+                                zone_width: parseInt(element.find('.autozone-size-width').val(), 10),
+                                zone_height: parseInt(element.find('.autozone-size-height').val(), 10),
+                                padding: 20
+                            };
+                        },
+                        validateAutozoneParams: function(params) {
+                            var fields = [
+                                '.autozone-layout-cols',
+                                '.autozone-layout-rows',
+                                '.autozone-size-width',
+                                '.autozone-size-height'
+                            ];
+                            var success = true;
+                            fields.forEach(function(field) {
+                                var element = _fn.build.$el.zones.tab.find(field);
+                                var val = element.val();
+                                var number = parseInt(element.val(), 10);
+                                // Make sure the user entered a positive integer number.
+                                if (number && number > 0 && String(number) === val) {
+                                    element.removeClass('field-error');
+                                } else {
+                                    element.addClass('field-error');
+                                    success = false;
+                                }
+                            });
+                            if (!success) {
+                                runtime.notify('error', {
+                                    'title': window.gettext("There was an error with your form."),
+                                    'message': window.gettext("Please check the values you entered.")
+                                });
+                            }
+                            return success;
+                        },
+                        calculateAutozoneData: function(params) {
+                            var rows = params.rows;
+                            var cols = params.cols;
+                            var zone_width = params.zone_width;
+                            var zone_height = params.zone_height;
+                            var padding = params.padding;
+
+                            var width = (zone_width * cols) + (padding * (cols + 1));
+                            var height = (zone_height * rows) + (padding * (rows + 1));
+
+                            var zones = [];
+                            for (var row = 0; row < rows; row++) {
+                                for (var col = 0; col < cols; col++) {
+                                    zones.push({
+                                        width: zone_width,
+                                        height: zone_height,
+                                        x: (padding * (col + 1) + (col * zone_width)),
+                                        y: (padding * (row + 1) + (row * zone_height))
+                                    });
+                                }
+                            }
+
+                            return {
+                                width: width,
+                                height: height,
+                                zones: zones
+                            };
+                        },
+                        generateBackgroundDataUri: function(autozone_data, params) {
+                            var autozone_data = _fn.build.form.zone.calculateAutozoneData(params);
+                            var svg = _fn.tpl.autozoneSvg(autozone_data).trim();
+                            var data_uri_params = _fn.build.encodeDataUriParams({
+                                producer: 'dndv2',
+                                cols: params.cols,
+                                rows: params.rows,
+                                zone_width: params.zone_width,
+                                zone_height: params.zone_height
+                            });
+                            return 'data:image/svg+xml;' + data_uri_params + ',' + encodeURIComponent(svg);
+                        },
+                        generateZones: function(zones) {
+                            // First remove all existing zones.
+                            _fn.build.$el.zones.form.find('.zone-row').remove();
+                            _fn.build.form.zone.zoneObjects = [];
+                            // Now generate new zones.
+                            zones.forEach(function(zone) {
+                                _fn.build.form.zone.add({
+                                    width: zone.width,
+                                    height: zone.height,
+                                    x: zone.x,
+                                    y: zone.y,
+                                    align: 'center'
+                                });
+                            });
+                        },
+                        generateBackgroundAndZones: function() {
+                            var params = _fn.build.form.zone.getAutozoneParams();
+                            if (!_fn.build.form.zone.validateAutozoneParams(params)) {
+                                return;
+                            }
+                            var autozone_data = _fn.build.form.zone.calculateAutozoneData(params);
+                            // Generate zones.
+                            _fn.build.form.zone.generateZones(autozone_data.zones);
+                            // Set background img src.
+                            var data_uri = _fn.build.form.zone.generateBackgroundDataUri(autozone_data, params);
+                            _fn.data.targetImg = data_uri;
+                            _fn.build.$el.targetImage.attr('src', data_uri);
+                            // Make sure "Display label names on the image" is checked.
+                            _fn.data.displayLabels = true;
+                            $('.display-labels-form input', element).prop('checked', true);
+                        }
                     },
                     createCheckboxes: function(selectedZones) {
                         var template = _fn.tpl.zoneCheckbox;

drag_and_drop_v2/templates/html/drag_and_drop_edit.html

@@ -91,18 +91,76 @@
             </header>
             <div class="tab-content">
                 <form class="target-image-form">
+                    <fieldset>
+                        <legend class="h4">{% trans "Background Image" %}</legend>
+                        <label class="background-image-type">
+                            <input type="radio" name="background-image-type-{{id_suffix}}" value="manual" />
+                            {% trans "Provide custom image" %}
+                        </label>
+                        <label class="background-image-type">
+                            <input type="radio" name="background-image-type-{{id_suffix}}" value="auto" />
+                            {% trans "Generate image automatically" %}
+                        </label>
+                    </fieldset>
+                    <fieldset class="background-manual">
                         <label class="h4" for="background-url-{{id_suffix}}">
                             <span>{% trans "Background URL" %}</span>
                         </label>
                         <input class="background-url"
                               id="background-url-{{id_suffix}}"
                               type="text"
-                           aria-describedby="background-url-{{id_suffix}}" />
+                              aria-describedby="background-url-description-{{id_suffix}}" />
                         </label>
                         <button type="button" class="btn">{% trans "Change background" %}</button>
                         <div id="background-url-description-{{id_suffix}}" class="form-help">
                             {% trans "For example, 'http://example.com/background.png' or '/static/background.png'." %}
                         </div>
+                    </fieldset>
+                    <fieldset class="background-auto">
+                        <fieldset>
+                            <legend class="h4">{% trans "Zone Layout" %}</legend>
+                            <label class="sr" for="autozone-cols-{{id_suffix}}">
+                                {% trans "Number of columns" %}
+                            </label>
+                            <input id="autozone-cols-{{id_suffix}}"
+                                   class="autozone-layout autozone-layout-cols"
+                                   type="text"
+                                   aria-describedby="autozone-layout-description-{{id_suffix}}" />
+                            <span>&times;</span>
+                            <label class="sr" for="autozone-rows-{{id_suffix}}">
+                                {% trans "Number of rows" %}
+                            </label>
+                            <input id="autozone-rows-{{id_suffix}}"
+                                   class="autozone-layout autozone-layout-rows"
+                                   type="text"
+                                   aria-describedby="autozone-layout-description-{{id_suffix}}" />
+                            <div id="autozone-layout-description-{{id_suffix}}" class="form-help">
+                                {% trans "Number of columns and rows." %}
+                            </div>
+                        </fieldset>
+                        <fieldset>
+                            <legend class="h4">{% trans "Zone Size" %}</legend>
+                            <label class="sr" for="autozone-zone-width-{{id_suffix}}">
+                                {% trans "Zone width" %}
+                            </label>
+                            <input id="autozone-zone-width-{{id_suffix}}"
+                                   class="autozone-size autozone-size-width"
+                                   type="text"
+                                   aria-describedby="autozone-size-description-{{id_suffix}}" />
+                            <span>&times;</span>
+                            <label class="sr" for="autozone-zone-height-{{id_suffix}}">
+                                {% trans "Zone height" %}
+                            </label>
+                            <input id="autozone-zone-height-{{id_suffix}}"
+                                   class="autozone-size autozone-size-height"
+                                   type="text"
+                                   aria-describedby="autozone-size-description-{{id_suffix}}" />
+                            <div id="autozone-size-description-{{id_suffix}}" class="form-help">
+                                {% trans "Size of a single zone in pixels." %}
+                            </div>
+                        </fieldset>
+                        <button type="button" class="btn">{% trans "Generate image and zones" %}</button>
+                    </fieldset>
                     <label class="h4">
                         <span>{% trans "Background description" %}</span>
                         <textarea required class="background-description"

drag_and_drop_v2/templates/html/js_templates.html

@@ -172,3 +172,21 @@
         </div>
     </fieldset>
 </script>
+
+<script class="autozone-tpl" type="text/html">
+    <svg xmlns="http://www.w3.org/2000/svg" width="{{width}}" height="{{height}}">
+        <rect x="0" y="0" width="100%" height="100%" fill="#fff" />
+        {{#each zones}}
+            <rect x="{{x}}"
+                  y="{{y}}"
+                  width="{{width}}"
+                  height="{{height}}"
+                  fill="#f7f7f7"
+                  rx="10"
+                  ry="10"
+                  stroke="#d6d6d6"
+                  stroke-width="2"
+                  stroke-dasharray="3,3" />
+        {{/each}}
+    </svg>
+</script>

tests/integration/test_studio.py

+from xblockutils.studio_editable_test import StudioEditableBaseTest
+
+
+class TestStudio(StudioEditableBaseTest):
+    """
+    Tests that cover the editing interface in the Studio.
+    """
+
+    def load_scenario(self, xml='<drag-and-drop-v2 url_name="defaults" />'):
+        self.set_scenario_xml(xml)
+        self.element = self.go_to_view('studio_view')
+        self.fix_js_environment()
+
+    def click_continue(self):
+        continue_button = self.element.find_element_by_css_selector('.continue-button')
+        self.scroll_into_view(continue_button)
+        continue_button.click()
+
+    def scroll_into_view(self, element):
+        """
+        Scrolls to the element and places cursor above it.
+        Useful when you want to click an element that is scrolled off
+        the visible area of the screen.
+        """
+        # We have to use block: 'end' rather than the default 'start' because there's a fixed
+        # title bar in the studio view in the workbench that can obstruct the element.
+        script = "arguments[0].scrollIntoView({behavior: 'instant', block: 'end'})"
+        self.browser.execute_script(script, element)
+
+    @property
+    def feedback_tab(self):
+        return self.element.find_element_by_css_selector('.feedback-tab')
+
+    @property
+    def zones_tab(self):
+        return self.element.find_element_by_css_selector('.zones-tab')
+
+    @property
+    def items_tab(self):
+        return self.element.find_element_by_css_selector('.items-tab')
+
+    @property
+    def background_image_type_radio_buttons(self):
+        radio_buttons = self.zones_tab.find_elements_by_css_selector('.background-image-type input[type="radio"]')
+        self.assertEqual(len(radio_buttons), 2)
+        self.assertEqual(radio_buttons[0].get_attribute('value'), 'manual')
+        self.assertEqual(radio_buttons[1].get_attribute('value'), 'auto')
+        return {'manual': radio_buttons[0], 'auto': radio_buttons[1]}
+
+    @property
+    def display_labels_checkbox(self):
+        return self.zones_tab.find_element_by_css_selector('.display-labels')
+
+    @property
+    def background_image_url_field(self):
+        return self.zones_tab.find_element_by_css_selector('.background-manual .background-url')
+
+    @property
+    def background_image_url_button(self):
+        return self.zones_tab.find_element_by_css_selector('.background-manual button')
+
+    @property
+    def autozone_cols_field(self):
+        return self.zones_tab.find_element_by_css_selector('.background-auto .autozone-layout-cols')
+
+    @property
+    def autozone_rows_field(self):
+        return self.zones_tab.find_element_by_css_selector('.background-auto .autozone-layout-rows')
+
+    @property
+    def autozone_width_field(self):
+        return self.zones_tab.find_element_by_css_selector('.background-auto .autozone-size-width')
+
+    @property
+    def autozone_height_field(self):
+        return self.zones_tab.find_element_by_css_selector('.background-auto .autozone-size-height')
+
+    @property
+    def autozone_generate_button(self):
+        return self.zones_tab.find_element_by_css_selector('.background-auto button')
+
+    @property
+    def target_preview_img(self):
+        return self.zones_tab.find_element_by_css_selector('.target-img')
+
+    @property
+    def zones(self):
+        return self.zones_tab.find_elements_by_css_selector('.zone-row')
+
+    def test_defaults(self):
+        """
+        Basic test to verify stepping through the editor steps and saving works.
+        """
+        self.load_scenario()
+        # We start on the feedback tab.
+        self.assertTrue(self.feedback_tab.is_displayed())
+        self.assertFalse(self.zones_tab.is_displayed())
+        self.assertFalse(self.items_tab.is_displayed())
+        # Continue to the zones tab.
+        self.click_continue()
+        self.assertFalse(self.feedback_tab.is_displayed())
+        self.assertTrue(self.zones_tab.is_displayed())
+        self.assertFalse(self.items_tab.is_displayed())
+        # And finally to the items tab.
+        self.click_continue()
+        self.assertFalse(self.feedback_tab.is_displayed())
+        self.assertFalse(self.zones_tab.is_displayed())
+        self.assertTrue(self.items_tab.is_displayed())
+        # Save the block and expect success.
+        self.click_save(expect_success=True)
+
+    def test_custom_image(self):
+        """"
+        Verify user can provide a custom background image URL.
+        """
+        default_bg_img_src = 'http://localhost:8081/resource/drag-and-drop-v2/public/img/triangle.png'
+        # In order to use a working image and avoid load errors, we use the default image with a custom
+        # query string
+        custom_bg_img_src = '{}?my-custom-image=true'.format(default_bg_img_src)
+
+        self.load_scenario()
+        # Go to zones tab.
+        self.click_continue()
+        radio_buttons = self.background_image_type_radio_buttons
+        # Manual mode should be selected by default.
+        self.assertTrue(radio_buttons['manual'].is_selected())
+        self.assertFalse(radio_buttons['auto'].is_selected())
+        url_field = self.background_image_url_field
+        self.assertEqual(url_field.get_attribute('value'), '')
+        self.assertEqual(self.target_preview_img.get_attribute('src'), default_bg_img_src)
+        url_field.send_keys(custom_bg_img_src)
+        self.scroll_into_view(self.background_image_url_button)
+        self.background_image_url_button.click()
+        self.assertEqual(self.target_preview_img.get_attribute('src'), custom_bg_img_src)
+        self.click_continue()
+        self.click_save(expect_success=True)
+
+        # Verify the custom image src was saved successfully.
+        self.element = self.go_to_view('student_view')
+        target_img = self.element.find_element_by_css_selector('.target-img')
+        self.assertEqual(target_img.get_attribute('src'), custom_bg_img_src)
+
+        # Verify the background image URL field is set to custom image src when we go back to studio view.
+        self.element = self.go_to_view('studio_view')
+        self.click_continue()
+        self.assertEqual(self.background_image_url_field.get_attribute('value'), custom_bg_img_src)
+
+    def _verify_autogenerated_zones(self, cols, rows, zone_width, zone_height, padding):
+        zones = self.zones
+        self.assertEqual(len(zones), rows * cols)
+        for col in range(cols):
+            for row in range(rows):
+                idx = col + (row * cols)
+                zone = zones[idx]
+                expected_values = {
+                    'zone-title': 'Zone {}'.format(idx + 1),
+                    'zone-width': zone_width,
+                    'zone-height': zone_height,
+                    'zone-x': (zone_width * col) + (padding * (col + 1)),
+                    'zone-y': (zone_height * row) + (padding * (row + 1)),
+                }
+                for name, expected_value in expected_values.iteritems():
+                    field = zone.find_element_by_css_selector('.' + name)
+                    self.assertEqual(field.get_attribute('value'), str(expected_value))
+
+    def test_auto_generated_image(self):
+        """
+        Verify that background image and zones get generated successfully.
+        """
+        cols = 3
+        rows = 2
+        zone_width = 150
+        zone_height = 100
+        padding = 20
+
+        self.load_scenario()
+        # Go to zones tab.
+        self.click_continue()
+        radio_buttons = self.background_image_type_radio_buttons
+        self.scroll_into_view(radio_buttons['auto'])
+        radio_buttons['auto'].click()
+        # Manual background controls should be hidden.
+        self.assertFalse(self.background_image_url_field.is_displayed())
+        self.assertFalse(self.background_image_url_button.is_displayed())
+        # Display labels checkbox should be unchecked by default.
+        self.assertFalse(self.display_labels_checkbox.is_selected())
+        # Enter zone properties for automatic generation.
+        self.autozone_cols_field.clear()
+        self.autozone_cols_field.send_keys(cols)
+        self.autozone_rows_field.clear()
+        self.autozone_rows_field.send_keys(rows)
+        self.autozone_width_field.clear()
+        self.autozone_width_field.send_keys(zone_width)
+        self.autozone_height_field.clear()
+        self.autozone_height_field.send_keys(zone_height)
+        # Click the generate button.
+        self.scroll_into_view(self.autozone_generate_button)
+        self.autozone_generate_button.click()
+        # Verify generated data-uri was set successfully.
+        generated_url = self.target_preview_img.get_attribute('src')
+        self.assertTrue(generated_url.startswith('data:image/svg+xml;'))
+        expected_width = (zone_width * cols) + (padding * (cols + 1))
+        expected_height = (zone_height * rows) + (padding * (rows + 1))
+        self.assertEqual(self.target_preview_img.get_attribute('naturalWidth'), str(expected_width))
+        self.assertEqual(self.target_preview_img.get_attribute('naturalHeight'), str(expected_height))
+        # Display labels checkbox should be automatically selected.
+        self.assertTrue(self.display_labels_checkbox.is_selected())
+        # Verify there are exactly 6 zones, and their properties are correct.
+        self._verify_autogenerated_zones(cols, rows, zone_width, zone_height, padding)
+
+        # Fill in zone descriptions to make the form valid (zone descriptions are required).
+        for zone in self.zones:
+            zone.find_element_by_css_selector('.zone-description').send_keys('Description')
+
+        # Save the block.
+        self.click_continue()
+        self.click_save(expect_success=True)
+
+        # Verify the custom image src was saved successfully.
+        self.element = self.go_to_view('student_view')
+        target_img = self.element.find_element_by_css_selector('.target-img')
+        self.assertTrue(target_img.get_attribute('src').startswith('data:image/svg+xml'))
+        self.assertEqual(target_img.get_attribute('naturalWidth'), str(expected_width))
+        self.assertEqual(target_img.get_attribute('naturalHeight'), str(expected_height))
+
+        # Verify the background image URL field is set to custom image src when we go back to studio view.
+        self.element = self.go_to_view('studio_view')
+        self.click_continue()
+        radio_buttons = self.background_image_type_radio_buttons
+        self.assertFalse(radio_buttons['manual'].is_selected())
+        self.assertTrue(radio_buttons['auto'].is_selected())
+        self.assertEqual(self.autozone_cols_field.get_attribute('value'), str(cols))
+        self.assertEqual(self.autozone_rows_field.get_attribute('value'), str(rows))
+        self.assertEqual(self.autozone_width_field.get_attribute('value'), str(zone_width))
+        self.assertEqual(self.autozone_height_field.get_attribute('value'), str(zone_height))
+
+    def test_autozone_parameter_validation(self):
+        """
+        Test that autozone parameters are verified to be valid.
+        """
+        self.load_scenario()
+        # Go to zones tab.
+        self.click_continue()
+        radio_buttons = self.background_image_type_radio_buttons
+        self.scroll_into_view(radio_buttons['auto'])
+        radio_buttons['auto'].click()
+        # All fields are valid initially.
+        self.assertFalse('field-error' in self.autozone_cols_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_rows_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_width_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_height_field.get_attribute('class'))
+        # Set two of the fields to invalid values.
+        self.autozone_cols_field.clear()
+        self.autozone_cols_field.send_keys('2.5')
+        self.autozone_height_field.clear()
+        self.autozone_height_field.send_keys('100A')
+        # Try to generate the image.
+        self.scroll_into_view(self.autozone_generate_button)
+        self.autozone_generate_button.click()
+        # The two bad fields should show errors.
+        self.assertTrue('field-error' in self.autozone_cols_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_rows_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_width_field.get_attribute('class'))
+        self.assertTrue('field-error' in self.autozone_height_field.get_attribute('class'))
+        # Fix the faulty values.
+        self.autozone_cols_field.clear()
+        self.autozone_cols_field.send_keys('2')
+        self.autozone_height_field.clear()
+        self.autozone_height_field.send_keys('100')
+        self.scroll_into_view(self.autozone_generate_button)
+        self.autozone_generate_button.click()
+        # All good now.
+        self.assertFalse('field-error' in self.autozone_cols_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_rows_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_width_field.get_attribute('class'))
+        self.assertFalse('field-error' in self.autozone_height_field.get_attribute('class'))