Allow overriding node, link colors in field formatter.

d3_sankey.module

@@ -188,6 +188,65 @@ function d3_sankey_libraries_info_alter(&$libraries) {
     . 'd3.sankey';
 }
 
+/* Form element validation callbacks. */
+
+/**
+ * Form element validation callback: Validate a required list of colors.
+ *
+ * @param array $element
+ *   The form element to validate.
+ * @param array $form_state
+ *   The current state of the form.
+ */
+function d3_sankey_element_validate_required_color_list($element, &$form_state) {
+  $invalid_color_strings = array();
+  $value = $element['#value'];
+
+  // Parse the element value into a list of colors.
+  $colors = _d3_sankey_explode_csv_nsv_list((string) $value);
+
+  // Validate each color. If we find an invalid one, keep track of it so we can
+  // write a unified error message at the end.
+  foreach ($colors as $color) {
+    if (!_d3_sankey_color_string_is_valid((string) $color)) {
+      $invalid_color_strings[] = (string) $color;
+    }
+  }
+
+  // Set a form element error if we found any invalid color strings.
+  $num_invalid_color_strings = count($invalid_color_strings);
+  if ($num_invalid_color_strings > 0) {
+    $error_message = format_plural($num_invalid_color_strings,
+      'Invalid color string %colors.',
+      'Invalid color strings %colors.',
+      array(
+      '%colors' => implode(', ', $invalid_color_strings),
+    ));
+    form_error($element, $error_message);
+  }
+}
+
+/**
+ * Form element validation callback: Validate an optional list of colors.
+ *
+ * @param array $element
+ *   The form element to validate.
+ * @param array $form_state
+ *   The current state of the form.
+ */
+function d3_sankey_element_validate_optional_color_list($element, &$form_state) {
+  $value = $element['#value'];
+
+  // Special case: if the value is empty, return without doing anything.
+  if (empty($value)) {
+    return;
+  }
+
+  // If we get here, the color list is not empty and should be validated
+  // normally.
+  return d3_sankey_element_validate_required_color_list($element, $form_state);
+}
+
 /* Helper functions. */
 
 /**
@@ -247,3 +306,94 @@ function _d3_sankey_js_library_path_prefix($reset = FALSE) {
 
   return (string) $path;
 }
+
+/**
+ * Explode a string containing a list of comma- or newline-separated values.
+ *
+ * @param $input_string
+ *   A string to parse.
+ *
+ * @return array
+ *   An array of sub-strings.
+ */
+function _d3_sankey_explode_csv_nsv_list($input_string) {
+  $answer = array();
+
+  // Trim the input string.
+  $input_string = trim((string) $input_string);
+
+  // Separate everything that is comma-separated.
+  $initial_array = explode(',', $input_string);
+
+  // Handle the case when explode returns an array with one element (an empty
+  // string) if passed an empty string.
+  if (count($initial_array) === 1 && reset($initial_array) === '') {
+    $initial_array = array();
+  }
+
+  // Loop through the new array and separate everything that is newline-
+  // separated.
+  foreach ($initial_array as $substring) {
+    $sub_array = explode("\n", $substring);
+
+    // Handle the case when explode returns an array with one element (an empty
+    // string) if passed an empty string.
+    if (count($sub_array) === 1 && reset($sub_array) === '') {
+      $sub_array = array();
+    }
+
+    foreach ($sub_array as $item) {
+      $answer[] = (string) $item;
+    }
+  }
+
+  return $answer;
+}
+
+/**
+ * Validate that a string represents a valid color.
+ *
+ * Currently only supports hexidecimal strings.
+ *
+ * @param string $color
+ *   The string to validate as a color.
+ *
+ * @return bool
+ *   TRUE if the color is valid; FALSE otherwise.
+ */
+function _d3_sankey_color_string_is_valid($color) {
+  $is_valid = FALSE;
+
+  // Validate a hexidecimal color string. See color_valid_hexadecimal_string().
+  if (preg_match('/^#([a-f0-9]{3}){1,2}$/iD', $color) === 1) {
+    $is_valid = TRUE;
+  }
+
+  return $is_valid;
+}
+
+/**
+ * Modify a chart definition to include the contents of a color string.
+ *
+ * @param array &$chart
+ *   The chart definition to modify.
+ * @param string $key
+ *   The key to place the color(s) in the chart definition.
+ * @param string $colors_string
+ *   The color string to parse.
+ */
+function _d3_sankey_add_colors_to_chart(&$chart, $key, $colors_string) {
+  $colors_array = _d3_sankey_explode_csv_nsv_list($colors_string);
+  $num_colors = count($colors_array);
+
+  // If we found one color, return it as a string.
+  if ($num_colors === 1) {
+    $chart[(string) $key] = (string) array_shift($colors_array);
+  }
+  // If we found more than one color, return them in an array.
+  elseif ($num_colors > 1) {
+    $chart[(string) $key] = $colors_array;
+  }
+
+  // If we get here, don't touch the chart array, because there were no colors.
+}

modules/d3_sankey_table_group_pp/d3_sankey_table_group_pp.module

@@ -36,6 +36,8 @@ function d3_sankey_table_group_pp_field_formatter_info() {
       'spread' => TRUE,
       'iterations' => 5,
       'alignLabel' => D3_SANKEY_ALIGNLABEL_AUTO,
+      'node_colors' => '',
+      'link_colors' => '',
     ),
   );
 
@@ -113,6 +115,24 @@ function d3_sankey_table_group_pp_field_formatter_settings_form($field, $instanc
       '#options' => d3_sankey_options_alignlabel(),
       '#default_value' => $settings['alignLabel'],
     );
+
+    // Node colors.
+    $element['node_colors'] = array(
+      '#type' => 'textarea',
+      '#title' => t('Override node colors'),
+      '#description' => t('Enter a comma- or newline-separated list of colors to use for the nodes in the diagram.'),
+      '#default_value' => $settings['node_colors'],
+      '#element_validate' => array('d3_sankey_element_validate_optional_color_list'),
+    );
+
+    // Link colors.
+    $element['link_colors'] = array(
+      '#type' => 'textarea',
+      '#title' => t('Override link colors'),
+      '#description' => t('Enter a comma- or newline-separated list of colors to use for the links in the diagram.'),
+      '#default_value' => $settings['link_colors'],
+      '#element_validate' => array('d3_sankey_element_validate_optional_color_list'),
+    );
   }
 
   return $element;
@@ -184,6 +204,10 @@ function d3_sankey_table_group_pp_field_formatter_view($entity_type, $entity, $f
           'alignLabel' => (string) $settings['alignLabel'],
         ) + _d3_sankey_table_group_pp_default_chart_options();
 
+      // If the user chose any node or link colors, add them to the chart.
+      _d3_sankey_add_colors_to_chart($chart, 'node_colors', $settings['node_colors']);
+      _d3_sankey_add_colors_to_chart($chart, 'link_colors', $settings['link_colors']);
+
       // Calculate an HTML ID and add that to the chart. Note this is required
       // in order for the appropriate chart settings to be applied to the chart.
       $id_parts = array(