Gravity Forms: Dynamically populate field label or placeholder - php

Question

I want to populate an input field with data from the current user.
At the moment I populate the fields value parameter but I want to keep the input empty.
Therefore it would be great if I could populate the label or the placeholder parameter of the input field.
I couldn't find anything in the docs.
Here's my current code:
add_filter('gform_field_value_username', create_function("", '$value = populate_usermeta(\'nickname\'); return $value;' ));

Answer 1

I believe this should work out-of-the-box with Gravity Forms:

Answer 2

With some help from the Gravity Forms support and some own testing, I came up with a solution:
function populate_usermeta($meta_key){
global $current_user;
return $current_user->__get($meta_key);
}
add_filter( 'gform_pre_render', 'populate_text' );
//Note: when changing choice values, we also need to use the gform_pre_validation so that the new values are available when validating the field.
add_filter( 'gform_pre_validation', 'populate_text' );
//Note: this will allow for the labels to be used during the submission process in case values are enabled
add_filter( 'gform_pre_submission_filter', 'populate_text' );
function populate_text( $form ) {
$items = array();
$fields = $form['fields'];
foreach( $form['fields'] as &$field ) {
if ( $field->type != 'text' || strpos( $field->cssClass, 'populate-placeholder' ) === false ) {
continue;
}
$field->placeholder = populate_usermeta($field->inputName);
}
return $form;
}