How to limit characters but keep line breaks/formatting? - silverstripe

Question

I am using the standard Content field that is automatically generated by default to add some text.
"Content" => "HTMLText"
If I use a limiting function e.g
$Content.BigSummary(300)
This limits the words but doesn't keep the line breaks. Aka strips the HTML out.
Looking through the framework code, there is ContextSummary()
public function ContextSummary($characters = 500, $string = false, $striphtml = true, $highlight = true,
$prefix = "... ", $suffix = "...")
However upon testing, using this on an HTMLText field doesn't seem to work, it limits the characters but it doesn't keep the HTML unless the field type is Text e.g
HTMLText:
$Content.ContextSummary(200, false, false) - Strips HTML still
Text:
$Content.ContextSummary(200, false, false) - Keeps HTML (Which is what I want)
Am I doing something wrong? Or is there another function I can use to achieve what I want? Or create a custom function?

Answer 1

The issue is with conversion to simple text and back to html - <br> tags are lost as I encountered once. This is a similar hack I used.
// override ContextSummary from the Page_Controller
public function ContextSummary($field = 'Content', $characters = 500, $string = false) {
$content = $this->dbObject($field);
$content->setValue(str_replace('<br>', '__br__', $content->getValue);
$summary = $content->ContextSummary($characters, $string, $stripHtml = false);
return str_replace('__br__', '<br>', $summary);
}
and use $ContextSummary(Content) instead of $Content.ContextSummary in template