AttributedString: last line disappearing when preceding line was wrapped

General JUCE discussion
1

Hello everyone,

I’m encountering a peculiar issue with AttributedString where the last text I append is not drawn under the following conditions:

  • Previously appended text is wrapped
  • the box I draw in is smaller than the text height (even by just half a pixel).

Here’s the code to reproduce the problem:

void MainComponent::paint (juce::Graphics& g)
{
  g.fillAll(juce::Colours::white);
  juce::AttributedString attributedString;
  attributedString.append("Here's a potentially multiline text (make your window smaller if needed)\n");
  attributedString.append("=>> Watch this text disappear <<=");
  juce::TextLayout layout;
  layout.createLayout(attributedString, getWidth());
  attributedString.draw(g, juce::Rectangle<float>(0, 0, getWidth(), layout.getHeight()-0.5));
  DBG(layout.getHeight());
}

Is this a bug or a feature? Does it only affect MacOS/iOS (I can’t test it currently on other platforms)?

This issue has caused headings to disappear in my markup display class. I’ll publish a fix for my code soon.

2

A small update: I initially thought that the part that would disappear was the last appended part of the AttributedString. But it turns out that it is simply the last line, as can be observed with this piece of code where I call append only once:

void MainComponent::paint (juce::Graphics& g)
{
  g.fillAll(juce::Colours::white);
  juce::AttributedString attributedString;
  attributedString.append("Here's a potentially multiline text (make your window smaller if needed)\n=>> Watch this text disappear <<=");
  juce::TextLayout layout;
  layout.createLayout(attributedString, getWidth());
  attributedString.draw(g, juce::Rectangle<float>(0, 0, getWidth(), layout.getHeight()-0.5));
}