A DESCRIPTION OF THE PROBLEM :
When using a retina display, AppleColorEmoji font render too small, the emojis only have half of the height and width as it should be.

CTFontStrike get font ref with a CGAffineTransform, the arg matrix has field a and d value 2.0:
fontRef = OS.CTFontCreateWithName(psNameRef, size, matrix);
This works for ordinary font, but not for AppleColorEmoji font. It may be a bug for feature of Core Text.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the source code and run, a window showing emoji and plain text will show.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Emoji has same height as plain text, and take full width of it's frame.
ACTUAL -
Emoji only occupies 1/4 of its frame, leaving other region as blank space.  

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.text.Font;
import javafx.stage.Stage;

public class Test extends Application {

    @Override
    public void start(Stage stage) {
        var label = new Label("Text🐶Text");
        label.setFont(new Font(40));

        Scene scene = new Scene(label);
        stage.setWidth(400);
        stage.setHeight(100);
        stage.setScene(scene);

        stage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

}

---------- END SOURCE ----------