Here's a minimal example to illustrate the problem. When the button is clicked, 500 TextView objects should get added, each containing some text. What actually happens is that there is a short delay, 500 empty TextViews get added, there is a much longer delay and then they all get populated with text at once and the layout sizes itself properly. Code below:
import gtk.Button;
import gtk.Main;
import gtk.MainWindow;
import gtk.Notebook;
import gtk.ScrolledWindow;
import gtk.Statusbar;
import gtk.TextView;
import gtk.TextBuffer;
import gtk.UIManager;
import gtk.VBox;
import gtk.Window;
import std.stdio;
class UI : MainWindow
{
Notebook notebook;
this() {
super("Test");
setDefaultSize(200, 100);
VBox box = new VBox(false, 2);
notebook = new Notebook();
Button button = new Button("add lines");
button.addOnClicked(&addLines);
box.packStart(notebook, true, true, 0);
box.packStart(button, false, false, 2);
add(box);
showAll();
}
void addLines(Button b) {
VBox box = new VBox(false, 2);
for (int i = 0; i < 500; i++) {
auto tv = new TextView();
tv.getBuffer().setText("line");
box.packStart(tv, false, false, 1);
}
ScrolledWindow swin = new ScrolledWindow(box);
notebook.add(swin);
showAll();
}
}
void main(string[] args)
{
Main.init(args);
auto ui = new UI();
Main.run();
}
Edit: this thread suggests that creating a bunch of text views is intrinsically expensive, and that I should be rewriting using a treeview.
After some more googling and experimenting, it turns out that GtkTextViews are intrinsically expensive to instantiate, and I should not have been trying to create so many of them. As per the advice in this thread I will be reworking my code to use a GtkTreeView instead.