Re: Please fill out the GtkLabel questionnaire

[Benjamin Otte <otte gnome org>]

Here's my answers (and sorry for messing up the reply of the last 2
mails, I blame gmail)

I've also attached the sources for the program I used to generate the
GTK2/3 answers I posted above. Please look at it if there's any
questions remaining after looking at that long table.

When I put "5/10" in there, I'm referring to not knowing exactly how a
"natural size" algorithm would be implemented that tries to find the
ideal width when it's allowed to wrap a text any way it wants. So both
values are fine with me.

wrap        ellipsize   width_chars max_width_chars  minimum   natural
false       false       -1          -1               10        10
true        false       -1          -1               5         5/10
false       true        -1          -1               3         5/10
true        true        -1          -1               3         5/10
false       false        4          -1               10        10
true        false        4          -1               5         5/10
false       true         4          -1               4         5/10
true        true         4          -1               4         5/10
false       false        8          -1               10        10
true        false        8          -1               8         5/10
false       true         8          -1               8         5/10
true        true         8          -1               8         5/10
false       false       12          -1               12        12
true        false       12          -1               12        12
false       true        12          -1               12        12
true        true        12          -1               12        12
false       false       -1           4               10        10
true        false       -1           4               5         5/10
false       true        -1           4               3         5/10
true        true        -1           4               3         5/10
false       false        4           4               10        10
true        false        4           4               5         5/10
false       true         4           4               4         5/10
true        true         4           4               4         5/10
false       false        8           4               10        10
true        false        8           4               5         5/10
false       true         8           4               8         5/10
true        true         8           4               8         5/10
false       false       12           4               12        12
true        false       12           4               12        12
false       true        12           4               12        12
true        true        12           4               12        12
false       false       -1           8               10        10
true        false       -1           8               5         8/10
false       true        -1           8               3         8/10
true        true        -1           8               3         8/10
false       false        4           8               10        10
true        false        4           8               5         8/10
false       true         4           8               4         8/10
true        true         4           8               4         8/10
false       false        8           8               10        10
true        false        8           8               5         8/10
false       true         8           8               8         8/10
true        true         8           8               8         8/10
false       false       12           8               12        12
true        false       12           8               12        12
false       true        12           8               12        12
true        true        12           8               12        12
false       false       -1          12               10        12
true        false       -1          12               5         12
false       true        -1          12               3         12
true        true        -1          12               3         12
false       false        4          12               10        12
true        false        4          12               5         12
false       true         4          12               4         12
true        true         4          12               4         12
false       false        8          12               10        12
true        false        8          12               8         12
false       true         8          12               8         12
true        true         8          12               8         12
false       false       12          12               12        12
true        false       12          12               12        12
false       true        12          12               12        12
true        true        12          12               12        12

The algorithm I tried to use above follows:
First, compute the minimum size:
1) Set the minimum size to the width of the text. If wrapped, use the
size of the text wrapped as often as possible.
2) If the label is ellipsized, reduce the minimum size to at most 3 characters.
3) If the label has width-chars set, make sure the minimum size fits
at least this many characters.
Second, compute the natural size:
1) Compute an ideally wrapped text (see disclaimer above: I have no
idea what that means exactly.) Take its width.
2) If a max-width-chars is set, reduce the natural size to this many characters.
3) Ensure the natural size is at least as big as the minimum size.

This is the algorithm I'll try to implement if nothing better comes up.

Benjamin

#include <gtk/gtk.h>

static void
check_width (GtkWidget *label,
             gboolean   wrap,
             gboolean   ellipsize,
             gint       width_chars,
             gint       max_width_chars)
{
#if GTK_CHECK_VERSION (3, 0, 0)
  int min, natural;
#else
  GtkRequisition req;
#endif

  gtk_label_set_line_wrap (GTK_LABEL (label), wrap);
  gtk_label_set_ellipsize (GTK_LABEL (label), ellipsize);
  gtk_label_set_width_chars (GTK_LABEL (label), width_chars);
  gtk_label_set_max_width_chars (GTK_LABEL (label), max_width_chars);

#if GTK_CHECK_VERSION (3, 0, 0)
  gtk_widget_get_preferred_width (label, &min, &natural);
#else
  gtk_widget_size_request (label, &req);
#endif

  g_print ("%s       %s       %2d          %2d               %2d       %2d\n",
           wrap ? "true " : "false",
           ellipsize ? "true " : "false",
           width_chars, max_width_chars,
#if GTK_CHECK_VERSION (3, 0, 0)
           min / 10, natural / 10);
#else
           req.width / 10, req.width / 10);
#endif
}

static void
check (GtkWidget *label)
{
  int sizes[] = { -1, 4, 8, 12 };
  guint width, max_width;

  g_print ("properties                                           characters requested\n");
  g_print ("wrap        ellipsize   width_chars max_width_chars  minimum  natural\n");

  for (max_width = 0; max_width < G_N_ELEMENTS (sizes); max_width++)
    {
      for (width = 0; width < G_N_ELEMENTS (sizes); width++)
        {
          check_width (label, FALSE, FALSE, sizes[width], sizes[max_width]);
          check_width (label, TRUE,  FALSE, sizes[width], sizes[max_width]);
          check_width (label, FALSE, TRUE,  sizes[width], sizes[max_width]);
          check_width (label, TRUE,  TRUE,  sizes[width], sizes[max_width]);
        }
    }
}

int 
main (int argc, char **argv)
{
  GtkWidget *window, *label;
  PangoFontDescription *font;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

  label = gtk_label_new ("12345 1234");
  gtk_container_add (GTK_CONTAINER (window), label);

  font = pango_font_description_from_string ("Monospace 10");
#if GTK_CHECK_VERSION (3, 0, 0)
  gtk_widget_override_font (label, font);
#else
  gtk_widget_modify_font (label, font);
#endif
  pango_font_description_free (font);

  gtk_widget_realize (window);

  check (label);

  return 0;
}