Re: "draw" icon with string

[Chris Moller <moller mollerware com>]

Here's a sample I came across some time ago.. Basically, you need to do 
all the drawing using cairo primitives.


/*
    Test drawing on a toggle button.

    gcc -Wall cairobutton.c -o cairobutton `pkg-config --cflags --libs 
gtk+-3.0`

    C. Eric Cashon
*/

#include <gtk/gtk.h>

gboolean
draw_button1 (GtkWidget *widget, cairo_t *cr, gpointer user_data)
{
  guint width = gtk_widget_get_allocated_width(GTK_WIDGET(widget));
  guint height = gtk_widget_get_allocated_height(GTK_WIDGET(widget));

  if (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget))) {
    cairo_set_source_rgb (cr, 1.0, 0.0, 0.0);
    cairo_paint (cr);
  }
  else {
    cairo_set_source_rgb (cr, 0.1, 0.1, 0.1);
    cairo_paint (cr);
  }

  //Draw rectangle around the button.
  cairo_set_line_width (cr, 10.0);
  cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
  cairo_rectangle (cr, 0, 0, width, height);
  cairo_stroke (cr);

  //Add the text.
  cairo_set_source_rgb (cr, 1.0, 1.0, 0.0);
  cairo_text_extents_t extents;
  cairo_select_font_face (cr, "Courier", CAIRO_FONT_SLANT_NORMAL,
              CAIRO_FONT_WEIGHT_BOLD);
  cairo_set_font_size (cr, 20);
  cairo_text_extents (cr, "Cairo Toggle!", &extents);
  cairo_move_to (cr, width/2 - extents.width/2, height/2 + 
extents.height/2);
  cairo_show_text (cr, "Cairo Toggle!");

  return TRUE;
}

int
main (int argc, char **argv)
{
  gtk_init (&argc, &argv);

  GtkWidget *window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_position (GTK_WINDOW(window), GTK_WIN_POS_CENTER);
  gtk_window_set_default_size (GTK_WINDOW (window), 200, 100);
  gtk_window_set_title (GTK_WINDOW (window), "Toggle Button");
  g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

  GtkWidget *button1 = gtk_toggle_button_new ();
  gtk_widget_set_app_paintable (button1, TRUE);
  gtk_widget_set_hexpand (button1, TRUE);
  gtk_widget_set_vexpand (button1, TRUE);
  g_signal_connect (button1, "draw", G_CALLBACK (draw_button1), NULL);

  GtkWidget *grid = gtk_grid_new ();
  gtk_container_set_border_width (GTK_CONTAINER (grid), 10);
  gtk_grid_attach (GTK_GRID (grid), button1, 0, 0, 1, 1);

  gtk_container_add (GTK_CONTAINER (window), grid);

  gtk_widget_show_all (window);
  gtk_main ();
  return 0;
}


On 09/09/18 17:14, c.buhtz--- via gtk-app-devel-list wrote:
> On 2018-09-09 23:01 "c.buhtz--- via gtk-app-devel-list"
> <gtk-app-devel-list gnome org> wrote:
> > It is unclear to me how to create a cairo.Surface instance.
> > <https://pycairo.readthedocs.io/en/latest/reference/surfaces.html#cairo.Surface>
> And I can not see any text/string drawing methods in the surface class.
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