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
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