GTK example 3 is outdated and uses deprecated function. What function do I use as replacement ?

[plain mortar]

Hi guys, I am trying to learn GTK and example 3 uses a deprecated function called gdk_surface_create_similar_surface. However, I don't know what to use instead of this.
This is the relevant example
https://docs.gtk.org/gtk4/getting_started.html#drawing-in-response-to-input
compiled with

gcc $(pkg-config --cflags gtk4) -o example example-3 example-3.c $(pkg-config -- libs gtk4) 

This is the error I get,

example-3.c: In function ‘resize_cb’:
example-3.c:30:9: warning: ‘gdk_surface_create_similar_surface’ is deprecated [-Wdeprecated-declarations]
   30 |         surface = gdk_surface_create_similar_surface (gtk_native_get_surface (gtk_widget_get_native (widget)),      |         ^~~~~~~
In file included from /usr/include/gtk-4.0/gdk/gdkseat.h:27,
                 from /usr/include/gtk-4.0/gdk/gdkdisplay.h:30,
                 from /usr/include/gtk-4.0/gdk/gdk.h:43,
                 from /usr/include/gtk-4.0/gtk/gtk.h:30,
                 from example-3.c:1:
/usr/include/gtk-4.0/gdk/gdksurface.h:111:15: note: declared here
  111 |               gdk_surface_create_similar_surface (GdkSurface *surface,
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/ld: cannot find example-3: No such file or directory
collect2: error: ld returned 1 exit status

Gtk documentation
https://docs.gtk.org/gdk4/method.Surface.create_similar_surface.html

[native lantern]

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[plain mortar]

This is my whole program

GTK example 3 is outdated and uses deprecated function. What function do I use as replacement ?

[empty mulch]

judging by the note in the docs:

Create a suitable cairo image surface yourself.

and: https://chromium.googlesource.com/external/github.com/GNOME/gtk/+/refs/heads/upstream/font-rendering-demo/gdk/gdksurface.c#4134

you need to call cairo_image_surface_create yourself

well, a better repo just for reference is likely https://gitlab.gnome.org/GNOME/gtk/-/blob/main/gdk/gdksurface.c?ref_type=heads#L2317

[plain mortar]

Sorry but, could you please show me how I could tweak the resize_cb function to call cairo_image_surface_create ?

[plain mortar]

I have changed my code. However, I get this new runtime error

This is my new code

@empty mulch

[empty mulch]

it looks like you are not passing libraries to link to a linker

[plain mortar]

this is what I am using as per the example

gcc $(pkg-config --cflags gtk4) -o example-3 example-3.c $(pkg-config -- libs gtk4) 

Is there something more I should have added ?

[empty mulch]

remove space before libs

[plain mortar]

tysm !!!

I can new mark this as solved

Unless you have anything more to add.

[empty mulch]

nope