hl_cairo_viewer.f90 example: big pictures not shown entirely at start

[vmagnin]

Describe the bug
When choosing in the Add window at start a picture bigger than the window, a resize event is detected in the show_image() subroutine, the window is resized but the picture is not shown entirely. But the problem does not occur if the filename is passed in command line.

Expected behavior
The whole image should be drawn.

Your system:

• OS version: Ubuntu 22.10 64 bits
• Compiler version: gfortran 12.2.0
• GTK branch: gtk4 (gtk-fortran 4.3.0) and gtk3