New way of scaling images using pixbuf and gtk

gtk4-image-scale.py

#!/usr/bin/env python3

# https://discourse.gnome.org/t/scaling-images-with-cairo-is-much-slower-in-gtk4/7701
# https://blog.gtk.org/2018/03/16/textures-and-paintables/

import gi
gi.require_version("Gtk", "4.0")
gi.require_version("Gdk", "4.0")
gi.require_version("GdkPixbuf", "2.0")
from gi.repository import Gtk, Gdk, GdkPixbuf

def clicked(btn):
    # btn.img.scale *= 1.5
    btn.img.scale *= 0.8
    btn.img.queue_resize()

def build_ui(app):
    win = Gtk.Window()
    win.set_default_size(500, 500)
    win.set_application(app)

    box = Gtk.Box()
    win.set_child(box)

    btn = Gtk.Button()
    btn.set_label("Scale")
    box.append(btn)
    btn.connect('clicked', clicked)

    scrolled_win = Gtk.ScrolledWindow()
    box.append(scrolled_win)

    img = MyWidget("/home/thomas/Pictures/14MB Helmcken_House.jpeg")
    img.set_vexpand(True)
    img.set_hexpand(True)
    img.set_valign(Gtk.Align.CENTER)
    img.set_halign(Gtk.Align.CENTER)
    scrolled_win.set_child(img)

    btn.img = img
    win.present()

class MyWidget(Gtk.Widget):
    def __init__(self, path, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.texture = Gdk.Texture.new_from_filename(path)
        # self.pixbuf = GdkPixbuf.Pixbuf.new_from_file(path)
        # self.texture = Gdk.Texture.new_for_pixbuf(self.pixbuf)
        self.scale = 1
    def do_snapshot(self, snapshot):
        width = self.texture.get_intrinsic_width() * self.scale
        height = self.texture.get_intrinsic_height() * self.scale
        self.texture.snapshot(snapshot, width, height)
    def do_get_request_mode(self):
        return Gtk.SizeRequestMode.CONSTANT_SIZE
    def do_measure(self, orientation, for_size):
        if orientation == Gtk.Orientation.HORIZONTAL:
            width = self.texture.get_intrinsic_width() * self.scale
            return (width, width, -1, -1)
        else:
            height = self.texture.get_intrinsic_height() * self.scale
            return (height, height, -1, -1)

def main():
    app = Gtk.Application()
    app.connect("activate", build_ui)
    app.run()

if __name__ == '__main__':
    main()