3

请运行下面的代码以获得如下内容：

在此处输入图像描述

基本上，我已经设置了一个 Gtk.DrawingArea，它位于 Gtk.Viewport 中，它也在 Gtk.Scrolledwindow 中。在所述 DrawingArea 中，我绘制了一个图像，使用 2 个按钮可以缩放所述图像。

# -*- encoding: utf-8 -*-

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from gi.repository import Gdk
from gi.repository import GdkPixbuf


class MyWindow(Gtk.Window):

    def __init__(self):

        Gtk.Window.__init__(self, title="DrawingTool")
        self.set_default_size(800, 600)

        # The ratio
        self.ratio = 1.

        # Image
        filename = "image.jpg"
        self.original_image = GdkPixbuf.Pixbuf.new_from_file(filename)
        self.displayed_image = GdkPixbuf.Pixbuf.new_from_file(filename)

        box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=6)
        # Zoom buttons
        self.button_zoom_in = Gtk.Button(label="Zoom-In")
        self.button_zoom_out = Gtk.Button(label="Zoom-Out")      
        # |ScrolledWindow
        # |-> Viewport
        # |--> DrawingArea 
        scrolledwindow = Gtk.ScrolledWindow()
        viewport = Gtk.Viewport()
        self.drawing_area = Gtk.DrawingArea()
        self.drawing_area.set_size_request(
                              self.displayed_image.get_width(), self.displayed_image.get_height())
        self.drawing_area.set_events(Gdk.EventMask.ALL_EVENTS_MASK)

        # Pack
        viewport.add(self.drawing_area)
        scrolledwindow.add(viewport)
        box.pack_start(self.button_zoom_in, False, True, 0)
        box.pack_start(self.button_zoom_out, False, True, 0)
        box.pack_start(scrolledwindow, True, True, 0)
        self.add(box)

        # Connect
        self.connect("destroy", Gtk.main_quit)
        self.button_zoom_in.connect("clicked", self.on_button_zoom_in_clicked)
        self.button_zoom_out.connect("clicked", self.on_button_zoom_out_clicked)
        self.drawing_area.connect("enter-notify-event", self.on_drawing_area_mouse_enter)
        self.drawing_area.connect("leave-notify-event", self.on_drawing_area_mouse_leave)
        self.drawing_area.connect("motion-notify-event", self.on_drawing_area_mouse_motion)
        self.drawing_area.connect("draw", self.on_drawing_area_draw)

        self.show_all()

    def on_button_zoom_in_clicked(self, widget):
        self.ratio += 0.1
        self.scale_image()
        self.drawing_area.queue_draw()

    def on_button_zoom_out_clicked(self, widget):
        self.ratio -= 0.1
        self.scale_image()
        self.drawing_area.queue_draw()

    def scale_image(self):
        self.displayed_image = self.original_image.scale_simple(self.original_image.get_width() * self.ratio, 
                                   self.original_image.get_height() * self.ratio, 2)

    def on_drawing_area_draw(self, drawable, cairo_context):
        pixbuf = self.displayed_image           
        self.drawing_area.set_size_request(pixbuf.get_width(), pixbuf.get_height())
        Gdk.cairo_set_source_pixbuf(cairo_context, pixbuf, 0, 0)
        cairo_context.paint()

    def on_drawing_area_mouse_enter(self, widget, event):
        print("In - DrawingArea")

    def on_drawing_area_mouse_leave(self, widget, event):
        print("Out - DrawingArea")

    def on_drawing_area_mouse_motion(self, widget, event):

        (x, y) = int(event.x), int(event.y)
        offset = ( (y*self.displayed_image.get_rowstride()) + 
                   (x*self.displayed_image.get_n_channels()) )
        pixel_intensity = self.displayed_image.get_pixels()[offset]
        print("(" + str(x) + ", " + str(y) + ") = " + str(pixel_intensity))



MyWindow()
Gtk.main()

运行应用程序。我还设置了一些回调，因此当您将鼠标指针悬停在图像上时，您会知道：

i) 当您进入绘图区时

ii) 当您离开绘图区时

iii) DrawingArea 处的 (x, y) 和图像像素强度

我面临的问题是，当您缩小足够的时间时，图像将如下所示：

在此处输入图像描述

但是，“鼠标进入”和“鼠标离开”信号以及“鼠标运动”信号的发送就像 DrawingArea 仍然具有创建时的大小一样。请将鼠标悬停在图像上方和图像外部但在绘图区域内以查看终端中的输出。

我希望在图像外悬停时不要发送信号。也就是说，如果可能，将 DrawingArea 大小调整为显示的图像大小。

4

1 回答 1

1

我已经使用了 gtk_window_resize()，因为它在这里提到：Cannot reduce size of gtk window programatically

def on_drawing_area_draw(self, drawable, cairo_context):
        pixbuf = self.displayed_image
        # New line. Get DrawingArea's window and resize it.
        drawable.get_window().resize(pixbuf.get_width(), pixbuf.get_height())           
        drawable.set_size_request(pixbuf.get_width(), pixbuf.get_height())
        Gdk.cairo_set_source_pixbuf(cairo_context, pixbuf, 0, 0)
        cairo_context.paint()
于 2019-11-04T15:36:50.947 回答