请运行以下代码以获取如下内容:
基本上,我已经建立了一个Gtk.DrawingArea,它位于一个Gtk.Viewport内部,它也位于一个Gtk.Scrolledwindow中。在上述的DrawingArea中,我绘制图像,并使用2个按钮可以缩放该图像。
# -*- 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,0)
box.pack_start(scrolledwindow,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)
cairo_context.paint()
def on_drawing_area_mouse_enter(self,widget,event):
print("In - DrawingArea")
def on_drawing_area_mouse_leave(self,event):
print("Out - DrawingArea")
def on_drawing_area_mouse_motion(self,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()
运行该应用程序。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)当您输入DrawingArea
ii)离开绘图区时
iii)在DrawingArea处的(x,y)和图像像素强度
我面临的问题是,当您缩小足够多的时间时,图像将如下所示:
但是,“鼠标进入”和“鼠标离开”信号以及“鼠标运动”信号都被发送,就像DrawingArea仍具有创建时的尺寸一样。请将鼠标悬停在图像上方和图像外部但在DrawingArea内部,以查看终端中的输出。
我希望将信号悬停在图像之外时不要发送自己。也就是说,如果可能,请将DrawingArea大小调整为显示的图像大小。