输入半径，计算圆的周长、面积、球体体积，并画出这个圆。
拖动条、输入框和图像控件的数据保持一致！

Fedora下测试通过

复制代码 代码如下:
#https://github.com/RobberPhex/GTK-Example-CalcArea
from gi.repository import Gtk, Gdk, GdkPixbuf
from PIL import Image, ImageDraw
from io import BytesIO
from math import pi

class Model:
'''
模型类
存储半径，计算周长、面积、体积
'''

def __init__(self):
self._radius = 0

def setRadius(self, radius):
self._radius = float(radius)

def getRadius(self):
return self._radius

def getPerimeter(self):
return pi * self._radius * 2

def getArea(self):
return self._radius ** 2 * pi

def getVolume(self):
return 4 * pi * self._radius ** 3 / 3

class Controller:
'''
控制器类
控制视图和模型的更新
'''

def __init__(self, model):
self.model = model
self._observers = []

def addObserver(self, observer):
self._observers.append(observer)

def setRadius(self, radius):
model.setRadius(radius)
self.notify()

def notify(self):
for observer in self._observers:
observer.update()

class TextView:
'''
文字视图类
处理文本输入框的视图
'''

def __init__(self, model, rEntry, pEntry, aEntry, vEntry):
'''
:type model Model
'''
self.model = model
self.rEntry = rEntry
self.pEntry = pEntry
self.aEntry = aEntry
self.vEntry = vEntry

def update(self):
self.rEntry.set_text('%2.2f' % self.model.getRadius())
self.pEntry.set_text('%2.2f' % self.model.getPerimeter())
self.aEntry.set_text('%2.2f' % self.model.getArea())
self.vEntry.set_text('%2.2f' % self.model.getVolume())

class ScaleView:
'''
拖动条视图
处理拖动条的视图
'''

def __init__(self, model, scale):
'''
:type model Model
'''
self.model = model
self.scale = scale

def update(self):
self.scale.set_value(self.model.getRadius())

class ImageView:
'''
图像视图
处理图像的视图
'''

@classmethod
def imgToPixbuf(cls, img):
'''
:type img Image
'''
buff = BytesIO()
img.save(buff, 'ppm')
contents = buff.getvalue()
buff.close()

loader = GdkPixbuf.PixbufLoader.new_with_type('pnm')
loader.write(contents)
pixbuf = loader.get_pixbuf()
loader.close()
return pixbuf

@classmethod
def ellipse(cls, radius):
'''
:type radius int
'''
image = Image.new("RGBA", (300, 300), "white")
draw = ImageDraw.Draw(image)
minor = 150 - radius
major = 150 + radius
draw.ellipse((minor, minor, major, major), outline='red')
pixbuf = ImageView.imgToPixbuf(image)
return pixbuf

def __init__(self, model, image):
self.model = model
self.image = image

def update(self):
radius = self.model.getRadius()
pixbuf = ImageView.ellipse(radius)
self.image.set_from_pixbuf(pixbuf)

class MainWindow(Gtk.Window):
'''
主窗口类
负责整体界面的显示
'''

def textCallback(self, widget, controller):
'''
文本输入回调
'''
try:
radius = float(widget.get_text())
controller.setRadius(radius)
except ValueError as e:
pass

def scaleCallback(self, widget, controller):
'''
拖动条回调
'''
radius = widget.get_value()
controller.setRadius(radius)

def __init__(self):
Gtk.Window.__init__(self, title="Title")

self.set_default_size(600, 400)
self.set_position(Gtk.WindowPosition.CENTER)

hbox = Gtk.HBox(spacing=5)
self.add(hbox)

vbox = Gtk.VBox(spacing=5)
hbox.pack_start(vbox, True, True, 2)

table = Gtk.Table.new(4, 2, False)
vbox.pack_start(table, True, True, 2)

label = Gtk.Label('半径：')
table.attach_defaults(label, 0, 1, 0, 1)
label = Gtk.Label('周长：')
table.attach_defaults(label, 0, 1, 1, 2)
label = Gtk.Label('面积：')
table.attach_defaults(label, 0, 1, 2, 3)
label = Gtk.Label('体积：')
table.attach_defaults(label, 0, 1, 3, 4)

self.radiusEntry = Gtk.Entry.new()
self.radiusEntry.connect('changed', self.textCallback, controller)
table.attach_defaults(self.radiusEntry, 1, 2, 0, 1)
self.perimeterEntry = Gtk.Entry.new()
self.perimeterEntry.set_sensitive(False)
self.perimeterEntry.set_text('周长')
table.attach_defaults(self.perimeterEntry, 1, 2, 1, 2)
self.areaEntry = Gtk.Entry.new()
self.areaEntry.set_sensitive(False)
self.areaEntry.set_text('面积')
table.attach_defaults(self.areaEntry, 1, 2, 2, 3)
self.volumeEntry = Gtk.Entry.new()
self.volumeEntry.set_sensitive(False)
self.volumeEntry.set_text('体积')
table.attach_defaults(self.volumeEntry, 1, 2, 3, 4)

self.scale = Gtk.HScale.new_with_range(0, 100, 1)
self.scale.connect('value-changed', self.scaleCallback, controller)
vbox.pack_start(self.scale, False, False, 2)

pixbuf = GdkPixbuf.Pixbuf.new(GdkPixbuf.Colorspace.RGB, True, 8, 300, 300)
pixbuf.fill(0xaaaaaaaa)
self.image = Gtk.Image.new_from_pixbuf(pixbuf)
hbox.pack_start(self.image, True, True, 2)

self.connect('delete-event', Gtk.main_quit)

model = Model()
controller = Controller(model)

if __name__ == '__main__':
Gdk.threads_init()
Gdk.threads_enter()
win = MainWindow()

iv = ImageView(model, win.image)
controller.addObserver(iv)

tv = TextView(model, win.radiusEntry, win.perimeterEntry, win.areaEntry, win.volumeEntry)
controller.addObserver(tv)

sv = ScaleView(model, win.scale)
controller.addObserver(sv)

win.show_all()
Gtk.main()
Gdk.threads_leave()