在Python中，如何在用户交互后从模块中的类传递pixbuf

Question

我正在开发一个python模块来处理屏幕截图。如果单独使用，模块本身工作良好。然而，当我把它导入到我的主项目中时，我不知道如何在等待用户选择要捕获的区域后返回pixbuf。这是屏幕截图模块：

class CaptureRegion():
def __init__(self):
self.ThePic = None
self.drawArea = Gtk.DrawingArea()
self.drawArea.connect('draw',self.onDraw)
mBox = Gtk.VBox(False,2) 
mBox.pack_start(self.drawArea,True,True,2)
self.MaskWin = Gtk.Window()
self.MaskWin.set_position(Gtk.WindowPosition.CENTER)
self.MaskWin.connect("key-press-event", self.KeyPress)
self.MaskWin.connect("button-press-event", self.ButtonPress)
self.MaskWin.connect("button-release-event", self.ButtonRelease)
self.MaskWin.connect("motion-notify-event", self.Motion)
self.MaskWin.add(mBox)
self.button_x = 0
self.button_y = 0
self.button_down = False
self.sel_rect = Gdk.Rectangle(-10, -10, 10, 10)
self.capfull = CaptureScreen() 
self.fullpixbuf = self.capfull.Go()
def onDraw(self, widget, event):
print("Draw")
myGdkWindow = self.MaskWin.get_window()
self.cr = Gdk.cairo_create(myGdkWindow)
self.cr.set_operator(cairo.OPERATOR_SOURCE)
self.cr.set_source_rgb(1,1,1)
Gdk.cairo_set_source_pixbuf(self.cr, self.fullpixbuf, 5, 5)
self.cr.paint()
self.cr.set_line_width(1)
self.cr.set_source_rgb(0,0,0)

if self.button_down == True:
x = self.sel_rect.x
y = self.sel_rect.y
w = self.sel_rect.width
h = self.sel_rect.height
if w <= 0 or h <= 0:
return True
self.cr.rectangle(x,y,w,h)
self.cr.set_source_rgba(0.2, 0.6, 0.8, 0.35)
self.cr.set_line_width(2)
self.cr.stroke()
return True
def Motion(self,widget,event):
if self.button_down == False:
return False
x1,y1 = self.button_x, self.button_y
x2,y2 = event.x, event.y
x = int(min(x1,x2))
y = int(min(y1,y2))
w = int(abs(x1-x2))
h = int(abs(y1-y2))
old = self.sel_rect
self.sel_rect.x = x
self.sel_rect.y = y
self.sel_rect.width = w
self.sel_rect.height = h
win = self.MaskWin.get_window()
sx, sy, sw, sh = self.MaskWin.get_window().get_geometry()
self.drawArea.queue_draw_area(sx,sy,sw,sh)
def ButtonPress(self,widget,event):
if not event.button == 1:
return False
print("button down")
self.debounce = 0
self.button_x, self.button_y = event.x, event.y
self.button_down = True
return True
def ButtonRelease(self,widget,event):
self.button_down = False
x = self.sel_rect.x
y = self.sel_rect.y
w = self.sel_rect.width
h = self.sel_rect.height
self.drawArea.queue_draw_area(x-1, y-1, w-1, h-1)
if self.debounce == 0:
self.debounce += 1
print("Snipping x:%s y:%s w:%s h:%s" %(x,y,w,h))
self.ThePic = Gdk.pixbuf_get_from_window(self.MaskWin.get_window(), x, y, w, h)
self.MaskWin.hide()
#option 2:    to return ThePic here after the selection is made thru a callback to a function in the main class 
# i.e.
#self.CallbackInMain(self.ThePic)    (not sure how to callback to the main class, self is wrong maybe?)

def KeyPress(self,widget,event):
if event.keyval == Gdk.KEY_Escape:
self.ThePic = None
return
def WaitThread(self):
for i in range(1, 50):
time.sleep(0.1)
print(i)
self.done_waiting.set() 

def Go(self):
self.MaskWin.fullscreen()
self.MaskWin.show_all()
self.MaskWin.set_decorated(False)
#option 1 find a way to wait for the selection to complete like this:  
#(this code doesnt end, the self.done_waiting.set() call doesnt stop it)
# self.done_waiting = threading.Event()
# self.thread = threading.Thread(target=self.WaitThread)
# self.thread.start()
# self.done_waiting.wait(1)
# print("Main thread is done waiting")
return(self.ThePic)
class CaptureScreen():  
def __init__(self):
self.ThePic = None
def Go(self):
screen = Gdk.get_default_root_window()
x, y, width, height = screen.get_geometry()
self.fullpixbuf = Gdk.pixbuf_get_from_window(screen, x, y, width, height)
return(self.fullpixbuf)

我这样称呼这个班：

import Screentshot as Shot
self.captureregion = Shot.CaptureRegion()
pic = self.captureregion.Go()
pic.savev("region.png",'png',(),())

使用CaptureScreen类，我只捕获整个屏幕，这样我就可以直接从CaptureScreen.Go((函数返回pixbuf。然而，对于CaptureRegion类，我必须等待用户选择一个区域，并且我不确定如何让CaptureRegion.Go((在用户选择后返回pixbuf。我有两个想法，一个是使用线程等待选择完成，然后从CaptureRegion.Go((返回pixbuf(代码中的选项1(，另一个是以某种方式让屏幕截图类回调以在主屏幕中使用pigbuf作为arg(代码的选项2(

我对类不是很熟悉，也从来没有使用过线程模块。我搜索并找到了很多信息，我只是无法完全理解我需要做什么。

Answer 1

当然，现在我终于发布了一个关于这方面的问题，我明白了。我只需要在Go中添加第二个arg(self，mainself(，然后回调主代码中的一个函数。

这就是我改变的：

def ButtonRelease(self,widget,event):
self.button_down = False
x = self.sel_rect.x
y = self.sel_rect.y
w = self.sel_rect.width
h = self.sel_rect.height
self.drawArea.queue_draw_area(x-1, y-1, w-1, h-1)
if self.debounce == 0:
self.debounce += 1
print("Snipping x:%s y:%s w:%s h:%s" %(x,y,w,h))
self.ThePic = Gdk.pixbuf_get_from_window(self.MaskWin.get_window(), x, y, w, h)
self.MaskWin.hide()
self.GotTheShot = True
self.mainself.ScreenShotCallBack(self.ThePic)
def Go(self,main):
self.mainself = main
self.GotTheShot = False
self.MaskWin.fullscreen()
self.MaskWin.show_all()
self.MaskWin.set_decorated(False)

这是呼叫和回叫：

def ScreenShotRegion(self):
pic = self.captureregion.Go(self)# self,mainself... self passed by default
pic.savev("region.png",'png',(),())
def ScreenShotCallBack(self,capturepixbuf):
self.window.show_all()
capturepixbuf.savev("region.png",'png',(),())