在PIL / TKinter中使用绘图

Question

I'm trying to use PIL and Tkinter to make some custom image processing software. I want to use the mouse to select a region of interest in the image, grab those pixel values, and pass it to scipy/numpy for some number crunching and possible PIL for some more image editing.

So far I have a RegionOfInterest class:

class RegionOfInterest:
    def __init__(self,image,boundingBox):
        #take bounding box, draw an oval on the image, save boundingBox locally                                                                                                                                
        self.box = boundingBox
        self.avgInt = 0
        self.draw = ImageDraw.Draw(image)
        self.draw.rectangle(boundingBox,outline='white')

    def capture(self):
        region_to_capture = image.crop(box)
        region_to_capture.save('output.jpg')

which takes a PIL image object and a boundingBox (with a capture method for cropping and saving the image). This gets called by a draw function:

def draw(event):
    global image
    global region
    global listOfRegions
    mouse_X = event.x
    mouse_Y = event.y
    region.append(mouse_X)
    region.append(mouse_Y)
    if len(region) == 4:
        roi = RegionOfInterest(image,region)
        listOfRegions.append(roi)
        canvas.update()
        roi.findPixels()
        roi.calcIntensity()
        region = []

Which is in turn called by a control-click through Tkinter

mouse_X = 0
mouse_Y = 0
region = []
listOfRegions = []

image = Image.open('test.jpg')
image = image.convert('L')
imPix = image.load()
canvas = Tkinter.Canvas(window, width=image.size[0], height=image.size[1])
canvas.pack()
image_tk = ImageTk.PhotoImage(image)
canvas.create_image(image.size[0]//2, image.size[1]//2, image=image_tk)

window.bind("<Control-Button-1>", draw)
window.bind("<Control-space>", lambda e: nextFrame(sequence_object=sequence,event=e))
Tkinter.mainloop()

My biggest problem at the moment is that when I draw the rectangle (way back in RegionOfIntereste. init ()), the rectangles don't show up!

Any advice on how to get this to work? Perhaps any suggestions for resources on learning how to interface tkinter/pil better?

Answer 1

What about something like this:

from Tkinter import *
from PIL import Image, ImageTk

class ScrolledCanvas(Frame):
    def __init__(self, master, **kwargs):
        Frame.__init__(self, master, **kwargs)

        self.grid_rowconfigure(0, weight=1)
        self.grid_columnconfigure(0, weight=1)

        self.canv = Canvas(self, bd=0, highlightthickness=0)
        self.hScroll = Scrollbar(self, orient='horizontal',
                                 command=self.canv.xview)
        self.hScroll.grid(row=1, column=0, sticky='we')
        self.vScroll = Scrollbar(self, orient='vertical',
                                 command=self.canv.yview)
        self.vScroll.grid(row=0, column=1, sticky='ns')
        self.canv.grid(row=0, column=0, sticky='nsew', padx=4, pady=4)        
        self.canv.configure(xscrollcommand=self.hScroll.set,
                            yscrollcommand=self.vScroll.set)


class MyApp(Tk):
    def __init__(self):
        Tk.__init__(self)
        self.grid_rowconfigure(0, weight=1)
        self.grid_columnconfigure(0, weight=1)

        self.main = ScrolledCanvas(self)
        self.main.grid(row=0, column=0, sticky='nsew')
        self.c = self.main.canv

        self.currentImage = {}
        self.load_imgfile('test.jpg')

        self.c.bind('<ButtonPress-1>', self.on_mouse_down)
        self.c.bind('<B1-Motion>', self.on_mouse_drag)
        self.c.bind('<ButtonRelease-1>', self.on_mouse_up)
        self.c.bind('<Button-3>', self.on_right_click)

    def load_imgfile(self, filename):        
        img = Image.open(filename)
        img = img.convert('L')
        self.currentImage['data'] = img

        photo = ImageTk.PhotoImage(img)
        self.c.xview_moveto(0)
        self.c.yview_moveto(0)
        self.c.create_image(0, 0, image=photo, anchor='nw', tags='img')
        self.c.config(scrollregion=self.c.bbox('all'))
        self.currentImage['photo'] = photo

    def on_mouse_down(self, event):        
        self.anchor = (event.widget.canvasx(event.x),
                       event.widget.canvasy(event.y))
        self.item = None

    def on_mouse_drag(self, event):        
        bbox = self.anchor + (event.widget.canvasx(event.x),
                              event.widget.canvasy(event.y))
        if self.item is None:
            self.item = event.widget.create_rectangle(bbox, outline="yellow")
        else:
            event.widget.coords(self.item, *bbox)

    def on_mouse_up(self, event):        
        if self.item:
            self.on_mouse_drag(event) 
            box = tuple((int(round(v)) for v in event.widget.coords(self.item)))

            roi = self.currentImage['data'].crop(box) # region of interest
            values = roi.getdata() # <----------------------- pixel values
            print roi.size, len(values)
            #print list(values)

    def on_right_click(self, event):        
        found = event.widget.find_all()
        for iid in found:
            if event.widget.type(iid) == 'rectangle':
                event.widget.delete(iid)


app =  MyApp()
app.mainloop()

The image in your canvas is like a 'replica' of your main Image object (which is in memory).

A rectangle drawn on the canvas then translates (hopefully) to the corresponding area of your main image, and away you go.

Answer 2

If you are indeed drawing the rectangle where you think you are, most likely what is happening is that it has a lower stacking level so that it is below the image. Try lift ing or lower ing either the rectangle or image.