canvas.py

import tkinter as tk
import numpy as np
from PIL import ImageTk
from styles import MARGIN
from image import Image
from PIL import Image as PImage
from vertexes import VertexFinder
import styles


def center(coords):
    '''Get the center of an rectangle'''
    return (coords[0] + coords[2]) // 2, (coords[1] + coords[3]) // 2


class ImageCanvas(tk.Canvas):
    '''A canvas which display the thumbnail of the image'''

    def __init__(self, controller=None, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.controller = controller
        self.image = None
        self.thumbnail = None
        self.image_to_show = 'product'

    def config_size(self, size):
        '''Update the canvas size'''
        self.width, self.height = size
        self.config(width=self.width, height=self.height)

    def show_image(self, image):
        '''Show an PIL Image'''
        self.image = image
        size = self.image_size(image)
        self.config_size(size)

        self.make_thumbnail()

        self.create_image(
            (0, 0), anchor=tk.NW, image=self.thumbnail)

    def make_thumbnail(self):
        '''Make a thumbnail of an PIL image'''
        result = self.image.copy()
        result.thumbnail((self.width, self.height), PImage.NEAREST)
        self.thumbnail = ImageTk.PhotoImage(image=result)

    def image_size(self, image):
        '''Get the size of the thumbnail'''
        if image.width > image.height:
            width = self.controller.width
            image_width = (width - 2*MARGIN) // 2
            image_height = int(image_width * (image.height / image.width))
            return image_width, image_height

        height = self.controller.height
        image_height = (height * 3) // 4
        image_width = int(image_height * (image.width / image.height))
        return image_width, image_height


class DragableCanvas(ImageCanvas):
    '''A ImageCanvas which can drag the vertexes point'''

    def __init__(self, controller, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.controller = controller
        self.r = 15
        self.selected = None
        self.image_to_show = 'origin'

        self.tag_bind('vertex', '<Button-1>', self.on_click)
        self.bind('<Motion>', self.on_motion)
        self.bind('<ButtonRelease-1>', self.on_release)

        self.callback = None

    def set_callback(self, callback):
        '''Set the callback being called when the coords updates'''
        self.callback = callback

    def show_image(self, image, coords):
        '''Show the image and draw the vertexes'''
        super().show_image(image)
        self.draw_vertexes(coords)

    def draw_vertexes(self, coords):
        '''Draw the four vertexes on the canvas'''
        self.delete('vertex')
        r = self.r
        if coords is None:
            coords = self.image.default_vertexes()

        coords = self.coords_transform(coords)
        [
            self.create_oval(
                x-r, y-r, x+r, y+r, fill=styles.COLOR, outline=styles.COLOR, tags=('vertex'))
            for x, y in coords
        ]
        self.draw_lines()

    def draw_lines(self):
        '''Draw the line between the vertexes'''
        coords = self.get_coords()
        coords = self.coords_transform(coords).tolist()
        coords.append(coords[0])
        self.delete('lines')
        self.create_line(*coords, tags=('lines',), fill=styles.COLOR)

    def on_click(self, event):
        '''Find the current selected vertex'''
        self.selected = self.find_closest(event.x, event.y)

    def on_motion(self, event):
        '''Move the selected vertex to the mouse'''
        if self.selected:
            self.coords(
                self.selected, (event.x-self.r, event.y-self.r, event.x + self.r, event.y + self.r))
            self.draw_lines()

    def on_release(self, event):
        '''Call the callback to update the coords'''
        self.selected = None
        self.callback(self.get_coords())

    def get_coords(self):
        '''Get the canvas coords of vertexes and transform to the image coords'''
        coords = np.float32([center(self.coords(vertex))
                             for vertex in self.find_withtag('vertex')]) * self.image.width / self.width
        print(coords.__repr__())
        return coords

    def coords_transform(self, coords):
        '''Transform image coords to the canvas coords'''
        return coords * self.width / self.image.width