fonteditor/canvas.py

import base64
import platform
import tkinter

GRID_COLOR = "#808080"
GRID_GUIDE_COLOR = (128, 128, 255)

class EditorCanvas(tkinter.Canvas):
    def __init__(self,project,*args,**kwargs):
        super().__init__(*args,**kwargs)
        self.project=project
        self.grid_size = 32
        self.current_char=33
        self.current_char_pixels=[]
        self.current_char_modified=False
        self.width=0
        self.height=0
        self.prev_mouse_x=0
        self.prev_mouse_y=0
        self.view_x=0
        self.view_y=0
        self.bind("<B1-Motion>",self.handle_draw)
        self.bind("<Button-1>",self.handle_draw)
        self.bind("<Button-3>",self.handle_move_start)
        self.bind("<B3-Motion>",self.handle_move)
        if platform.system()=="Windows" or platform.system()=="Darwin":
            self.bind("<MouseWheel>",lambda event: self.handle_zoom(event.delta))
        else:
            # This will probably work only on X11
            self.bind("<Button-4>",lambda _: self.handle_zoom(1))
            self.bind("<Button-5>",lambda _: self.handle_zoom(-1))


    def draw(self):
        self.delete("all")

        # draw grid
        for x in range(self.project.char_res[0] + 1):
            x = x * self.grid_size+self.view_x
            self.create_line((x,self.view_y),(x,self.view_y+self.height),width=1,fill=GRID_COLOR)
        for y in range(self.project.char_res[1] + 1):
            y = y * self.grid_size+self.view_y
            self.create_line((self.view_x,y),(self.view_x+self.width,y),width=1,fill=GRID_COLOR)

        if self.project.does_char_exist(self.current_char) or self.current_char_modified:
            for i in range(len(self.current_char_pixels)):
                x=i//self.project.char_res[1]*self.grid_size+self.view_x
                y=i%self.project.char_res[1]*self.grid_size+self.view_y
                if self.current_char_pixels[i]>0:
                    self.create_rectangle((x,y),(x+self.grid_size,y+self.grid_size),fill="white")
        else:
            self.create_line((self.view_x,self.view_y),(self.view_x+self.width,self.view_y+self.height),width=3,fill="red")
            self.create_line((self.view_x+self.width,self.view_y),(self.view_x,self.view_y+self.height),width=3,fill="red")


    def handle_draw(self,event):
        self.current_char_modified=True
        pixel_pos=self.cursor_pos_to_pixel((event.x,event.y))
        if not pixel_pos:
            return
        self.current_char_pixels[pixel_pos[0]*self.project.char_res[1]+pixel_pos[1]]=1
        self.draw()


    def handle_move_start(self,event):
        self.prev_mouse_x=event.x
        self.prev_mouse_y=event.y


    def handle_move(self,event):
        self.view_x+=event.x-self.prev_mouse_x
        self.view_y+=event.y-self.prev_mouse_y
        self.prev_mouse_x=event.x
        self.prev_mouse_y=event.y
        self.draw()


    def handle_zoom(self,delta):
        self.grid_size+=delta
        self.width=self.project.char_res[0]*self.grid_size
        self.height=self.project.char_res[1]*self.grid_size
        self.draw()


    def load_char(self):
        self.current_char_modified=False
        if not self.project.does_char_exist(self.current_char):
            for x in range(len(self.current_char_pixels)):
                self.current_char_pixels[x]=0
            return
        base64_data=self.project.chars[chr(self.current_char)]
        pixels=base64.b64decode(base64_data.encode("ascii"))
        pixel_index=0
        for pixel in pixels:
            if pixel_index>=len(self.current_char_pixels):
                break
            for x in range(8):
                if pixel_index>=len(self.current_char_pixels):
                    break
                self.current_char_pixels[pixel_index]=(pixel>>(7-x))&1
                pixel_index+=1
        self.draw()


    def save_char(self):
        if not self.current_char_modified:
            return

        empty=True
        for x in range(len(self.current_char_pixels)):
            if self.current_char_pixels[x]>0:
                empty=False
                break
        if empty:
            if self.project.does_char_exist(self.current_char):
                del(self.project.chars[chr(self.current_char)])
            return

        packed_data=[]
        bit_counter=0
        current_value=0
        for pixel in self.current_char_pixels:
            if bit_counter==8:
                packed_data.append(current_value)
                bit_counter=0
                current_value=0
            current_value|=(pixel<<(7-bit_counter))
            bit_counter+=1
        if bit_counter>1:
            packed_data.append(current_value)

        self.project.chars[chr(self.current_char)]=base64.b64encode(bytes(packed_data)).decode("ascii")


    def prev_glyph(self):
        self.save_char()
        self.current_char-=1
        self.keep_current_char_in_bounds()
        self.load_char()
        self.draw()


    def next_glyph(self):
        self.save_char()
        self.current_char+=1
        self.keep_current_char_in_bounds()
        self.load_char()
        self.draw()


    def cursor_pos_to_pixel(self,pos):
        pixel_pos = ((pos[0]-self.view_x) // self.grid_size, (pos[1]-self.view_y) // self.grid_size)
        if pixel_pos[0]<0 or pixel_pos[0]>=self.project.char_res[0] or pixel_pos[1]<0 or pixel_pos[1]>=self.project.char_res[1]:
            return None
        return pixel_pos


    def keep_current_char_in_bounds(self):
        if self.current_char<0:
            self.current_char=0
        elif self.current_char>99999:
            self.current_char=99999


    def after_project_load(self):
        self.width=self.project.char_res[0]*self.grid_size
        self.height=self.project.char_res[1]*self.grid_size
        self.current_char_pixels=[0 for _ in range(self.project.char_res[0]*self.project.char_res[1])]
        self.load_char()