generate_image.py

import os
from textwrap import wrap
from PIL import Image, ImageDraw, ImageFont

# DEV
BOTDIR = os.getcwd() + '/'

sprite_map_rows = [ ('W', 0, 22, 22),
                    ('@', 22, 44, 20),
                    ('AMVXYZmw%', 44, 66, 14),
                    ('CDGHKNOPQRU#_', 66, 88, 12),
                    ('BEFLSTabcdeghnopquvyk234567890?$^&+=', 88, 110, 10),
                    ('Jsxz/"<>\\', 110, 132, 8),
                    ('1*{}', 132, 154, 6),
                    ('frt()-;[], ', 154, 176, 4),
                    ("ijlI.!':|", 176, 198, 2)
                    ] 



def build_sprite_map(chars, top, bottom, width):
    """
    Automatically build a sprite map dictionary.

    Takes:
    
        chars: String of characters like 'abcde'
        top: X of top row of sprites
        bottom: X of bottom of row of sprites
        width: the width of each sprite
    """

    sprite_map = {}
    
    for idx, char in enumerate(chars):
        sprite_map[char] = (idx * width,  top, (idx * width) + width, bottom)

    return sprite_map

def build_sprite_dict(sprite_map, sprite_img):
    """
    Build a dictionary of the actual sprites

    Takes:

        sprite_map: a dictionary of charcters/crop positions
        sprite_img: a PIL image object of the sprite sheet to process

    """

    sprite_dict = {}

    for char, pos in sprite_map.items():
        img = sprite_img.copy()
        img = img.crop(box=pos)
        sprite_dict[char] = img

    return sprite_dict

def composite_msgs(msgs, bg_img, x, y, sprite_dict, char_height=22, kerning=2, line_spacing=5, msg_margin_bottom=20, wrap_width=200, bullet=None):
    """
    Composites a list of of messages to a background image, returning a new copy of
    the composite.

    Takes:

        Required
        - msgs: A list of messages to composite
        - bg_img: The background image to composite text onto
        - x, y: Upper left corner starting coordinates
        - sprite_dict: A dictioanry of sprite PIL image objects (the hacked together win 3.1 font)
    
        Optional
        - char_height: height of characters in font
        - kerning: Amount of space between characters
        - line_spacing: Space between lines in multiple line message
        - msg_margin_bottom: Space between messages
        - wrap_width: maximum width of message 
        - Bullet: Autuomatically add bullet text to beginning of each message

    """

    new_bg_img = bg_img.copy()
    x_pos, x_indent, y_pos = x, x, y
    for msg in msgs:
        
        # Composite bullet before message
        if bullet:
            indent_length = 0
            for char in bullet:
                new_bg_img.paste(sprite_dict[char], (x_pos, y_pos))
                x_pos = x_pos + sprite_dict[char].width + kerning
                indent_length += sprite_dict[char].width + kerning

            x_indent = x + indent_length

        # Split message into lines
        msg = wrap(msg, wrap_width)

        for line in msg:
            for char in line:
                new_bg_img.paste(sprite_dict[char], (x_pos, y_pos))
                x_pos = x_pos + sprite_dict[char].width + kerning

            # New Line, reset X and increment Y
            x_pos = x_indent
            y_pos = y_pos + char_height + line_spacing

        # Reset x-pos and x-indent after each message
        x_pos, x_indent = x, x
        y_pos = y_pos + msg_margin_bottom

    return new_bg_img


def init_chars():
    """
    Build sprite dict and store in memory on program run
    """
    sprite_img = Image.open("%sspritesheet.png" % BOTDIR).convert('RGBA')

    sprite_map = {}
    for row in sprite_map_rows:
        result = build_sprite_map(row[0], row[1], row[2], row[3])
        sprite_map = dict( sprite_map.items() + result.items() )

    sprite_dict = build_sprite_dict(sprite_map, sprite_img)
    return sprite_dict

def generate_image(msgs, screen, BOTDIR):
    chars = init_chars()
    background = Image.open("%s/templates/%s.png" % (BOTDIR, screen) ).convert('RGBA')
    result = composite_msgs(msgs, background, 500, 380, chars, wrap_width=57, bullet="-    ")
    return result.save("tweetme.png", "PNG")