import math
import sys

from PIL import Image
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap, QImage, qRgb
from PyQt5.QtWidgets import (
    QApplication,
    QLabel,
    QMainWindow
)

class Surface:
    def __init__(self, image_file):
        im = Image.open(image_file)
        self.pixels = im.tobytes()
        self.w = im.width
        self.h = im.height

class Palette:
    def __init__(self, image_file):
        im = Image.open(image_file)
        pal = im.getpalette()
        pal_size = math.floor(len(pal)/3)
        self.colors = []
        for i in range(pal_size):
            self.colors.append(qRgb(pal[i*3],pal[1+i*3],pal[2+i*3]))

class Canvas:
    def __init__(self, palette):
        # Crear el QImage
        self.img = QImage(320, 240, QImage.Format.Format_Indexed8)

        # Omplir la paleta
        for i in range(len(palette.colors)):
            self.img.setColor(i, palette.colors[i])

        for y in range(240):
            for x in range(320):
                self.img.setPixel(x,y,20)

        # Preparem els indices de sustitucio de la paleta
        self.pal = bytearray(256)
        for i in range(256):
            self.pal[i] = i

    def blt(self, dx, dy, surface, sx, sy, sw, sh, color):
        self.pal[1] = color
        for y in range(sh):
            for x in range(sw):
                col = self.pal[surface.pixels[(sx+x)+(sy+y)*surface.w]]
                if col != 0:
                    self.img.setPixel(dx+x,dy+y,col)
        self.pal[1] = 1

class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        self.setWindowTitle("My App")

        label = QLabel("Hello")

        surface = Surface("data/gat.gif")
        paleta = Palette("data/test.gif")
        canvas = Canvas(paleta)
        canvas.blt(10, 10, surface, 0, 0, 22, 35, 18)

        label.setPixmap(QPixmap.fromImage(canvas.img).scaled(640,480, Qt.IgnoreAspectRatio, Qt.FastTransformation))

        label.setAlignment(Qt.AlignHCenter | Qt.AlignVCenter)
        label.setScaledContents(True)
        self.setCentralWidget(label)

app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()