Implementation of Python to Generate bmp Image

The previous use of c, java, go language to generate solid color BMP picture function.

This function is now completed by python language.

from array import array

class bmp:
    """ bmp data structure """

    def __init__(self, w=1080, h=1920, color = 0xffffff):
        self.w = w
        self.h = h
        self.gen_bmp_header()
        self.paint_bgcolor(color)

    def calc_data_size (self):
        if((self.w*3)%4 == 0):
            self.dataSize = self.w * 3 * self.h
        else:
            self.dataSize = (((self.w * 3) // 4 + 1) * 4) * self.h

        self.fileSize = self.dataSize + 54

    def conv2byte(self, l, num, len):
        tmp = num
        for i in range(len):
            l.append(tmp & 0x000000ff)
            tmp >>= 8

    def gen_bmp_header (self):
        self.calc_data_size();
        self.bmp_header = [0x42, 0x4d]
        self.conv2byte(self.bmp_header, self.fileSize, 4) #file size
        self.conv2byte(self.bmp_header, 0, 2)
        self.conv2byte(self.bmp_header, 0, 2)
        self.conv2byte(self.bmp_header, 54, 4) #rgb data offset
        self.conv2byte(self.bmp_header, 40, 4) #info block size
        self.conv2byte(self.bmp_header, self.w, 4)
        self.conv2byte(self.bmp_header, self.h, 4)
        self.conv2byte(self.bmp_header, 1, 2)
        self.conv2byte(self.bmp_header, 24, 2) #888
        self.conv2byte(self.bmp_header, 0, 4)  #no compression
        self.conv2byte(self.bmp_header, self.dataSize, 4) #rgb data size
        self.conv2byte(self.bmp_header, 0, 4)
        self.conv2byte(self.bmp_header, 0, 4)
        self.conv2byte(self.bmp_header, 0, 4)
        self.conv2byte(self.bmp_header, 0, 4)

    def print_bmp_header (self):
        length = len(self.bmp_header)
        for i in range(length):
            print("{:0>2x}".format(self.bmp_header[i]), end=' ')
            if i%16 == 15:
                print('')
        print('')

    def paint_bgcolor(self, color=0xffffff):
        self.rgbData = []
        for r in range(self.h):
            self.rgbDataRow = []
            for c in range(self.w):
                self.rgbDataRow.append(color)
            self.rgbData.append(self.rgbDataRow)

    def paint_line(self, x1, y1, x2, y2, color):
        k = (y2 - y1) / (x2 - x1)
        for x in range(x1, x2+1):
            y = int(k * (x - x1) + y1)
            self.rgbData[y][x] = color

    def paint_rect(self, x1, y1, w, h, color):
        for x in range(x1, x1+w):
            for y in range(y1, y1+h):
                self.rgbData[y][x] = color

    def paint_point(self, x, y, color=0x000000):
        self.rgbData[y][x] = color

    def save_image(self, name="save.bmp"):
        f = open(name, 'wb')

        #write bmp header
        f.write(array('B', self.bmp_header).tobytes())

        #write rgb data
        zeroBytes = self.dataSize // self.h - self.w * 3

        for r in range(self.h):
            l = []
            for i in range(len(self.rgbData[r])):
                p = self.rgbData[r][i]
                l.append(p & 0x0000ff)
                p >>= 8
                l.append(p & 0x0000ff)
                p >>= 8
                l.append(p & 0x0000ff)

            f.write(array('B', l).tobytes())

            for i in range(zeroBytes):
                f.write(bytes([0x00]))

        #close file
        f.close()

if __name__ == '__main__':


    image = bmp(35, 35)

    for i in range(35):
        image.paint_point(i, i, 0xff0000)

    image.save_image("save1.bmp")
    import os
    os.system("save1.bmp")