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aneuhaeuser revised this gist . Go to revision
No changes
aneuhaeuser revised this gist . Go to revision
1 file changed, 62 insertions
bmp.py(file created)
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| 1 | + | class BMPImage: | |
| 2 | + | def __init__(self, data): | |
| 3 | + | self.data = data | |
| 4 | + | self._get_bmp_header() | |
| 5 | + | self._get_bmp_info_header() | |
| 6 | + | self._get_bmp_color_table() | |
| 7 | + | ||
| 8 | + | offset = self.header["offset"] | |
| 9 | + | ||
| 10 | + | self.BITMAP = memoryview(data[offset:]) | |
| 11 | + | self.HEIGHT = self.info_header["height"] | |
| 12 | + | self.WIDTH = self.info_header["width"] | |
| 13 | + | self.COLORS = self.info_header["colors_used"] | |
| 14 | + | self.BPP = self.info_header["bit_count"] # Bits per pixel | |
| 15 | + | self.PALLETTE = self.color_table | |
| 16 | + | ||
| 17 | + | def _get_bmp_header(self): | |
| 18 | + | d = self.data | |
| 19 | + | self.header = { | |
| 20 | + | "signature": d[0:2].decode("ascii"), | |
| 21 | + | "file_size": int.from_bytes(data[2:6], "little"), | |
| 22 | + | "offset": int.from_bytes(data[10:14], "little"), | |
| 23 | + | "header_size": int.from_bytes(data[14:18], "little"), | |
| 24 | + | } | |
| 25 | + | ||
| 26 | + | def _get_bmp_info_header(self): | |
| 27 | + | offset = 14 # BMP header size | |
| 28 | + | data = self.data[offset:] | |
| 29 | + | ||
| 30 | + | self.info_header = { | |
| 31 | + | "size": int.from_bytes(data[0:4], "little"), | |
| 32 | + | "width": int.from_bytes(data[4:8], "little"), | |
| 33 | + | "height": int.from_bytes(data[8:12], "little"), | |
| 34 | + | "planes": int.from_bytes(data[12:14], "little"), | |
| 35 | + | "bit_count": int.from_bytes(data[14:16], "little"), | |
| 36 | + | "compression": int.from_bytes(data[16:20], "little"), | |
| 37 | + | "image_size": int.from_bytes(data[20:24], "little"), | |
| 38 | + | "x_pixels_per_meter": int.from_bytes(data[24:28], "little"), | |
| 39 | + | "y_pixels_per_meter": int.from_bytes(data[28:32], "little"), | |
| 40 | + | "colors_used": int.from_bytes(data[32:36], "little"), | |
| 41 | + | "important_colors": int.from_bytes(data[36:40], "little"), | |
| 42 | + | } | |
| 43 | + | ||
| 44 | + | ||
| 45 | + | def _get_bmp_color_table(self): | |
| 46 | + | bpp = self.info_header["bit_count"] | |
| 47 | + | color_amount = self.info_header["colors_used"] | |
| 48 | + | ||
| 49 | + | if bpp > 8: | |
| 50 | + | self.color_table = [] | |
| 51 | + | return | |
| 52 | + | ||
| 53 | + | if color_amount == 0: | |
| 54 | + | color_amount = 2 ** bpp | |
| 55 | + | ||
| 56 | + | offset = 14 + 40 # File header + Info header | |
| 57 | + | data = self.data[offset:offset + color_amount * 4] | |
| 58 | + | ||
| 59 | + | self.color_table = [ | |
| 60 | + | int.from_bytes(data[i:i+4], "little") | |
| 61 | + | for i in range(0, len(data), 4) | |
| 62 | + | ] | |
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