Initial data commit

Task/Bitmap-Write-a-PPM-file/Python/bitmap-write-a-ppm-file.py

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+# String masquerading as ppm file (version P3)
+import io
+ppmfileout = io.StringIO('')
+
+def writeppmp3(self, f):
+    self.writeppm(f, ppmformat='P3')
+
+def writeppm(self, f, ppmformat='P6'):
+    assert ppmformat in ['P3', 'P6'], 'Format wrong'
+    magic = ppmformat + '\n'
+    comment = '# generated from Bitmap.writeppm\n'
+    maxval = max(max(max(bit) for bit in row) for row in self.map)
+    assert ppmformat == 'P3' or 0 <= maxval < 256, 'R,G,B must fit in a byte'
+    if ppmformat == 'P6':
+        fwrite = lambda s: f.write(bytes(s, 'UTF-8'))
+        maxval = 255
+    else:
+        fwrite = f.write
+        numsize=len(str(maxval))
+    fwrite(magic)
+    fwrite(comment)
+    fwrite('%i %i\n%i\n' % (self.width, self.height, maxval))
+    for h in range(self.height-1, -1, -1):
+        for w in range(self.width):
+            r, g, b = self.get(w, h)
+            if ppmformat == 'P3':
+                fwrite('   %*i %*i %*i' % (numsize, r, numsize, g, numsize, b))
+            else:
+                fwrite('%c%c%c' % (r, g, b))
+        if ppmformat == 'P3':
+            fwrite('\n')
+
+Bitmap.writeppmp3 = writeppmp3
+Bitmap.writeppm = writeppm
+
+# Draw something simple
+bitmap = Bitmap(4, 4, black)
+bitmap.fillrect(1, 0, 1, 2, white)
+bitmap.set(3, 3, Colour(127, 0, 63))
+# Write to the open 'file' handle
+bitmap.writeppmp3(ppmfileout)
+# Whats in the generated PPM file
+print(ppmfileout.getvalue())
+
+'''
+The print statement above produces the following output :
+
+P3
+# generated from Bitmap.writeppmp3
+4 4
+255
+     0   0   0     0   0   0     0   0   0   127   0  63
+     0   0   0     0   0   0     0   0   0     0   0   0
+     0   0   0   255 255 255     0   0   0     0   0   0
+     0   0   0   255 255 255     0   0   0     0   0   0
+
+'''
+
+# Write a P6 file
+ppmfileout = open('tmp.ppm', 'wb')
+bitmap.writeppm(ppmfileout)
+ppmfileout.close()