1Ppmmix User Manual(0) Ppmmix User Manual(0)
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6 ppmmix - blend together two PPM images
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10 ppmmix fadefactor ppmfile1 ppmfile2
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14 This program is part of Netpbm(1).
15 ppmmix reads two PPM images as input and mixes them together using the
17 specified fade factor. The fade factor may be in the range from 0.0
18 (only ppmfile1's image data) to 1.0 (only ppmfile2's image data). Any‐
19 thing in between specifies a smooth blend between the two images.
20 The two images must have the same dimensions and the same maxval.
22 Before Netpbm 10.54 (March 2011), they must also have the same type
23 (PBM/PGM/PPM).
24 The fade factor is applied to brightness, not light intensity. That
26 means for example that if you have a series of images you generated
27 using ppmmix of a black and a white image with a linearly increasing
28 fade factor, you will see an image getting linearly brighter, but the
29 light intensity will increase faster at the end. That is because it
30 requires more intensity change at the bright end of the scale than at
31 the dark end for the human eye to perceive the same brightness change.
32 This also means that if the original images aren't all one color, the
33 mixed image is distorted, since the intensity relationship between pix‐
34 els is different from the original image.
35 pamcomp is a more general alternative. It allows you to mix images of
37 different size and to have the fade factor vary throughout the image
38 (through the use of a transparency mask). It does not have the same-
39 maxval and same-type restrictions. It mixes light intensity, not
40 brightness.
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44 pamcomp(1), ppm(1)
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48 Copyright (C) 1993 by Frank Neumann
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51 This manual page was generated by the Netpbm tool 'makeman' from HTML
52 source. The master documentation is at
53 http://netpbm.sourceforge.net/doc/ppmmix.html
55netpbm documentation 23 March 2010 Ppmmix User Manual(0)