MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Why does ImageCompose degrade the result and can you do anything

  • To: mathgroup at
  • Subject: [mg98469] Why does ImageCompose degrade the result and can you do anything
  • From: Bob F <deepyogurt at>
  • Date: Fri, 10 Apr 2009 04:56:01 -0400 (EDT)

I wanted to play around with one of the new version 7 image routines,
called ImageCompose[], which can be used to add images together.

When I was trying to use it, the resultant image was a much degraded
image for some of the examples I was playing with, compared to the
originals (looked like the resolution was significantly less than the
originals), so when you change the magnification the resultant image
gets worse and worse and worse as you increase the magnification.
Especially noticeable was the text on the tick labels, and the jaggies
in the curves and the rasterization becomes more and more prominent,
even though the original images don't show this.

So, anyone have an idea of why ImageCompose does this and is there a
way to use it to add two images together and have the result be as
good as the originals, as long as the two have the same resolution?

Here is an simple example that shows what I mean:

i1 = Plot[Sin[x], {x, -3 Pi, 3 Pi}]
i2 = Plot[Cos[x], {x, -3 Pi, 3 Pi}]
ImageCompose[i1, i2]

So if you up the magnification the ImageCompose version gets more and
more jaggies, as well as the axes and ticks and tick labels getting
worse and worse.



  • Prev by Date: Re: passing both arbitary and defined options
  • Next by Date: Re: Integrate and Piecewise
  • Previous by thread: Re: Replace Table[Sum...]...] with Functional code
  • Next by thread: Re: combining contourplot and regionplot [Addendum]