What about large images?

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What about large images?

Post by mtnviewmark »

You can render very large images with Context Free.

Images for most common uses aren't really large enough to be a concern:
  • Web image: 600 x 600 = 1/3 mega-pixel
  • Screen background: 1024 x 864 = 1 mega-pixel
  • 4" x 6" print @ 300dpi: 1200 x 1800 = 2 mega-pixels
  • Tee shirt: 2000 x 2000 = 4 mega-pixels
  • A2 chart @ 80ppc: 3360 x 4752 = 16 mega-pixels
It may take at most a few minutes to render the larger of these, and depending on the design, it may have to use several temporary files. However, for the most part, the program will have no trouble displaying or saving images at these sizes.

Even images over 50 mega-pixels won't seriously strain the resources of the program, if your computer has enough resources.
  • Large poster @ 200dpi: 7000 x 4600 = 32 mega-pixels
  • A0 poster @ 80ppc: 6728 x 9512 = 61 mega-pixels
  • Biggest we've ever done: 10,000 x 10,000 = 95 mega-pixels
In the program, each pixel is represented one byte in memory. So the largest of these is almost 100 mega-bytes of memory. And it all needs to be accessible at once, since drawing takes place all over the canvas. So if your computer has at least 512 Meg of RAM, these should be doable.

These large images may take a while to render, but will probably take even longer to save to disk! The PNG compression process can take quite a lot of computation on an image this big.

We've generated 10k x 10k images on both the Windows and Macintosh version. Our computers have 512 Meg RAM each and are a 1.2GHz Pentium and a 800MHz G4 respectively. It takes under 5 min. or so to generate and save. (We don't know exactly, we got bored watching it and made tea...) The images look great!
I'm the "m" in "mtree.cfdg"

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What about REALLY large images?

Post by nharendt »

MtnViewMark wrote:You can render very large images with Context Free.

Biggest we've ever done: 10,000 x 10,000 = 95 mega-pixels

what about REALLY LARGE images ?? I want to create an image for high resolution printing (3000dpi) and tried "Render to Size..." and wanted to use something like 42000 pixels width and height, but the dialog says something like 32768 is maximum :cry:

Where does that limiting value come from ?? Is it possible to render images with more than 32768 Pixels ??

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Post by MtnViewJohn »

I was able to generate a 42000x42000 grayscale image using the command-line version, cfdg. If you want to do a color image then you will need to compile it for 64-bit address space on a 64-bit OS. A 42,000x42,000x32-bit image can't fit in a 32-bit virtual address space and Context Free has no facility for generating images in sections.

The border is sized so that a shape of a given size will never be closer than its size to the edge. You can control whether Context Free does this in the preferences. CFDG has a '-b' command-line option for controlling the border size too.

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