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Min Samples Sets the minimum sample rate. The value represents the number
of samples per pixel. A value greater than or equal to 1 indicates that one or
more samples are computed per pixel. A fractional value indicates that one
sample is computed for every N pixels (for example, 1/4 computes a minimum
of one sample for every four pixels). Default=1/4.
Max Samples Sets the maximum sample rate. If neighboring samples find a
difference in contrast that exceeds the contrast limit, the area containing the
contrast is subdivided to the depth specified by Maximum. Default=1.
The values of the Min Samples and Max Samples lists are "locked" together so
that the value of Min Samples can't exceed the value of Max Samples.
Filter Type Determines how multiple samples are combined into a single pixel
value.
■ Box. Sums all samples in the filter area with equal weight. This is the
quickest sampling method.
■ Gauss. Weights the samples using a Gauss (bell) curve centered on the
pixel.
■ Triangle. Weights the samples using a pyramid centered on the pixel.
■ Mitchell. Weights the samples using a curve (steeper than Gauss) centered
on the pixel.
■ Lanczos. Weights the samples using a curve (steeper than Gauss) centered
on the pixel, diminishing the effect of samples at the edge of the filter
area.
Filter Width and Filter Height Specifies the size of the filtered area. Increasing
the value of Filter Width and Filter Height can soften the image; however, it
will increase rendering time.
Contrast Color Clicking [...] opens the Select Color dialog box where you
interactively specify the R,G,B threshold values.
Contrast Red, Blue, Green Specifies the threshold values for the red, blue,
and green components of samples. These values are normalized, and range
from 0.0 to 1.0, where 0.0 indicates the color component is fully unsaturated
(black, or 0 in eight-bit encoding) and 1.0 indicates the color component is
fully saturated (white, or 255 in eight-bit encoding).
Contrast Alpha Specifies the threshold value for the alpha component of
samples. This value is normalized, and ranges from 0.0 (fully transparent, or
0 in eight-bit encoding) to 1.0 (fully opaque, or 255 in eight-bit encoding).
1674 | Chapter 18 R Commands