Crop Node
The Crop node enables you to crop, or trim, images to a smaller size or to a desired area of the input image. The position and dimensions of the cropped image can be defined in either of two ways:
- numerically, using the appropriate Crop tab parameter fields to specify a new XY Size and the location of the Lower Left Corner, or
- interactively, using the cropping tool in the work monitor to frame the image area to be output.
The cropping tool in the work monitor is tied to the corner and size parameter fields on the Crop tab; when one is changed the other is updated automatically to reflect the changes. In fact, it is usually most efficient to use both methods together.
Crop Parameter Tab
Work Monitor / At Resolution
First, select a display resolution for the work monitor from the At Resolution popup menu. Then click the plus icon to display the work monitor for this node, which displays the source image under a cropping box that defines the desired dimensions of the cropped image.
You adjust the size and position of the cropping box interactively:
- Use the mouse to click and drag the edges of the cropping box to resize it.
- Click on the circle-and-crosshairs icon in the center of the box to drag the box to a new position within the larger monitor image.
Work In...
Use this menu to specify whether the parameter values you enter for size and position represent pixels or fractional multipliers. The default is to work in fractional values--floating point values between 0 and 1.
Fractions
Working in fractions enables you to use proxies, where a lower resolution proxy input is eventually replaced by a full resolution input, without having to account for the change in the input resolution--a fractional value of 0.5 in the X size field will reduce the width of both the proxy and the full resolution image by half.
Pixels
On the other hand, working in pixels is useful when you know the exact pixel dimensions to which you want to crop as, for example, when converting imagery digitized from full aperture film format to standard Academy format.
- Tip:
- You can use pixel values to set the crop size values and then switch to fractions. Chalice will translate the pixel values to percentages, to enable the Crop node to successfully accommodate a later change from a lower resolution input to a full resolution input.
Lower Left Corner
These parameter fields are used to enter the x,y values that define the lower left corner of the crop area. Along with the XY Size parameters, this defines the crop; that is, the total area to be included in the output image.
XY Size
These parameter fields are used to enter the X and Y resolution of the crop area, starting from the lower left corner (which is defined by the parameter above) .
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