Reference for Image-based Procedures

Basic Image Operations

(image-new width height): DrFu procedure. Create a new image of specified width and height.
(image-load filename): DrFu procedure. Load an image from a file. The name of the file is a string (and, unless a named value, typically surrounded by quotation marks).
(image-show image): DrFu procedure. Opens a new window with the image.
(image-height image): DrFu procedure. Determine the height of the given image
(image-width image): DrFu procedure. Determine the width of the given image.

Pixel-Based Operations

(image-get-pixel image column row): DrFu procedure. Get the pixel at the specified posi tion in the image.
(image-set-pixel! image column row rgb-color): DrFu procedure. Set the pixel at the specified position to the new color.
(image-transform-pixel! image column row func): DrFu procedure. Modify the pixel at (col,row) in image by applying func to its old color and setting that pixel to the resulting color.

Higher-Order Procedures

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(image-transform! image fun): DrFu procedure. Transform image in place by setting each pixel to the result of applying fun to that current pixel color.
(image-compute-pixels! image first-col first-row last-col last-row function): DrFu procedure. Create a portion of an image by setting each pixel in the specified region to the result of applying function to the position of the pixel. function must be a function from position to rgb-color. Warning! The current version is buggy, and may affect other pixels.

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Samuel A. Rebelsky, rebelsky@grinnell.edu

This material is based upon work partially supported by the National Science Foundation under Grant No. CCLI-0633090. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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