imago

# Imago
![CI](https://github.com/tokenrove/imago/workflows/CI/badge.svg)

Imago is an image manipulation library for Common Lisp. It supports images in
png, pcx, portable bitmap (.pnm), Truevision TGA (.tga) and jpeg formats. You
can read an image with `imago:read-image` and write an image with
`imago:write-format` where `format` is one of `png`, `pcx`, `pnm`, `tga` or
`jpg`.

## Reading from and writing to jpeg files with libjpeg-turbo

You can use more advanced [libjpeg-turbo](https://libjpeg-turbo.org/) library to
deal with jpeg files by loading `imago/jpeg-turbo` system. Make sure that
`libjpeg-turbo` is installed on your system. Use
`imago-jpeg-turbo:read-jpg-turbo` and `imago-jpeg-turbo:write-jpg-turbo`
functions (or just `imago:read-image` and `imago:write-image`) to use this
functionality.

## Alternative png I/O with imago/pngio

You can use more advanced and faster
[pngload](https://github.com/bufferswap/pngload) library to read png files by
loading `imago/pngio` system. Use `imago-pngio:read-png` (or just
`imago:read-image`) to use this functionality. **NB:** `pngload` automatically
converts indexed color images to RGB (or ARGB) images. If you want to work with
indexed images, use old png loader instead. Also
[zpng](https://github.com/xach/zpng) (via `imago-pngio:write-png`) library will
be used for saving png images.

## Creating an image

To create an image look at the documentation for image classes (like
`imago:rgb-image` or `imago:grayscale-image`). You need to make an instance of
one of those classes by passing `:w`, `:h` and optionally `:initial-color`
keyword arguments to `make-instance`. Alternatively, you can use
`make-XXX-image` and `make-XXX-image-from-pixels` functions:

~~~~{.lisp}
;; Create 100x100 px black grayscale image
(imago:make-grayscale-image 100 100)

;; Create 400x100 px red RGB image
(imago:make-rgb-image 400 100 (imago:make-color 255 0 0))

;; Create 400x100 px half-transparent red RGB image
(imago:make-rgb-image 400 100 (imago:make-color 255 0 0 127))

;; Create an image from an array of pixels
(imago:make-rgb-image-from-pixels
 (make-array '(100 100)
             :element-type 'imago:rgb-pixel
             :initial-element (imago:make-color 0 255 255)))
~~~~

## Usage examples

Most of the examples are taken from
[here](http://matthieu.villeneuve.free.fr/dev/imago/examples.html).

### Resizing an image

`(resize *image* 400 150)`

| Original | Processed |
| -------- | --------- |
| ![Original](docs/country.png) | ![Resized](docs/country-resize.png) |

### Rotating an image

`(rotate *image* 45)`

| Original | Processed |
| -------- | --------- |
| ![Original](docs/lena.png) | ![Resized](docs/lena-rot.png) |


### Applying an emboss effect

`(emboss *image* :angle (* pi 0.75) :depth 1.0)`

| Original | Processed |
| -------- | --------- |
| ![Original](docs/horse.png) | ![Processed](docs/horse-emboss.png) |

### Using a custom convolution kernel

~~~~{.lisp}
(let ((kernel #2A((0  0  0  0  0)
                  (0  0  1  0  0)
                  (0  1 -4  1  0)
                  (0  0  1  0  0)
                  (0  0  0  0  0))))
  (convolve *image* kernel 1 0))
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/car.png) | ![Processed](docs/car-edge-detect.png) |

### Inverting a rectangular region

~~~~
(do-region-pixels (*image* color x y 70 65 140 125)
  (setf color (invert-color color)))
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/oranges.png) | ![Processed](docs/oranges-region-invert.png) |

### Adjusting contrast of a grayscale image

~~~~
(enhance-contrast *grayscale-image*)
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/house.jpg) | ![Processed](docs/house-enchanced-contrast.jpg) |

### Manipulating color components

~~~~{.lisp}
(do-image-pixels (*image* color x y)
  (multiple-value-bind (r g b) (color-rgb color)
    (setf color (make-color b
                            (floor (* g 0.8))
                            r))))
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/flowers.png) | ![Processed](docs/flowers-color-change.png) |

### Composing pictures

~~~~{.lisp}
(let ((operator (default-compose-operator *image1*)))
  (compose nil *image1* *image2* 20 20 operator))
~~~~

| Original 1 | Original 2 | Processed |
| ---------- | ---------- | --------- |
| ![City](docs/city.png) | ![Text](docs/text.png) | ![Composed](docs/city-text.png) |

### Drawing simple primitives

~~~~{.lisp}
(let ((points '(83 45 73 150 73 150 198 106 198 106 83 45)))
  (draw-polygon *image* points +white+ :closed t))
(draw-circle *image* 83 45 15 +white+)
(draw-circle *image* 73 150 15 +white+)
(draw-circle *image* 198 106 15 +white+)
(draw-bezier-curve *image* 10 80 150 60 100 170 200 170 +red+)
(draw-line *image* 0 5 254 5 +yellow+)
(draw-line *image* 0 10 254 10 +yellow+ :dash-length 1 :dash-interval 1)
(draw-line *image* 0 15 254 15 +yellow+ :dash-length 4 :dash-interval 2)
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/fish.png) | ![Processed](docs/fish-drawing.png) |

### A more complex example

~~~~{.lisp}
(defun sea-view (image)
  (let ((image2 (flip nil image :horizontal)))
    (do-image-pixels (image2 color x y)
      (multiple-value-bind (r g b)
          (color-rgb color)
        (setf color (make-color (floor r 3) (floor g 3) (floor b 2)))))
    (let* ((width (image-width image))
           (height (image-height image))
           (result (make-instance (class-of image)
                                  :width width :height (* height 2))))
      (copy result image)
      (copy result image2 :dest-y height)
      result)))
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/citynight.png) | ![Processed](docs/citynight-sea.png) |

### Connected components labeling

This example requires snakes and array-operations systems (available in
quicklisp).

~~~~{.lisp}
(defpackage components-example
  (:use #:cl
        #:snakes
        #:imago)
  (:export #:convert-to-image))
(in-package :components-example)

(defgenerator generate-colors ()
  (loop while t do
    (yield (make-color (random 256)
                       (random 256)
                       (random 256)))))

(defgenerator black ()
  (yield (make-color 0 0 0)))

(defun convert-to-image (components)
  (declare (type (simple-array fixnum (* *)) components))
  (let ((colors (take (1+ (reduce #'max (aops:flatten components)))
                      (chain (black)
                             (generate-colors))))
        (image (make-array (array-dimensions components)
                           :element-type 'rgb-pixel)))
    (array-operations/utilities:nested-loop (i j)
        (array-dimensions components)
      (setf (aref image i j)
            (nth (aref components i j) colors)))
    (make-instance 'rgb-image :pixels image)))

(in-package :cl-user)
(let* ((image (imago:read-image "~/.quicklisp/local-projects/imago/tests/spheres.png"))
       (components (imago:label-components (imago:convert-to-binary image 1))))
  (components-example:convert-to-image components))
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](tests/spheres.png) | ![Processed](docs/spheres-colored.png) |


### Distance transform

Calculating squared Euclidean distance transform (also Manhattan distance
transform is available). This example requires `array-operations`.

~~~~{.lisp}
(defun edt-image (image)
  (declare (type imago:binary-image image))
  (let* ((dt (imago:distance-transform image :type :edt))
         (max (reduce #'max (aops:flatten dt)))
         (pixels (make-array (array-dimensions dt) :element-type 'imago:grayscale-pixel)))
    (map-into (aops:flatten pixels)
              (lambda (x) (imago:make-gray (floor (* 255 x) max)))
              (aops:flatten dt))
    (make-instance 'imago:grayscale-image :pixels pixels)))

(edt-image original-image)
~~~~

| Original | Processed |
| -------- | --------- |
| ![Original](docs/edt-orig.png) | ![Processed](docs/edt.png) |

## Intergation with common-lisp-jupyter

You can view imago images in Jupyter by installing `imago/jupyter`
system. Then call `imago-jupyter:show-image` function to show an image.

![Jupyter example](docs/jupyter.png)


alexandria

cl-jpeg

zlib

jpeg-turbo

imago/jpeg-turbo

pngload

imago/pngload

fiveam

imago/tests

imago

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