image_new

Builtin index · Images

result = image_new(width, height, [r=0, g=0, b=0])

Input: width, height, r · Output: result

What it is

Creates a blank solid-color canvas. width and height are positive integers giving the canvas size in pixels. r, g, b are optional named numbers 0–255 giving the fill color's channel values (default 0, i.e. solid black).

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`result = image_new(width, height, [r=0, g=0, b=0])`	`width` —`width` and `height` are positive integers giving the canvas size in pixels. `height` —`width` and `height` are positive integers giving the canvas size in pixels. `r` number, optional (default `0, g=0, b=0`)`r`, `g`, `b` are optional named numbers 0–255 giving the fill color's channel values (default 0, i.e.	`result` Image	Returns a new `Image` of exactly `width` x `height` pixels. The only way to build a synthetic image with no file on disk.

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

img = image_new(10, 10, r=0, g=0, b=0)
big = resize(img, 20, 15, method="bilinear")
print(big.width, big.height)   # 20 15

output

20 15

from images

img = image_new(20, 20, r=0, g=0, b=0)

shifted = imtranslate(img, 5, 3, fill=255)
scaled = imscale(img, 1.5, fill=0)
imshow(shifted)

M = affine_scale(2, 1.5) * affine_shear(0.2, 0) * affine_identity()
print(shifted.width, scaled.width, M)

output

20 30 [2, 0.4, 0; 0, 1.5, 0; 0, 0, 1]

from images

canvas = image_new(40, 30, r=200, g=200, b=200)

m = [10, 40, 250; 90, 140, 190; 220, 255, 30]
gray = image_from_matrix(m)
save_image("/tmp/gray.bmp", gray)

imagesc(m, colormap="viridis")          # false-color view of the same matrix


big = resize(canvas, 80, 60, method="bilinear")
piece = crop(big, 10, 10, 30, 20)
print(piece.width, piece.height)
imshow(piece)

from images

How it works

image_new(width, height, [r=0, g=0, b=0]) — a blank solid- color canvas; the constructor load_image's round trip otherwise has no Qu-level counterpart for (there's no Image literal syntax, matching zeros/ones filling the same gap for matrices). Lets a script build and test a synthetic image entirely in Qu, with no external file needed.

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.