langs a-z

Task/Bitmap/Octave/bitmap-1.octave

@@ -0,0 +1,10 @@
+im = zeros(W, H, 3, "uint8"); % create an RGB image of width W and height H
+                              % and intensity from 0 to 255; black (all zeros)
+im(:,:,1) = 255;              % set R to 255
+im(:,:,2) = 100;              % set G to 100
+im(:,:,3) = 155;              % set B to 155
+im(floor(W/2), floor(H/2), :) = 0;  % pixel in the center made black
+disp(im(floor(W/3), floor(H/3), :)) % display intensities of the pixel
+                                    % at W/3, H/3
+p = im(40,40,:); % or just store it in the vector p, so that
+                 % p(1) is R, p(2) G and p(3) is B

Task/Bitmap/Octave/bitmap-2.octave

@@ -0,0 +1,21 @@
+function im = create_rgb_image(w, h)
+  im = zeros(w, h, 3, "uint8");
+endfunction
+
+function set_background(im, colorvector)
+  im(:,:,1) = colorvector(1);
+  im(:,:,2) = colorvector(2);
+  im(:,:,3) = colorvector(3);
+endfunction
+
+function set_pixel(im, coord, colorvector)
+  im(coord(1), coord(2), 1) = colorvector(1);
+  im(coord(1), coord(2), 2) = colorvector(2);
+  im(coord(1), coord(2), 3) = colorvector(3);
+endfunction
+
+function [r, g, b] = get_pixel(im, coord)
+  r = im(coord(1), coord(2), 1)
+  g = im(coord(1), coord(2), 2)
+  b = im(coord(1), coord(2), 3)
+endfunction

Task/Bitmap/Octave/bitmap-3.octave

@@ -0,0 +1,8 @@
+%example
+im = create_rgb_image(200,200);
+for x = 1:128
+   im = set_pixel(im, [x, x], [200, 50, 220]);
+endfor
+
+% it seems like saveimage wants double class on [0,1]
+saveimage("image.ppm", double(im)./256, "ppm");