Script optimization

Author: Raphael-Boichot

SD/Script_for_animated_gif/Gif_Maker_from_png_data.m

@@ -2,33 +2,64 @@
 clear
 
 disp('-----------------------------------------------------------')
-disp('|Beware, this code is for GNU Octave ONLY !!!             |')
+disp('| Optimized Indexed GIF creator for GNU Octave (bzip)     |')
 disp('-----------------------------------------------------------')
 
 pkg load image
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%User parameters
+% User parameters
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-target_gif_file='Animation.gif'; %target file for animated gif
-gif_deadtime=0.05;               %delay is seconds between pictures for animated gifs
-gif_skip=1;                      %keep every 1 out of gif_skip image for gif
-scaling_factor=1;                %because you may want to change the image format which is 4x natively
+target_gif_file = 'Animation.gif';  % target file for animated gif
+gif_deadtime    = 0.05;             % delay in seconds between pictures
+gif_skip        = 4;                % keep every 1 out of gif_skip images
+scaling_factor  = 1;                % scale images if needed
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+% Load file list
 listing = dir('./Pictures/*.png');
-for i=1:1:length(listing)
-    name=listing(i).name;
-    disp(['Processing ',listing(i).name]);
-    [frame,map]=imread(['./Pictures/',name]);
-    frame=imresize(frame,scaling_factor,'nearest');
-    if i==1
-        imwrite(frame,map,target_gif_file,'gif', 'Loopcount',inf,'DelayTime',gif_deadtime,'Compression','bzip');
-    else
-        if rem(i,gif_skip)==0
-        imwrite(frame,map,target_gif_file,'gif','WriteMode','append','DelayTime',gif_deadtime,'Compression','bzip');
+n_files = numel(listing);
+
+if n_files == 0
+    error("No PNG images found in ./Pictures/")
+end
+
+% Preload frames + maps
+frames = {};
+maps   = {};
+disp('Reading and resizing images...')
+for i = 1:n_files
+    name = listing(i).name;
+    fprintf("Processing %s (%d/%d)\n", name, i, n_files);
+
+    if rem(i,gif_skip) == 0
+        [frame, map] = imread(fullfile('./Pictures', name));
+        if scaling_factor ~= 1
+            frame = imresize(frame, scaling_factor, 'nearest');
         end
+        frames{end+1} = frame;
+        maps{end+1}   = map;
     end
 end
 
+fprintf("Total frames to write: %d\n", numel(frames));
+
+% Write GIF (with mandatory bzip compression)
+disp("Writing animated GIF...")
+imwrite(frames{1}, maps{1}, target_gif_file, ...
+        "gif", "LoopCount", Inf, ...
+        "DelayTime", gif_deadtime, ...
+        "Compression", "bzip");
+
+for i = 2:numel(frames)
+    fprintf("Appending frame %d/%d\n", i, numel(frames));
+    imwrite(frames{i}, maps{i}, target_gif_file, ...
+            "gif", "WriteMode", "append", ...
+            "DelayTime", gif_deadtime, ...
+            "Compression", "bzip");
+end
+
+disp('-----------------------------------------------------------')
 disp('End of conversion, enjoy your fancy animations !')
+disp('-----------------------------------------------------------')
+

SD/Script_for_animated_gif/Gif_Maker_from_png_data_progressive.m

@@ -0,0 +1,78 @@
+clc
+clear
+
+disp('-----------------------------------------------------------')
+disp('| Progressive Averaged Grayscale GIF for Octave (bzip)    |')
+disp('-----------------------------------------------------------')
+
+pkg load image
+
+% Parameters
+target_gif_file = 'Animation_progressive.gif';
+gif_deadtime    = 0.05;
+gif_skip        = 9;
+scaling_factor  = 1;
+n_colors        = 256;
+
+% Generate fixed grayscale colormap
+gray_map = repmat((0:255)'/255, 1, 3);  % 256×3
+
+listing = dir('./Pictures/*.png');
+n_files = numel(listing);
+if n_files == 0
+    error("No PNG images found in ./Pictures/")
+end
+
+disp('Reading and averaging images...')
+
+% Read first frame
+[frame, map] = imread(fullfile('./Pictures', listing(1).name));
+if scaling_factor ~= 1
+    frame = imresize(frame, scaling_factor, 'nearest');
+end
+
+% Convert to RGB and then to grayscale
+current_avg = ind2rgb(frame, map);
+current_avg = rgb2gray(current_avg);  % double [0,1]
+
+frames_idx = {};
+frame_counter = 1;
+
+% Convert first frame to indexed using fixed grayscale map
+frames_idx{1} = uint8(current_avg*255);
+
+% Process remaining frames
+for i = 2:n_files
+    if rem(i,gif_skip) == 0
+        [frame, map] = imread(fullfile('./Pictures', listing(i).name));
+        if scaling_factor ~= 1
+            frame = imresize(frame, scaling_factor, 'nearest');
+        end
+
+        rgb = ind2rgb(frame, map);
+        gray = rgb2gray(rgb);
+
+        current_avg = ((frame_counter)*current_avg + gray) / (frame_counter+1);
+        frame_counter += 1;
+
+        frames_idx{end+1} = uint8(current_avg*255);
+
+        fprintf("Processed %s (%d/%d)\n", listing(i).name, i, n_files);
+    end
+end
+
+disp('Writing animated GIF...')
+
+imwrite(frames_idx{1}, gray_map, target_gif_file, ...
+        'gif', 'LoopCount', Inf, 'DelayTime', gif_deadtime, 'Compression', 'bzip');
+
+for k = 2:numel(frames_idx)
+    fprintf("Appending frame %d/%d\n", k, numel(frames_idx));
+    imwrite(frames_idx{k}, gray_map, target_gif_file, ...
+            'gif', 'WriteMode', 'append', 'DelayTime', gif_deadtime, 'Compression', 'bzip');
+end
+
+disp('-----------------------------------------------------------')
+disp('Done! Progressive averaged grayscale GIF is ready!')
+disp('-----------------------------------------------------------')
+