Using a 'for' loop to read gif RGB and pixel index, cant get textscan with 'if' statement to work

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Travis Potter
Travis Potter 2018-9-19
评论： Travis Potter 2018-9-20
Hello All,
I have been working on a porting program to take a gif frame by frame, read each pixel and RGB value, then put it into a formatted text file. I have gotten it to work but I am trying to make the code output smaller. I am trying to read each frame, then read the previous frame to see if the pixel index number and RGB value match, if they do not match, add a new entry into the formatted file. If there is a match just skip adding a entry and check the next pixel index number and RGB value. Here is my code,
sourceimage = '/Users/tapotter/Animations/leda36.gif'; %Pull file to load
numframes = numel(imfinfo(sourceimage)); %Pull the number of frames
fida = fopen('FastLEDAnimation.txt', 'a+'); %Open files to use.
fidp = fopen('previousframe.txt', 'wt+'); %Create and open a temporary file to check values against.
for frame = 1:numframes %Go through each frame of the gif
[img, map] = imread(sourceimage, frame); % Open the image and create the map
rgbimg = im2uint8(ind2rgb(img, map)); %turn the index into unit8 rgb format
crgb = reshape(permute(rgbimg, [3, 1, 2]), 3, []); %makes a 3xnumpixels array
framedelay = imfinfo(sourceimage); %Pulls the frame delay from imfinfo
fdelay = framedelay.DelayTime; %Get the frame delay
pixcrgb = [1:size(crgb, 2); double(crgb)]; %Sets up the readout to include what pixel its on but only goes through 255, then repeats 200 times with 255
P = textscan(fidp, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb'); %Go through and see if textscan can find these values
if isempty(P) %If the textscan returns empty write to the file
fprintf(fida, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb);
end
fprintf(fida, '\nFastLED.delay(%d);\nFastLED.show();\n', fdelay); %Add the delay to the formatted text
fprintf(fidp, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb); %Add all of the current pixel 'index' numbers and RGB values for reference as the 'previous' frame next iteration
end
fclose(fida); %Close the files and delete the fidp file.
fclose(fidp);
delete(fidp);
fprintf('\nComplete!\n\n');
Currently it does not return anything during the loop and never writes the 'fprintf(fida, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb);' portion to the file. When looking at the previousframe.txt, it continously writes information and append's it. What I was hoping for was it would clear the previousframe.txt and only store the last frames values. I have tried a couple different loops but cant seem to wrap my head around it. Any suggestions on how I might right the loop section? Specifically this part is where I need help,
P = textscan(fidp, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb'); %Go through and see if textscan can find these values
if isempty(P) %If the textscan returns empty write to the file
fprintf(fida, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb);
end
fprintf(fida, '\nFastLED.delay(%d);\nFastLED.show();\n', fdelay); %Add the delay to the formatted text
fprintf(fidp, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb); %Add all of the current pixel 'index' numbers and RGB values for reference as the 'previous' frame next iteration
end
  1 个评论
Jan
Jan 2018-9-19
I'm surprised that this command does not throw an error:
P = textscan(fidp, 'leds[%d].setRGB(%d, %d, %d);\n', pixcrgb')
The 3rd argument is not valid, because textscan expects "N — Number of times to apply formatSpec", but not a matrix.

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采纳的回答

Jan
Jan 2018-9-19
编辑：Jan 2018-9-19
It is not clear, what you want to achieve. Do you want to omit writing e.g. "leds[1].setRGB(2, 3, 4)", if this string occurs in the former block already? Then using a file to store the temporary values is very indirect. Why not using the available values instead?
% [Code EDITED]
sourceimage = '/Users/tapotter/Animations/leda36.gif'; %Pull file to load
numframes = numel(imfinfo(sourceimage)); %Pull the number of frames
fid = fopen('FastLEDAnimation.txt', 'a+'); %Open files to use.
framedelay = imfinfo(sourceimage); % Once only outside the loop
fdelay = framedelay.DelayTime; % Get the frame delay
oldFrame = Inf; % Arbitrary unique value
for iframe = 1:numframes %Go through each frame of the gif
[img, map] = imread(sourceimage, iframe);
rgbimg = im2uint8(ind2rgb(img, map));
crgb = reshape(permute(rgbimg, [3, 1, 2]), 3, []);
Frame = [1:size(crgb, 2); double(crgb)];
changed = any(Frame ~= oldFrame, 1);
oldFrame = Frame;
fprintf(fid, 'leds[%d].setRGB(%d, %d, %d);\n', Frame(:, changed));
fprintf(fid, '\nFastLED.delay(%d);\nFastLED.show();\n', fdelay);
end
fclose(fid);
% delete(fidp); % No DELETE for file identifier of closed file!
fprintf('\nComplete!\n\n');
Please read doc delete. If the former file identifier was e.g. 4. Then delete(4) tries to delete a figure with the handle 4. delete needs a file name for removing a file.
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Travis Potter
Travis Potter 2018-9-20
One last question, the pixel index starts at '1' in the file, but I need it to start at 0 and go to 483. How would I bring the
fprintf(fid, 'leds[%d].setRGB(%d, %d, %d);\n', Frame(:, changed));
To always minus 1 from the first variable '%d' in the "leds[]" section listed above.

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