how to increase getframe dimensions and quality ?

Question

Osama Alkurdi 2020-4-22

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https://ww2.mathworks.cn/matlabcentral/answers/519886-how-to-increase-getframe-dimensions-and-quality

编辑： Adnan 2023-6-1

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hi.

I have a code that plots data and moving it.

and I used getframe to save the plots for making a movie later from it.

the problem is that the output movie comes with very low quality and dimensions of 700x525.

what I have to change in my script code to get HD Quality 1280x720?

by the way this is my code, and I will attach the function raafabdshm1 and the script so you can run it on your computer.

f=figure;plotLocation=axes(f);
hold(plotLocation,'on')
counter=0;
fixedAxisOfRotation=[0,0];
linkLength=5;
startingEndingAngularPositions=[0,pi];
periodicTime=3;
exponentialDecay=0.6;
pathStatus=true;
instantaneousAngularPosition=zeros(25,1);
instantaneousAngularVelocity=zeros(25,1);
instantaneousAngularAcceleration=zeros(25,1);
M = struct('cdata',cell(25,1),'colormap',cell(25,1));
for instantaneousTime=0:0.04:0.96
    
    counter=counter+1;
    
    [instantaneousAngularPosition(counter),...
    instantaneousAngularVelocity(counter),...
    instantaneousAngularAcceleration(counter)]=...
    raafabdshm1(fixedAxisOfRotation,linkLength,...
    startingEndingAngularPositions,periodicTime,exponentialDecay,...
    pathStatus,instantaneousTime,plotLocation);
    
    axis(plotLocation,[-20,20,-10,10])
    pbaspect(plotLocation,[2,1,1])
    
    M(counter)=getframe(f);
    
    cla(plotLocation)
end
myVideo=VideoWriter('animationVideo');
myVideo.FrameRate=25;
open(myVideo)
writeVideo(myVideo,M)
close(myVideo)
close(f)

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Answer 1

darova 2020-4-22

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在 MATLAB Online 中打开

Try this madness

clc,clear,cla
wobj = VideoWriter('test1.avi');
wobj.FrameRate = 10;                  % frames per second (video speed)
open(wobj);                           % open file
t = linspace(0,2*pi);
[x,y] = pol2cart(t,1);                % simpe circle
plot(x,y)
axis equal
mkdir('test')
set(0,'defaultlinelinesmoothing')
for i = 1:1:length(x)-1
    line(x(i:i+1),y(i:i+1),'linew',2) % add line
    fname = ['test\test' num2str(i)]; % full name of image
    print('-djpeg','-r200',fname)     % save image with '-r200' resolution
    I = imread([fname '.jpg']);       % read saved image
    frame = im2frame(I);              % convert image to frame
    writeVideo(wobj,frame);           % save frame into video
end
close(wobj);                          % close file

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Osama Alkurdi 2020-4-22

@darova

thank you :)

Adnan 2023-6-1

编辑：Adnan 2023-6-1

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Changing the for loop to the following also works:

for i = 1:1:length(x)-1
    line(x(i:i+1),y(i:i+1),'linew',2)           % add line
    cdata = print('-RGBImage','-r600','-noui'); % increased dpi to 600 (beware)
    frame = im2frame(cdata);                    % convert image to frame
    writeVideo(wobj,frame);                     % save frame into video
end

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Answer 2

Image Analyst 2020-4-22

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https://ww2.mathworks.cn/matlabcentral/answers/519886-how-to-increase-getframe-dimensions-and-quality#answer_427712

编辑：darova 2020-4-22

在 MATLAB Online 中打开

Since getframe() essentially gets a screenshot bitmap of what's in your display adapter, the resolution is whatever it is when it's displayed on your scree. To get that as high as possible, you need to maximize your figure window and use 'tight' option if you use imshow:

hFig = figure;                       % Bring up new figure
imshow('board.tif','Border','tight') % The axes will fill up the entire figure as much as possible without changing aspect ratio.
hFig.WindowState = 'maximized';      % Maximize the figure to your whole screen.
thisFrame = getframe();              % This is as large as you can get.

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Osama Alkurdi 2020-4-22

I don't know how this will resolve my problem and how I would implement it in my code, are you shure you read my question well? can you explain more clearly please?