plot with reversed y-axis in a normal y-axis
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I have a video plotted (or played frame by fame) and I want to plot a shape representing the corresponding eye position.
The video has its y-axis reversed (can't control it) (0 up). The eye position is with coordinates in which the y-axis is normal (0 at bottom).
I need to plot this eye position somehow with reversed y-axis on the video.
I'm using insertShape but I can't change the position of the shape to be plotted in a reversed y-axis on the video. I tried flip, axis handel, and many things, nothing is working.
Any suggestion please?!
Jack on 30 Mar 2023
You can use the image function in MATLAB to display the video frames and then use insertShape to plot the eye position on top of the frame. To reverse the y-axis, you can set the YDir property of the axes object to 'reverse'. Here's some sample code to get you started:
% Load the video file
v = VideoReader('my_video.mp4');
% Create a figure and axes to display the frames
fig = figure;
ax = axes('Parent', fig);
% Set the y-axis direction to 'reverse'
set(ax, 'YDir', 'reverse');
% Loop through the frames and display them
frame = readFrame(v);
% Get the eye position for the current frame
eye_pos = [x, y, width, height]; % Replace with your own code
% Plot the eye position on top of the frame
insertShape(ax, 'Rectangle', eye_pos, 'Color', 'red');
% Update the figure
In this code, x, y, width, and height are the coordinates of the eye position in a normal y-axis coordinate system. You may need to adjust these values to match the dimensions of your video frames. The insertShape function plots a red rectangle at the specified eye position, and the drawnow function updates the figure to display the current frame with the eye position.