The aim is for a given GIF file including several images inside to extract those image pixels, edit (change them) and put them back to the GIF file.
Trying to do it using giflib.
The language used is C.
I have successfully read the Gif file and have an access to the pixels of image using the following code:
GifFileType *gifFile = DGifOpenFileName(filename);
DGifSlurp(gifFile);
But as it is said in the Documentation:
About the DGifSlurp function:
When you have modified the image to taste, write it out with
EGifSpew().
However using that function results in:
GIF-LIB error: Given file was not opened for write.
In the following code:
GifFileType *gifFile = DGifOpenFileName(filename);
DGifSlurp(gifFile);
EGifSpew(gifFile);
Do you know how to save the edited gif image?
Your doc is outdated. You should take a look here: http://giflib.sourceforge.net/gif_lib.html#idp26995312
You can write to a GIF file through a function hook. Initialize with
GifFileType *EGifOpen(void *userPtr, OutputFunc writeFunc, int *ErrorCode)
and see the library header file for the type of OutputFunc.
Moreover the function EGifSpew() takes a fd in second argument to a gifFile.
Hope it helped.
Related
I'm a beginner so sorry in advance for the mistakes.
I have a set of data from a camera recording saved in a 4D array with these dimensions (250x300x10603x12).
The first is the dimensions of the video (pixels). The 10603 are the FrameRatexTime. 12 are the subjects I recorded.
I extract one subject at a time for analysis in this way:
subj1 = data(:,:,:,1);
This brings me to an array containing the frames of subject 1, which I can display with implay.
Now I would like to write a video of this new array and save it in .avi format, I use this code:
v = VideoWriter('subj1.avi')
open(v)
writeVideo(v,subj1)
close(v)
but it keeps giving me this error
Error using VideoWriter/writeVideo (line 410) IMG must be an array of
either grayscale or RGB images.
In fact, looking at the shape of the array, there is nothing that points to a grayscale or RGB index. How can I get a .avi file in this case? Do I have to transform the array?
Why does it still display the video with implay?
clarification: the fact that I have to transform the array into an .avi file is because I will have to analyse it by exporting it to Python with OpenCv.
In fact, if I export the .mat file directly to Python, I can't get the list of Frames.
Matlab's documentation for writeVideo says that for a sequence of grayscale images like you have, it is expecting a "height-by-width-by-1-by-frames" array. You are only passing it "height-by-width-by-frames".
So, you need to reshape your subj1. Maybe try doing it like this:
newsubj = zeros(250, 300, 1, 10603)
newsubj(:,:,1,:) = subj1
and then save newsubj instead of subj1:
writeVideo(v,newsubj)
Finally, I think you may get some lossy compression when you save as an avi, so it may not be the best way to export it from Matlab and importing it to Python.
I'm trying to make game like "Duke Nukem 3D". I will have many maps in my game and each map will have it's own (and no more!) data files such as textures, sounds and so on, that's why I need to compress all these data files to one "map" file.
So, let's image that I want to test my maps one by one, and after compiling my code I want to test my first map with her textures and sounds, And when I type in my command line something like this: ./game_name "mymap.rce" or ./game_name "mymap.zip" my game must start with map what I typed and this map must have textures and sounds which I compressed with her.
You can download demo here.
To run demo you can type this for example: ./rce demo1.rce
So, I just made my archiver(without compress). If you need it, you can find it here.
I need help about tiff files. I need to resolve tags and return user image details (such as imageWidth, imageHeight, orientation etc.) without using any special library. With this and this I resolved header and found first IFD, but I couldn't understand finding tag and next inside a single IFD.
for example, documentation says,
Offset - 2+x*12
Datatype - Tag structure
Value - Tag data
but there is not any information about x. OR it says 2+(number of tags in IFD)*12 for next IFD offset, but the result is out of range.
In conclusion, I want to know how to find tags address and get their data, and find next IFD.
i would like to know how can i cut a jpg file using a coordinates i want to retrieve using artoolkit and opencv, see:
Blob Detection
i want to retrieve coordinates of the white sheet and then use those coordinates to cut a jpg file I'm took before.
Find this but how can this help?
How to slice/cut an image into pieces
If you already have the coordinates, you might want to deskew the image first:
http://nuigroup.com/?ACT=28&fid=27&aid=1892_H6eNAaign4Mrnn30Au8d
This post uses cv::warpPerspective() to achieve that effect.
The references above use the C++ interface of OpenCV, but I'm sure you are capable of converting between the two.
Second, cutting a particular area of an image is known as extracting a Region Of Interest (ROI). The general procedure is: create a CvRect to define your ROI and then call cvSetImageROI() followed by cvSaveImage() to save it on the disk.
This post shares C code to achieve this task.
I want to display mat file's content to see all the results. I know that I can load it and then double click on it the content are display in the workspace, this case happen when the mat file content few information but when I have mat file content information for more than 13000 record I can't display it. could please any one help me to find any way to display mat file as table?
thanks
I do not know the format of your data (multi-dimensional, structs, cell-arrays), but there is a function called "openvar" which can be very useful for these things.
Let's define a large random 500x500x10 3d-matrix:
large = rand(500,500,10);
This variable contains 2.5 million double-values and takes up close to 20MB of memory. Opening this in the variable editor by double click in the Workspace window on "large" will usually (atleast on my system) give the following message:
"Cannot display summaries of variables with more than 524288 elements."
But you can use the "openvar"-function to open certain parts:
openvar('large(:,:,1)'); %# pass the argument as a string.
This will open the first "layer" of matrices in your Variable Editor (a 500x500 matrix in this case). This is useful if you need to look into certain parts of a large variable.
Of course you can always define new variables that contain subsets of your larger variable:
less_large = large(:,:,1);
... and then open "less_large" in the variable editor by double clicking on it in the workspace-window. But sometimes the "openvar"-method is a bit faster/easier.
You have a few options. Starting from a clear workspace, you could load the mat file into the workspace. Anything now in the workspace is in the mat file. You can use the variable viewer or parse with scripts.
If you have the Simulink toolbox, you can use Simulink.saveVars to save the contents of the workspace to a human readable m-script that would generate the same contents. It's a shame that you need Simulink to do this, as this function has nothing to do with Simulink.
How about after loading the data, and use whos to display the variables in current workspace? Note that you may want to clear all the other variables before displaying them.