I've managed to compile this on Cygwin (under Win 8.1) using the following patch:

diff --git a/Makefile b/Makefile
index db49cec..f9a1bb7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,6 @@
 imcat: imcat.c
-       cc -std=c99 -Wall -g -o imcat imcat.c -lm
+       x86_64-w64-mingw32-gcc -std=c99 -Wall -g -o imcat imcat.c -lm
+       #gcc -std=c99 -Wall -g -o imcat imcat.c -lm

 run: imcat
        ./imcat ~/Desktop/*.png
diff --git a/imcat.c b/imcat.c
index 635fbc0..7b681b1 100644
--- a/imcat.c
+++ b/imcat.c
@@ -21,6 +21,12 @@ static unsigned char termbg[3] = { 0,0,0 };

 #if defined(_WIN64)
 #      include <windows.h>
+
+#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
+#define ENABLE_VIRTUAL_TERMINAL_PROCESSING  0x0004
+#endif
+
+
 static void get_terminal_size(void)
 {
        const HANDLE hStdout = GetStdHandle( STD_OUTPUT_HANDLE );

Yeah, you need MinGW for Cygwin.

The output works for a small and original PNG:

The Original:

The Result (in Cygwin Bash):

In ConEmu (PowerShell 5.1.1)

• trying to output the png you included in ./image/*.png silently fails.
  (Please add real png for testing!)
• Running this in PowerShell fails on most systems not using ConPty or newest ConHost.
  (I.e. on OS < Win10)
• If your terminal window is smaller (in character count) than the image pixel count (in any direction) the image gets broken up.
• Also works on ConEmu, but look very ugly!

I just compiled your software and I get a segmentation fault when trying to open the example images. Can you help me out?

chymera@bartholin ~/src $ git clone [email protected]:stolk/imcat.git
Cloning into 'imcat'...
remote: Enumerating objects: 69, done.
remote: Total 69 (delta 0), reused 0 (delta 0), pack-reused 69
Receiving objects: 100% (69/69), 587.25 KiB | 1.55 MiB/s, done.
Resolving deltas: 100% (30/30), done.
chymera@bartholin ~/src $ cd imcat/
chymera@bartholin ~/src/imcat $ git rev-parse HEAD
ee82fdbbc3789fd13aad0365b0549bb33ade2f4d
chymera@bartholin ~/src/imcat $ make
cc -std=c99 -Wall -g -o imcat imcat.c -lm
imcat.c: In function ‘get_terminal_size’:
imcat.c:48:12: warning: implicit declaration of function ‘popen’; did you mean ‘fopen’? [-Wimplicit-function-declaration]
   48 |  FILE* f = popen( "stty size", "r" );
      |            ^~~~~
      |            fopen
imcat.c:48:12: warning: initialization of ‘FILE *’ {aka ‘struct _IO_FILE *’} from ‘
int’ makes pointer from integer without a cast [-Wint-conversion]
imcat.c:56:2: warning: implicit declaration of function ‘pclose’; did you mean ‘fclose’? [-Wimplicit-function-declaration]
   56 |  pclose( f );
      |  ^~~~~~
      |  fclose
chymera@bartholin ~/src/imcat $ ./imcat images/imcat_tiger.png 
Segmentation fault (core dumped)
chymera@bartholin ~/src/imcat $ ./imcat images/sampledesktop.png 
Segmentation fault (core dumped)

Idea behind this FR is:
If more than 1 image is to be displayed, then it would be nice if imcat could scale them and display them afterwards.

I imagine one could divide the screen into 4 rectangles and display 2 rows with 2 scales images each (2x2).

Testing under Windows 10 ([Version 10.0.17692.1004]) I fail to redirect the output to a file. The file only contains a handful escape sequences.

In this case, only 311 bytes were written.

% make 
cc -D_POSIX_C_SOURCE=2 -std=c99 -Wall -g -o imcat imcat.c -lm
imcat.c:87:4: error: implicitly declaring library function 'snprintf' with type 'int (char *, unsigned long, const char *, ...)' [-Werror,-Wimplicit-function-declaration]
                        snprintf( tripl, sizeof(tripl), "%d;%d;%dm ", r,g,b );
                        ^
imcat.c:87:4: note: include the header <stdio.h> or explicitly provide a declaration for 'snprintf'
1 error generated.
make: *** [imcat] Error 1

My envairement:

% gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 13.0.0 (clang-1300.0.29.30)
Target: arm64-apple-darwin21.3.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
% g++ -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 13.0.0 (clang-1300.0.29.30)
Target: arm64-apple-darwin21.3.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

If I use imcat to display an image, I find that it seems to overestimate the terminal's height, proceeding as if it has more (horizontal) lines than it really does, with the result that I can scroll up and down a few lines to view the image, but I can't see the whole image on screen at once.

An example image I used: https://wikilovesmonuments.org.uk/wp-content/uploads/2020/11/Perch_Rock_Lighthouse_in_rock_pool.jpg

I found that resizing my PuTTY window to be shorter, did not have any effect on the output of imcat. If I resized my PuTTY window to be both shorter and narrower, this had the desired effect of causing imcat to generate a smaller output (so that on restoring it to its full size, I could see the full image at once).

I'm using Ubuntu 20.10/AArch64. On the client side I'm using PuTTY 0.74. I'm not using tmux or GNU Screen or anything like that.

Redirecting stdout to a file and cat in rxvt shows the same wrong colours.
Other files like https://github.com/thiderman/doge/blob/master/doge/static/doge.txt are displayed correctly in rxvt.

Here is the scenario:
Assume you have a linux guest that you are managing through Vagrant (Kali in my case).
My host platform is Windows 10. Open a Windows console/command-line (cmd.exe) and start up the linux VM using "vagrant up". Then establish an SSH session on the Windows console using "vagrant ssh".

When you use imcat to view an image in the ssh session, the Windows console window does not interpret the data as desired, and the image doesn't work. Here is a screenshot:

If you view the same image in the Kali GUI, from a normal terminal window, it works fine as seen here:

As seen in the Vagrant ssh session, here is the $TERM:

root@kali:/opt/imcat# echo $TERM
cygwin
root@kali:/opt/imcat#

Hey,

any chance to get this brilliant piece of software as brew formula?

Thanks!

It's actually quite hard to get that compiler working

Actually, you can skip getting the whole VS package if it's just about clang. Just install LLVM.

The README currently states:

License

• Public Domain.

It would be better to use a widely-recognized open source license instead — there's less legal uncertainty around them. See Choose a License for more information 🙂