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sábado, 22 de outubro de 2016

WxWidgets / GTK and Vulkan



There is a project called RPCS3 which aims to emulate the PS3 gaming console.
Being a Linux user and a someone who enjoys emulation i felt i could give a hand , limited to my knowledge and time, but something that would help.
After some time, too much in fact, and helped by the community surrounding the emulator - https://github.com/RPCS3/rpcs3/issues/2186#issuecomment-255329581 - i was able to achieve something.

Also due to take a look at https://gist.github.com/graphitemaster/e162a24e57379af840d4 if you are willing to start with Vulkan.

The application uses WxWidgets as its GUI lib, and it can have a lot of backends (GTK2,GTK3,Windows) etc.. so the main work was to retrieve the X11 surface id to create a swapchain and integrate it with all the amazing code the team had already made.
A snippet of the code, for GTK2, is below



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GtkWidget * widget=(GtkWidget*)m_frame->handle();
    gtk_widget_realize(widget);
    Display* display = GDK_DISPLAY_XDISPLAY(gtk_widget_get_display(widget));
     xcb_connection_t * c=XGetXCBConnection(display);
    xcb_window_t w;    



More info can be found at http://stackoverflow.com/questions/14788439/getting-x11-window-handle-from-gtkwidget

Also GCC not being able to compile the code whereas Clang would was a nice surprise :) Go Apple Go i guess :)

There are some bugs to be handled, however

sábado, 28 de maio de 2016

PDF Signing with Smartcards without Applets.

One of my recent projects at work involved developing an alternative  to applets to digital sign PDF files.

After some search i came across open-eid and namely browser-token-signing a true great endeavour from the © Estonian Information System Authority.
You can download their official builds at installer.id.ee. This will install extensions on your browsers that will allow the communication with the smartcards.

https://github.com/open-eid/hwcrypto.js/wiki/ModernAPI

On the client side we will need hwcrypto.js . This lib makes use of Promises caniuse.com which are not available on all browsers however there is a legacy version and other dependencies which can be put in place if you need them.
As stated on their wiki:

    *Support for IE8-IE10 requires a Promises polyfill; IE8 and IE9 also require TypedArray polyfill. Complimentary code is bundled into hwcrypto-legacy.js:

        https://github.com/inexorabletash/polyfill (license: Public Domain / MIT)
        https://github.com/getify/native-promise-only/ (license: MIT)

    Distribution and installation of the necessary platform components is out of scope of this project.


Let's take a look at their example code

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// NB! This sample uses the legacy `hex` property!
window.hwcrypto.getCertificate({lang: 'en'}).then(function(certificate) {
   // Do something with the certificate, like prepare the hash to be signed
   var hash = calculateSHA256SignatureHashAsHexForCertificate(certificate.hex);
   // Now sign the hash
   window.hwcrypto.sign(certificate,
 {type: 'SHA-256', hex: hash}, {lang: 'en'}).then(function(signature) {
      // Do something with the signature
      storeSignature(signature.hex);
   }, function(error) {
      // Handle the error. `error.message` is one of the described error mnemonics
      console.log("Signing failed: " + error.message);
   });
});



 As our framework is Java based, to handle the PDF the itextpdf lib was used - itextpdf 5.5.9. I would like to state that with in some work / adaptation pdfsign.js may become the best way to implement such a system. 
To anyone implementing such a system i would like to leave the following notes:

  • If you use some objects to handle the PDF from the server side make sure they are the same all along the process. If not the PDF will still be signed but you may be faced with the "The document has been altered or corrupted since the signature was applied" error.
  • As Promises are  asynchronous take extra care when using it Ajax.

Taking the above into consideration just take a look at Bruno's amazing work/documentation itext-action-second-edition chapter-12  to proceed with the signature.

segunda-feira, 14 de março de 2016

On "New MIT Code Makes Web Pages Load 34 Percent Faster in Any Browser"

I would like to share some server side solutions that can speed up page and resource loading

https://github.com/galan/packtag - Have used this in Struts before and it does make a big difference
https://jawr.java.net/ -  Has Spring integration and seems really nice. A good starting point is showned on : http://memorynotfound.com/jawr-combine-minify-compress-javascript-css/

For .Net



With Apache/NGINX it is possible to develop a similar approach

https://www.nginx.com/resources/wiki/modules/concat/

RPCS3 + Ubuntu

This weekend i had some time to play around with a emulator ( RPCS3)  on my Ubuntu box.
After installing bison and libedit-dev and fiddling around with LD_LIBRARY_PATH i got it to build


What i don't understand is why i had to do"export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib/x86_64-linux-gnu/" considering on "/etc/ld.so.conf.d/"   when there was already a conf file with that path. Permissions issue perhaps? Can someone with more Ubuntu experience shed some light?
Now to the fun part of fidding with Asmjit and LLVM.

quarta-feira, 10 de fevereiro de 2016

Quartz Scheduler

A while back i had to work with Quartz (the scheduler) - Quartz - not to be confused with - Quartz (graphics_layer)  and i would like to share a website that helped me CronMaker.
Thanks to who had the work of making my life easier :)