I am building a kiosk application using webkitgtk on the raspberry pi 4.
This application will not be connected to the internet and all the html,css, javascript for the UI are all located on the local filesystem.
I am using buildroot to setup the Linux system, starting with the pi 4 defconfig provided in buildroot.
I have enabled all the packages needed to get webkitgtk running.
Also, the kiosk application has been tested on my desktop, using the same software stack and it works
However, when i try to launch the application on the raspberry pi, a blank page pops up. I have played around with the WebKitWebSettings object associated with my WebKitWebView by enabling local file access. It still shows up a blank screen.
Also included in my pi4 application bundle is a simple gtk3+ application. This launches successfully!
I will really appreciate some pointers as to why this is happening as i have sort of reached a dead end
UPDATE
I enabled the MiniBrowser app that comes with the Webkitgtk package.
Entering the local url, The page does not load. It only gives me a message at the top saying "Successfully downloaded".
It seems to be treating my input as a download
UPDATE 2
After some more experimenting, i was finally able to get webkitgtk working on the pi 4.
The problem seems to originate from using the webkit_web_view_load_uri() api.
It does not seem to recognize my html document as a web page.
I got around it using the webkit_web_view_load_html() call. This included some hacks by first reading in the contents of the html doc into a character buffer, and passing it to webkit_web_view_load_html().
You also have to provide a base path to this function call to be able to resolve all the urls (scripts, css, images etc) in your html document.
Another problem i haven't been able to work around is, SVG images are not loading in webkitgtk. I have used jpg formats and they work. I suspect this my be due to a configuration switch in building webkigtk
It's hard for me to figure out what might be happening without having access to your environment and settings. My gut feeling is that pages are showing blank because perhaps some shared libraries are missing. You can check that with:
$ ldd WebKitBuild/GTK/Release/bin/MiniBrowser
I am using buildroot to setup the Linux system, starting with the pi 4 defconfig provided in buildroot.
There's a buildroot repository for building WPE for RPi. WPE (WebPlatform for Embeded) is like WebKitGTK but doesn't depend on GTK toolkit. Another important difference is that WPE runs natively on Wayland.
If you're interested in having a webapp embedded in a browser running in a device with limited capabilities, WPE is a better choice than WebKitGTK. The buildroot repo for building WPE for RPi is here:
https://github.com/WebPlatformForEmbedded/buildroot
There's is also this very interesting step-by-step guide on how to build WPE for RPi3:
https://samdecrock.medium.com/building-wpe-webkit-for-raspberry-pi-3-cdbd7b5cb362
I'm not sure whether the buildroot recipe would work for RPi4. It seems to work for all previous versions, so you might be stepping in new land if you try to build WPE on RPi4.
If you have an RPi3 available I'd try to build WPE for RPi3 first, and make sure that works. Then try for RPi4.
Related
I am using MoltenVK on MacBook Air with Apple Silicon. I have set my environment according to instructions on Vulkan Tutorial website but when I try to run my program in Xcode I get the following two error messages from validation layer:
ERROR (Callback: Validation Layer): Loading layer library /usr/local/share/vulkan/explicit_layer.d/../../../lib/libVkLayer_api_dump.dylib
ERROR (Callback: Validation Layer): Loading layer library /usr/local/share/vulkan/explicit_layer.d/../../../lib/libVkLayer_khronos_validation.dylib
I have played around with the settings in vkconfig and added environment variable VK_INSTANCE_LAYERS pointing to list of those two layers that failed to load and VK_LAYER_PATH that points to path /Users/jakub/VulkanSDK/1.3.224.1/macOS/share/vulkan/explicit_layer.d. None of that worked.
Those environment variables only work on macOS if you launch the apps from the command line. Apple does not allow environment variables to be set for GUI apps launched from the desktop, etc. A better way to use layers on macOS is to use VKConfig. You can create a configuration with the layers you want (and there's a nice GUI for tweaking layer parameters). This creates a "metalayer" that the loader will always see and make use without the need for environment variables. Also, make sure you do not link statically to MoltenVK, as this does not use the actual loader and layers will not work (although linking statically is perfectly fine for shipping your apps).
The app starts with a blank screen for a while before the app really loads
I'm using electron-forge's react-typescript template.
I can make a dmg or deb file successfully, but I noticed when I run the packaged app, there will be a blank screen for a while before the app actually load especially the first time
I checked the distributable file and found the whole source code inside it, so I guess it's because it has to compile typescript every time?
Then how to "precompile" my source code and use that to make a distributable app?
update:
Since the project was developed by other colleague, I just found out this project is using electron-compile to compile it on the fly, maybe the solution has something to do with this?
I checked the distributable file and found the whole source code inside it, so I guess it's because it has to compile typescript every time?
This is not true. Current stable uses electron-prebuilt-compile (https://github.com/electron-userland/electron-forge/blob/1709af0bc53bd962466dd2025672b95f2e9399cc/packages/api/core/src/util/electron-version.ts#L6) which creates precompiled cache for typescript files for packaging time. Typescript source is only needed for module resolution in actual filesystem.
there will be a blank screen for a while before the app actually load especially the first time
This requires profiling application itself to find out what is happening in meanwhile. It is possible module resolution takes long or either any js execution time's blocking, but can't tell without profiling it.
Ok, so I trying to debug an Ionic 2 app in my iPad. The bug is that the PDF reader isn't working, but my main concern at the moment is getting my debugging on the iPad up and running.
Using the Developer menu item in Safari, I can see my iPad via its IP address and see console logs, element, resources, lock stock. I have even learned how to set breakpoints — how clever is that?
I have the problem now, however, that also applies to the desktop developer tools. How do I debug a webpack application in the browser? It turns all of my functions into "text" so it's not immediately apparent how to step through the code, for example.
I'm sure it has something to do with sourcemaps...am I missing something entirely basic?
Webpack puts the source maps in the file:// domain rather than the localhost so I guess this is where your confusion stems from.
Now depending on the version of ionic app scripts the structure may vary.
0.44 and above has the full path of the file in a huge list with the node modules used.
Below 0.44 has a folder called . and inside it all app related source maps(without the node modules)
I need to debug my CN1 app on Android. That's why I successfully followed the instructions given in this Codename One tutorial (I copied and updated the gradle files dependencies content as explained).
I am a little bit confused now with the updated sources part.
There is a portion we didn’t get into with the video, copying updated sources directly without sending a build. This is possible if you turn on the new Android Java 8 support. At this point you should be able to remove the libs jar file which contains your compiled data and place your source code directly into the native project for debugging on the device.
If I change things in the native implementation file and if I launch the debug process it seems to work. But do I have to remove the userClasses.jar file from libs directory ? When is this jar file being called actually ?
Furthermore can I also make changes to the CN1 code from Android Studio (eg changes in Main Class) or these need a proper build process on the servers ?
UPDATE November 22nd 2016
In my experience the first time you want to debug your app in Android you need to copy paste your source files AND the userClasses.jar (in libs folder). When you update ONLY the native implementation files you can run a debug without sending a build. But if you change something in the CN1 code it won't be reflected in Android as long as you don't update the userClasses.jar (seems logical since Android does not know anything about CN1).
Any piece of information appreciated,
Cheers,
The build server doesn't have access to your code, just the jar with bytecode/data files and the user jar is "almost" that jar.
We run some bytecode processing such as retrolambda and other things so it isn't exactly what you compiled when you built the project.
If you copy and paste your source directory into the project you will need to remove that jar so you won't see duplicate classes. You will also need to enable Android Studios Java 8 language support to get that to work.
I would like to make a Graphical interface for a home-made program using SFML on Raspberry Pi2. I am using Raspbian. I recompiled the graphical lib
It works fine unsing startx first, then using my application, which wors perfectly fine.
But I can't figure if it is possible or how to launch my application directly after boot without launching startx (just to optimise the cpu of the Raspberry).
Starting my program direcly after boot, I get the following error:
Failed to open X11 display: make sure the DISPLAY environnement variable is set correctly.
Aborted.
I already tested the classic export DISPLAY=:0.0 but without sucess.
I interested myself in x and xinit, but I am not sure that would even do it.
Where should I start looking? I don't need a complete solution, even a hint or an idea would be nice!
I checked to see if it was possible to open a graphical app without the X desktop environment and as that answer states, with Firefox at least, you need the X server which SFML also probably needs in order to create a window.
The answer states:
Basically something like:
$ X
Then you just start Firefox in this X server:
$ DISPLAY=:0 firefox
You can switch from the X server and the framebuffer by using
CTRL+ALT+F1 and CTRL+ALT+F7.
You could try that and see if it helps.
Also, still searching, I found a forum post on the sfml website about what you're trying to accomplish stating somewhere:
SFML requires OpenGL, so as far as I know you need at least X running,
but you probably don't need gnome, KDE or a similar Desktop
Environment on top.
The forum guy asking for help seems to have managed to get X11 and a SFML basic render window to work on Ubuntu server after someone posted a link to xinitrc. I guess, that's the route to go from here.