fuchsia-llui is a Rust library for doing low-level user-interface, talking directly to the software framebuffer and the HID devices. Currently only the framebuffer functionality is implemented.
There are two examples included in the library. rectangle draws some pleasing pastel rectangles on the screen. font uses Raph Levien's font-rs to render characters.
When Zircon detects that there is a GPU driver, it disables the software framebuffer. If you try to run the examples on such a device you will see an error message and no graphics.
If you would like to run this software on such a device, you can disable the GPU driver with a kernel command line option. The example below is for netbooting an intel-based device like Acer or NUC.
out/build-zircon/tools/bootserver \
out/build-zircon/build-zircon-pc-x86-64/zircon.bin \
out/release-x86-64/user.bootfs -- \
gfxconsole.font=18x32 \
driver.intel_gen_gpu.disable
If you have a different device, the shell command dm dump is useful for trying to find the name of the GPU driver to disable it. Below is the output of dm dump on an Intel NUC. Run dm dump on your target and try to find a similar set of drivers to the intel_gen_display, framebuffer and intel_gen_gpu below.
[root]
<root> pid=1864
[null] pid=1864 /boot/driver/builtin.so
[zero] pid=1864 /boot/driver/builtin.so
[misc]
<misc> pid=1920
[console] pid=1920 /boot/driver/console.so
[dmctl] pid=1920 /boot/driver/dmctl.so
[tapctl] pid=1920 /boot/driver/ethertap.so
[hidctl] pid=1920 /boot/driver/hidctl.so
[intel-pt] pid=1920 /boot/driver/intel-pt.so
[rtc] pid=1920 /boot/driver/intel-rtc.so
[ktrace] pid=1920 /boot/driver/ktrace.so
[ptmx] pid=1920 /boot/driver/pty.so
[ramctl] pid=1920 /boot/driver/ramdisk.so
[sysinfo] pid=1920 /boot/driver/sysinfo.so
[test] pid=1920 /boot/driver/test.so
[usb-virtual-bus] pid=1920 /boot/driver/usb-virtual-bus.so
[sys]
<sys> pid=1806 /boot/driver/bus-acpi.so
[acpi] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[acpi-battery] pid=1806 /boot/driver/bus-acpi.so
[pci] pid=1806 /boot/driver/bus-acpi.so
[pci] pid=1806 /boot/driver/bus-pci.so
[00:00:00] pid=1806 /boot/driver/bus-pci.so
[00:02:00] pid=1806 /boot/driver/bus-pci.so
<00:02:00> pid=3398 /boot/driver/bus-pci.so
[intel_gen_display] pid=3398 /boot/driver/libmsd_intel.so
[framebuffer] pid=3398 /boot/driver/framebuffer.so
[intel_gen_gpu] pid=3398 /boot/driver/libmsd_intel.so
[00:14:00] pid=1806 /boot/driver/bus-pci.so
<00:14:00> pid=3440 /boot/driver/bus-pci.so
[xhci] pid=3440 /boot/driver/xhci.so
[usb] pid=3440 /boot/driver/usb-bus.so
[065] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb-hub] pid=3440 /boot/driver/usb-hub.so
[066] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb-hub] pid=3440 /boot/driver/usb-hub.so
[001] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[ums] pid=3440 /boot/driver/usb-mass-storage.so
[lun-000] pid=3440 /boot/driver/usb-mass-storage.so
[block] pid=3440 /boot/driver/block.so
[part-000] pid=3440 /boot/driver/mbr.so
[block] pid=3440 /boot/driver/block.so
[002] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb-hub] pid=3440 /boot/driver/usb-hub.so
[003] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb_bt_hci] pid=3440 /boot/driver/usb-bt-hci.so
[ifc-001] pid=3440 /boot/driver/usb-bus.so
[004] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb-hid] pid=3440 /boot/driver/usb-hid.so
[hid-device-000] pid=3440 /boot/driver/hid.so
[005] pid=3440 /boot/driver/usb-bus.so
[ifc-000] pid=3440 /boot/driver/usb-bus.so
[usb-hid] pid=3440 /boot/driver/usb-hid.so
[hid-device-000] pid=3440 /boot/driver/hid.so
[ifc-001] pid=3440 /boot/driver/usb-bus.so
[usb-hid] pid=3440 /boot/driver/usb-hid.so
[hid-device-001] pid=3440 /boot/driver/hid.so
[00:14:02] pid=1806 /boot/driver/bus-pci.so
[00:16:00] pid=1806 /boot/driver/bus-pci.so
[00:17:00] pid=1806 /boot/driver/bus-pci.so
<00:17:00> pid=3514 /boot/driver/bus-pci.so
[ahci] pid=3514 /boot/driver/ahci.so
[00:1c:00] pid=1806 /boot/driver/bus-pci.so
[01:00:00] pid=1806 /boot/driver/bus-pci.so
[00:1e:00] pid=1806 /boot/driver/bus-pci.so
[00:1e:06] pid=1806 /boot/driver/bus-pci.so
<00:1e:06> pid=3590 /boot/driver/bus-pci.so
[pci-sdhci] pid=3590 /boot/driver/pci-sdhci.so
[sdhci] pid=3590 /boot/driver/sdhci.so
[00:1f:00] pid=1806 /boot/driver/bus-pci.so
[00:1f:02] pid=1806 /boot/driver/bus-pci.so
[00:1f:03] pid=1806 /boot/driver/bus-pci.so
<00:1f:03> pid=3653 /boot/driver/bus-pci.so
[intel-hda-000] pid=3653 /system/driver/ihda-controller.so
[intel-hda-codec-000] pid=3653 /system/driver/ihda-controller.so
[output-stream-001] pid=3653 /system/driver/realtek-ihda-codec.so
[input-stream-002] pid=3653 /system/driver/realtek-ihda-codec.so
[intel-hda-codec-002] pid=3653 /system/driver/ihda-controller.so
[00:1f:04] pid=1806 /boot/driver/bus-pci.so
[00:1f:06] pid=1806 /boot/driver/bus-pci.so
<00:1f:06> pid=3757 /boot/driver/bus-pci.so
[intel-ethernet] pid=3757 /boot/driver/intel-ethernet.so
[ethernet] pid=3757 /boot/driver/ethernet.so