Mouse Support In Linux Frame Buffer

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1

When using the Linux Frame Buffer backend the mouse doesn’t work. Does the backend support using the Mouse as input, and if so how to enable the Mouse support on a real Embedded Linux device (eg Raspberry Pi)?

2

Noticed in the documentation that LV Drivers uses the evdev library for mouse support. Unfortunately the generated static library file for the LV Drivers library doesn’t contain any defined evdev symbols. Here is the output after running nm --defined-only liblv_drivers.a:

CMakeCCompilerId.o:
00000000 t $a
00000000 r $d
00000000 d $d
000000e0 t $d
00000008 D info_arch
00000000 D info_compiler
0000000c D info_language_dialect_default
00000004 D info_platform
00000014 R info_version
00000000 T main

GC9A01.o:

ILI9341.o:

R61581.o:

SHARP_MIP.o:

SSD1963.o:

ST7565.o:

UC1610.o:

drm.o:

fbdev.o:
00000000 t $a
00000194 t $a
000001b8 t $a
0000071c t $a
0000077c t $a
00000000 b $d
00000000 r $d
00000160 t $d
000001b4 t $d
00000710 t $d
00000778 t $d
000007b8 t $d
00000194 T fbdev_exit
000001b8 T fbdev_flush
0000071c T fbdev_get_sizes
00000000 T fbdev_init
0000077c T fbdev_set_offset
000000ec b fbfd
000000e4 b fbp
000000a0 b finfo
000000e8 b screensize
00000000 b vinfo

gtkdrv.o:

AD_touch.o:

FT5406EE8.o:

XPT2046.o:

evdev.o:

libinput.o:

xkb.o:

sdl.o:

sdl_gpu.o:

wayland.o:

win32drv.o:

win_drv.o:

Is there a missing CMake option for including the evdev symbols in the static library file? Need to use the evdev_init function (to initialise all input devices including the mouse) in the program however the symbol isn’t included in the static library file for some strange reason.

3

Mouse support is working with the Linux Frame Buffer, however the mouse cursor doesn’t look like an actual mouse cursor, and when the cursor is moved there is graphical corruption shown on screen (rendering issues). Below is the code used to create the mouse cursor (using the Raspberry Pi 4 as the target device):

import kotlinx.cinterop.*
import lvgl.LV_IMG_CF_TRUE_COLOR_ALPHA
import lvgl.LV_IMG_PX_SIZE_ALPHA_BYTE
import lvgl.lv_img_dsc_t

@ExperimentalUnsignedTypes
// Pixel Format (16 colour depth with no colour swap): Alpha 8 bit, Red 5 bit, Green 6 bit, Blue 5 bit.
private val mouseCursorIconMap = arrayOf(
    0x19, 0x19, 0x19, 0xb8, 0x1e, 0x1e, 0x1e, 0xc8, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x48, 0x48, 0x48, 0xcc, 0xb2, 0xb2, 0xb2, 0xff, 0x3a, 0x3a, 0x3a, 0xcc, 0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x0a, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3b, 0x3b, 0x3b, 0xc8, 0xf6, 0xf6, 0xf6, 0xff, 0xdc, 0xdc, 0xdc, 0xff, 0x43, 0x43, 0x43, 0xe0, 0x00, 0x00, 0x00, 0x3b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x0a, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3b, 0x3b, 0x3b, 0xcb, 0xe6, 0xe6, 0xe6, 0xff, 0xff, 0xff, 0xff, 0xfc, 0xe5, 0xe5, 0xe5, 0xff, 0x59, 0x59, 0x59, 0xf3, 0x00, 0x00, 0x00, 0x4f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3c, 0x3c, 0x3c, 0xcb, 0xe9, 0xe9, 0xe9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf5, 0xf5, 0xf5, 0xff, 0x72, 0x72, 0x72, 0xff, 0x00, 0x00, 0x00, 0x73, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3d, 0x3d, 0x3d, 0xcb, 0xe9, 0xe9, 0xe9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x8a, 0x8a, 0x8a, 0xff, 0x00, 0x00, 0x00, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x99, 0x99, 0x99, 0x00, 0x04, 0x04, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3e, 0x3e, 0x3e, 0xcb, 0xe9, 0xe9, 0xe9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xa2, 0xa2, 0xa2, 0xff, 0x13, 0x13, 0x13, 0xab, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x3f, 0x3f, 0x3f, 0xcb, 0xe9, 0xe9, 0xe9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xb7, 0xb7, 0xb7, 0xff, 0x1f, 0x1f, 0x1f, 0xbb, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x41, 0x41, 0x41, 0xcc, 0xea, 0xea, 0xea, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xca, 0xca, 0xca, 0xff, 0x3d, 0x3d, 0x3d, 0xd8, 0x00, 0x00, 0x00, 0x37, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x41, 0x41, 0x41, 0xcc, 0xea, 0xea, 0xea, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xde, 0xde, 0xde, 0xff, 0x56, 0x56, 0x56, 0xef, 0x00, 0x00, 0x00, 0x4f, 0x00, 0x00, 0x00, 0x00,
    0x42, 0x42, 0x42, 0xcc, 0xea, 0xea, 0xea, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf3, 0xf3, 0xf3, 0xff, 0x76, 0x76, 0x76, 0xff, 0x00, 0x00, 0x00, 0x6b,
    0x43, 0x43, 0x43, 0xcc, 0xea, 0xea, 0xea, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xce, 0xce, 0xce, 0xff, 0x80, 0x80, 0x80, 0xf7, 0x74, 0x74, 0x74, 0xf8, 0x6d, 0x6d, 0x6d, 0xfb, 0x72, 0x72, 0x72, 0xf8, 0x57, 0x57, 0x57, 0xff, 0x0c, 0x0c, 0x0c, 0xb3,
    0x44, 0x44, 0x44, 0xcc, 0xeb, 0xeb, 0xeb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfc, 0xfb, 0xfb, 0xfb, 0xff, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc9, 0xc9, 0xc9, 0xff, 0x13, 0x13, 0x13, 0xb7, 0x00, 0x00, 0x00, 0x1b, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x0c, 0x29, 0x29, 0x29, 0x07,
    0x45, 0x45, 0x45, 0xcc, 0xe8, 0xe8, 0xe8, 0xff, 0xff, 0xff, 0xff, 0xff, 0xd9, 0xd9, 0xd9, 0xff, 0x5e, 0x5e, 0x5e, 0xff, 0xe2, 0xe2, 0xe2, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x62, 0x62, 0x62, 0xf0, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x45, 0x45, 0x45, 0xcc, 0xf9, 0xf9, 0xf9, 0xff, 0xec, 0xec, 0xec, 0xff, 0x4a, 0x4a, 0x4a, 0xd8, 0x00, 0x00, 0x00, 0x78, 0x8a, 0x8a, 0x8a, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc3, 0xc3, 0xc3, 0xff, 0x00, 0x00, 0x00, 0x8b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x58, 0x58, 0x58, 0xd3, 0xd9, 0xd9, 0xd9, 0xff, 0x5e, 0x5e, 0x5e, 0xef, 0x00, 0x00, 0x00, 0x34, 0x00, 0x00, 0x00, 0x00, 0x3b, 0x3b, 0x3b, 0xc7, 0xe9, 0xe9, 0xe9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf4, 0xf4, 0xf4, 0xff, 0x54, 0x54, 0x54, 0xdc, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,
    0x3e, 0x3e, 0x3e, 0xe0, 0x54, 0x54, 0x54, 0xff, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x57, 0x8e, 0x8e, 0x8e, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xb0, 0xb0, 0xb0, 0xff, 0x00, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x0c, 0x0c, 0x04, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x68, 0x00, 0x00, 0x00, 0x4f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x4c, 0x4c, 0x4c, 0xd0, 0xec, 0xec, 0xec, 0xff, 0xff, 0xff, 0xff, 0xfc, 0xf4, 0xf4, 0xf4, 0xff, 0x53, 0x53, 0x53, 0xd8, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1e, 0x1e, 0x1e, 0x00, 0x04, 0x04, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x6f, 0xab, 0xab, 0xab, 0xff, 0xf6, 0xf6, 0xf6, 0xff, 0x80, 0x80, 0x80, 0xff, 0x31, 0x31, 0x31, 0xac, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x09, 0x09, 0x09, 0x03, 0x02, 0x02, 0x02, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x2e, 0x2e, 0x2e, 0xd7, 0x38, 0x38, 0x38, 0xc7, 0x00, 0x00, 0x00, 0x47, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
).map { it.toUByte() }.toUByteArray()

@ExperimentalUnsignedTypes
internal fun createMouseCursorIcon(scope: MemScope): lv_img_dsc_t {
    val pinned = mouseCursorIconMap.pin()
    val result = scope.alloc<lv_img_dsc_t>().apply {
        header.always_zero = 0u
        header.w = 14u
        header.h = 20u
        data_size = 280u * LV_IMG_PX_SIZE_ALPHA_BYTE.toUInt()
        header.cf = LV_IMG_CF_TRUE_COLOR_ALPHA
        data = pinned.addressOf(0)
    }
    pinned.unpin()
    return result
}
4

Discovered a much easier way to set the mouse cursor. Just use a font symbol instead which is independent of the display configuration, eg:

    // ...
    val inDevDriver = scope.alloc<lv_indev_drv_t>()
    lv_indev_drv_init(inDevDriver.ptr)
    inDevDriver.type = lv_indev_type_t.LV_INDEV_TYPE_POINTER
    inDevDriver.read_cb = staticCFunction(::readMouse).reinterpret()
    val mouseInDev = lv_indev_drv_register(inDevDriver.ptr)
    val cursor = lv_img_create(lv_scr_act())
    lv_img_set_src(cursor, LV_SYMBOL_GPS.cstr)
    lv_indev_set_cursor(mouseInDev, cursor)
    // ...