touchscreen no work with sdl + drm

[Coloryr]

LVGL version

v9.1.0

What happened?

touchscreen no work runing in sdl + drm

/*==================
 * DEVICES
 *==================*/
/*Use SDL to open window on PC and handle mouse and keyboard*/
#define LV_USE_SDL              1
#if LV_USE_SDL
    #define LV_SDL_INCLUDE_PATH     <SDL2/SDL.h>
    #define LV_SDL_RENDER_MODE      LV_DISPLAY_RENDER_MODE_DIRECT   /*LV_DISPLAY_RENDER_MODE_DIRECT is recommended for best performance*/
    #define LV_SDL_BUF_COUNT        1    /*1 or 2*/
    #define LV_SDL_FULLSCREEN       0    /*1: Make the window full screen by default*/
    #define LV_SDL_DIRECT_EXIT      1    /*1: Exit the application when all SDL windows are closed*/
    #define LV_SDL_MOUSEWHEEL_MODE  LV_SDL_MOUSEWHEEL_MODE_ENCODER  /*LV_SDL_MOUSEWHEEL_MODE_ENCODER/CROWN*/
#endif

I touch the screen, it can go to

lvgl/src/drivers/sdl/lv_sdl_mouse.c

Line 120 in cac17b5

win_id = event->tfinger.windowID;

but, indev and disp always is null in

lvgl/src/drivers/sdl/lv_sdl_mouse.c

Lines 130 to 141 in cac17b5

	lv_display_t * disp = _lv_sdl_get_disp_from_win_id(win_id);
	/*Find a suitable indev*/
	lv_indev_t * indev = lv_indev_get_next(NULL);
	while(indev) {
	if(lv_indev_get_display(indev) == disp && lv_indev_get_type(indev) == LV_INDEV_TYPE_POINTER) {
	break;
	}
	indev = lv_indev_get_next(indev);
	}
	if(indev == NULL) return;

From debug, I sew win_id is 0, but no window with id 0 exists.

How to reproduce?

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "lvgl.h"

#include "demos/lv_demos.h"

int main(int, char **)
{
    lv_init();

    lv_display_t *display = lv_sdl_window_create(640, 480);
    lv_indev_t *mouse = lv_sdl_mouse_create();
    lv_indev_t *mousewheel = lv_sdl_mousewheel_create();
    lv_indev_t *keyboard = lv_sdl_keyboard_create();

    lv_demo_widgets();

    for (;;)
    {
        uint32_t time = lv_timer_handler();
        usleep(time * 1000);
    }
}

[kisvegabor]

I've checked in SDL's docs that for SDL_FINGER* events really event->tfinger shall be used. If SDL doesn't set the Window ID we cannot do much.

Can you ask it from the SDL developers?

[Coloryr]

I'm use is in DRM not X11, maybe these two are different.

[Coloryr]

/*Find a suitable indev*/
    lv_indev_t * indev = lv_indev_get_next(NULL);
    while(indev) {
        if(disp != NULL) {
            if(lv_indev_get_display(indev) == disp) {
                break;
            }
        }
        if(lv_indev_get_type(indev) == LV_INDEV_TYPE_POINTER) {
            break;
        }
        indev = lv_indev_get_next(indev);
    }

I have modified the lv_sdl_mouse.c code, that it can work properly.
after:
I found that my code was written incorrectly, and I have corrected it.

[kisvegabor]

I have modified the lv_sdl_mouse.c code, that it can work properly.

What is the difference? It seems to your code does the same thing, just the if is split into 2 parts. Am I missing something?

[Coloryr]

In drm, disp is null, but lv_indev_get_display(indev) is not null.

[kisvegabor]

This way always the first POINTER indev will be found. Which is better nothing, but worth mentioning.

I've opened #6194 to fix it.

[Coloryr]

I have tested it, this patch is work.

[kisvegabor]

Great, thank you!