Way to Rotate lvgl example?

RE: Way to Rotate lvgl example?

RHOOD — Mon, 09 Dec 2024 21:32:46 GMT

For anyone else who finds this: If you are using specifically the SSD1306 driver the way you get around this is you set up an LVGL canvas, write on the canvas, and then rotate that. I will post on example of writing simple text and then rotating it. It is somewhat version depenent though so check you Zephyr and LVGL version and find out what the current syntax is.

char count_str[11] = {0};
    const struct device *display_dev;

    display_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
    if (!device_is_ready(display_dev)) {
        LOG_ERR("Device not ready, aborting test");
        return 0;
    }

    static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];
    lv_obj_t *canvas = lv_canvas_create(lv_scr_act());
    lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_IMG_CF_TRUE_COLOR);
    lv_canvas_set_palette(canvas, 1, lv_color_hex(0xffffff));
    lv_canvas_set_palette(canvas, 0, lv_color_hex(0x000000));
    lv_obj_align(canvas, LV_ALIGN_DEFAULT, 0, 0);
    

    lv_color_t black; black.full = 1;
    lv_color_t white; white.full = 0;

    lv_canvas_fill_bg(canvas, black, LV_OPA_COVER);

    lv_draw_label_dsc_t label_dsc;
    lv_draw_label_dsc_init(&label_dsc);
    label_dsc.color = white;

    lv_draw_label_dsc_t label_dsc2;
    lv_draw_label_dsc_init(&label_dsc2);
    label_dsc2.color = label_dsc.color;

    lv_draw_label_dsc_t label_HR;
    lv_draw_label_dsc_init(&label_HR);
    label_HR.color = label_dsc.color;

    lv_draw_label_dsc_t label_BAS;
    lv_draw_label_dsc_init(&label_BAS);
    label_BAS.color = label_dsc.color;

    lv_draw_label_dsc_t label_PHN;
    lv_draw_label_dsc_init(&label_PHN);
    label_PHN.color = label_dsc.color;

    lv_draw_label_dsc_t label_PHN_val;
    lv_draw_label_dsc_init(&label_PHN_val);
    label_PHN_val.color = label_dsc.color;

    lv_draw_label_dsc_t label_Conn;
    lv_draw_label_dsc_init(&label_Conn);
    label_Conn.color = label_dsc.color;

    lv_draw_label_dsc_t label_Conn_val;
    lv_draw_label_dsc_init(&label_Conn_val);
    label_Conn_val.color = label_dsc.color;
    
    char bas_data_str[5];
    char hr_data_str[5];
    char phn_data_str[5];

    lv_task_handler();
    display_blanking_off(display_dev);
    while (1) {
        //printf("here\n");
        sprintf(bas_data_str, "%d", incoming_bas);
        sprintf(hr_data_str, "%d", incoming_hr);
        sprintf(phn_data_str, "%d", sent_data);
        lv_canvas_fill_bg(canvas, black, LV_OPA_COVER);
        lv_canvas_draw_text(canvas, 0, 28,100, &label_PHN, "Data Sent:");
        lv_canvas_draw_text(canvas, 100, 28,100, &label_PHN_val, phn_data_str);
        lv_canvas_draw_text(canvas, 0, 28+14,100, &label_Conn, "Connected:");
        lv_canvas_draw_text(canvas, 70, 28+14,100, &label_Conn_val, name_list[1]);
        lv_canvas_draw_text(canvas, 0, 14,100, &label_HR, "BAS Value:");
        lv_canvas_draw_text(canvas, 0, 0, 100, &label_dsc, "HR Value:");
        lv_canvas_draw_text(canvas, 100, 14, 30, &label_dsc2, bas_data_str);
        lv_canvas_draw_text(canvas, 100, 0, 30, &label_dsc, hr_data_str);
    
        static lv_color_t cbuf_tmp[CANVAS_WIDTH * CANVAS_HEIGHT];
        memcpy(cbuf_tmp, cbuf, sizeof(cbuf_tmp));
        lv_img_dsc_t img;
        img.data = (void *)cbuf_tmp;
        img.header.cf = LV_IMG_CF_TRUE_COLOR;
        img.header.w = CANVAS_WIDTH;
        img.header.h = CANVAS_HEIGHT;

        lv_canvas_transform(canvas, &img, 900, LV_IMG_ZOOM_NONE, -1, 0, 64 / 2, 64 / 2, true);
        lv_task_handler();
        //printk("here");
        //k_yield();
    }

RE: Way to Rotate lvgl example?

ovrebekk — Mon, 04 Mar 2024 12:05:46 GMT

Hi Rainier

Any chance you could open a new issue on this in the LVGL repo?

I can try to give it a go as well, but unfortunately I am quite busy at the moment and will not be able to prioritize this in the next couple of weeks.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Wed, 28 Feb 2024 14:00:48 GMT

Hi,

Yeah, I tried to implement that fix a little while ago. Unfortunately both LVGL and Zephyr have updated since then so a lot of the files they reference don't exist anymore. lvgl.c and lvgl_display_mono are still around but I don't see Kconfig.graphical anywhere in my zephyr directories and I believe I confirmed that this file no longer exists on current version when doing research online.I have been looking to see if there is an equivalent Kconfig they just renamed to something else but so far I havn't found it. If you know of where I could find such an equivalent config that would be awesome.

Thanks,

Rainier

RE: Way to Rotate lvgl example?

ovrebekk — Wed, 28 Feb 2024 09:07:55 GMT

Hi Rainier

I guess I should have read the entire thread properly, now I realize there is a known issue in LVGL regarding the SW rotate function.

Reading through the issues it doesn't seem this issue was ever fixed, but I see a patch is proposed here. Could you try this fix and see if you can get the rotate function to work?

[quote user="RHOOD"]I don't really care how slow it is. I just need to do it once during initialization. [/quote]

I expect software rotation will slow down every display update operation, not just initialization, but how big of an impact it will be I don't know. This would be resolution dependent, but since you are only using a 128x64 pixel display it would hopefully not be a very big impact.

Either way, it is something to be aware of if you are able to get the sw rotation feature working.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Tue, 27 Feb 2024 15:26:08 GMT

I did try lv_set_rotation with all the possible rotation values. None of them gave a legible output.

I tried setting driver->sw_rotate = LV_DISP_ROT_90 in the lv_disp_drv_init() function. Doesn't seem to accomplish anything. I have tried a few other things (like trying to change it in the lv_disp_drv_t typdef declaration) but I havn;t been able to get it to work. If you have an idea of how I could better use that then I would love to hear about it. I don't really care how slow it is. I just need to do it once during initialization.

Thanks,

Rainier

RE: Way to Rotate lvgl example?

ovrebekk — Tue, 27 Feb 2024 14:16:55 GMT

Really odd that the com-invdir change wouldn't work. Looking at the driver implementation this seems to be a standard feature.

Regarding the lv_disp_set_rotation command, did you try this with all possible rotation values?

Did you try to enable the software rotation feature?
Possibly this one will allow you to rotate the display, even if it is a slower method compared to hardware rotation.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Mon, 26 Feb 2024 13:32:05 GMT

Hi,

Thanks for the .dts clarification and the /delete-property clarification. I am not as good at the overlay stuff as I would like to be so I appreciate the patient clarification.

Deleting segment-remap rotates the screen by 180 degrees which is neat but not the 90 that I am looking for. Deleting com-invdir just breaks the output which is unfortunate. I tried messing around with some of the together settings to try to get a version working after deleting com-invdir but to no avail.

RE: Way to Rotate lvgl example?

ovrebekk — Mon, 26 Feb 2024 09:36:13 GMT

zephyr.dts is generated by the build system, changing this file will have no effect. Instead you can use this file to verify if the changes you make in the overlay or other places are actually picked up by the build system.

How did you try to remove the property?

There is an example here showing how you can delete a property in the overlay:

&serial0 {
     /delete-property/ some-unwanted-property;
};

After trying that, do a pristine build, and check zephyr.dts again to see if the property is still there.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Fri, 23 Feb 2024 14:42:38 GMT

Hi,

So I tried playing around with removing those two properties and as far as I can tell nothing happened? Im a little confused by that. I modified both the overlay and zephyr.dts tp remove one/both of those properties and as far as I can tell that had zero visual effect on the output. That doesn't feel right to me though. It feels like that should have done something.

RE: Way to Rotate lvgl example?

ovrebekk — Fri, 23 Feb 2024 09:28:53 GMT

My bad, you are correct that there is no rotation property for the ssd1306 driver.

Looking at the driver implementation in ssd1306.c I see that the set_orientation function will just return the not supported error:
https://github.com/nrfconnect/sdk-zephyr/blob/main/drivers/display/ssd1306.c#L365-L371

As far as I can tell from the SSD1306 datasheet the driver doesn't provide any kind of rotation register, which is why it is not supported in the driver.

What happens if you remove the segment-remap or com-invdir properties from the ssd1306 node?

Possibly you can invert the display horizontally or vertically this way, but I am not sure that will solve your issue or not.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Thu, 22 Feb 2024 18:01:53 GMT

Ah, I see. Unfortunately I am using I2C rather than SPI.

i2c1: arduino_i2c: i2c@9000 {
                compatible = "nordic,nrf-twim";
                #address-cells = < 0x1 >;
                #size-cells = < 0x0 >;
                reg = < 0x9000 0x1000 >;
                clock-frequency = < 0x61a80 >;
                interrupts = < 0x9 0x1 >;
                status = "okay";
                pinctrl-0 = < &i2c1_default >;
                pinctrl-1 = < &i2c1_sleep >;
                pinctrl-names = "default", "sleep";
                zephyr,concat-buf-size = < 0x1000 >;
                ssd1306_ssd1306_128x64: ssd1306: ssd1306@3c {
                    compatible = "solomon,ssd1306fb";
                    reg = < 0x3c >;
                    width = < 0x40 >;
                    height = < 0x80 >;
                    segment-offset = < 0x0 >;
                    page-offset = < 0x0 >;
                    display-offset = < 0x1f >;
                    multiplex-ratio = < 0x3f >;
                    segment-remap;
                    com-invdir;
                    prechargep = < 0x22 >;
                    com-sequential;
                };
            };

As you can see there is no rotation here.

RE: Way to Rotate lvgl example?

ovrebekk — Thu, 22 Feb 2024 08:53:16 GMT

Can you check the zephyr.dts file in the build/zephyr directory?

This file will contain the complete device tree configuration, after all board files, overlays etc has been compiled.

As an example, if I build the display/lvgl sample I can find the display node under spi3, and see that it includes the rotation property:

ili9340: ili9340@0 {
		compatible = "ilitek,ili9340";
		spi-max-frequency = < 0xe7319b >;
		reg = < 0x0 >;
		cmd-data-gpios = < &arduino_header 0xf 0x1 >;
		width = < 0x140 >;
		height = < 0xf0 >;
		pixel-format = < 0x1 >;
		rotation = < 0x5a >;
		frmctr1 = [ 00 18 ];
		pwctrl1 = [ 23 00 ];
		vmctrl1 = [ 3E 28 ];
		vmctrl2 = [ 86 ];
		pgamctrl = [ 0F 31 2B 0C 0E 08 4E F1 37 07 10 03 0E 09 00 ];
		ngamctrl = [ 00 0E 14 03 11 07 31 C1 48 08 0F 0C 31 36 0F ];
	};

You should be able to change this property through the overlay, yes.

Once the project gets more mature I would recommend making your own board definition, rather than relying on overlays.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Wed, 21 Feb 2024 20:07:07 GMT

I tried to but I was under them impression from research that there wasn't a rotation property. Can I just set that in the overlay?

RE: Way to Rotate lvgl example?

ovrebekk — Wed, 21 Feb 2024 08:35:31 GMT

Have you tried to change the rotation property in the device tree node for the display driver?

I believe this is the recommended way to set the orientation of the display.

Best regards
Torbjørn

RE: Way to Rotate lvgl example?

RHOOD — Thu, 15 Feb 2024 19:16:20 GMT

So looking more into it looks like the fixes posted on the LVGL forum are a little outdated. Kconfig.graphical doesn't exist anymore, for example and the fixes in the Zephyr forums don't work in isolation. Still looking into seeing if there is a fix.

RE: Way to Rotate lvgl example?

RHOOD — Thu, 15 Feb 2024 17:31:35 GMT

Hi,

Reading through those right now and working on implementing the little patch thing they are talking about. It's a little hard to describe how the display breaks exactly. It creates a little jumble of letters and numbers to the center right and there are little white streaks across the screen.

Do you happen to know where the flush callback is in this example?

RE: Way to Rotate lvgl example?

helsing — Thu, 15 Feb 2024 14:35:35 GMT

Hi,

[quote user=""]I tried the lv_disp_set _rotation command found in lv_hal_disp.c but rather than rotating the screen it just broke the display[/quote]

What does it look like when it breaks?

It seems like others are experiencing this with the SSD1306 driver:

https://github.com/lvgl/lvgl/issues/3379#issuecomment-1147954592

https://github.com/zephyrproject-rtos/zephyr/issues/46446

https://github.com/zmkfirmware/zmk/issues/1749