This repo should be reworked to make people easier to get started.

My vision is the following

Simple examples

Add very simple examples. It would be nice to use these examples in the documentation too (add lv_examples as a submodule to docs). I was collecting the recurring questions which could be answered with examples:

• mbox: modal (@embeddedt, lv_ex_mbox_2)
• slider: move the slider and set a label's text (@embeddedt, lv_ex_slider_2)
• button: styling
• image: recolor (@embeddedt, lv_ex_img_2)
• label: styling
• label: text shadow (@embeddedt, lv_ex_label_2)
• text area: password and one line mode (@embeddedt, lv_ex_ta_2)
• text area: finish on Enter
• text area: format text (e.g automatically add dots for IP address)
• image: slide show animation
• image: mosaic wallpaper
• display driver test (aded in FAQ)

Ready to use / easy to modify applications

• Android like menu LINK
• Car dashboard
• File browser
• Home automatization
• Audio players
• WiFi connect
• All in one example to show LittlevGL's features Example

External libraries

Create a separate repo for examples when external libraries are used:

• PNG decoder
• JPG decoder
• Video player
• QR code
• FatFS and Windows/Unix fs integration. Here I've already started something
• FreeType

Blog post

Create blog posts about longer, more complex topics

• responsive: fit, auto realign, layout, LV_DPI
• optimizations for monocrome: round, pixel_wr
• OSD menu
• FAQ: added to the documentation's welcome page instead

Tutorials

• lv_tutorial should be removed as it makes the examples and documentation fragile

Tests

• lv_tests are not designed for the users, so they can go to a separate repo: lv_tets

Feedback is very welcome

Hi,

A year ago @stepansnigirev did an excellent job adding Micropython examples to lv_examples.
Since then focused moved to v7. The Micropython examples were written for v6 and are not compatible with v7.

Looking at LVGL documentation, v6 documentation still contains all the examples from @stepansnigirev work, but v7 does not.
Unfortunately it looks like only the C examples were migrated to v7 while Micropython examples were removed.

I think it would be a good idea to migrate Micropython examples to v7.
The work required for migrating most examples is probably straightforward.
Currently I don't have the time to do it myself, so I'm opening this issue just to point this up.
In case other contributors don't have the bandwidth for this, I think this task could be tagged as "help wanted" and suggested to new contributors who are looking for a simple contribution task.

What do you think?

I don't like example 3 (auto text formatting)very much: It is supposed to show a text in form of 12:34.
However:

• If you press the accept button, all further input is rejected.
• If you press the reject button, the keyboard disappears altogether
• If you use the left button followed by a backspace you can easily create something like 1:234

When writing the micropython version of the example I created a different keyboard without the accept, reject, +- and . buttons. In the event handler I make sure that no more than 2 digits can appear before and after the : If you try, these digits are immediately deleted again.

The main README still refers to the examples using LVGL v6, how can it be updated?

The purpose of a README on each example would be to list the requirements it needs (fonts, LVGL special configuration, etc.), and features it shows.

Platform: Windows 7
LVGL version 7.2.0
Running Eclipse CDT 2018

Trying to compile lv_sim_eclipse_SDL demo with LV_USE_DEMO_PRINTER set 1. In main.c, lv_demo_printer() called. Added all SDL files following guideline in Simulator on PC.

Compile with build all gives the following error message:

'Building target: lv_sim_eclipse_sdl'
<skip for simplicity>
./lv_drivers/display/UC1610.o ./lv_drivers/display/fbdev.o ./lv_drivers/display/monitor.o  ./lv_drivers/win_drv.o  ./main.o ./mouse_cursor_icon.o   -lmingw32 -lSDL2main -lSDL2
gcc: error: ./lv_examples/src/lv_demo_printer/images/lv_demo_rinter_icon_eco.o: No such file or directory
make: *** [lv_sim_eclipse_sdl] Error 1

Is it somewhere in the source file mistyped lv_demo_rinter_icon_eco? I searched almost everywhere but could not locate it.

How to achieve screen size adaptation, Can Iset the size of the screen to a variable value obtained dynamically instead of a macro definition?

We're adding a Kconfig file to the lv_port_esp32 components and this repo is one of them, I'm wondering what should we add on the Kconfig configuration menu, here's what we were planning to add:

• Let the user choose what demo or example to run.
• Let the user enable or disable the task to 'emulate' user input, when available.

This changes will be first tested on the lv_port_esp32 repo and then added here when they are proven to work fine.

What do you think?

https://github.com/littlevgl/lv_examples/blob/rework-7/src/lv_ex_widgets/lv_ex_gauge/lv_ex_gauge_1.c#L13

I assume this is leftover code from debugging; do we want this left in the examples?

The benchmark code examples contain the merge-conflict artifacts. For instance:
https://github.com/lvgl/lv_examples/blob/4d31dd21cb753b3c4d50733cb380f777955b5be0/src/lv_demo_benchmark/lv_demo_benchmark.c#L554

There are some includes like this #include "lvgl/lvgl.h", should we update them to:

#ifdef LV_CONF_INCLUDE_SIMPLE
#include "lvgl.h"
#else
#include "lvgl/lvgl.h"
#endif

Hi,
I just started to use LVGL. The first program I run on 9341, TFT and Touchscreen works ok. The resulution of tft and touch is 320x240.
I tried to run a program on 9486 which is 480x320. I connected 9486 : touch recognise full 480x320 matrix, unfortunately screen works in 320x240 mode. Of coures I changed in menu config/component/lvgl configutation resulution to 480x320 but no result.
Kconfig keeps 480x 320 resolution. Is there any other place I have to enter the resolution?

wrong repo

I've just merged the music player demo to master and got this error from the depoly script:

main.c:76:5: error: implicit declaration of function 'lv_demo_music_list_btn_check' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    CHOSEN_DEMO();
    ^
<command line>:10:21: note: expanded from here
#define CHOSEN_DEMO lv_demo_music_list_btn_check

Seemingly it interprets the image files as demo.

@embeddedt could you take a look?

How make it work?

I have download lvgl and download lv_examples inside lvgl. But how i can run it into my raspberry pi 3?

In connecting to my raspberry pi 3 using SSH. I want run the examples, but there is nothing like a Makefile to build and run.

There is not documentation. The only decent tutorial that i found is a video that use eclipse and pc simulator.

Thanks.

for using lv_examples as library in the Arduino ecosystem please replace
#include <lv_examples/lv_demo.h>
with
#include "../lv_demo.h"
I thick this should also work in other environments.

Am I missing something I'm not sure.
When I look up the canvas examples Canvas's buffer is always 4 times bigger than the actual pixel buffer.
For example
https://github.com/lvgl/lv_examples/blob/master/src/lv_ex_widgets/lv_ex_canvas/lv_ex_canvas_2.c

line 16:
static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];

For a RGBA8888 format:
LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)
means this;
LV_IMG_BUF_SIZE_TRUE_COLOR(w, h) ((LV_COLOR_SIZE / 8) * w * h)
then w=200 h=150;
((32 / 8) * w * h) = 120 000 array elements
lv_color_t 4 bytes;
4 * 120 000 = 480 000 bytes!

Raw data should be
RGBA8888 x 150 x 200 = 120 000 bytes?

Is it a issue or not?

The definition of the img_lv_demo_music_cover_1 variable is found inside a #if LV_USE_DEMO_MUSIC block. That variable is used inside the lv_ex_img_3 example function, referenced using an extern declaration. If LV_USE_DEMO_MUSIC is not defined then the compilation fails with the following message in visual studio (for example).

Error	LNK2001	unresolved external symbol img_lv_demo_music_cover_1	lv_sim_visual_studio_sdl	C:\Users\mikef\source\repos\lv_sim_visual_studio_sdl\visual_studio_2017_sdl\lv_ex_img_3.obj	1

This could be fixed in a number of ways but I'm not sure what the vision for lv_ex_img_3 was. It seems odd that it pulls in a variable from the assets in the lv_demo_music directory tree. You could define LV_USE_DEMO_MUSIC inside the lv_ec_img_3.c file but that would seem like a misuse of that macro. Move that asset out of the lv_demo_muse and into the more general src/assets directory? Do not wrapt the definition of img_lv_demo_music_cover_1 in the #if/#endif block?

When compiling the examples with the Makefile I get an error:

lv_examples/src/lv_demo_stress/lv_demo_stress.c:246:37: error: cast between incompatible function types from ‘void (*)(lv_obj_t *, uint16_t)’ {aka ‘void (*)(struct _lv_obj_t *, short unsigned int)’} to ‘void (*)(void *, lv_anim_value_t)’ {aka ‘void (*)(void *, short int)’} [-Werror=cast-function-type]
  246 |             lv_anim_set_exec_cb(&a, (lv_anim_exec_xcb_t)lv_arc_set_end_angle);
      |                                     ^
lv_examples/src/lv_demo_stress/lv_demo_stress.c:256:37: error: cast between incompatible function types from ‘void (*)(lv_obj_t *, uint16_t)’ {aka ‘void (*)(struct _lv_obj_t *, short unsigned int)’} to ‘void (*)(void *, lv_anim_value_t)’ {aka ‘void (*)(void *, short int)’} [-Werror=cast-function-type]
  256 |             lv_anim_set_exec_cb(&a, (lv_anim_exec_xcb_t)lv_linemeter_set_angle_offset);

I got rid of it adding -Wno-cast-function-type
I am using gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

Hi,

I'm using the latest lvgl dev-7.0 branch and rework-7 branch of this repo on the lv_port_esp32 repo dev-7.0 branch.

I get the following errors while trying to compile an example application for a monochrome display.

../components/lv_examples/lv_examples/src/lv_demo_widgets/lv_demo_widgets.c: In function 'color_chg_event_cb':
../components/lv_examples/lv_examples/src/lv_demo_widgets/lv_demo_widgets.c:701:25: error: 'LV_THEME_MATERIAL_FLAG_LIGHT' undeclared (first use in this function); did you mean 'LV_THEME_MATERIAL_H'?
         uint32_t flag = LV_THEME_MATERIAL_FLAG_LIGHT;
                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
                         LV_THEME_MATERIAL_H
../components/lv_examples/lv_examples/src/lv_demo_widgets/lv_demo_widgets.c:701:25: note: each undeclared identifier is reported only once for each function it appears in
../components/lv_examples/lv_examples/src/lv_demo_widgets/lv_demo_widgets.c:702:44: error: 'LV_THEME_MATERIAL_FLAG_DARK' undeclared (first use in this function); did you mean 'LV_THEME_MATERIAL_H'?
         if(lv_switch_get_state(sw)) flag = LV_THEME_MATERIAL_FLAG_DARK;
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~
                                            LV_THEME_MATERIAL_H

Relevant part of my lv_config.h:

#define LV_USE_THEME_MONO 1

#define LV_THEME_DEFAULT_INIT lv_theme_mono_init
#define LV_THEME_DEFAULT_COLOR_PRIMARY LV_COLOR_BLACK
#define LV_THEME_DEFAULT_COLOR_SECONDARY LV_COLOR_WHITE
#define LV_THEME_DEFAULT_FLAG 0

Should the example check if the application is not using the MONO theme or the value of LV_THEME_DEFAULT_FLAG before trying to use the LV_THEME_MATERIAL_FLAG_DARK and LV_THEME_MATERIAL_FLAG_LIGHT symbols?

I thought it would be nice to convert excellent lv_port_stm32f769_disco_sw4stm32 example to the latest mbed-os 5 bare-metal.
I think I got all the initialization right but as soon as init_all_themes(0) gets called from lv_test_theme_2() the system crashes with hard fault exception, before lv_tick_inc() or lv_task_handler is executed even once.
What could be wrong? Too small stack size?

I've a basic script, based on lv_examples/lv_tutorial/1_hello_world:

/* gui.c */
#include "lvgl/lvgl.h"

int main()
{	 	 
    return 0;
}

void gui(void)
{
    lv_obj_t * scr = lv_disp_get_scr_act(NULL); /* just one line from the example */
}

I compile it with gcc gui.c and get the following error:

/tmp/cca5tFm7.o: In function `gui':
gui.c:(.text+0x2c): undefined reference to `lv_disp_get_scr_act'
collect2: error: ld returned 1 exit status

Where does lv_disp_get_scr_act() come from and what am I missing?

Thanks in advance!

lv_examples/lv_sim_emscripten are failing to build due to recent changes in LVGL which haven't been reflected in lv_examples.

https://github.com/lvgl/lv_examples/runs/2202515473

@kisvegabor Can you take a look?

As shown in the figure, i can't move the cursor to the end of line use mouse click.

This demo on website https://lvgl.io/demos, when you scroll up or down

There seems to be a wrong def. in it.

lv_test_stress_1(void) shoud be here instead of lv_test_object_1(void)

Function lv_obj_refresh_style requires now three arguments (only 2 in 7.1.0) but call to this function was not updated in
lv_demo_printer_theme.c
Also the documentation only details two parameters, though the part parameter is in the function definition.

Hi,

This issue was found while working on the lv_esp32_port repo. The hardfault seems to be triggered when using symbols with the unscii 8 font set as default (the project had all the 4 font types set to unscii 8). See here for more details.

Can symbols be used on unscii 8 font? the hardfault gets triggered with the wifi symbol.

I report this here because I think it can be sorted out on the demo code, transfer to lvgl main repo if you think it's more appropiate.

2020-06.zip

the new.mp4 is the lastest repo, the four desktop items' backgroud render is not smooth as the old one.

I can't compile the examples with lv_btnm_set_one_toggle in lv_test_theme_1. It seems like the function doesn't exist in dev-6.0?

Hello,

The file is missing. As a result, "lv_test_theme" won't compile.

Best Regards

TODO: There is not releases same as https://github.com/littlevgl/lvgl/releases

hi,I use the following code,An error occurred,maybe 《lv_fs_file_t * file_p》 Parameter transfer error
void test(void)
{
lv_obj_t *img;
img = lv_img_create(lv_scr_act(), NULL);
lv_img_set_src(img, "c:/1.bin");
}



but i used gif testcode,no error occurred;
void gif_demo(void)
{
lv_obj_t * img = lv_gif_create_from_file(lv_scr_act(), "c:/1.gif");

}

I USE LVGL "LV_EXAMPLES"&"LVGL_NEW_FS_API"&"lv_fs_if"&"lv_lib_gif"

Hi there! I am new to the use of this library, and I am very excited to start it, I loved how it is made.
I want to connect a STM32 Nucleo F746ZG board, it is a Cortex M7 processor, with a display with 800x600px SSD1963 driver, using parallel connection. I am a little dizzy in the method of configuring the MCU pins for each data. In the configuration definition, is the data port a complete port? Thank you

/*------------------
 *  Parallel port
 *-----------------*/
#define LV_DRV_DISP_PAR_CS(val)          /*par_cs_set(val)*/   /*Set the Parallel port's Chip select to 'val'*/
#define LV_DRV_DISP_PAR_SLOW             /*par_slow()*/        /*Set low speed on the parallel port*/
#define LV_DRV_DISP_PAR_FAST             /*par_fast()*/        /*Set high speed on the parallel port*/
#define LV_DRV_DISP_PAR_WR_WORD(data)    /*par_wr(data)*/      /*Write a word to the parallel port*/
#define LV_DRV_DISP_PAR_WR_ARRAY(adr, n) /*par_wr_mem(adr,n)*/ /*Write 'n' bytes to Parallel ports from 'adr'*/

This seems to be related to deleting the mbox in mbox_action.

I'm running this under mbed but not multi-threading.
I'm using the NUCLEO-F446RE dev board with this display connected in 16-bit parallel.
lv_tic_inc and lv_task_handler are called from the main loop context, not from a timer.
I can get it to not crash if I hide the mbox instead of deleting it in mbox_action.

In mbox_action, if I call

lv_obj_set_hidden(lv_obj_get_parent(mbox), true); 

instead of

lv_obj_del(lv_obj_get_parent(mbox));

The app does not crash.
If I create a variable to save the mbox on creation

static lv_obj_t * mbox = NULL;

Then I can change enable_action to delete the 'old' mbox and create a new one. This works fine.

static lv_res_t enable_action(lv_obj_t * btn)
{
   /*If the butto nsi released the show message box to be sure about the Enable*/
   if(lv_btn_get_state(btn) == LV_BTN_STATE_REL) {
      if (mbox != NULL) {
         printf("mbox existed previously, deleting prior to creating new.\r\n");
         lv_obj_del(lv_obj_get_parent(mbox));    /*Delete the black background. (it will delete the mbox too)*/
      }
...
      /*Create a message box*/
      //lv_obj_t * mbox = lv_mbox_create(bg, NULL);
      mbox = lv_mbox_create(bg, NULL);

Based on the crash report and the memory map, it seems to be crashing in memcpy after the object is deleted.

Is it possible that somehow a touch is trying to be delivered to the deleted mbox and deleting it later is ok?

Is possible to build some demo to test dev-7.0 ?

It looks like lv_demo_music_main.c has been commented out in its entirety and any occurrence of the word signal has been replaced with the string "Call the ancestor's event handler".

Was this intentional?

On the last release this error happened:
https://github.com/lvgl/lv_examples/actions/runs/367900030

I've fixed it here but obviously, it's not the best way. 🙁
789422b

need one line here

the origin of the three hands is not in the same when x/y is other than 0.
the scale is not centered wrt to background circle.

Awesome project! Thank you for your work.
I am on Ubuntu 16.04 platform. I want to build the examples without using IDEs.
Is it possible?
I need an example Makefile
Regards.

https://github.com/littlevgl/lv_examples/blob/2b3c4004cb1d8060f6a04172b038131cccd89b07/lv_tests/lv_test_theme/lv_test_theme_2.c#L213

Would this not be better ?

static void bar_set_value(lv_obj_t* bar, int16_t value)
{
    lv_bar_set_value(bar, value, LV_ANIM_OFF);
}
    a.exec_cb = bar_set_value;

As things are, each animation step could randomly spawn another animation instance ?

lv_draw_vbasic.c:448 lv_color_t px_color = (lv_color_t) * ((lv_color_t *)&map_p[(uint32_t)col * px_size_byte]);

causes a fault

Error[Pe119]: cast to type "lv_color_t" is not allowed lvgl\lv_draw\lv_draw_vbasic.c 448

with IAR ICC compiler.

Removing the outer cast (which seems to be unnessecary) solves the issue:

lv_color_t px_color = * ((lv_color_t *)&map_p[(uint32_t)col * px_size_byte]);

In the root component.mk, shouldn't the lines:
lv_test/lv_test_theme
lv_test/lv_test_group
lv_test/lv_test_group
be:
lv_tests/lv_test_theme
lv_tests/lv_test_group
lv_tests/lv_test_group \

I haven't really delved into makefiles before, not really ever had to, so apologies if I am missing something.

Here is my trace:

[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:177:lv_init] -- lv_init started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:236:lv_init] -- lv_init ready
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:278:lv_obj_create] -- Screen create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:278:lv_obj_create] -- Screen create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:278:lv_obj_create] -- Screen create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_widgets/lv_label.c:78:lv_label_create] -- label create started
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[INFO]  [../thirdparty/lvgl/src/lv_widgets/lv_label.c:166:lv_label_create] -- label created
[TRACE] [../thirdparty/lvgl/src/lv_widgets/lv_label.c:78:lv_label_create] -- label create started
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[INFO]  [../thirdparty/lvgl/src/lv_widgets/lv_label.c:166:lv_label_create] -- label created
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:94:lv_anim_start] -- animation create started
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:121:lv_anim_start] -- animation created
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:94:lv_anim_start] -- animation create started
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:121:lv_anim_start] -- animation created
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:94:lv_anim_start] -- animation create started
[TRACE] [../thirdparty/lvgl/src/lv_misc/lv_anim.c:121:lv_anim_start] -- animation created
[TRACE] [../thirdparty/lvgl/src/lv_core/lv_obj.c:310:lv_obj_create] -- Object create started
[INFO]  [../thirdparty/lvgl/src/lv_core/lv_obj.c:469:lv_obj_create] -- Object create ready
[WARN]  [../thirdparty/lvgl/src/lv_misc/lv_mem.c:208:lv_mem_alloc] -- Couldn't allocate memory
[WARN]  [../thirdparty/lvgl/src/lv_misc/lv_mem.c:323:lv_mem_realloc] -- Couldn't allocate memory

I'm well under the memory limit of my MCU. I'm using a same54n19a which has 512KB of flash and 192KB of ram. Here is my memory usage:

   text	   data	    bss	    dec	    hex	filename
 242140	   2232	  64760	 309132	  4b78c	rev_0.elf

Any ideas why the benchmark won't run?

@kisvegabor @embeddedt

Some branches, are not being used nor updated (test/no-tp and rework) can we delete them?

and merge rework-7 into dev-7.0?

When the message box is opened the emulated keyboard is disabled, which does not really make sense.

@embeddedt
I've released v7.6.1 but now the live examples are not working. It shows 404 error instead of the examples and I can't find the html files anywhere.

BTW, if the html files are added into the gh-pages branch how can we manage more branches (other than the master)?

Hello,

I'm working on rework-7 branch, tried to bring-up 7.0 tests. I came across issue with lvgl.h include paths - all demos, examples and assets are using:

#include "lvgl/lvgl.h"

This doesn't follow style used in rest of the framework and breaks build. Shouldn't be there a construction like:

#if defined(LV_CONF_INCLUDE_SIMPLE)
#include "lvgl.h"
#else
#include "lvgl/lvgl.h"
#endif 

or is it a problem in my integration only? I use LV_CONF_INCLUDE_SIMPLE=1 and LV_EX_CONF_INCLUDE_SIMPLE=1 for work.

Jozef