Rotate label via code

How to
1

Hello,

I am looking to achieve a “screen rotation” feature, via code. I can rotate images with “lv_img_set_angle(img, angle)”, but not a label.

Is there a way to rotate a label object?
Any ideas are much appreciated, as I would avoid building and maintaining 2 totally separate projects.

Thank you!
Marius

2

SLS now uses LVGL 8.2 but LVGL 8.3 can already rotate any widget. See here.

So you can update LVGL to v8.3.1 manually and add the rotation setting from code.

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3

This is great, I will give it a go. Will come back with my findings.
Thank you very much for your help, I really appreciate it.

Marius

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4

Hello, I have managed to install 8.3.1 (verified with lvgl arduino example and indeed the version is good).
However, I have tried 2 methods of transforming the angle (rotating) of both labels and images, like so:

Method 1

static lv_style_t style;
lv_style_init(&style);
lv_style_set_transform_angle(&style, 300);
lv_obj_add_style(ui_myImage, &style, 0);

Method 2

lv_obj_set_style_transform_angle(ui_myLabel, 150, 0);

Nothing seems to work, the widgets/objects disappear.
I have also tried some copy/paste code from the docs, the obj is not rendering, doesn’t show up.

Any ideas? @kisvegabor

Thank you!
Marius

5

Probably you also need to enable LV_COLOR_SCREEN_TRANSP in lv_conf.h.

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6

That was it! It’s written in the comments there that LV_COLOR_SCREEN_TRANSP = 1 is needed for transform actions - I didn’t notice.

I was able to rotate a label with:

lv_obj_set_style_transform_angle(ui_myLabel, 900, 0);

Thank you!
Marius

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7

Great! Thank for the feedback!

1 Like