App:Library:LVGL:docs:3rd party libraries:BMP decoder

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2022年6月29日 (水) 15:13時点におけるTakashi (トーク | 投稿記録)による版
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https://docs.lvgl.io/8.2/libs/bmp.html

BMP decoder

英文 自動翻訳

This extension allows the use of BMP images in LVGL. This implementation uses bmp-decoder library. The pixels are read on demand (not the whole image is loaded) so using BMP images requires very little RAM.

If enabled in lv_conf.h by LV_USE_BMP LVGL will register a new image decoder automatically so BMP files can be directly used as image sources. For example:

lv_img_set_src(my_img, "S:path/to/picture.bmp");

Note that, a file system driver needs to registered to open images from files. Read more about it here or just enable one in lv_conf.h with LV_USE_FS_...


Limitations

英文 自動翻訳
  • Only BMP files are supported and BMP images as C array (lv_img_dsc_t) are not. It's because there is no practical differences between how the BMP files and LVGL's image format stores the image data.
  • BMP files can be loaded only from file. If you want to store them in flash it's better to convert them to C array with LVGL's image converter.
  • The BMP files color format needs to match with LV_COLOR_DEPTH. Use GIMP to save the image in the required format. Both RGB888 and ARGB888 works with LV_COLOR_DEPTH 32
  • Palette is not supported.
  • Because not the whole image is read in can not be zoomed or rotated.


Example

英文 自動翻訳

Open a BMP image from file

LVGL docs others gridnav 03.png


API

英文 自動翻訳

Functions

void lv_bmp_init(void)



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