GIF Decoder¶

GIF Decoder is an LVGL extension that enables you to use GIF images in your LVGL UI.

The implementation uses the AnimatedGIF library.

Usage¶

Once enabled in lv_conf.h by setting LV_USE_GIF to 1, lv_gif_create(parent) can be used to create a gif widget.

Set the color format of the gif framebuffer with lv_gif_set_color_format(widget, color_format). Use LV_COLOR_FORMAT_ARGB8888 for gifs with transparency. It is set to LV_COLOR_FORMAT_ARGB8888 by default. Significant RAM can be saved by using a smaller color format. A color format conversion can be saved during rendering if the color format matches the display color format. This function can be called before lv_gif_set_src() to prevent the initial default ARGB8888 framebuffer from being allocated.

The supported color formats are:

lv_gif_set_src(widget, src) works very similarly to lv_image_set_src(). As source, it also accepts images as variables (lv_image_dsc_t) or files.

Converting GIF Files to C Arrays¶

Converting GIF files to an array of bytes is not supported in the online image converter since LVGL v9.0. However, there is still a way to do it through the ./scripts/LVGLImage.py Python script. This command line:

python  ./scripts/LVGLImage.py  --cf RAW  --ofmt C  -o .  --name my_gif_image_array  input.gif

will produce all the bytes from the input.gif in unaltered form in a C array, ready to use in this code:

LV_IMAGE_DECLARE(my_gif_image_array);
lv_obj_t * img;

img = lv_gif_create(lv_screen_active());
lv_gif_set_color_format(img, LV_COLOR_FORMAT_ARGB8888);
lv_gif_set_src(img, &my_gif_image_array);

Using GIF Images from Files¶

Example:

lv_gif_set_src(widget, "S:path/to/example.gif");

Note that, a file system driver needs to be registered to open images from files. To do so, follow the instructions in File System (lv_fs_drv).

Memory Requirements¶

To decode and display a GIF animation ~25 kB of RAM is needed plus (color format pixel size + 1) × image width × image height. RGB565 has a pixel size of 2, RGB888 has a pixel size of 3, and ARGB8888 has a pixel size of 4.

Example¶

Open a GIF image from file and variable¶

#include "../../lv_examples.h"
#if LV_USE_GIF && LV_BUILD_EXAMPLES

/**
 * Open a GIF image from a file and a variable
 */
void lv_example_gif_1(void)
{
    LV_IMAGE_DECLARE(img_bulb_gif);
    lv_obj_t * img;

    img = lv_gif_create(lv_screen_active());
    lv_gif_set_color_format(img, LV_COLOR_FORMAT_ARGB8888);
    lv_gif_set_src(img, &img_bulb_gif);
    lv_obj_align(img, LV_ALIGN_LEFT_MID, 20, 0);

    img = lv_gif_create(lv_screen_active());
    lv_gif_set_color_format(img, LV_COLOR_FORMAT_ARGB8888);
    /* Assuming a File system is attached to letter 'A'
     * E.g. set LV_USE_FS_STDIO 'A' in lv_conf.h */
    lv_gif_set_src(img, "A:lvgl/examples/libs/gif/bulb.gif");
    lv_obj_align(img, LV_ALIGN_RIGHT_MID, -20, 0);
}

#endif

API¶

lv_gif.h