Using Images

The simplest way to use an image in LVGL is to display it with an Image (lv_image) Widget:

lv_obj_t * icon = lv_image_create(lv_screen_active());

/* From variable */
lv_image_set_src(icon, &my_img_dsc);

/* From file */
lv_image_set_src(icon, "S:my_icon.bin");

/* From Unicode string */
lv_image_set_src(icon, LV_SYMBOL_BATTERY_FULL);

If the image was converted to a variable with the online or offline converter, you should use LV_IMAGE_DECLARE(my_img_dsc) to declare the image in the file where you want to use it.

Examples

Image from variable and symbol

C code  

 View on GitHub

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

void lv_example_image_1(void)
{
    LV_IMAGE_DECLARE(img_cogwheel_argb);
    lv_obj_t * img1 = lv_image_create(lv_screen_active());
    lv_image_set_src(img1, &img_cogwheel_argb);
    lv_obj_align(img1, LV_ALIGN_CENTER, 0, 0);

    lv_obj_t * img2 = lv_image_create(lv_screen_active());
    lv_image_set_src(img2, LV_SYMBOL_OK "Accept");
    lv_obj_align_to(img2, img1, LV_ALIGN_OUT_BOTTOM_MID, 0, 20);
}

#endif

---

Image recoloring

C code  

 View on GitHub

#include "../../lv_examples.h"
#if LV_USE_IMAGE && LV_USE_SLIDER && LV_BUILD_EXAMPLES

static lv_obj_t * create_slider(lv_color_t color);
static void slider_event_cb(lv_event_t * e);

static lv_obj_t * red_slider, * green_slider, * blue_slider, * intense_slider;
static lv_obj_t * img1;

/**
 * Demonstrate runtime image re-coloring
 */
void lv_example_image_2(void)
{
    /*Create 4 sliders to adjust RGB color and re-color intensity*/
    red_slider = create_slider(lv_palette_main(LV_PALETTE_RED));
    green_slider = create_slider(lv_palette_main(LV_PALETTE_GREEN));
    blue_slider = create_slider(lv_palette_main(LV_PALETTE_BLUE));
    intense_slider = create_slider(lv_palette_main(LV_PALETTE_GREY));

    lv_slider_set_value(red_slider, LV_OPA_20, LV_ANIM_OFF);
    lv_slider_set_value(green_slider, LV_OPA_90, LV_ANIM_OFF);
    lv_slider_set_value(blue_slider, LV_OPA_60, LV_ANIM_OFF);
    lv_slider_set_value(intense_slider, LV_OPA_50, LV_ANIM_OFF);

    lv_obj_align(red_slider, LV_ALIGN_LEFT_MID, 25, 0);
    lv_obj_align_to(green_slider, red_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);
    lv_obj_align_to(blue_slider, green_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);
    lv_obj_align_to(intense_slider, blue_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);

    /*Now create the actual image*/
    LV_IMAGE_DECLARE(img_cogwheel_argb);
    img1 = lv_image_create(lv_screen_active());
    lv_image_set_src(img1, &img_cogwheel_argb);
    lv_obj_align(img1, LV_ALIGN_RIGHT_MID, -20, 0);

    lv_obj_send_event(intense_slider, LV_EVENT_VALUE_CHANGED, NULL);
}

static void slider_event_cb(lv_event_t * e)
{
    LV_UNUSED(e);

    /*Recolor the image based on the sliders' values*/
    lv_color_t color  = lv_color_make((uint8_t)lv_slider_get_value(red_slider),
                                      (uint8_t)lv_slider_get_value(green_slider),
                                      (uint8_t)lv_slider_get_value(blue_slider));
    lv_opa_t intense = (lv_opa_t)lv_slider_get_value(intense_slider);
    lv_obj_set_style_image_recolor_opa(img1, intense, 0);
    lv_obj_set_style_image_recolor(img1, color, 0);
}

static lv_obj_t * create_slider(lv_color_t color)
{
    lv_obj_t * slider = lv_slider_create(lv_screen_active());
    lv_slider_set_range(slider, 0, 255);
    lv_obj_set_size(slider, 10, 200);
    lv_obj_set_style_bg_color(slider, color, LV_PART_KNOB);
    lv_obj_set_style_bg_color(slider, lv_color_darken(color, LV_OPA_40), LV_PART_INDICATOR);
    lv_obj_add_event_cb(slider, slider_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    return slider;
}

#endif

---

Rotate and zoom

C code  

 View on GitHub

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

static void set_angle(void * img, int32_t v)
{
    lv_image_set_rotation((lv_obj_t *)img, v);
}

static void set_scale(void * img, int32_t v)
{
    lv_image_set_scale((lv_obj_t *)img, v);
}

/**
 * Show transformations (zoom and rotation) using a pivot point.
 */
void lv_example_image_3(void)
{
    LV_IMAGE_DECLARE(img_cogwheel_argb);

    /*Now create the actual image*/
    lv_obj_t * img = lv_image_create(lv_screen_active());
    lv_image_set_src(img, &img_cogwheel_argb);
    lv_obj_align(img, LV_ALIGN_CENTER, 50, 50);
    lv_image_set_pivot(img, 0, 0);    /*Rotate around the top left corner*/

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_var(&a, img);
    lv_anim_set_exec_cb(&a, set_angle);
    lv_anim_set_values(&a, 0, 3600);
    lv_anim_set_duration(&a, 5000);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);

    lv_anim_set_exec_cb(&a, set_scale);
    lv_anim_set_values(&a, 128, 256);
    lv_anim_set_reverse_duration(&a, 3000);
    lv_anim_start(&a);
}

#endif

---

Image offset and styling

C code  

 View on GitHub

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

static void ofs_y_anim(void * img, int32_t v)
{
    lv_image_set_offset_y((lv_obj_t *)img, v);
}

/**
 * Image styling and offset
 */
void lv_example_image_4(void)
{
    LV_IMAGE_DECLARE(img_skew_strip);

    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_bg_color(&style, lv_palette_main(LV_PALETTE_YELLOW));
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_image_recolor_opa(&style, LV_OPA_COVER);
    lv_style_set_image_recolor(&style, lv_color_black());

    lv_obj_t * img = lv_image_create(lv_screen_active());
    lv_obj_add_style(img, &style, 0);
    lv_image_set_src(img, &img_skew_strip);
    lv_obj_set_size(img, 150, 100);
    lv_obj_center(img);

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_var(&a, img);
    lv_anim_set_exec_cb(&a, ofs_y_anim);
    lv_anim_set_values(&a, 0, 100);
    lv_anim_set_duration(&a, 3000);
    lv_anim_set_reverse_duration(&a, 500);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);

}

#endif

---

Open a BMP image from file

C code  

 View on GitHub

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

/**
 * Open a BMP file from a file
 */
void lv_example_bmp_1(void)
{
    lv_obj_t * img = lv_image_create(lv_screen_active());
    /* Assuming a File system is attached to letter 'A'
     * E.g. set LV_USE_FS_STDIO 'A' in lv_conf.h */
    lv_image_set_src(img, "A:lvgl/examples/libs/bmp/example_32bit.bmp");
    lv_obj_center(img);

}

#endif

---

Open a PNG image from file and variable

C code  

 View on GitHub

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

#if LV_USE_LIBPNG

/**
 * Open a PNG image from a file
 */
void lv_example_libpng_1(void)
{
    LV_IMAGE_DECLARE(img_png_demo);
    lv_obj_t * img;

    img = lv_image_create(lv_screen_active());
    lv_image_set_src(img, &img_png_demo);
    lv_obj_align(img, LV_ALIGN_LEFT_MID, 10, 0);

    img = lv_image_create(lv_screen_active());
    /* Assuming a File system is attached to letter 'A'
     * E.g. set LV_USE_FS_STDIO 'A' in lv_conf.h */
    lv_image_set_src(img, "A:lvgl/examples/libs/libpng/png_demo.png");
    lv_obj_align(img, LV_ALIGN_RIGHT_MID, -10, 0);
}

#else

void lv_example_libpng_1(void)
{
    lv_obj_t * label = lv_label_create(lv_screen_active());
    lv_label_set_text(label, "LibPNG is not installed");
    lv_obj_center(label);
}

#endif

#endif

---