This project experiments with LVGL and the VEX vision sensor. Debugging the vision sensor is difficult without an interface that can see what the vision sensor sees. Thus, I used LVGL to display "blobs" of color from the vision sensor.
I also experimented with gif-pros, an open-source VEX library for displaying gifs.
This project uses PROS. Download at your own risk.
There are 3 primary functions I used for LVGL (lines 79-135 in, main.cpp). Much of the code is inspired by this tutorial, by Dennis Ranish from Vexmen team 81K.
lv_obj_t * createBtn(lv_obj_t * parent, lv_coord_t x, lv_coord_t y, lv_coord_t width, lv_coord_t height,
int id, const char * title)
{
lv_obj_t * btn = lv_btn_create(parent, NULL);
lv_obj_set_pos(btn, x, y);
lv_obj_set_size(btn, width, height);
lv_obj_set_free_num(btn, id);
lv_obj_t * label = lv_label_create(btn, NULL);
lv_label_set_text(label, title);
lv_obj_align(label, NULL, LV_ALIGN_IN_TOP_MID, 0, 5);
return btn;
}
lv_style_t * createBtnStyle(lv_style_t * copy, lv_color_t rel, lv_color_t pr,
lv_color_t tglRel, lv_color_t tglPr, lv_color_t tglBorder, lv_color_t textColor, lv_obj_t * btn)
{
lv_style_t * btnStyle = (lv_style_t *)malloc(sizeof(lv_style_t) * 4);
for(int i = 0; i < 4; i++) lv_style_copy(&btnStyle[i], copy);
btnStyle[0].body.main_color = rel;
btnStyle[0].body.grad_color = rel;
btnStyle[0].text.color = textColor;
btnStyle[1].body.main_color = pr;
btnStyle[1].body.grad_color = pr;
btnStyle[1].text.color = textColor;
btnStyle[2].body.main_color = tglRel;
btnStyle[2].body.grad_color = tglRel;
btnStyle[2].body.border.width = 2;
btnStyle[2].body.border.color = tglBorder;
btnStyle[2].text.color = textColor;
btnStyle[3].body.main_color = tglPr;
btnStyle[3].body.grad_color = tglPr;
btnStyle[3].body.border.width = 2;
btnStyle[3].body.border.color = tglBorder;
btnStyle[3].text.color = textColor;
lv_btn_set_style(btn, LV_BTN_STYLE_REL, &btnStyle[0]);
lv_btn_set_style(btn, LV_BTN_STYLE_PR, &btnStyle[1]);
lv_btn_set_style(btn, LV_BTN_STYLE_TGL_REL, &btnStyle[2]);
lv_btn_set_style(btn, LV_BTN_STYLE_TGL_PR, &btnStyle[3]);
return btnStyle;
}
void setBtnStyle(lv_style_t * btnStyle, lv_obj_t * btn)
{
lv_btn_set_style(btn, LV_BTN_STYLE_REL, &btnStyle[0]);
lv_btn_set_style(btn, LV_BTN_STYLE_PR, &btnStyle[1]);
lv_btn_set_style(btn, LV_BTN_STYLE_TGL_REL, &btnStyle[2]);
lv_btn_set_style(btn, LV_BTN_STYLE_TGL_PR, &btnStyle[3]);
}To display feedback from the vision sensor, I continuously updated the dimensions and locations of a box in a loop.
while(true) {
//background
background = lv_btn_create(lv_scr_act(), NULL); //create button, lv_scr_act() is deafult screen object
lv_obj_set_free_num(background, 0); //set button is to 0
lv_obj_set_style(background, &backgroundStyle);
lv_obj_set_size(background, LVGL_SCREEN_WIDTH, LVGL_SCREEN_HEIGHT); //set the button size
lv_obj_align(background, NULL, LV_ALIGN_CENTER, 0, 0); //set the position to top mid
pros::vision_object_s_t rtn = vision.get_by_size(0);
myButton = lv_btn_create(lv_scr_act(), NULL); //create button, lv_scr_act() is deafult screen object
lv_obj_set_free_num(myButton, 0); //set button is to 0
lv_obj_set_style(myButton, &style);
double visionW = (double)rtn.width / (VISION_FOV_WIDTH/2) * (LVGL_SCREEN_WIDTH/2);
double visionH = (double)rtn.height / (VISION_FOV_HEIGHT/2) * (LVGL_SCREEN_HEIGHT/2);
lv_obj_set_size(myButton, visionW, visionH); //set the button size
double visionX = (double)rtn.x_middle_coord / (VISION_FOV_WIDTH/2) * (LVGL_SCREEN_WIDTH/2);
double visionY = (double)rtn.y_middle_coord / (VISION_FOV_HEIGHT/2) * (VISION_FOV_HEIGHT/2);
lv_obj_align(myButton, NULL, LV_ALIGN_CENTER, visionX, visionY); //set the position to top mid
pros::delay(40); // fat delay to minimize lag
}