/** * @file lv_hello_world.c * */ /* * The basic building blocks (components or widgets) in LittlevGL are the graphical objects. * For example: * - Buttons * - Labels * - Charts * - Sliders etc * * In this part you can learn the basics of the objects like creating, positioning, sizing etc. * You will also meet some different object types and their attributes. * * Regardless to the object type the 'lv_obj_t' variable type is used stores the objects * and you can refer to an object with an lv_obj_t pointer (lv_obj_t *) * * INHERITANCE * ------------- * Similarly to object oriented languages some kind of inheritance is used * among the object types. * * Every object is derived from the 'Basic object'. (lv_obj) * * The types are backward compatible which means a type can use all the ancestor * attributes/functions too. * * For example a 'Button' is derived from 'Container' which is derived from 'Basic objects'. * Therefore a button can use container attributes like automatically fit size to the content. * * PARENT-CHILD * ------------- * A parent can be considered as the container of its children. * Every object has exactly one parent object (except screens). * A parent can have unlimited number of children. * There is no limitation for the type of the parent. * * The children are visible only on their parent. The parts outside will be cropped (not displayed) * * If the parent is moved the children will be moved with it. * * The earlier created object (and its children) will drawn earlier. * Using this layers can be built. * * LEARN MORE * ------------- * - General overview: http://www.gl.littlev.hu/objects * - Detailed description of types: http://www.gl.littlev.hu/object-types * * NOTES * ------------- * - Be sure 'LV_OBJ_FREE_P' is enabled in 'lv_conf.h' */ /********************* * INCLUDES *********************/ #include "obj_usage.h" #if USE_LV_EXAMPLE != 0 #include "lvgl/lvgl.h" /********************* * DEFINES *********************/ /********************** * TYPEDEFS **********************/ /********************** * STATIC PROTOTYPES **********************/ static lv_action_res_t btn_rel_action(lv_obj_t * btn, lv_dispi_t * dispi); static lv_action_res_t ddlist_action(lv_obj_t * ddlist, lv_dispi_t * dispi); /********************** * STATIC VARIABLES **********************/ /********************** * MACROS **********************/ /********************** * GLOBAL FUNCTIONS **********************/ /** * Initialize the Object usage example */ void lv_obj_usage_init(void) { /******************** * CREATE A SCREEN *******************/ /* Create a new screen and load it * Screen can be created from any type object * Now a Page is used which is an objects with scrollable content*/ lv_obj_t * scr = lv_page_create(NULL, NULL); lv_scr_load(scr); /**************** * ADD A TITLE ****************/ lv_obj_t * label = lv_label_create(scr, NULL); /*First parameters (scr) is the parent*/ lv_label_set_text(label, "Object usage demo"); /*Set the text*/ lv_obj_set_x(label, 50); /*Labels are inherited from Basic object so 'lv_obj_...' functions can be used*/ /******************** * CREATE TWO BUTTONS ********************/ /*Create a button*/ lv_obj_t * btn1 = lv_btn_create(lv_scr_act(), NULL); /*Create a button on the currently loaded screen*/ lv_btn_set_rel_action(btn1, btn_rel_action); /*Set function to call when the button is released*/ lv_obj_align(btn1, label, LV_ALIGN_OUT_BOTTOM_LEFT, 0, 20); /*Align below the label*/ label = lv_label_create(btn1, NULL); /*Create a label on the button (the 'label' variable can be reused)*/ lv_label_set_text(label, "Button 1"); /*Copy the previous button*/ lv_obj_t * btn2 = lv_btn_create(lv_scr_act(), btn1); /*Second parameter is an object to copy*/ lv_obj_align(btn2, btn1, LV_ALIGN_OUT_RIGHT_MID, 50, 0);/*Align next to the prev. button.*/ label = lv_label_create(btn2, NULL); /*Create a label on the button*/ lv_label_set_text(label, "Button 2"); /**************** * ADD A SLIDER ****************/ /*Add a slider (inheritance: lv_obj -> lv_bar -> lv_slider)*/ lv_obj_t * slider = lv_slider_create(scr, NULL); /*Create a slider*/ lv_obj_set_size(slider, lv_obj_get_width(lv_scr_act()) / 3, LV_DPI / 3); /*Set the size*/ lv_obj_align(slider, btn1, LV_ALIGN_OUT_BOTTOM_LEFT, 0, 20); /*Align below the first button*/ lv_bar_set_value(slider, 30); /*Slider is a 'bar' so set its value like a 'bar'*/ /*********************** * ADD A DROP DOWN LIST ************************/ lv_obj_t * ddlist = lv_ddlist_create(lv_scr_act(), NULL); lv_obj_align(ddlist, slider, LV_ALIGN_OUT_RIGHT_TOP, 20, 0); /*Align next to the slider*/ lv_obj_set_free_p(ddlist, slider); /*Save the pointer of the slider in the ddlist (used in 'ddlist_action()')*/ lv_ddlist_set_options_str(ddlist, "None\nLittle\nHalf\nA lot\nAll"); /*Set the options*/ lv_ddlist_set_action(ddlist, ddlist_action); /*Set function to call on new option choose*/ lv_obj_set_top(ddlist, true); /*Enable the drop down list always be on the top*/ /**************** * CREATE A CHART ****************/ lv_obj_t * chart = lv_chart_create(lv_scr_act(), NULL); /*Craete the chart*/ lv_obj_set_size(chart, lv_obj_get_width(scr) / 2, lv_obj_get_width(scr) / 4); /*Set the size*/ lv_obj_align(chart, slider, LV_ALIGN_OUT_BOTTOM_LEFT, 0, 20); /*Align below the slider*/ lv_chart_set_dl_width(chart, 3 * LV_DOWNSCALE); /*Set the line width (LV_DOWNSCALE compensates anti-aliasing if enabled)*/ /*Add a RED data line and set some points*/ lv_chart_dl_t * dl1 = lv_chart_add_data_line(chart, COLOR_RED); lv_chart_set_next(chart, dl1, 10); lv_chart_set_next(chart, dl1, 25); lv_chart_set_next(chart, dl1, 45); lv_chart_set_next(chart, dl1, 80); /*Add a BLUE data line and set some points*/ lv_chart_dl_t * dl2 = lv_chart_add_data_line(chart, COLOR_MAKE(0x40, 0x70, 0xC0)); lv_chart_set_next(chart, dl2, 10); lv_chart_set_next(chart, dl2, 25); lv_chart_set_next(chart, dl2, 45); lv_chart_set_next(chart, dl2, 80); lv_chart_set_next(chart, dl2, 75); lv_chart_set_next(chart, dl2, 505); } /********************** * STATIC FUNCTIONS **********************/ /** * Called when a button is released * @param btn pointer to the released button * @param dispi pointer to caller display input (e.g. touchpad) * @return LV_ACTION_RES_OK because the object is not deleted in this function */ static lv_action_res_t btn_rel_action(lv_obj_t * btn, lv_dispi_t * dispi) { /*Increase the button width*/ cord_t width = lv_obj_get_width(btn); lv_obj_set_width(btn, width + 20); return LV_ACTION_RES_OK; } /** * Called when a new option is chosen in the drop down list * @param ddlist pointer to the drop down list * @param dispi pointer to caller display input (e.g. touchpad) * @return LV_ACTION_RES_OK because the object is not deleted in this function */ static lv_action_res_t ddlist_action(lv_obj_t * ddlist, lv_dispi_t * dispi) { uint16_t opt = lv_ddlist_get_selected(ddlist); /*Get the id of selected option*/ lv_obj_t * slider = lv_obj_get_free_p(ddlist); /*Get the saved slider*/ lv_bar_set_value(slider, (opt * 100) / 4); /*Modify the slider value according to the selection*/ return LV_ACTION_RES_OK; } #endif /*USE_LV_EXAMPLE != 0*/