一、前言
这里将介绍一系列控件，了解后就可以开始基础的开发了。
二、示例
1、Base Obj（基础对象）
1.1、示例1
#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES
void lv_example_obj_1(void)
{
lv_obj_t * obj1;
obj1 = lv_obj_create(lv_screen_active());
lv_obj_set_size(obj1, 100, 50);
lv_obj_align(obj1, LV_ALIGN_CENTER, -60, -30);
static lv_style_t style_shadow;
lv_style_init(&style_shadow);
lv_style_set_shadow_width(&style_shadow, 10);
lv_style_set_shadow_spread(&style_shadow, 5);
lv_style_set_shadow_color(&style_shadow, lv_palette_main(LV_PALETTE_BLUE));
lv_obj_t * obj2;
obj2 = lv_obj_create(lv_screen_active());
lv_obj_add_style(obj2, &style_shadow, 0);
lv_obj_align(obj2, LV_ALIGN_CENTER, 60, 30);
}
#endif
1.2、示例2
#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES
static void drag_event_handler(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
lv_indev_t * indev = lv_indev_active();
if(indev == NULL) return;
lv_point_t vect;
lv_indev_get_vect(indev, &vect);
int32_t x = lv_obj_get_x_aligned(obj) + vect.x;
int32_t y = lv_obj_get_y_aligned(obj) + vect.y;
lv_obj_set_pos(obj, x, y);
}
/**
* Make an object draggable.
*/
void lv_example_obj_2(void)
{
lv_obj_t * obj;
obj = lv_obj_create(lv_screen_active());
lv_obj_set_size(obj, 150, 100);
lv_obj_add_event_cb(obj, drag_event_handler, LV_EVENT_PRESSING, NULL);
lv_obj_t * label = lv_label_create(obj);
lv_label_set_text(label, "Drag me");
lv_obj_center(label);
}
#endif
2、Arc（圆弧）
2.1、示例1
#include "../../lv_examples.h"
#if LV_USE_ARC && LV_BUILD_EXAMPLES
static void value_changed_event_cb(lv_event_t * e);
void lv_example_arc_1(void)
{
lv_obj_t * label = lv_label_create(lv_screen_active());
/*Create an Arc*/
lv_obj_t * arc = lv_arc_create(lv_screen_active());
lv_obj_set_size(arc, 150, 150);
lv_arc_set_rotation(arc, 135);
lv_arc_set_bg_angles(arc, 0, 270);
lv_arc_set_value(arc, 10);
lv_obj_center(arc);
lv_obj_add_event_cb(arc, value_changed_event_cb, LV_EVENT_VALUE_CHANGED, label);
/*Manually update the label for the first time*/
lv_obj_send_event(arc, LV_EVENT_VALUE_CHANGED, NULL);
}
static void value_changed_event_cb(lv_event_t * e)
{
lv_obj_t * arc = lv_event_get_target(e);
lv_obj_t * label = lv_event_get_user_data(e);
lv_label_set_text_fmt(label, "%" LV_PRId32 "%%", lv_arc_get_value(arc));
/*Rotate the label to the current position of the arc*/
lv_arc_rotate_obj_to_angle(arc, label, 25);
}
#endif
2.2、示例2
#include "../../lv_examples.h"
#if LV_USE_ARC && LV_BUILD_EXAMPLES
static void set_angle(void * obj, int32_t v)
{
lv_arc_set_value(obj, v);
}
/**
* Create an arc which acts as a loader.
*/
void lv_example_arc_2(void)
{
/*Create an Arc*/
lv_obj_t * arc = lv_arc_create(lv_screen_active());
lv_arc_set_rotation(arc, 270);
lv_arc_set_bg_angles(arc, 0, 360);
lv_obj_remove_style(arc, NULL, LV_PART_KNOB); /*Be sure the knob is not displayed*/
lv_obj_remove_flag(arc, LV_OBJ_FLAG_CLICKABLE); /*To not allow adjusting by click*/
lv_obj_center(arc);
lv_anim_t a;
lv_anim_init(&a);
lv_anim_set_var(&a, arc);
lv_anim_set_exec_cb(&a, set_angle);
lv_anim_set_duration(&a, 1000);
lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE); /*Just for the demo*/
lv_anim_set_repeat_delay(&a, 500);
lv_anim_set_values(&a, 0, 100);
lv_anim_start(&a);
}
#endif
3、bar（进度条）
3.1、示例1
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
void lv_example_bar_1(void)
{
lv_obj_t * bar1 = lv_bar_create(lv_screen_active());
lv_obj_set_size(bar1, 200, 20);
lv_obj_center(bar1);
lv_bar_set_value(bar1, 70, LV_ANIM_OFF);
}
#endif
3.2、示例2
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
/**
* Example of styling the bar
*/
void lv_example_bar_2(void)
{
static lv_style_t style_bg;
static lv_style_t style_indic;
lv_style_init(&style_bg);
lv_style_set_border_color(&style_bg, lv_palette_main(LV_PALETTE_BLUE));
lv_style_set_border_width(&style_bg, 2);
lv_style_set_pad_all(&style_bg, 6); /*To make the indicator smaller*/
lv_style_set_radius(&style_bg, 6);
lv_style_set_anim_duration(&style_bg, 1000);
lv_style_init(&style_indic);
lv_style_set_bg_opa(&style_indic, LV_OPA_COVER);
lv_style_set_bg_color(&style_indic, lv_palette_main(LV_PALETTE_BLUE));
lv_style_set_radius(&style_indic, 3);
lv_obj_t * bar = lv_bar_create(lv_screen_active());
lv_obj_remove_style_all(bar); /*To have a clean start*/
lv_obj_add_style(bar, &style_bg, 0);
lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);
lv_obj_set_size(bar, 200, 20);
lv_obj_center(bar);
lv_bar_set_value(bar, 100, LV_ANIM_ON);
}
#endif
3.3、示例3
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
static void set_temp(void * bar, int32_t temp)
{
lv_bar_set_value(bar, temp, LV_ANIM_ON);
}
/**
* A temperature meter example
*/
void lv_example_bar_3(void)
{
static lv_style_t style_indic;
lv_style_init(&style_indic);
lv_style_set_bg_opa(&style_indic, LV_OPA_COVER);
lv_style_set_bg_color(&style_indic, lv_palette_main(LV_PALETTE_RED));
lv_style_set_bg_grad_color(&style_indic, lv_palette_main(LV_PALETTE_BLUE));
lv_style_set_bg_grad_dir(&style_indic, LV_GRAD_DIR_VER);
lv_obj_t * bar = lv_bar_create(lv_screen_active());
lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);
lv_obj_set_size(bar, 20, 200);
lv_obj_center(bar);
lv_bar_set_range(bar, -20, 40);
lv_anim_t a;
lv_anim_init(&a);
lv_anim_set_exec_cb(&a, set_temp);
lv_anim_set_duration(&a, 3000);
lv_anim_set_playback_duration(&a, 3000);
lv_anim_set_var(&a, bar);
lv_anim_set_values(&a, -20, 40);
lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
lv_anim_start(&a);
}
#endif
3.4、示例4
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
/**
* Bar with stripe pattern and ranged value
*/
void lv_example_bar_4(void)
{
LV_IMAGE_DECLARE(img_skew_strip);
static lv_style_t style_indic;
lv_style_init(&style_indic);
lv_style_set_bg_image_src(&style_indic, &img_skew_strip);
lv_style_set_bg_image_tiled(&style_indic, true);
lv_style_set_bg_image_opa(&style_indic, LV_OPA_30);
lv_obj_t * bar = lv_bar_create(lv_screen_active());
lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);
lv_obj_set_size(bar, 260, 20);
lv_obj_center(bar);
lv_bar_set_mode(bar, LV_BAR_MODE_RANGE);
lv_bar_set_value(bar, 90, LV_ANIM_OFF);
lv_bar_set_start_value(bar, 20, LV_ANIM_OFF);
}
#endif
4.5、示例5
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
/**
* Bar with LTR and RTL base direction
*/
void lv_example_bar_5(void)
{
lv_obj_t * label;
lv_obj_t * bar_ltr = lv_bar_create(lv_screen_active());
lv_obj_set_size(bar_ltr, 200, 20);
lv_bar_set_value(bar_ltr, 70, LV_ANIM_OFF);
lv_obj_align(bar_ltr, LV_ALIGN_CENTER, 0, -30);
label = lv_label_create(lv_screen_active());
lv_label_set_text(label, "Left to Right base direction");
lv_obj_align_to(label, bar_ltr, LV_ALIGN_OUT_TOP_MID, 0, -5);
lv_obj_t * bar_rtl = lv_bar_create(lv_screen_active());
lv_obj_set_style_base_dir(bar_rtl, LV_BASE_DIR_RTL, 0);
lv_obj_set_size(bar_rtl, 200, 20);
lv_bar_set_value(bar_rtl, 70, LV_ANIM_OFF);
lv_obj_align(bar_rtl, LV_ALIGN_CENTER, 0, 30);
label = lv_label_create(lv_screen_active());
lv_label_set_text(label, "Right to Left base direction");
lv_obj_align_to(label, bar_rtl, LV_ALIGN_OUT_TOP_MID, 0, -5);
}
#endif
4.6、示例6
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
static void set_value(void * bar, int32_t v)
{
lv_bar_set_value(bar, v, LV_ANIM_OFF);
}
static void event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
lv_draw_label_dsc_t label_dsc;
lv_draw_label_dsc_init(&label_dsc);
label_dsc.font = LV_FONT_DEFAULT;
char buf[8];
lv_snprintf(buf, sizeof(buf), "%d", (int)lv_bar_get_value(obj));
lv_point_t txt_size;
lv_text_get_size(&txt_size, buf, label_dsc.font, label_dsc.letter_space, label_dsc.line_space, LV_COORD_MAX,
label_dsc.flag);
lv_area_t txt_area;
txt_area.x1 = 0;
txt_area.x2 = txt_size.x - 1;
txt_area.y1 = 0;
txt_area.y2 = txt_size.y - 1;
lv_bar_t * bar = (lv_bar_t *) obj;
const lv_area_t * indic_area = &bar->indic_area;
/*If the indicator is long enough put the text inside on the right*/
if(lv_area_get_width(indic_area) > txt_size.x + 20) {
lv_area_align(indic_area, &txt_area, LV_ALIGN_RIGHT_MID, -10, 0);
label_dsc.color = lv_color_white();
}
/*If the indicator is still short put the text out of it on the right*/
else {
lv_area_align(indic_area, &txt_area, LV_ALIGN_OUT_RIGHT_MID, 10, 0);
label_dsc.color = lv_color_black();
}
label_dsc.text = buf;
label_dsc.text_local = true;
lv_layer_t * layer = lv_event_get_layer(e);
lv_draw_label(layer, &label_dsc, &txt_area);
}
/**
* Custom drawer on the bar to display the current value
*/
void lv_example_bar_6(void)
{
lv_obj_t * bar = lv_bar_create(lv_screen_active());
lv_obj_set_size(bar, 200, 20);
lv_obj_center(bar);
lv_obj_add_event_cb(bar, event_cb, LV_EVENT_DRAW_MAIN_END, NULL);
lv_anim_t a;
lv_anim_init(&a);
lv_anim_set_var(&a, bar);
lv_anim_set_values(&a, 0, 100);
lv_anim_set_exec_cb(&a, set_value);
lv_anim_set_duration(&a, 4000);
lv_anim_set_playback_duration(&a, 4000);
lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
lv_anim_start(&a);
}
#endif
4.7、示例7
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES
/**
* Bar with opposite direction
*/
void lv_example_bar_7(void)
{
lv_obj_t * label;
lv_obj_t * bar_tob = lv_bar_create(lv_screen_active());
lv_obj_set_size(bar_tob, 20, 200);
lv_bar_set_range(bar_tob, 100, 0);
lv_bar_set_value(bar_tob, 70, LV_ANIM_OFF);
lv_obj_align(bar_tob, LV_ALIGN_CENTER, 0, -30);
label = lv_label_create(lv_screen_active());
lv_label_set_text(label, "From top to bottom");
lv_obj_align_to(label, bar_tob, LV_ALIGN_OUT_TOP_MID, 0, -5);
}
#endif
4、button（按钮）略
按钮在最开始的三大控件那里已经介绍过了。
5、button matrix（矩阵按钮）
5.1、示例1
#include "../../lv_examples.h"
#if LV_USE_BUTTONMATRIX && LV_BUILD_EXAMPLES
static void event_handler(lv_event_t * e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_target(e);
if(code == LV_EVENT_VALUE_CHANGED) {
uint32_t id = lv_buttonmatrix_get_selected_button(obj);
const char * txt = lv_buttonmatrix_get_button_text(obj, id);
LV_UNUSED(txt);
LV_LOG_USER("%s was pressed\n", txt);
}
}
static const char * btnm_map[] = {"1", "2", "3", "4", "5", "\n",
"6", "7", "8", "9", "0", "\n",
"Action1", "Action2", ""
};
void lv_example_buttonmatrix_1(void)
{
lv_obj_t * btnm1 = lv_buttonmatrix_create(lv_screen_active());
lv_buttonmatrix_set_map(btnm1, btnm_map);
lv_buttonmatrix_set_button_width(btnm1, 10, 2); /*Make "Action1" twice as wide as "Action2"*/
lv_buttonmatrix_set_button_ctrl(btnm1, 10, LV_BUTTONMATRIX_CTRL_CHECKABLE);
lv_buttonmatrix_set_button_ctrl(btnm1, 11, LV_BUTTONMATRIX_CTRL_CHECKED);
lv_obj_align(btnm1, LV_ALIGN_CENTER, 0, 0);
lv_obj_add_event_cb(btnm1, event_handler, LV_EVENT_ALL, NULL);
}
#endif
5.2、示例2
#include "../../lv_examples.h"
#if LV_USE_BUTTONMATRIX && LV_BUILD_EXAMPLES
static void event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
/*When the button matrix draws the buttons...*/
if(base_dsc->part == LV_PART_ITEMS) {
bool pressed = false;
if(lv_buttonmatrix_get_selected_button(obj) == base_dsc->id1 && lv_obj_has_state(obj, LV_STATE_PRESSED)) {
pressed = true;
}
/*Change the draw descriptor of the 2nd button*/
if(base_dsc->id1 == 1) {
lv_draw_fill_dsc_t * fill_draw_dsc = lv_draw_task_get_fill_dsc(draw_task);
if(fill_draw_dsc) {
fill_draw_dsc->radius = 0;
if(pressed) fill_draw_dsc->color = lv_palette_darken(LV_PALETTE_BLUE, 3);
else fill_draw_dsc->color = lv_palette_main(LV_PALETTE_BLUE);
}
lv_draw_box_shadow_dsc_t * box_shadow_draw_dsc = lv_draw_task_get_box_shadow_dsc(draw_task);
if(box_shadow_draw_dsc) {
box_shadow_draw_dsc->width = 6;
box_shadow_draw_dsc->ofs_x = 3;
box_shadow_draw_dsc->ofs_y = 3;
}
lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
if(label_draw_dsc) {
label_draw_dsc->color = lv_color_white();
}
}
/*Change the draw descriptor of the 3rd button*/
else if(base_dsc->id1 == 2) {
lv_draw_fill_dsc_t * fill_draw_dsc = lv_draw_task_get_fill_dsc(draw_task);
if(fill_draw_dsc) {
fill_draw_dsc->radius = LV_RADIUS_CIRCLE;
if(pressed) fill_draw_dsc->color = lv_palette_darken(LV_PALETTE_RED, 3);
else fill_draw_dsc->color = lv_palette_main(LV_PALETTE_RED);
}
}
else if(base_dsc->id1 == 3) {
lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
if(label_draw_dsc) {
label_draw_dsc->opa = 0;
}
if(draw_task->type == LV_DRAW_TASK_TYPE_FILL) {
LV_IMAGE_DECLARE(img_star);
lv_image_header_t header;
lv_result_t res = lv_image_decoder_get_info(&img_star, &header);
if(res != LV_RESULT_OK) return;
lv_area_t a;
a.x1 = 0;
a.x2 = header.w - 1;
a.y1 = 0;
a.y2 = header.h - 1;
lv_area_align(&draw_task->area, &a, LV_ALIGN_CENTER, 0, 0);
lv_draw_image_dsc_t img_draw_dsc;
lv_draw_image_dsc_init(&img_draw_dsc);
img_draw_dsc.src = &img_star;
img_draw_dsc.recolor = lv_color_black();
if(pressed) img_draw_dsc.recolor_opa = LV_OPA_30;
lv_draw_image(base_dsc->layer, &img_draw_dsc, &a);
}
}
}
}
/**
* Add custom drawer to the button matrix to customize buttons one by one
*/
void lv_example_buttonmatrix_2(void)
{
lv_obj_t * btnm = lv_buttonmatrix_create(lv_screen_active());
lv_obj_add_event_cb(btnm, event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
lv_obj_add_flag(btnm, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
lv_obj_center(btnm);
}
#endif
5.3、示例3
#include "../../lv_examples.h"
#if LV_USE_BUTTONMATRIX && LV_BUILD_EXAMPLES
static void event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
uint32_t id = lv_buttonmatrix_get_selected_button(obj);
bool prev = id == 0;
bool next = id == 6;
if(prev || next) {
/*Find the checked button*/
uint32_t i;
for(i = 1; i < 7; i++) {
if(lv_buttonmatrix_has_button_ctrl(obj, i, LV_BUTTONMATRIX_CTRL_CHECKED)) break;
}
if(prev && i > 1) i--;
else if(next && i < 5) i++;
lv_buttonmatrix_set_button_ctrl(obj, i, LV_BUTTONMATRIX_CTRL_CHECKED);
}
}
/**
* Make a button group (pagination)
*/
void lv_example_buttonmatrix_3(void)
{
static lv_style_t style_bg;
lv_style_init(&style_bg);
lv_style_set_pad_all(&style_bg, 0);
lv_style_set_pad_gap(&style_bg, 0);
lv_style_set_clip_corner(&style_bg, true);
lv_style_set_radius(&style_bg, LV_RADIUS_CIRCLE);
lv_style_set_border_width(&style_bg, 0);
static lv_style_t style_btn;
lv_style_init(&style_btn);
lv_style_set_radius(&style_btn, 0);
lv_style_set_border_width(&style_btn, 1);
lv_style_set_border_opa(&style_btn, LV_OPA_50);
lv_style_set_border_color(&style_btn, lv_palette_main(LV_PALETTE_GREY));
lv_style_set_border_side(&style_btn, LV_BORDER_SIDE_INTERNAL);
lv_style_set_radius(&style_btn, 0);
static const char * map[] = {LV_SYMBOL_LEFT, "1", "2", "3", "4", "5", LV_SYMBOL_RIGHT, ""};
lv_obj_t * btnm = lv_buttonmatrix_create(lv_screen_active());
lv_buttonmatrix_set_map(btnm, map);
lv_obj_add_style(btnm, &style_bg, 0);
lv_obj_add_style(btnm, &style_btn, LV_PART_ITEMS);
lv_obj_add_event_cb(btnm, event_cb, LV_EVENT_VALUE_CHANGED, NULL);
lv_obj_set_size(btnm, 225, 35);
/*Allow selecting on one number at time*/
lv_buttonmatrix_set_button_ctrl_all(btnm, LV_BUTTONMATRIX_CTRL_CHECKABLE);
lv_buttonmatrix_clear_button_ctrl(btnm, 0, LV_BUTTONMATRIX_CTRL_CHECKABLE);
lv_buttonmatrix_clear_button_ctrl(btnm, 6, LV_BUTTONMATRIX_CTRL_CHECKABLE);
lv_buttonmatrix_set_one_checked(btnm, true);
lv_buttonmatrix_set_button_ctrl(btnm, 1, LV_BUTTONMATRIX_CTRL_CHECKED);
lv_obj_center(btnm);
}
#endif
6、Calendar（日历）
#include "../../lv_examples.h"
#if LV_USE_CALENDAR && LV_BUILD_EXAMPLES
static void event_handler(lv_event_t * e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_current_target(e);
if(code == LV_EVENT_VALUE_CHANGED) {
lv_calendar_date_t date;
if(lv_calendar_get_pressed_date(obj, &date)) {
LV_LOG_USER("Clicked date: %02d.%02d.%d", date.day, date.month, date.year);
}
}
}
void lv_example_calendar_1(void)
{
lv_obj_t * calendar = lv_calendar_create(lv_screen_active());
lv_obj_set_size(calendar, 185, 230);
lv_obj_align(calendar, LV_ALIGN_CENTER, 0, 27);
lv_obj_add_event_cb(calendar, event_handler, LV_EVENT_ALL, NULL);
lv_calendar_set_today_date(calendar, 2021, 02, 23);
lv_calendar_set_showed_date(calendar, 2021, 02);
/*Highlight a few days*/
static lv_calendar_date_t highlighted_days[3]; /*Only its pointer will be saved so should be static*/
highlighted_days[0].year = 2021;
highlighted_days[0].month = 02;
highlighted_days[0].day = 6;
highlighted_days[1].year = 2021;
highlighted_days[1].month = 02;
highlighted_days[1].day = 11;
highlighted_days[2].year = 2022;
highlighted_days[2].month = 02;
highlighted_days[2].day = 22;
lv_calendar_set_highlighted_dates(calendar, highlighted_days, 3);
#if LV_USE_CALENDAR_HEADER_DROPDOWN
lv_calendar_header_dropdown_create(calendar);
#elif LV_USE_CALENDAR_HEADER_ARROW
lv_calendar_header_arrow_create(calendar);
#endif
}
#endif
7、Canvas（画布）
7.1、示例1
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 200
#define CANVAS_HEIGHT 150
void lv_example_canvas_1(void)
{
lv_draw_rect_dsc_t rect_dsc;
lv_draw_rect_dsc_init(&rect_dsc);
rect_dsc.radius = 10;
rect_dsc.bg_opa = LV_OPA_COVER;
rect_dsc.bg_grad.dir = LV_GRAD_DIR_VER;
rect_dsc.bg_grad.stops[0].color = lv_palette_main(LV_PALETTE_RED);
rect_dsc.bg_grad.stops[0].opa = LV_OPA_100;
rect_dsc.bg_grad.stops[1].color = lv_palette_main(LV_PALETTE_BLUE);
rect_dsc.bg_grad.stops[1].opa = LV_OPA_50;
rect_dsc.border_width = 2;
rect_dsc.border_opa = LV_OPA_90;
rect_dsc.border_color = lv_color_white();
rect_dsc.shadow_width = 5;
rect_dsc.shadow_offset_x = 5;
rect_dsc.shadow_offset_y = 5;
lv_draw_label_dsc_t label_dsc;
lv_draw_label_dsc_init(&label_dsc);
label_dsc.color = lv_palette_main(LV_PALETTE_ORANGE);
label_dsc.text = "Some text on text canvas";
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf_16bpp, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_RGB565);
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf_16bpp);
lv_obj_center(canvas);
lv_canvas_fill_bg(canvas, lv_palette_lighten(LV_PALETTE_GREY, 3), LV_OPA_COVER);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_area_t coords_rect = {30, 20, 100, 70};
lv_draw_rect(&layer, &rect_dsc, &coords_rect);
lv_area_t coords_text = {40, 80, 100, 120};
lv_draw_label(&layer, &label_dsc, &coords_text);
lv_canvas_finish_layer(canvas, &layer);
/*Test the rotation. It requires another buffer where the original image is stored.
*So use previous canvas as image and rotate it to the new canvas*/
LV_DRAW_BUF_DEFINE(draw_buf_32bpp, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf_32bpp);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_canvas_fill_bg(canvas, lv_palette_lighten(LV_PALETTE_GREY, 1), LV_OPA_COVER);
lv_canvas_init_layer(canvas, &layer);
lv_image_dsc_t img;
lv_draw_buf_to_image(&draw_buf_16bpp, &img);
lv_draw_image_dsc_t img_dsc;
lv_draw_image_dsc_init(&img_dsc);
img_dsc.rotation = 120;
img_dsc.src = &img;
img_dsc.pivot.x = CANVAS_WIDTH / 2;
img_dsc.pivot.y = CANVAS_HEIGHT / 2;
lv_area_t coords_img = {0, 0, CANVAS_WIDTH - 1, CANVAS_HEIGHT - 1};
lv_draw_image(&layer, &img_dsc, &coords_img);
lv_canvas_finish_layer(canvas, &layer);
}
#endif
7.2、示例2
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 80
#define CANVAS_HEIGHT 40
/**
* Create a transparent canvas with transparency
*/
void lv_example_canvas_2(void)
{
lv_obj_set_style_bg_color(lv_screen_active(), lv_palette_lighten(LV_PALETTE_RED, 5), 0);
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_obj_center(canvas);
/*Red background (There is no dedicated alpha channel in indexed images so LV_OPA_COVER is ignored)*/
lv_canvas_fill_bg(canvas, lv_palette_main(LV_PALETTE_BLUE), LV_OPA_COVER);
/*Create hole on the canvas*/
uint32_t x;
uint32_t y;
for(y = 10; y < 20; y++) {
for(x = 5; x < 75; x++) {
lv_canvas_set_px(canvas, x, y, lv_palette_main(LV_PALETTE_BLUE), LV_OPA_50);
}
}
for(y = 20; y < 30; y++) {
for(x = 5; x < 75; x++) {
lv_canvas_set_px(canvas, x, y, lv_palette_main(LV_PALETTE_BLUE), LV_OPA_20);
}
}
for(y = 30; y < 40; y++) {
for(x = 5; x < 75; x++) {
lv_canvas_set_px(canvas, x, y, lv_palette_main(LV_PALETTE_BLUE), LV_OPA_0);
}
}
}
#endif
7.3、示例3
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 50
#define CANVAS_HEIGHT 50
/**
* Draw a rectangle to the canvas
*/
void lv_example_canvas_3(void)
{
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_draw_rect_dsc_t dsc;
lv_draw_rect_dsc_init(&dsc);
dsc.bg_color = lv_palette_main(LV_PALETTE_RED);
dsc.border_color = lv_palette_main(LV_PALETTE_BLUE);
dsc.border_width = 3;
dsc.outline_color = lv_palette_main(LV_PALETTE_GREEN);
dsc.outline_width = 2;
dsc.outline_pad = 2;
dsc.outline_opa = LV_OPA_50;
dsc.radius = 5;
dsc.border_width = 3;
lv_area_t coords = {10, 10, 40, 30};
lv_draw_rect(&layer, &dsc, &coords);
lv_canvas_finish_layer(canvas, &layer);
}
#endif
7.4、示例4
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_FONT_MONTSERRAT_14 && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 50
#define CANVAS_HEIGHT 50
/**
* Draw a text to the canvas
*/
void lv_example_canvas_4(void)
{
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_draw_label_dsc_t dsc;
lv_draw_label_dsc_init(&dsc);
dsc.color = lv_palette_main(LV_PALETTE_RED);
dsc.font = &lv_font_montserrat_14;
dsc.decor = LV_TEXT_DECOR_UNDERLINE;
dsc.text = "Hello";
lv_area_t coords = {10, 10, 30, 60};
lv_draw_label(&layer, &dsc, &coords);
lv_canvas_finish_layer(canvas, &layer);
}
#endif这里把原来的LV_FONT_MONTSERRAT_18改成LV_FONT_MONTSERRAT_14，lv_font_montserrat_18也改成lv_font_montserrat_14。
模拟环境一些依赖库没有。
7.5、示例5
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 50
#define CANVAS_HEIGHT 50
/**
* Draw an arc to the canvas
*/
void lv_example_canvas_5(void)
{
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_draw_arc_dsc_t dsc;
lv_draw_arc_dsc_init(&dsc);
dsc.color = lv_palette_main(LV_PALETTE_RED);
dsc.width = 5;
dsc.center.x = 25;
dsc.center.y = 25;
dsc.width = 10;
dsc.radius = 15;
dsc.start_angle = 0;
dsc.end_angle = 220;
lv_draw_arc(&layer, &dsc);
lv_canvas_finish_layer(canvas, &layer);
}
#endif
7.6、示例6
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 50
#define CANVAS_HEIGHT 50
/**
* Draw an image to the canvas
*/
void lv_example_canvas_6(void)
{
/*Create a buffer for the canvas*/
static uint8_t cbuf[LV_CANVAS_BUF_SIZE(CANVAS_WIDTH, CANVAS_HEIGHT, 32, LV_DRAW_BUF_STRIDE_ALIGN)];
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
LV_IMAGE_DECLARE(img_star);
lv_draw_image_dsc_t dsc;
lv_draw_image_dsc_init(&dsc);
dsc.src = &img_star;
lv_area_t coords = {10, 10, 10 + img_star.header.w - 1, 10 + img_star.header.h - 1};
lv_draw_image(&layer, &dsc, &coords);
}
#endif
7.7、示例7
#include "../../lv_examples.h"
#if LV_USE_CANVAS&& LV_BUILD_EXAMPLES
#define CANVAS_WIDTH 50
#define CANVAS_HEIGHT 50
/**
* Draw a line to the canvas
*/
void lv_example_canvas_7(void)
{
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_draw_line_dsc_t dsc;
lv_draw_line_dsc_init(&dsc);
dsc.color = lv_palette_main(LV_PALETTE_RED);
dsc.width = 4;
dsc.round_end = 1;
dsc.round_start = 1;
dsc.p1.x = 15;
dsc.p1.y = 15;
dsc.p2.x = 35;
dsc.p2.y = 10;
lv_draw_line(&layer, &dsc);
lv_canvas_finish_layer(canvas, &layer);
}
#endif
7.8、示例8
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
#if LV_USE_VECTOR_GRAPHIC
#define CANVAS_WIDTH 150
#define CANVAS_HEIGHT 150
/**
* Draw a path to the canvas
*/
void lv_example_canvas_8(void)
{
/*Create a buffer for the canvas*/
LV_DRAW_BUF_DEFINE(draw_buf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_COLOR_FORMAT_ARGB8888);
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, &draw_buf);
lv_canvas_fill_bg(canvas, lv_color_hex3(0xccc), LV_OPA_COVER);
lv_obj_center(canvas);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
lv_vector_dsc_t * dsc = lv_vector_dsc_create(&layer);
lv_vector_path_t * path = lv_vector_path_create(LV_VECTOR_PATH_QUALITY_MEDIUM);
lv_fpoint_t pts[] = {{10, 10}, {130, 130}, {10, 130}};
lv_vector_path_move_to(path, &pts[0]);
lv_vector_path_line_to(path, &pts[1]);
lv_vector_path_line_to(path, &pts[2]);
lv_vector_path_close(path);
lv_vector_dsc_set_fill_color(dsc, lv_color_make(0x00, 0x80, 0xff));
lv_vector_dsc_add_path(dsc, path);
lv_draw_vector(dsc);
lv_vector_path_delete(path);
lv_vector_dsc_delete(dsc);
lv_canvas_finish_layer(canvas, &layer);
}
#else
void lv_example_canvas_8(void)
{
/*fallback for online examples*/
lv_obj_t * label = lv_label_create(lv_screen_active());
lv_label_set_text(label, "Vector graphics is not enabled");
lv_obj_center(label);
}
#endif /*LV_USE_VECTOR_GRAPHIC*/
#endif可以在lv_conf.h中开启对应扩展：
#define LV_USE_VECTOR_GRAPHIC 1
不开启矢量图扩展会提示：
8、chart（图表）
8.1、示例1
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
/**
* A very basic line chart
*/
void lv_example_chart_1(void)
{
/*Create a chart*/
lv_obj_t * chart;
chart = lv_chart_create(lv_screen_active());
lv_obj_set_size(chart, 200, 150);
lv_obj_center(chart);
lv_chart_set_type(chart, LV_CHART_TYPE_LINE); /*Show lines and points too*/
/*Add two data series*/
lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_PRIMARY_Y);
lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_SECONDARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
/*Set the next points on 'ser1'*/
lv_chart_set_next_value(chart, ser1, lv_rand(10, 50));
/*Directly set points on 'ser2'*/
ser2->y_points[i] = lv_rand(50, 90);
}
lv_chart_refresh(chart); /*Required after direct set*/
}
#endif
8.2、示例2
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
/**
* Use lv_scale to add ticks to a scrollable chart
*/
void lv_example_chart_2(void)
{
/*Create a container*/
lv_obj_t * main_cont = lv_obj_create(lv_screen_active());
lv_obj_set_size(main_cont, 200, 150);
lv_obj_center(main_cont);
/*Create a transparent wrapper for the chart and the scale.
*Set a large width, to make it scrollable on the main container*/
lv_obj_t * wrapper = lv_obj_create(main_cont);
lv_obj_remove_style_all(wrapper);
lv_obj_set_size(wrapper, lv_pct(300), lv_pct(100));
lv_obj_set_flex_flow(wrapper, LV_FLEX_FLOW_COLUMN);
/*Create a chart on the wrapper
*Set it's width to 100% to fill the large wrapper*/
lv_obj_t * chart = lv_chart_create(wrapper);
lv_obj_set_width(chart, lv_pct(100));
lv_obj_set_flex_grow(chart, 1);
lv_chart_set_type(chart, LV_CHART_TYPE_BAR);
lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 100);
lv_chart_set_range(chart, LV_CHART_AXIS_SECONDARY_Y, 0, 400);
lv_chart_set_point_count(chart, 12);
lv_obj_set_style_radius(chart, 0, 0);
/*Create a scale also with 100% width*/
lv_obj_t * scale_bottom = lv_scale_create(wrapper);
lv_scale_set_mode(scale_bottom, LV_SCALE_MODE_HORIZONTAL_BOTTOM);
lv_obj_set_size(scale_bottom, lv_pct(100), 25);
lv_scale_set_total_tick_count(scale_bottom, 12);
lv_scale_set_major_tick_every(scale_bottom, 1);
lv_obj_set_style_pad_hor(scale_bottom, lv_chart_get_first_point_center_offset(chart), 0);
static const char * month[] = {"Jan", "Febr", "March", "Apr", "May", "Jun", "July", "Aug", "Sept", "Oct", "Nov", "Dec", NULL};
lv_scale_set_text_src(scale_bottom, month);
/*Add two data series*/
lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_lighten(LV_PALETTE_GREEN, 2), LV_CHART_AXIS_PRIMARY_Y);
lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_darken(LV_PALETTE_GREEN, 2), LV_CHART_AXIS_PRIMARY_Y);
/*Set the next points on 'ser1'*/
uint32_t i;
for(i = 0; i < 12; i++) {
lv_chart_set_next_value(chart, ser1, lv_rand(10, 60));
lv_chart_set_next_value(chart, ser2, lv_rand(50, 90));
}
lv_chart_refresh(chart); /*Required after direct set*/
}
#endif
8.3、示例3
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
static void event_cb(lv_event_t * e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * chart = lv_event_get_target(e);
if(code == LV_EVENT_VALUE_CHANGED) {
lv_obj_invalidate(chart);
}
if(code == LV_EVENT_REFR_EXT_DRAW_SIZE) {
int32_t * s = lv_event_get_param(e);
*s = LV_MAX(*s, 20);
}
else if(code == LV_EVENT_DRAW_POST_END) {
int32_t id = lv_chart_get_pressed_point(chart);
if(id == LV_CHART_POINT_NONE) return;
LV_LOG_USER("Selected point %d", (int)id);
lv_chart_series_t * ser = lv_chart_get_series_next(chart, NULL);
while(ser) {
lv_point_t p;
lv_chart_get_point_pos_by_id(chart, ser, id, &p);
int32_t * y_array = lv_chart_get_y_array(chart, ser);
int32_t value = y_array[id];
char buf[16];
lv_snprintf(buf, sizeof(buf), LV_SYMBOL_DUMMY"$%d", value);
lv_draw_rect_dsc_t draw_rect_dsc;
lv_draw_rect_dsc_init(&draw_rect_dsc);
draw_rect_dsc.bg_color = lv_color_black();
draw_rect_dsc.bg_opa = LV_OPA_50;
draw_rect_dsc.radius = 3;
draw_rect_dsc.bg_image_src = buf;
draw_rect_dsc.bg_image_recolor = lv_color_white();
lv_area_t a;
a.x1 = chart->coords.x1 + p.x - 20;
a.x2 = chart->coords.x1 + p.x + 20;
a.y1 = chart->coords.y1 + p.y - 30;
a.y2 = chart->coords.y1 + p.y - 10;
lv_layer_t * layer = lv_event_get_layer(e);
lv_draw_rect(layer, &draw_rect_dsc, &a);
ser = lv_chart_get_series_next(chart, ser);
}
}
else if(code == LV_EVENT_RELEASED) {
lv_obj_invalidate(chart);
}
}
/**
* Show the value of the pressed points
*/
void lv_example_chart_3(void)
{
/*Create a chart*/
lv_obj_t * chart;
chart = lv_chart_create(lv_screen_active());
lv_obj_set_size(chart, 200, 150);
lv_obj_center(chart);
lv_obj_add_event_cb(chart, event_cb, LV_EVENT_ALL, NULL);
lv_obj_refresh_ext_draw_size(chart);
/*Zoom in a little in X*/
// lv_chart_set_scale_x(chart, 800);
/*Add two data series*/
lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_PRIMARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
lv_chart_set_next_value(chart, ser1, lv_rand(60, 90));
lv_chart_set_next_value(chart, ser2, lv_rand(10, 40));
}
}
#endif
8.4、示例4
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_SW_COMPLEX && LV_BUILD_EXAMPLES
static void draw_event_cb(lv_event_t * e)
{
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
if(base_dsc->part != LV_PART_ITEMS) {
return;
}
lv_draw_fill_dsc_t * fill_dsc = lv_draw_task_get_fill_dsc(draw_task);
if(fill_dsc) {
lv_obj_t * chart = lv_event_get_target(e);
int32_t * y_array = lv_chart_get_y_array(chart, lv_chart_get_series_next(chart, NULL));
int32_t v = y_array[base_dsc->id2];
uint32_t ratio = v * 255 / 100;
fill_dsc->color = lv_color_mix(lv_palette_main(LV_PALETTE_GREEN), lv_palette_main(LV_PALETTE_RED), ratio);
}
}
/**
* Recolor the bars of a chart based on their value
*/
void lv_example_chart_4(void)
{
/*Create a chart1*/
lv_obj_t * chart = lv_chart_create(lv_screen_active());
lv_chart_set_type(chart, LV_CHART_TYPE_BAR);
lv_chart_set_point_count(chart, 24);
lv_obj_set_style_pad_column(chart, 2, 0);
lv_obj_set_size(chart, 260, 160);
lv_obj_center(chart);
lv_chart_series_t * ser = lv_chart_add_series(chart, lv_color_hex(0xff0000), LV_CHART_AXIS_PRIMARY_Y);
lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
lv_obj_add_flag(chart, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
uint32_t i;
for(i = 0; i < 24; i++) {
lv_chart_set_next_value(chart, ser, lv_rand(10, 90));
}
}
#endif
8.5、示例5
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_SW_COMPLEX && LV_BUILD_EXAMPLES
static void hook_division_lines(lv_event_t * e);
static void add_faded_area(lv_event_t * e);
static void draw_event_cb(lv_event_t * e);
/**
* Add a faded area effect to the line chart and make some division lines ticker
*/
void lv_example_chart_5(void)
{
/*Create a chart*/
lv_obj_t * chart = lv_chart_create(lv_screen_active());
lv_chart_set_type(chart, LV_CHART_TYPE_LINE); /*Show lines and points too*/
lv_obj_set_size(chart, 200, 150);
lv_obj_set_style_pad_all(chart, 0, 0);
lv_obj_set_style_radius(chart, 0, 0);
lv_obj_center(chart);
lv_chart_set_div_line_count(chart, 5, 7);
lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
lv_obj_add_flag(chart, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
lv_chart_set_next_value(chart, ser, lv_rand(10, 80));
}
}
static void draw_event_cb(lv_event_t * e)
{
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
if(base_dsc->part == LV_PART_ITEMS && draw_task->type == LV_DRAW_TASK_TYPE_LINE) {
add_faded_area(e);
}
/*Hook the division lines too*/
if(base_dsc->part == LV_PART_MAIN && draw_task->type == LV_DRAW_TASK_TYPE_LINE) {
hook_division_lines(e);
}
}
static void add_faded_area(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
const lv_chart_series_t * ser = lv_chart_get_series_next(obj, NULL);
/*Draw a triangle below the line witch some opacity gradient*/
lv_draw_line_dsc_t * draw_line_dsc = draw_task->draw_dsc;
lv_draw_triangle_dsc_t tri_dsc;
lv_draw_triangle_dsc_init(&tri_dsc);
tri_dsc.p[0].x = draw_line_dsc->p1.x;
tri_dsc.p[0].y = draw_line_dsc->p1.y;
tri_dsc.p[1].x = draw_line_dsc->p2.x;
tri_dsc.p[1].y = draw_line_dsc->p2.y;
tri_dsc.p[2].x = draw_line_dsc->p1.y < draw_line_dsc->p2.y ? draw_line_dsc->p1.x : draw_line_dsc->p2.x;
tri_dsc.p[2].y = LV_MAX(draw_line_dsc->p1.y, draw_line_dsc->p2.y);
tri_dsc.bg_grad.dir = LV_GRAD_DIR_VER;
int32_t full_h = lv_obj_get_height(obj);
int32_t fract_uppter = (int32_t)(LV_MIN(draw_line_dsc->p1.y, draw_line_dsc->p2.y) - obj->coords.y1) * 255 / full_h;
int32_t fract_lower = (int32_t)(LV_MAX(draw_line_dsc->p1.y, draw_line_dsc->p2.y) - obj->coords.y1) * 255 / full_h;
tri_dsc.bg_grad.stops[0].color = ser->color;
tri_dsc.bg_grad.stops[0].opa = 255 - fract_uppter;
tri_dsc.bg_grad.stops[0].frac = 0;
tri_dsc.bg_grad.stops[1].color = ser->color;
tri_dsc.bg_grad.stops[1].opa = 255 - fract_lower;
tri_dsc.bg_grad.stops[1].frac = 255;
lv_draw_triangle(base_dsc->layer, &tri_dsc);
/*Draw rectangle below the triangle*/
lv_draw_rect_dsc_t rect_dsc;
lv_draw_rect_dsc_init(&rect_dsc);
rect_dsc.bg_grad.dir = LV_GRAD_DIR_VER;
rect_dsc.bg_grad.stops[0].color = ser->color;
rect_dsc.bg_grad.stops[0].frac = 0;
rect_dsc.bg_grad.stops[0].opa = 255 - fract_lower;
rect_dsc.bg_grad.stops[1].color = ser->color;
rect_dsc.bg_grad.stops[1].frac = 255;
rect_dsc.bg_grad.stops[1].opa = 0;
lv_area_t rect_area;
rect_area.x1 = (int32_t)draw_line_dsc->p1.x;
rect_area.x2 = (int32_t)draw_line_dsc->p2.x - 1;
rect_area.y1 = (int32_t)LV_MAX(draw_line_dsc->p1.y, draw_line_dsc->p2.y) - 1;
rect_area.y2 = (int32_t)obj->coords.y2;
lv_draw_rect(base_dsc->layer, &rect_dsc, &rect_area);
}
static void hook_division_lines(lv_event_t * e)
{
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
lv_draw_line_dsc_t * line_dsc = draw_task->draw_dsc;
/*Vertical line*/
if(line_dsc->p1.x == line_dsc->p2.x) {
line_dsc->color = lv_palette_lighten(LV_PALETTE_GREY, 1);
if(base_dsc->id1 == 3) {
line_dsc->width = 2;
line_dsc->dash_gap = 0;
line_dsc->dash_width = 0;
}
else {
line_dsc->width = 1;
line_dsc->dash_gap = 6;
line_dsc->dash_width = 6;
}
}
/*Horizontal line*/
else {
if(base_dsc->id1 == 2) {
line_dsc->width = 2;
line_dsc->dash_gap = 0;
line_dsc->dash_width = 0;
}
else {
line_dsc->width = 2;
line_dsc->dash_gap = 6;
line_dsc->dash_width = 6;
}
if(base_dsc->id1 == 1 || base_dsc->id1 == 3) {
line_dsc->color = lv_palette_main(LV_PALETTE_GREEN);
}
else {
line_dsc->color = lv_palette_lighten(LV_PALETTE_GREY, 1);
}
}
}
#endif
8.6、示例6
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
static lv_obj_t * chart;
static lv_chart_series_t * ser;
static lv_chart_cursor_t * cursor;
static void value_changed_event_cb(lv_event_t * e)
{
static int32_t last_id = -1;
lv_obj_t * obj = lv_event_get_target(e);
last_id = lv_chart_get_pressed_point(obj);
if(last_id != LV_CHART_POINT_NONE) {
lv_chart_set_cursor_point(obj, cursor, NULL, last_id);
}
}
/**
* Show cursor on the clicked point
*/
void lv_example_chart_6(void)
{
chart = lv_chart_create(lv_screen_active());
lv_obj_set_size(chart, 200, 150);
lv_obj_align(chart, LV_ALIGN_CENTER, 0, -10);
// lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 40);
// lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 10, 5, 10, 1, true, 30);
lv_obj_add_event_cb(chart, value_changed_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
lv_obj_refresh_ext_draw_size(chart);
cursor = lv_chart_add_cursor(chart, lv_palette_main(LV_PALETTE_BLUE), LV_DIR_LEFT | LV_DIR_BOTTOM);
ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
lv_chart_set_next_value(chart, ser, lv_rand(10, 90));
}
// lv_chart_set_scale_x(chart, 500);
lv_obj_t * label = lv_label_create(lv_screen_active());
lv_label_set_text(label, "Click on a point");
lv_obj_align_to(label, chart, LV_ALIGN_OUT_TOP_MID, 0, -5);
}
#endif
8.7、示例7
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
static void draw_event_cb(lv_event_t * e)
{
lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
lv_draw_dsc_base_t * base_dsc = draw_task->draw_dsc;
if(base_dsc->part == LV_PART_INDICATOR) {
lv_obj_t * obj = lv_event_get_target(e);
lv_chart_series_t * ser = lv_chart_get_series_next(obj, NULL);
lv_draw_rect_dsc_t * rect_draw_dsc = draw_task->draw_dsc;
uint32_t cnt = lv_chart_get_point_count(obj);
/*Make older value more transparent*/
rect_draw_dsc->bg_opa = (LV_OPA_COVER * base_dsc->id2) / (cnt - 1);
/*Make smaller values blue, higher values red*/
int32_t * x_array = lv_chart_get_x_array(obj, ser);
int32_t * y_array = lv_chart_get_y_array(obj, ser);
/*dsc->id is the tells drawing order, but we need the ID of the point being drawn.*/
uint32_t start_point = lv_chart_get_x_start_point(obj, ser);
uint32_t p_act = (start_point + base_dsc->id2) % cnt; /*Consider start point to get the index of the array*/
lv_opa_t x_opa = (x_array[p_act] * LV_OPA_50) / 200;
lv_opa_t y_opa = (y_array[p_act] * LV_OPA_50) / 1000;
rect_draw_dsc->bg_color = lv_color_mix(lv_palette_main(LV_PALETTE_RED),
lv_palette_main(LV_PALETTE_BLUE),
x_opa + y_opa);
}
}
static void add_data(lv_timer_t * timer)
{
LV_UNUSED(timer);
lv_obj_t * chart = timer->user_data;
lv_chart_set_next_value2(chart, lv_chart_get_series_next(chart, NULL), lv_rand(0, 200), lv_rand(0, 1000));
}
/**
* A scatter chart
*/
void lv_example_chart_7(void)
{
lv_obj_t * chart = lv_chart_create(lv_screen_active());
lv_obj_set_size(chart, 200, 150);
lv_obj_align(chart, LV_ALIGN_CENTER, 0, 0);
lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
lv_obj_add_flag(chart, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
lv_obj_set_style_line_width(chart, 0, LV_PART_ITEMS); /*Remove the lines*/
lv_chart_set_type(chart, LV_CHART_TYPE_SCATTER);
lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_X, 0, 200);
lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 1000);
lv_chart_set_point_count(chart, 50);
lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
uint32_t i;
for(i = 0; i < 50; i++) {
lv_chart_set_next_value2(chart, ser, lv_rand(0, 200), lv_rand(0, 1000));
}
lv_timer_create(add_data, 100, chart);
}
#endif
8.8、示例8
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_SW_COMPLEX && LV_BUILD_EXAMPLES
static void add_data(lv_timer_t * t)
{
lv_obj_t * chart = t->user_data;
lv_chart_series_t * ser = lv_chart_get_series_next(chart, NULL);
lv_chart_set_next_value(chart, ser, lv_rand(10, 90));
uint16_t p = lv_chart_get_point_count(chart);
uint16_t s = lv_chart_get_x_start_point(chart, ser);
int32_t * a = lv_chart_get_y_array(chart, ser);
a[(s + 1) % p] = LV_CHART_POINT_NONE;
a[(s + 2) % p] = LV_CHART_POINT_NONE;
a[(s + 2) % p] = LV_CHART_POINT_NONE;
lv_chart_refresh(chart);
}
/**
* Circular line chart with gap
*/
void lv_example_chart_8(void)
{
/*Create a stacked_area_chart.obj*/
lv_obj_t * chart = lv_chart_create(lv_screen_active());
lv_chart_set_update_mode(chart, LV_CHART_UPDATE_MODE_CIRCULAR);
lv_obj_set_style_size(chart, 0, 0, LV_PART_INDICATOR);
lv_obj_set_size(chart, 280, 150);
lv_obj_center(chart);
lv_chart_set_point_count(chart, 80);
lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
/*Prefill with data*/
uint32_t i;
for(i = 0; i < 80; i++) {
lv_chart_set_next_value(chart, ser, lv_rand(10, 90));
}
lv_timer_create(add_data, 300, chart);
}
#endif
9、checkbox（复选框）
9.1、示例1
#include "../../lv_examples.h"
#if LV_USE_CHECKBOX && LV_BUILD_EXAMPLES
static void event_handler(lv_event_t * e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_target(e);
if(code == LV_EVENT_VALUE_CHANGED) {
LV_UNUSED(obj);
const char * txt = lv_checkbox_get_text(obj);
const char * state = lv_obj_get_state(obj) & LV_STATE_CHECKED ? "Checked" : "Unchecked";
LV_UNUSED(txt);
LV_UNUSED(state);
LV_LOG_USER("%s: %s", txt, state);
}
}
void lv_example_checkbox_1(void)
{
lv_obj_set_flex_flow(lv_screen_active(), LV_FLEX_FLOW_COLUMN);
lv_obj_set_flex_align(lv_screen_active(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_CENTER);
lv_obj_t * cb;
cb = lv_checkbox_create(lv_screen_active());
lv_checkbox_set_text(cb, "Apple");
lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);
cb = lv_checkbox_create(lv_screen_active());
lv_checkbox_set_text(cb, "Banana");
lv_obj_add_state(cb, LV_STATE_CHECKED);
lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);
cb = lv_checkbox_create(lv_screen_active());
lv_checkbox_set_text(cb, "Lemon");
lv_obj_add_state(cb, LV_STATE_DISABLED);
lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);
cb = lv_checkbox_create(lv_screen_active());
lv_obj_add_state(cb, LV_STATE_CHECKED | LV_STATE_DISABLED);
lv_checkbox_set_text(cb, "Melon\nand a new line");
lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);
lv_obj_update_layout(cb);
}
#endif
9.2、示例2
#include "../../lv_examples.h"
#if LV_USE_CHECKBOX && LV_BUILD_EXAMPLES
static lv_style_t style_radio;
static lv_style_t style_radio_chk;
static uint32_t active_index_1 = 0;
static uint32_t active_index_2 = 0;
static void radio_event_handler(lv_event_t * e)
{
uint32_t * active_id = lv_event_get_user_data(e);
lv_obj_t * cont = lv_event_get_current_target(e);
lv_obj_t * act_cb = lv_event_get_target(e);
lv_obj_t * old_cb = lv_obj_get_child(cont, *active_id);
/*Do nothing if the container was clicked*/
if(act_cb == cont) return;
lv_obj_remove_state(old_cb, LV_STATE_CHECKED); /*Uncheck the previous radio button*/
lv_obj_add_state(act_cb, LV_STATE_CHECKED); /*Uncheck the current radio button*/
*active_id = lv_obj_get_index(act_cb);
LV_LOG_USER("Selected radio buttons: %d, %d", (int)active_index_1, (int)active_index_2);
}
static void radiobutton_create(lv_obj_t * parent, const char * txt)
{
lv_obj_t * obj = lv_checkbox_create(parent);
lv_checkbox_set_text(obj, txt);
lv_obj_add_flag(obj, LV_OBJ_FLAG_EVENT_BUBBLE);
lv_obj_add_style(obj, &style_radio, LV_PART_INDICATOR);
lv_obj_add_style(obj, &style_radio_chk, LV_PART_INDICATOR | LV_STATE_CHECKED);
}
/**
* Checkboxes as radio buttons
*/
void lv_example_checkbox_2(void)
{
/* The idea is to enable `LV_OBJ_FLAG_EVENT_BUBBLE` on checkboxes and process the
* `LV_EVENT_CLICKED` on the container.
* A variable is passed as event user data where the index of the active
* radiobutton is saved */
lv_style_init(&style_radio);
lv_style_set_radius(&style_radio, LV_RADIUS_CIRCLE);
lv_style_init(&style_radio_chk);
lv_style_set_bg_image_src(&style_radio_chk, NULL);
uint32_t i;
char buf[32];
lv_obj_t * cont1 = lv_obj_create(lv_screen_active());
lv_obj_set_flex_flow(cont1, LV_FLEX_FLOW_COLUMN);
lv_obj_set_size(cont1, lv_pct(40), lv_pct(80));
lv_obj_add_event_cb(cont1, radio_event_handler, LV_EVENT_CLICKED, &active_index_1);
for(i = 0; i < 5; i++) {
lv_snprintf(buf, sizeof(buf), "A %d", (int)i + 1);
radiobutton_create(cont1, buf);
}
/*Make the first checkbox checked*/
lv_obj_add_state(lv_obj_get_child(cont1, 0), LV_STATE_CHECKED);
lv_obj_t * cont2 = lv_obj_create(lv_screen_active());
lv_obj_set_flex_flow(cont2, LV_FLEX_FLOW_COLUMN);
lv_obj_set_size(cont2, lv_pct(40), lv_pct(80));
lv_obj_set_x(cont2, lv_pct(50));
lv_obj_add_event_cb(cont2, radio_event_handler, LV_EVENT_CLICKED, &active_index_2);
for(i = 0; i < 3; i++) {
lv_snprintf(buf, sizeof(buf), "B %d", (int)i + 1);
radiobutton_create(cont2, buf);
}
/*Make the first checkbox checked*/
lv_obj_add_state(lv_obj_get_child(cont2, 0), LV_STATE_CHECKED);
}
#endif
10、dropdown（下拉列表）
10.1、示例1
#include "../../lv_examples.h"
#if LV_USE_DROPDOWN && LV_BUILD_EXAMPLES
static void event_handler(lv_event_t * e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_target(e);
if(code == LV_EVENT_VALUE_CHANGED) {
char buf[32];
lv_dropdown_get_selected_str(obj, buf, sizeof(buf));
LV_LOG_USER("Option: %s", buf);
}
}
void lv_example_dropdown_1(void)
{
/*Create a normal drop down list*/
lv_obj_t * dd = lv_dropdown_create(lv_screen_active());
lv_dropdown_set_options(dd, "Apple\n"
"Banana\n"
"Orange\n"
"Cherry\n"
"Grape\n"
"Raspberry\n"
"Melon\n"
"Orange\n"
"Lemon\n"
"Nuts");
lv_obj_align(dd, LV_ALIGN_TOP_MID, 0, 20);
lv_obj_add_event_cb(dd, event_handler, LV_EVENT_ALL, NULL);
}
#endif
10.2、示例2
#include "../../lv_examples.h"
#if LV_USE_DROPDOWN && LV_BUILD_EXAMPLES
/**
* Create a drop down, up, left and right menus
*/
void lv_example_dropdown_2(void)
{
static const char * opts = "Apple\n"
"Banana\n"
"Orange\n"
"Melon";
lv_obj_t * dd;
dd = lv_dropdown_create(lv_screen_active());
lv_dropdown_set_options_static(dd, opts);
lv_obj_align(dd, LV_ALIGN_TOP_MID, 0, 10);
dd = lv_dropdown_create(lv_screen_active());
lv_dropdown_set_options_static(dd, opts);
lv_dropdown_set_dir(dd, LV_DIR_BOTTOM);
lv_dropdown_set_symbol(dd, LV_SYMBOL_UP);
lv_obj_align(dd, LV_ALIGN_BOTTOM_MID, 0, -10);
dd = lv_dropdown_create(lv_screen_active());
lv_dropdown_set_options_static(dd, opts);
lv_dropdown_set_dir(dd, LV_DIR_RIGHT);
lv_dropdown_set_symbol(dd, LV_SYMBOL_RIGHT);
lv_obj_align(dd, LV_ALIGN_LEFT_MID, 10, 0);
dd = lv_dropdown_create(lv_screen_active());
lv_dropdown_set_options_static(dd, opts);
lv_dropdown_set_dir(dd, LV_DIR_LEFT);
lv_dropdown_set_symbol(dd, LV_SYMBOL_LEFT);
lv_obj_align(dd, LV_ALIGN_RIGHT_MID, -10, 0);
}
#endif
10.3、示例3
#include "../../lv_examples.h"
#if LV_USE_DROPDOWN && LV_BUILD_EXAMPLES
static void event_cb(lv_event_t * e)
{
lv_obj_t * dropdown = lv_event_get_target(e);
char buf[64];
lv_dropdown_get_selected_str(dropdown, buf, sizeof(buf));
LV_LOG_USER("'%s' is selected", buf);
}
/**
* Create a menu from a drop-down list and show some drop-down list features and styling
*/
void lv_example_dropdown_3(void)
{
/*Create a drop down list*/
lv_obj_t * dropdown = lv_dropdown_create(lv_screen_active());
lv_obj_align(dropdown, LV_ALIGN_TOP_LEFT, 10, 10);
lv_dropdown_set_options(dropdown, "New project\n"
"New file\n"
"Save\n"
"Save as ...\n"
"Open project\n"
"Recent projects\n"
"Preferences\n"
"Exit");
/*Set a fixed text to display on the button of the drop-down list*/
lv_dropdown_set_text(dropdown, "Menu");
/*Use a custom image as down icon and flip it when the list is opened*/
LV_IMAGE_DECLARE(img_caret_down);
lv_dropdown_set_symbol(dropdown, &img_caret_down);
lv_obj_set_style_transform_rotation(dropdown, 1800, LV_PART_INDICATOR | LV_STATE_CHECKED);
/*In a menu we don't need to show the last clicked item*/
lv_dropdown_set_selected_highlight(dropdown, false);
lv_obj_add_event_cb(dropdown, event_cb, LV_EVENT_VALUE_CHANGED, NULL);
}
#endif
三、最后
接下来我们进行其他控件的总结，总共有三十类左右的控件，我们大体都过一遍，其他的UI开发其实都是可以触类旁通的。
