Chart (lv_chart)¶
Overview¶
Charts are a basic object to visualize data points. Currently Line charts (connect points with lines and/or draw points on them) and Bar charts are supported.
Charts can have:
division lines
2 y axis
axis ticks and texts on ticks
cursors
scrolling and zooming
Parts and Styles¶
LV_PART_MAINThe background of the chart. Uses all the typical background and line (for the division lines) related style properties. Padding makes the series area smaller. For column chartspad_columnsets the space between the columns of the adjacent indices.LV_PART_SCROLLBARThe scrollbar used if the chart is zoomed. See the Base object's documentation for details.LV_PART_ITEMSRefers to the line or bar series.Line chart: The line properties are used by the lines.
width,height,bg_colorandradiusis used to set the appearance of points.Bar chart: The typical background properties are used to style the bars.
pad_columnsets the space between the columns on the same index.
LV_PART_INDICATORRefers to the points on line and scatter chart (small circles or squares).LV_PART_CURSORLine properties are used to style the cursors.width,height,bg_colorandradiusare used to set the appearance of points.LV_PART_TICKSLine and Text style properties are used to style the ticks
Usage¶
Chart type¶
The following data display types exist:
LV_CHART_TYPE_NONEDo not display any data. Can be used to hide the series.LV_CHART_TYPE_LINEDraw lines between the data points and/or points (rectangles or circles) on the data points.LV_CHART_TYPE_BAR- Draw bars.LV_CHART_TYPE_SCATTER- X/Y chart drawing point's and lines between the points. .
You can specify the display type with lv_chart_set_type(chart, LV_CHART_TYPE_...).
Data series¶
You can add any number of series to the charts by lv_chart_add_series(chart, color, axis). This allocates an lv_chart_series_t structure which contains the chosen color and an array for the data points.
axis can have the following values:
LV_CHART_AXIS_PRIMARY_YLeft axisLV_CHART_AXIS_SECONDARY_YRight axisLV_CHART_AXIS_PRIMARY_XBottom axisLV_CHART_AXIS_SECONDARY_XTop axis
axis tells which axis's range should be used te scale the values.
lv_chart_set_ext_y_array(chart, ser, value_array) makes the chart use an external array for the given series.
value_array should look like this: lv_coord_t * value_array[num_points]. The array size needs to be large enough to hold all the points of that series.
The array's pointer will be saved in the chart so it needs to be global, static or dynamically allocated.
Note: you should call lv_chart_refresh(chart) after the external data source has been updated to update the chart.
The value array of a series can be obtained with lv_chart_get_y_array(chart, ser), which can be used with ext_array or normal arrays.
For LV_CHART_TYPE_SCATTER type lv_chart_set_ext_x_array(chart, ser, value_array) and lv_chart_get_x_array(chart, ser) can be used as well.
Modify the data¶
You have several options to set the data of series:
Set the values manually in the array like
ser1->points[3] = 7and refresh the chart withlv_chart_refresh(chart).Use
lv_chart_set_value_by_id(chart, ser, id, value)whereidis the index of the point you wish to update.Use the
lv_chart_set_next_value(chart, ser, value).Initialize all points to a given value with:
lv_chart_set_all_value(chart, ser, value).
Use LV_CHART_POINT_NONE as value to make the library skip drawing that point, column, or line segment.
For LV_CHART_TYPE_SCATTER type lv_chart_set_value_by_id2(chart, ser, id, value) and lv_chart_set_next_value2(chart, ser, x_valuem y_value) can be used as well.
Update modes¶
lv_chart_set_next_value can behave in two ways depending on update mode:
LV_CHART_UPDATE_MODE_SHIFTShift old data to the left and add the new one to the right.LV_CHART_UPDATE_MODE_CIRCULAR- Add the new data in circular fashion, like an ECG diagram.
The update mode can be changed with lv_chart_set_update_mode(chart, LV_CHART_UPDATE_MODE_...).
Number of points¶
The number of points in the series can be modified by lv_chart_set_point_count(chart, point_num). The default value is 10.
Note: this also affects the number of points processed when an external buffer is assigned to a series, so you need to be sure the external array is large enough.
Handling large number of points¶
On line charts, if the number of points is greater than the pixels horizontally, the Chart will draw only vertical lines to make the drawing of large amount of data effective. If there are, let's say, 10 points to a pixel, LVGL searches the smallest and the largest value and draws a vertical lines between them to ensure no peaks are missed.
Vertical range¶
You can specify the minimum and maximum values in y-direction with lv_chart_set_range(chart, axis, min, max).
axis can be LV_CHART_AXIS_PRIMARY (left axis) or LV_CHART_AXIS_SECONDARY (right axis).
The value of the points will be scaled proportionally. The default range is: 0..100.
Division lines¶
The number of horizontal and vertical division lines can be modified by lv_chart_set_div_line_count(chart, hdiv_num, vdiv_num).
The default settings are 3 horizontal and 5 vertical division lines.
If there is a visible border on a side and no padding on that side, the division line would be drawn on top of the border and therefore it won't be drawn.
Override default start point for series¶
If you want a plot to start from a point other than the default which is point[0] of the series, you can set an alternative
index with the function lv_chart_set_x_start_point(chart, ser, id) where id is the new index position to start plotting from.
Note that LV_CHART_UPDATE_MODE_SHIFT also changes the start_point.
Tick marks and labels¶
Ticks and labels can be added to the axis with lv_chart_set_axis_tick(chart, axis, major_len, minor_len, major_cnt, minor_cnt, label_en, draw_size).
axiscan beLV_CHART_AXIS_X/PRIMARY_Y/SECONDARY_Ymajor_lenis the length of major ticksminor_lenis the length of minor ticksmajor_cntis the number of major ticks on the axisminor_cntin the number of minor ticks between two major tickslabel_entrue: enable label drawing on major ticksdraw_sizeextra size required to draw the tick and labels (start with 20 px and increase if the ticks/labels are clipped)
Zoom¶
The chart can be zoomed independently in x and y directions with lv_chart_set_zoom_x(chart, factor) and lv_chart_set_zoom_y(chart, factor).
If factor is 256 there is no zoom. 512 means double zoom, etc. Fractional values are also possible but < 256 value is not allowed.
Cursor¶
A cursor can be added with lv_chart_cursor_t * c1 = lv_chart_add_cursor(chart, color, dir);.
The possible values of dir LV_DIR_NONE/RIGHT/UP/LEFT/DOWN/HOR/VER/ALL or their OR-ed values to tell in which direction(s) should the cursor be drawn.
lv_chart_set_cursor_pos(chart, cursor, &point) sets the position of the cursor.
pos is a pointer to an lv_point_t variable. E.g. lv_point_t point = {10, 20};. If the chart is scrolled the cursor will remain in the same place.
lv_chart_get_point_pos_by_id(chart, series, id, &point_out) gets the coordinate of a given point. It's useful to place the cursor at a given point.
lv_chart_set_cursor_point(chart, cursor, series, point_id) sticks the cursor at a point. If the point's position changes (new value or scrolling) the cursor will move with the point.
Events¶
LV_EVENT_VALUE_CHANGEDSent when a new point is clicked pressed.lv_chart_get_pressed_point(chart)returns the zero-based index of the pressed point.LV_EVENT_DRAW_PART_BEGINandLV_EVENT_DRAW_PART_ENDare sent with the following types:LV_CHART_DRAW_PART_DIV_LINE_INITUsed before/after drawn the div lines to add masks to any extra drawings. The following fields are set:part:LV_PART_MAINline_dsc
LV_CHART_DRAW_PART_DIV_LINE_HOR,LV_CHART_DRAW_PART_DIV_LINE_VERUsed for each horizontal and vertical division lines.part:LV_PART_MAINid: index of the linep1,p2: points of the lineline_dsc
LV_CHART_DRAW_PART_LINE_AND_POINTUsed on line and scatter charts for lines and points.part:LV_PART_ITEMSid: index of the pointvalue: value ofidth pointp1,p2: points of the linedraw_area: area of the pointline_dscrect_dscsub_part_ptr: pointer to the series
LV_CHART_DRAW_PART_BARUsed on bar charts for the rectangles.part:LV_PART_ITEMSid: index of the pointvalue: value ofidth pointdraw_area: area of the pointrect_dsc:sub_part_ptr: pointer to the series
LV_CHART_DRAW_PART_CURSORUsed on cursor lines and points.part:LV_PART_CURSORp1,p2: points of the lineline_dscrect_dscdraw_area: area of the points
LV_CHART_DRAW_PART_TICK_LABELUsed on tick lines and labels.part:LV_PART_TICKSid: axisvalue: value of the ticktext:valueconverted to decimal orNULLfor minor ticksline_dsc,label_dsc,
See the events of the Base object too.
Learn more about Events.
Example¶
Line Chart¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
void lv_example_chart_1(void)
{
/*Create a chart*/
lv_obj_t * chart;
chart = lv_chart_create(lv_scr_act());
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_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_SECONDARY_Y);
/*Set the next points on 'ser1'*/
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 30);
lv_chart_set_next_value(chart, ser1, 70);
lv_chart_set_next_value(chart, ser1, 90);
/*Directly set points on 'ser2'*/
ser2->y_points[0] = 90;
ser2->y_points[1] = 70;
ser2->y_points[2] = 65;
ser2->y_points[3] = 65;
ser2->y_points[4] = 65;
ser2->y_points[5] = 65;
ser2->y_points[6] = 65;
ser2->y_points[7] = 65;
ser2->y_points[8] = 65;
ser2->y_points[9] = 65;
lv_chart_refresh(chart); /*Required after direct set*/
}
#endif
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()
chart.set_type(lv.chart.TYPE.LINE) # Show lines and points too
# Add two data series
ser1 = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.SECONDARY_Y)
print(ser2)
# Set next points on ser1
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,30)
chart.set_next_value(ser1,70)
chart.set_next_value(ser1,90)
# Directly set points on 'ser2'
ser2.y_points = [90, 70, 65, 65, 65, 65, 65, 65, 65, 65]
chart.refresh() # Required after direct set
Faded area line chart with custom division lines¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_COMPLEX && LV_BUILD_EXAMPLES
static lv_obj_t * chart1;
static lv_chart_series_t * ser1;
static lv_chart_series_t * ser2;
static void draw_event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
/*Add the faded area before the lines are drawn*/
lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
if(dsc->part == LV_PART_ITEMS) {
if(!dsc->p1 || !dsc->p2) return;
/*Add a line mask that keeps the area below the line*/
lv_draw_mask_line_param_t line_mask_param;
lv_draw_mask_line_points_init(&line_mask_param, dsc->p1->x, dsc->p1->y, dsc->p2->x, dsc->p2->y,
LV_DRAW_MASK_LINE_SIDE_BOTTOM);
int16_t line_mask_id = lv_draw_mask_add(&line_mask_param, NULL);
/*Add a fade effect: transparent bottom covering top*/
lv_coord_t h = lv_obj_get_height(obj);
lv_draw_mask_fade_param_t fade_mask_param;
lv_draw_mask_fade_init(&fade_mask_param, &obj->coords, LV_OPA_COVER, obj->coords.y1 + h / 8, LV_OPA_TRANSP,
obj->coords.y2);
int16_t fade_mask_id = lv_draw_mask_add(&fade_mask_param, NULL);
/*Draw a rectangle that will be affected by the mask*/
lv_draw_rect_dsc_t draw_rect_dsc;
lv_draw_rect_dsc_init(&draw_rect_dsc);
draw_rect_dsc.bg_opa = LV_OPA_20;
draw_rect_dsc.bg_color = dsc->line_dsc->color;
lv_area_t a;
a.x1 = dsc->p1->x;
a.x2 = dsc->p2->x - 1;
a.y1 = LV_MIN(dsc->p1->y, dsc->p2->y);
a.y2 = obj->coords.y2;
lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);
/*Remove the masks*/
lv_draw_mask_free_param(&line_mask_param);
lv_draw_mask_free_param(&fade_mask_param);
lv_draw_mask_remove_id(line_mask_id);
lv_draw_mask_remove_id(fade_mask_id);
}
/*Hook the division lines too*/
else if(dsc->part == LV_PART_MAIN) {
if(dsc->line_dsc == NULL || dsc->p1 == NULL || dsc->p2 == NULL) return;
/*Vertical line*/
if(dsc->p1->x == dsc->p2->x) {
dsc->line_dsc->color = lv_palette_lighten(LV_PALETTE_GREY, 1);
if(dsc->id == 3) {
dsc->line_dsc->width = 2;
dsc->line_dsc->dash_gap = 0;
dsc->line_dsc->dash_width = 0;
}
else {
dsc->line_dsc->width = 1;
dsc->line_dsc->dash_gap = 6;
dsc->line_dsc->dash_width = 6;
}
}
/*Horizontal line*/
else {
if(dsc->id == 2) {
dsc->line_dsc->width = 2;
dsc->line_dsc->dash_gap = 0;
dsc->line_dsc->dash_width = 0;
}
else {
dsc->line_dsc->width = 2;
dsc->line_dsc->dash_gap = 6;
dsc->line_dsc->dash_width = 6;
}
if(dsc->id == 1 || dsc->id == 3) {
dsc->line_dsc->color = lv_palette_main(LV_PALETTE_GREEN);
}
else {
dsc->line_dsc->color = lv_palette_lighten(LV_PALETTE_GREY, 1);
}
}
}
}
static void add_data(lv_timer_t * timer)
{
LV_UNUSED(timer);
static uint32_t cnt = 0;
lv_chart_set_next_value(chart1, ser1, lv_rand(20, 90));
if(cnt % 4 == 0) lv_chart_set_next_value(chart1, ser2, lv_rand(40, 60));
cnt++;
}
/**
* Add a faded area effect to the line chart and make some division lines ticker
*/
void lv_example_chart_2(void)
{
/*Create a chart1*/
chart1 = lv_chart_create(lv_scr_act());
lv_obj_set_size(chart1, 200, 150);
lv_obj_center(chart1);
lv_chart_set_type(chart1, LV_CHART_TYPE_LINE); /*Show lines and points too*/
lv_chart_set_div_line_count(chart1, 5, 7);
lv_obj_add_event_cb(chart1, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
lv_chart_set_update_mode(chart1, LV_CHART_UPDATE_MODE_CIRCULAR);
/*Add two data series*/
ser1 = lv_chart_add_series(chart1, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
ser2 = lv_chart_add_series(chart1, lv_palette_main(LV_PALETTE_BLUE), LV_CHART_AXIS_SECONDARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
lv_chart_set_next_value(chart1, ser1, lv_rand(20, 90));
lv_chart_set_next_value(chart1, ser2, lv_rand(30, 70));
}
lv_timer_create(add_data, 200, NULL);
}
#endif
def draw_event_cb(e):
obj = e.get_target()
# Add the faded area before the lines are drawn
dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
if dsc.part != lv.PART.ITEMS:
return
if not dsc.p1 or not dsc.p2:
return
# Add a line mask that keeps the area below the line
line_mask_param = lv.draw_mask_line_param_t()
line_mask_param.points_init(dsc.p1.x, dsc.p1.y, dsc.p2.x, dsc.p2.y, lv.DRAW_MASK_LINE_SIDE.BOTTOM)
# line_mask_id = line_mask_param.draw_mask_add(None)
line_mask_id = lv.draw_mask_add(line_mask_param, None)
# Add a fade effect: transparent bottom covering top
h = obj.get_height()
fade_mask_param = lv.draw_mask_fade_param_t()
coords = lv.area_t()
obj.get_coords(coords)
fade_mask_param.init(coords, lv.OPA.COVER, coords.y1 + h // 8, lv.OPA.TRANSP,coords.y2)
fade_mask_id = lv.draw_mask_add(fade_mask_param,None)
# Draw a rectangle that will be affected by the mask
draw_rect_dsc = lv.draw_rect_dsc_t()
draw_rect_dsc.init()
draw_rect_dsc.bg_opa = lv.OPA._20
draw_rect_dsc.bg_color = dsc.line_dsc.color
a = lv.area_t()
a.x1 = dsc.p1.x
a.x2 = dsc.p2.x - 1
a.y1 = min(dsc.p1.y, dsc.p2.y)
coords = lv.area_t()
obj.get_coords(coords)
a.y2 = coords.y2
dsc.draw_ctx.rect(draw_rect_dsc, a)
# Remove the masks
lv.draw_mask_remove_id(line_mask_id)
lv.draw_mask_remove_id(fade_mask_id)
def add_data(timer):
# LV_UNUSED(timer);
cnt = 0
chart1.set_next_value(ser1, lv.rand(20, 90))
if cnt % 4 == 0:
chart1.set_next_value(ser2, lv.rand(40, 60))
cnt +=1
#
# Add a faded area effect to the line chart
#
# Create a chart1
chart1 = lv.chart(lv.scr_act())
chart1.set_size(200, 150)
chart1.center()
chart1.set_type(lv.chart.TYPE.LINE) # Show lines and points too
chart1.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
chart1.set_update_mode(lv.chart.UPDATE_MODE.CIRCULAR)
# Add two data series
ser1 = chart1.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart1.add_series(lv.palette_main(lv.PALETTE.BLUE), lv.chart.AXIS.SECONDARY_Y)
for i in range(10):
chart1.set_next_value(ser1, lv.rand(20, 90))
chart1.set_next_value(ser2, lv.rand(30, 70))
timer = lv.timer_create(add_data, 200, None)
Axis ticks and labels with scrolling¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
static void draw_event_cb(lv_event_t * e)
{
lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
if(!lv_obj_draw_part_check_type(dsc, &lv_chart_class, LV_CHART_DRAW_PART_TICK_LABEL)) return;
if(dsc->id == LV_CHART_AXIS_PRIMARY_X && dsc->text) {
const char * month[] = {"Jan", "Febr", "March", "Apr", "May", "Jun", "July", "Aug", "Sept", "Oct", "Nov", "Dec"};
lv_snprintf(dsc->text, dsc->text_length, "%s", month[dsc->value]);
}
}
/**
* Add ticks and labels to the axis and demonstrate scrolling
*/
void lv_example_chart_3(void)
{
/*Create a chart*/
lv_obj_t * chart;
chart = lv_chart_create(lv_scr_act());
lv_obj_set_size(chart, 200, 150);
lv_obj_center(chart);
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_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
/*Add ticks and label to every axis*/
lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 10, 5, 12, 3, true, 40);
lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 2, true, 50);
lv_chart_set_axis_tick(chart, LV_CHART_AXIS_SECONDARY_Y, 10, 5, 3, 4, true, 50);
/*Zoom in a little in X*/
lv_chart_set_zoom_x(chart, 800);
/*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_SECONDARY_Y);
/*Set the next points on 'ser1'*/
lv_chart_set_next_value(chart, ser1, 31);
lv_chart_set_next_value(chart, ser1, 66);
lv_chart_set_next_value(chart, ser1, 10);
lv_chart_set_next_value(chart, ser1, 89);
lv_chart_set_next_value(chart, ser1, 63);
lv_chart_set_next_value(chart, ser1, 56);
lv_chart_set_next_value(chart, ser1, 32);
lv_chart_set_next_value(chart, ser1, 35);
lv_chart_set_next_value(chart, ser1, 57);
lv_chart_set_next_value(chart, ser1, 85);
lv_chart_set_next_value(chart, ser1, 22);
lv_chart_set_next_value(chart, ser1, 58);
lv_coord_t * ser2_array = lv_chart_get_y_array(chart, ser2);
/*Directly set points on 'ser2'*/
ser2_array[0] = 92;
ser2_array[1] = 71;
ser2_array[2] = 61;
ser2_array[3] = 15;
ser2_array[4] = 21;
ser2_array[5] = 35;
ser2_array[6] = 35;
ser2_array[7] = 58;
ser2_array[8] = 31;
ser2_array[9] = 53;
ser2_array[10] = 33;
ser2_array[11] = 73;
lv_chart_refresh(chart); /*Required after direct set*/
}
#endif
def draw_event_cb(e):
dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
if dsc.part == lv.PART.TICKS and dsc.id == lv.chart.AXIS.PRIMARY_X:
month = ["Jan", "Febr", "March", "Apr", "May", "Jun", "July", "Aug", "Sept", "Oct", "Nov", "Dec"]
# dsc.text is defined char text[16], I must therefore convert the Python string to a byte_array
dsc.text = bytes(month[dsc.value],"ascii")
#
# Add ticks and labels to the axis and demonstrate scrolling
#
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()
chart.set_type(lv.chart.TYPE.BAR)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, 0, 100)
chart.set_range(lv.chart.AXIS.SECONDARY_Y, 0, 400)
chart.set_point_count(12)
chart.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
# Add ticks and label to every axis
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 10, 5, 12, 3, True, 40)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 2, True, 50)
chart.set_axis_tick(lv.chart.AXIS.SECONDARY_Y, 10, 5, 3, 4,True, 50)
# Zoom in a little in X
chart.set_zoom_x(800)
# Add two data series
ser1 = lv.chart.add_series(chart, lv.palette_lighten(lv.PALETTE.GREEN, 2), lv.chart.AXIS.PRIMARY_Y)
ser2 = lv.chart.add_series(chart, lv.palette_darken(lv.PALETTE.GREEN, 2), lv.chart.AXIS.SECONDARY_Y)
# Set the next points on 'ser1'
chart.set_next_value(ser1, 31)
chart.set_next_value(ser1, 66)
chart.set_next_value(ser1, 10)
chart.set_next_value(ser1, 89)
chart.set_next_value(ser1, 63)
chart.set_next_value(ser1, 56)
chart.set_next_value(ser1, 32)
chart.set_next_value(ser1, 35)
chart.set_next_value(ser1, 57)
chart.set_next_value(ser1, 85)
chart.set_next_value(ser1, 22)
chart.set_next_value(ser1, 58)
# Directly set points on 'ser2'
ser2.y_points = [92,71,61,15,21,35,35,58,31,53,33,73]
chart.refresh() # Required after direct set
Show the value of the pressed points¶
C code
GitHub#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) {
lv_coord_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);
lv_coord_t * y_array = lv_chart_get_y_array(chart, ser);
lv_coord_t value = y_array[id];
char buf[16];
lv_snprintf(buf, sizeof(buf), LV_SYMBOL_DUMMY"$%d", value);
lv_draw_rect_dsc_t draw_rect_dsc;
lv_draw_rect_dsc_init(&draw_rect_dsc);
draw_rect_dsc.bg_color = lv_color_black();
draw_rect_dsc.bg_opa = LV_OPA_50;
draw_rect_dsc.radius = 3;
draw_rect_dsc.bg_img_src = buf;
draw_rect_dsc.bg_img_recolor = lv_color_white();
lv_area_t a;
a.x1 = chart->coords.x1 + p.x - 20;
a.x2 = chart->coords.x1 + p.x + 20;
a.y1 = chart->coords.y1 + p.y - 30;
a.y2 = chart->coords.y1 + p.y - 10;
lv_draw_ctx_t * draw_ctx = lv_event_get_draw_ctx(e);
lv_draw_rect(draw_ctx, &draw_rect_dsc, &a);
ser = lv_chart_get_series_next(chart, ser);
}
}
else if(code == LV_EVENT_RELEASED) {
lv_obj_invalidate(chart);
}
}
/**
* Show the value of the pressed points
*/
void lv_example_chart_4(void)
{
/*Create a chart*/
lv_obj_t * chart;
chart = lv_chart_create(lv_scr_act());
lv_obj_set_size(chart, 200, 150);
lv_obj_center(chart);
lv_obj_add_event_cb(chart, event_cb, LV_EVENT_ALL, NULL);
lv_obj_refresh_ext_draw_size(chart);
/*Zoom in a little in X*/
lv_chart_set_zoom_x(chart, 800);
/*Add two data series*/
lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_PRIMARY_Y);
uint32_t i;
for(i = 0; i < 10; i++) {
lv_chart_set_next_value(chart, ser1, lv_rand(60, 90));
lv_chart_set_next_value(chart, ser2, lv_rand(10, 40));
}
}
#endif
def event_cb(e):
code = e.get_code()
chart = e.get_target()
if code == lv.EVENT.VALUE_CHANGED:
chart.invalidate()
if code == lv.EVENT.REFR_EXT_DRAW_SIZE:
e.set_ext_draw_size(20)
elif code == lv.EVENT.DRAW_POST_END:
id = lv.chart.get_pressed_point(chart)
if id == lv.CHART_POINT.NONE:
return
# print("Selected point ", id)
for i in range(len(series)):
p = lv.point_t()
chart.get_point_pos_by_id(series[i], id, p)
value = series_points[i][id]
buf = lv.SYMBOL.DUMMY + "$" + str(value)
draw_rect_dsc = lv.draw_rect_dsc_t()
draw_rect_dsc.init()
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_img_src = buf
draw_rect_dsc.bg_img_recolor = lv.color_white()
a = lv.area_t()
coords = lv.area_t()
chart.get_coords(coords)
a.x1 = coords.x1 + p.x - 20
a.x2 = coords.x1 + p.x + 20
a.y1 = coords.y1 + p.y - 30
a.y2 = coords.y1 + p.y - 10
clip_area = lv.area_t.__cast__(e.get_param())
lv.draw_rect(a, clip_area, draw_rect_dsc)
elif code == lv.EVENT.RELEASED:
chart.invalidate()
#
# Add ticks and labels to the axis and demonstrate scrolling
#
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()
chart.add_event_cb(event_cb, lv.EVENT.ALL, None)
chart.refresh_ext_draw_size()
# Zoom in a little in X
chart.set_zoom_x(800)
# Add two data series
ser1 = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.PRIMARY_Y)
ser1_p = []
ser2_p = []
for i in range(10):
ser1_p.append(lv.rand(60,90))
ser2_p.append(lv.rand(10,40))
ser1.y_points = ser1_p
ser2.y_points = ser2_p
series = [ser1,ser2]
series_points=[ser1_p,ser2_p]
Display 1000 data points with zooming and scrolling¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_USE_SLIDER && LV_BUILD_EXAMPLES
static lv_obj_t * chart;
/* Source: https://github.com/ankur219/ECG-Arrhythmia-classification/blob/642230149583adfae1e4bd26c6f0e1fd8af2be0e/sample.csv*/
static const lv_coord_t ecg_sample[] = {
-2, 2, 0, -15, -39, -63, -71, -68, -67, -69, -84, -95, -104, -107, -108, -107, -107, -107, -107, -114, -118, -117,
-112, -100, -89, -83, -71, -64, -58, -58, -62, -62, -58, -51, -46, -39, -27, -10, 4, 7, 1, -3, 0, 14, 24, 30, 25, 19,
13, 7, 12, 15, 18, 21, 13, 6, 9, 8, 17, 19, 13, 11, 11, 11, 23, 30, 37, 34, 25, 14, 15, 19, 28, 31, 26, 23, 25, 31,
39, 37, 37, 34, 30, 32, 22, 29, 31, 33, 37, 23, 13, 7, 2, 4, -2, 2, 11, 22, 33, 19, -1, -27, -55, -67, -72, -71, -63,
-49, -18, 35, 113, 230, 369, 525, 651, 722, 730, 667, 563, 454, 357, 305, 288, 274, 255, 212, 173, 143, 117, 82, 39,
-13, -53, -78, -91, -101, -113, -124, -131, -131, -131, -129, -128, -129, -125, -123, -123, -129, -139, -148, -153,
-159, -166, -183, -205, -227, -243, -248, -246, -254, -280, -327, -381, -429, -473, -517, -556, -592, -612, -620,
-620, -614, -604, -591, -574, -540, -497, -441, -389, -358, -336, -313, -284, -222, -167, -114, -70, -47, -28, -4, 12,
38, 52, 58, 56, 56, 57, 68, 77, 86, 86, 80, 69, 67, 70, 82, 85, 89, 90, 89, 89, 88, 91, 96, 97, 91, 83, 78, 82, 88, 95,
96, 105, 106, 110, 102, 100, 96, 98, 97, 101, 98, 99, 100, 107, 113, 119, 115, 110, 96, 85, 73, 64, 69, 76, 79,
78, 75, 85, 100, 114, 113, 105, 96, 84, 74, 66, 60, 75, 85, 89, 83, 67, 61, 67, 73, 79, 74, 63, 57, 56, 58, 61, 55,
48, 45, 46, 55, 62, 55, 49, 43, 50, 59, 63, 57, 40, 31, 23, 25, 27, 31, 35, 34, 30, 36, 34, 42, 38, 36, 40, 46, 50,
47, 32, 30, 32, 52, 67, 73, 71, 63, 54, 53, 45, 41, 28, 13, 3, 1, 4, 4, -8, -23, -32, -31, -19, -5, 3, 9, 13, 19,
24, 27, 29, 25, 22, 26, 32, 42, 51, 56, 60, 57, 55, 53, 53, 54, 59, 54, 49, 26, -3, -11, -20, -47, -100, -194, -236,
-212, -123, 8, 103, 142, 147, 120, 105, 98, 93, 81, 61, 40, 26, 28, 30, 30, 27, 19, 17, 21, 20, 19, 19, 22, 36, 40,
35, 20, 7, 1, 10, 18, 27, 22, 6, -4, -2, 3, 6, -2, -13, -14, -10, -2, 3, 2, -1, -5, -10, -19, -32, -42, -55, -60,
-68, -77, -86, -101, -110, -117, -115, -104, -92, -84, -85, -84, -73, -65, -52, -50, -45, -35, -20, -3, 12, 20, 25,
26, 28, 28, 30, 28, 25, 28, 33, 42, 42, 36, 23, 9, 0, 1, -4, 1, -4, -4, 1, 5, 9, 9, -3, -1, -18, -50, -108, -190,
-272, -340, -408, -446, -537, -643, -777, -894, -920, -853, -697, -461, -251, -60, 58, 103, 129, 139, 155, 170, 173,
178, 185, 190, 193, 200, 208, 215, 225, 224, 232, 234, 240, 240, 236, 229, 226, 224, 232, 233, 232, 224, 219, 219,
223, 231, 226, 223, 219, 218, 223, 223, 223, 233, 245, 268, 286, 296, 295, 283, 271, 263, 252, 243, 226, 210, 197,
186, 171, 152, 133, 117, 114, 110, 107, 96, 80, 63, 48, 40, 38, 34, 28, 15, 2, -7, -11, -14, -18, -29, -37, -44, -50,
-58, -63, -61, -52, -50, -48, -61, -59, -58, -54, -47, -52, -62, -61, -64, -54, -52, -59, -69, -76, -76, -69, -67,
-74, -78, -81, -80, -73, -65, -57, -53, -51, -47, -35, -27, -22, -22, -24, -21, -17, -13, -10, -11, -13, -20, -20,
-12, -2, 7, -1, -12, -16, -13, -2, 2, -4, -5, -2, 9, 19, 19, 14, 11, 13, 19, 21, 20, 18, 19, 19, 19, 16, 15, 13, 14,
9, 3, -5, -9, -5, -3, -2, -3, -3, 2, 8, 9, 9, 5, 6, 8, 8, 7, 4, 3, 4, 5, 3, 5, 5, 13, 13, 12, 10, 10, 15, 22, 17,
14, 7, 10, 15, 16, 11, 12, 10, 13, 9, -2, -4, -2, 7, 16, 16, 17, 16, 7, -1, -16, -18, -16, -9, -4, -5, -10, -9, -8,
-3, -4, -10, -19, -20, -16, -9, -9, -23, -40, -48, -43, -33, -19, -21, -26, -31, -33, -19, 0, 17, 24, 9, -17, -47,
-63, -67, -59, -52, -51, -50, -49, -42, -26, -21, -15, -20, -23, -22, -19, -12, -8, 5, 18, 27, 32, 26, 25, 26, 22,
23, 17, 14, 17, 21, 25, 2, -45, -121, -196, -226, -200, -118, -9, 73, 126, 131, 114, 87, 60, 42, 29, 26, 34, 35, 34,
25, 12, 9, 7, 3, 2, -8, -11, 2, 23, 38, 41, 23, 9, 10, 13, 16, 8, -8, -17, -23, -26, -25, -21, -15, -10, -13, -13,
-19, -22, -29, -40, -48, -48, -54, -55, -66, -82, -85, -90, -92, -98, -114, -119, -124, -129, -132, -146, -146, -138,
-124, -99, -85, -72, -65, -65, -65, -66, -63, -64, -64, -58, -46, -26, -9, 2, 2, 4, 0, 1, 4, 3, 10, 11, 10, 2, -4,
0, 10, 18, 20, 6, 2, -9, -7, -3, -3, -2, -7, -12, -5, 5, 24, 36, 31, 25, 6, 3, 7, 12, 17, 11, 0, -6, -9, -8, -7, -5,
-6, -2, -2, -6, -2, 2, 14, 24, 22, 15, 8, 4, 6, 7, 12, 16, 25, 20, 7, -16, -41, -60, -67, -65, -54, -35, -11, 30,
84, 175, 302, 455, 603, 707, 743, 714, 625, 519, 414, 337, 300, 281, 263, 239, 197, 163, 136, 109, 77, 34, -18, -50,
-66, -74, -79, -92, -107, -117, -127, -129, -135, -139, -141, -155, -159, -167, -171, -169, -174, -175, -178, -191,
-202, -223, -235, -243, -237, -240, -256, -298, -345, -393, -432, -475, -518, -565, -596, -619, -623, -623, -614,
-599, -583, -559, -524, -477, -425, -383, -357, -331, -301, -252, -198, -143, -96, -57, -29, -8, 10, 31, 45, 60, 65,
70, 74, 76, 79, 82, 79, 75, 62,
};
static void slider_x_event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
int32_t v = lv_slider_get_value(obj);
lv_chart_set_zoom_x(chart, v);
}
static void slider_y_event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
int32_t v = lv_slider_get_value(obj);
lv_chart_set_zoom_y(chart, v);
}
/**
* Display 1000 data points with zooming and scrolling.
* See how the chart changes drawing mode (draw only vertical lines) when
* the points get too crowded.
*/
void lv_example_chart_5(void)
{
/*Create a chart*/
chart = lv_chart_create(lv_scr_act());
lv_obj_set_size(chart, 200, 150);
lv_obj_align(chart, LV_ALIGN_CENTER, -30, -30);
lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, -1000, 1000);
/*Do not display points on the data*/
lv_obj_set_style_size(chart, 0, LV_PART_INDICATOR);
lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
uint32_t pcnt = sizeof(ecg_sample) / sizeof(ecg_sample[0]);
lv_chart_set_point_count(chart, pcnt);
lv_chart_set_ext_y_array(chart, ser, (lv_coord_t *)ecg_sample);
lv_obj_t * slider;
slider = lv_slider_create(lv_scr_act());
lv_slider_set_range(slider, LV_IMG_ZOOM_NONE, LV_IMG_ZOOM_NONE * 10);
lv_obj_add_event_cb(slider, slider_x_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
lv_obj_set_size(slider, 200, 10);
lv_obj_align_to(slider, chart, LV_ALIGN_OUT_BOTTOM_MID, 0, 20);
slider = lv_slider_create(lv_scr_act());
lv_slider_set_range(slider, LV_IMG_ZOOM_NONE, LV_IMG_ZOOM_NONE * 10);
lv_obj_add_event_cb(slider, slider_y_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
lv_obj_set_size(slider, 10, 150);
lv_obj_align_to(slider, chart, LV_ALIGN_OUT_RIGHT_MID, 20, 0);
}
#endif
# Source: https://github.com/ankur219/ECG-Arrhythmia-classification/blob/642230149583adfae1e4bd26c6f0e1fd8af2be0e/sample.csv
ecg_sample = [
-2, 2, 0, -15, -39, -63, -71, -68, -67, -69, -84, -95, -104, -107, -108, -107, -107, -107, -107, -114, -118, -117,
-112, -100, -89, -83, -71, -64, -58, -58, -62, -62, -58, -51, -46, -39, -27, -10, 4, 7, 1, -3, 0, 14, 24, 30, 25, 19,
13, 7, 12, 15, 18, 21, 13, 6, 9, 8, 17, 19, 13, 11, 11, 11, 23, 30, 37, 34, 25, 14, 15, 19, 28, 31, 26, 23, 25, 31,
39, 37, 37, 34, 30, 32, 22, 29, 31, 33, 37, 23, 13, 7, 2, 4, -2, 2, 11, 22, 33, 19, -1, -27, -55, -67, -72, -71, -63,
-49, -18, 35, 113, 230, 369, 525, 651, 722, 730, 667, 563, 454, 357, 305, 288, 274, 255, 212, 173, 143, 117, 82, 39,
-13, -53, -78, -91, -101, -113, -124, -131, -131, -131, -129, -128, -129, -125, -123, -123, -129, -139, -148, -153,
-159, -166, -183, -205, -227, -243, -248, -246, -254, -280, -327, -381, -429, -473, -517, -556, -592, -612, -620,
-620, -614, -604, -591, -574, -540, -497, -441, -389, -358, -336, -313, -284, -222, -167, -114, -70, -47, -28, -4, 12,
38, 52, 58, 56, 56, 57, 68, 77, 86, 86, 80, 69, 67, 70, 82, 85, 89, 90, 89, 89, 88, 91, 96, 97, 91, 83, 78, 82, 88, 95,
96, 105, 106, 110, 102, 100, 96, 98, 97, 101, 98, 99, 100, 107, 113, 119, 115, 110, 96, 85, 73, 64, 69, 76, 79,
78, 75, 85, 100, 114, 113, 105, 96, 84, 74, 66, 60, 75, 85, 89, 83, 67, 61, 67, 73, 79, 74, 63, 57, 56, 58, 61, 55,
48, 45, 46, 55, 62, 55, 49, 43, 50, 59, 63, 57, 40, 31, 23, 25, 27, 31, 35, 34, 30, 36, 34, 42, 38, 36, 40, 46, 50,
47, 32, 30, 32, 52, 67, 73, 71, 63, 54, 53, 45, 41, 28, 13, 3, 1, 4, 4, -8, -23, -32, -31, -19, -5, 3, 9, 13, 19,
24, 27, 29, 25, 22, 26, 32, 42, 51, 56, 60, 57, 55, 53, 53, 54, 59, 54, 49, 26, -3, -11, -20, -47, -100, -194, -236,
-212, -123, 8, 103, 142, 147, 120, 105, 98, 93, 81, 61, 40, 26, 28, 30, 30, 27, 19, 17, 21, 20, 19, 19, 22, 36, 40,
35, 20, 7, 1, 10, 18, 27, 22, 6, -4, -2, 3, 6, -2, -13, -14, -10, -2, 3, 2, -1, -5, -10, -19, -32, -42, -55, -60,
-68, -77, -86, -101, -110, -117, -115, -104, -92, -84, -85, -84, -73, -65, -52, -50, -45, -35, -20, -3, 12, 20, 25,
26, 28, 28, 30, 28, 25, 28, 33, 42, 42, 36, 23, 9, 0, 1, -4, 1, -4, -4, 1, 5, 9, 9, -3, -1, -18, -50, -108, -190,
-272, -340, -408, -446, -537, -643, -777, -894, -920, -853, -697, -461, -251, -60, 58, 103, 129, 139, 155, 170, 173,
178, 185, 190, 193, 200, 208, 215, 225, 224, 232, 234, 240, 240, 236, 229, 226, 224, 232, 233, 232, 224, 219, 219,
223, 231, 226, 223, 219, 218, 223, 223, 223, 233, 245, 268, 286, 296, 295, 283, 271, 263, 252, 243, 226, 210, 197,
186, 171, 152, 133, 117, 114, 110, 107, 96, 80, 63, 48, 40, 38, 34, 28, 15, 2, -7, -11, -14, -18, -29, -37, -44, -50,
-58, -63, -61, -52, -50, -48, -61, -59, -58, -54, -47, -52, -62, -61, -64, -54, -52, -59, -69, -76, -76, -69, -67,
-74, -78, -81, -80, -73, -65, -57, -53, -51, -47, -35, -27, -22, -22, -24, -21, -17, -13, -10, -11, -13, -20, -20,
-12, -2, 7, -1, -12, -16, -13, -2, 2, -4, -5, -2, 9, 19, 19, 14, 11, 13, 19, 21, 20, 18, 19, 19, 19, 16, 15, 13, 14,
9, 3, -5, -9, -5, -3, -2, -3, -3, 2, 8, 9, 9, 5, 6, 8, 8, 7, 4, 3, 4, 5, 3, 5, 5, 13, 13, 12, 10, 10, 15, 22, 17,
14, 7, 10, 15, 16, 11, 12, 10, 13, 9, -2, -4, -2, 7, 16, 16, 17, 16, 7, -1, -16, -18, -16, -9, -4, -5, -10, -9, -8,
-3, -4, -10, -19, -20, -16, -9, -9, -23, -40, -48, -43, -33, -19, -21, -26, -31, -33, -19, 0, 17, 24, 9, -17, -47,
-63, -67, -59, -52, -51, -50, -49, -42, -26, -21, -15, -20, -23, -22, -19, -12, -8, 5, 18, 27, 32, 26, 25, 26, 22,
23, 17, 14, 17, 21, 25, 2, -45, -121, -196, -226, -200, -118, -9, 73, 126, 131, 114, 87, 60, 42, 29, 26, 34, 35, 34,
25, 12, 9, 7, 3, 2, -8, -11, 2, 23, 38, 41, 23, 9, 10, 13, 16, 8, -8, -17, -23, -26, -25, -21, -15, -10, -13, -13,
-19, -22, -29, -40, -48, -48, -54, -55, -66, -82, -85, -90, -92, -98, -114, -119, -124, -129, -132, -146, -146, -138,
-124, -99, -85, -72, -65, -65, -65, -66, -63, -64, -64, -58, -46, -26, -9, 2, 2, 4, 0, 1, 4, 3, 10, 11, 10, 2, -4,
0, 10, 18, 20, 6, 2, -9, -7, -3, -3, -2, -7, -12, -5, 5, 24, 36, 31, 25, 6, 3, 7, 12, 17, 11, 0, -6, -9, -8, -7, -5,
-6, -2, -2, -6, -2, 2, 14, 24, 22, 15, 8, 4, 6, 7, 12, 16, 25, 20, 7, -16, -41, -60, -67, -65, -54, -35, -11, 30,
84, 175, 302, 455, 603, 707, 743, 714, 625, 519, 414, 337, 300, 281, 263, 239, 197, 163, 136, 109, 77, 34, -18, -50,
-66, -74, -79, -92, -107, -117, -127, -129, -135, -139, -141, -155, -159, -167, -171, -169, -174, -175, -178, -191,
-202, -223, -235, -243, -237, -240, -256, -298, -345, -393, -432, -475, -518, -565, -596, -619, -623, -623, -614,
-599, -583, -559, -524, -477, -425, -383, -357, -331, -301, -252, -198, -143, -96, -57, -29, -8, 10, 31, 45, 60, 65,
70, 74, 76, 79, 82, 79, 75, 62,
]
def slider_x_event_cb(e):
slider = e.get_target()
v = slider.get_value()
chart.set_zoom_x(v)
def slider_y_event_cb(e):
slider = e.get_target()
v = slider.get_value()
chart.set_zoom_y(v)
#
# Display 1000 data points with zooming and scrolling.
# See how the chart changes drawing mode (draw only vertical lines) when
# the points get too crowded.
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.align(lv.ALIGN.CENTER, -30, -30)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, -1000, 1000)
# Do not display points on the data
chart.set_style_size(0, lv.PART.INDICATOR)
ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
pcnt = len(ecg_sample)
chart.set_point_count(pcnt)
chart.set_ext_y_array(ser, ecg_sample)
slider = lv.slider(lv.scr_act())
slider.set_range(lv.IMG_ZOOM.NONE, lv.IMG_ZOOM.NONE * 10)
slider.add_event_cb(slider_x_event_cb, lv.EVENT.VALUE_CHANGED, None)
slider.set_size(200,10)
slider.align_to(chart, lv.ALIGN.OUT_BOTTOM_MID, 0, 20)
slider = lv.slider(lv.scr_act())
slider.set_range(lv.IMG_ZOOM.NONE, lv.IMG_ZOOM.NONE * 10)
slider.add_event_cb(slider_y_event_cb, lv.EVENT.VALUE_CHANGED, None)
slider.set_size(10, 150)
slider.align_to(chart, lv.ALIGN.OUT_RIGHT_MID, 20, 0)
Show cursor on the clicked point¶
C code
GitHub#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 event_cb(lv_event_t * e)
{
static int32_t last_id = -1;
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) {
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);
}
}
else if(code == LV_EVENT_DRAW_PART_END) {
lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
if(!lv_obj_draw_part_check_type(dsc, &lv_chart_class, LV_CHART_DRAW_PART_CURSOR)) return;
if(dsc->p1 == NULL || dsc->p2 == NULL || dsc->p1->y != dsc->p2->y || last_id < 0) return;
lv_coord_t * data_array = lv_chart_get_y_array(chart, ser);
lv_coord_t v = data_array[last_id];
char buf[16];
lv_snprintf(buf, sizeof(buf), "%d", v);
lv_point_t size;
lv_txt_get_size(&size, buf, LV_FONT_DEFAULT, 0, 0, LV_COORD_MAX, LV_TEXT_FLAG_NONE);
lv_area_t a;
a.y2 = dsc->p1->y - 5;
a.y1 = a.y2 - size.y - 10;
a.x1 = dsc->p1->x + 10;
a.x2 = a.x1 + size.x + 10;
lv_draw_rect_dsc_t draw_rect_dsc;
lv_draw_rect_dsc_init(&draw_rect_dsc);
draw_rect_dsc.bg_color = lv_palette_main(LV_PALETTE_BLUE);
draw_rect_dsc.radius = 3;
lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);
lv_draw_label_dsc_t draw_label_dsc;
lv_draw_label_dsc_init(&draw_label_dsc);
draw_label_dsc.color = lv_color_white();
a.x1 += 5;
a.x2 -= 5;
a.y1 += 5;
a.y2 -= 5;
lv_draw_label(dsc->draw_ctx, &draw_label_dsc, &a, buf, NULL);
}
}
/**
* Show cursor on the clicked point
*/
void lv_example_chart_6(void)
{
chart = lv_chart_create(lv_scr_act());
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, event_cb, LV_EVENT_ALL, 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_zoom_x(chart, 500);
lv_obj_t * label = lv_label_create(lv_scr_act());
lv_label_set_text(label, "Click on a point");
lv_obj_align_to(label, chart, LV_ALIGN_OUT_TOP_MID, 0, -5);
}
#endif
class ExampleChart_6():
def __init__(self):
self.last_id = -1
#
# Show cursor on the clicked point
#
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.align(lv.ALIGN.CENTER, 0, -10)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 5, True, 40)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 10, 5, 10, 1, True, 30)
chart.add_event_cb(self.event_cb, lv.EVENT.ALL, None)
chart.refresh_ext_draw_size()
self.cursor = chart.add_cursor(lv.palette_main(lv.PALETTE.BLUE), lv.DIR.LEFT | lv.DIR.BOTTOM)
self.ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
self.ser_p = []
for i in range(10):
self.ser_p.append(lv.rand(10,90))
self.ser.y_points = self.ser_p
newser = chart.get_series_next(None)
# print("length of data points: ",len(newser.points))
chart.set_zoom_x(500)
label = lv.label(lv.scr_act())
label.set_text("Click on a point")
label.align_to(chart, lv.ALIGN.OUT_TOP_MID, 0, -5)
def event_cb(self,e):
code = e.get_code()
chart = e.get_target()
if code == lv.EVENT.VALUE_CHANGED:
# print("last_id: ",self.last_id)
self.last_id = chart.get_pressed_point()
if self.last_id != lv.CHART_POINT.NONE:
p = lv.point_t()
chart.get_point_pos_by_id(self.ser, self.last_id, p)
chart.set_cursor_point(self.cursor, None, self.last_id)
elif code == lv.EVENT.DRAW_PART_END:
# print("EVENT.DRAW_PART_END")
dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
# if dsc.p1 and dsc.p2:
# print("p1, p2", dsc.p1,dsc.p2)
# print("p1.y, p2.y", dsc.p1.y, dsc.p2.y)
# print("last_id: ",self.last_id)
if dsc.part == lv.PART.CURSOR and dsc.p1 and dsc.p2 and dsc.p1.y == dsc.p2.y and self.last_id >= 0:
v = self.ser_p[self.last_id]
# print("value: ",v)
value_txt = str(v)
size = lv.point_t()
lv.txt_get_size(size, value_txt, lv.font_default(), 0, 0, lv.COORD.MAX, lv.TEXT_FLAG.NONE)
a = lv.area_t()
a.y2 = dsc.p1.y - 5
a.y1 = a.y2 - size.y - 10
a.x1 = dsc.p1.x + 10
a.x2 = a.x1 + size.x + 10
draw_rect_dsc = lv.draw_rect_dsc_t()
draw_rect_dsc.init()
draw_rect_dsc.bg_color = lv.palette_main(lv.PALETTE.BLUE)
draw_rect_dsc.radius = 3
lv.draw_rect(a, dsc.clip_area, draw_rect_dsc)
draw_label_dsc = lv.draw_label_dsc_t()
draw_label_dsc.init()
draw_label_dsc.color = lv.color_white()
a.x1 += 5
a.x2 -= 5
a.y1 += 5
a.y2 -= 5
lv.draw_label(a, dsc.clip_area, draw_label_dsc, value_txt, None)
example_chart_6 = ExampleChart_6()
Scatter chart¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES
static void draw_event_cb(lv_event_t * e)
{
lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
if(dsc->part == LV_PART_ITEMS) {
lv_obj_t * obj = lv_event_get_target(e);
lv_chart_series_t * ser = lv_chart_get_series_next(obj, NULL);
uint32_t cnt = lv_chart_get_point_count(obj);
/*Make older value more transparent*/
dsc->rect_dsc->bg_opa = (LV_OPA_COVER * dsc->id) / (cnt - 1);
/*Make smaller values blue, higher values red*/
lv_coord_t * x_array = lv_chart_get_x_array(obj, ser);
lv_coord_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 + dsc->id) % 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;
dsc->rect_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_scr_act());
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_PART_BEGIN, NULL);
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_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 5, 5, 5, 1, true, 30);
lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 50);
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
#!/opt/bin/lv_micropython -i
import utime as time
import lvgl as lv
import display_driver
def draw_event_cb(e):
dsc = e.get_draw_part_dsc()
if dsc.part == lv.PART.ITEMS:
obj = e.get_target()
ser = obj.get_series_next(None)
cnt = obj.get_point_count()
# print("cnt: ",cnt)
# Make older value more transparent
dsc.rect_dsc.bg_opa = (lv.OPA.COVER * dsc.id) // (cnt - 1)
# Make smaller values blue, higher values red
# x_array = chart.get_x_array(ser)
# y_array = chart.get_y_array(ser)
# dsc->id is the tells drawing order, but we need the ID of the point being drawn.
start_point = chart.get_x_start_point(ser)
# print("start point: ",start_point)
p_act = (start_point + dsc.id) % cnt # Consider start point to get the index of the array
# print("p_act", p_act)
x_opa = (x_array[p_act] * lv.OPA._50) // 200
y_opa = (y_array[p_act] * lv.OPA._50) // 1000
dsc.rect_dsc.bg_color = lv.palette_main(lv.PALETTE.RED).color_mix(
lv.palette_main(lv.PALETTE.BLUE),
x_opa + y_opa)
def add_data(timer,chart):
# print("add_data")
x = lv.rand(0,200)
y = lv.rand(0,1000)
chart.set_next_value2(ser, x, y)
# chart.set_next_value2(chart.gx, y)
x_array.pop(0)
x_array.append(x)
y_array.pop(0)
y_array.append(y)
#
# A scatter chart
#
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.align(lv.ALIGN.CENTER, 0, 0)
chart.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
chart.set_style_line_width(0, lv.PART.ITEMS) # Remove the lines
chart.set_type(lv.chart.TYPE.SCATTER)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 5, 5, 5, 1, True, 30)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 5, True, 50)
chart.set_range(lv.chart.AXIS.PRIMARY_X, 0, 200)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, 0, 1000)
chart.set_point_count(50)
ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
x_array = []
y_array = []
for i in range(50):
x_array.append(lv.rand(0, 200))
y_array.append(lv.rand(0, 1000))
ser.x_points = x_array
ser.y_points = y_array
# Create an `lv_timer` to update the chart.
timer = lv.timer_create_basic()
timer.set_period(100)
timer.set_cb(lambda src: add_data(timer,chart))
Stacked area chart¶
C code
GitHub#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_COMPLEX && LV_BUILD_EXAMPLES
/* A struct is used to keep track of the series list because later we need to draw to the series in the reverse order to which they were initialised. */
typedef struct {
lv_obj_t * obj;
lv_chart_series_t * series_list[3];
} stacked_area_chart_t;
static stacked_area_chart_t stacked_area_chart;
/**
* Callback which draws the blocks of colour under the lines
**/
static void draw_event_cb(lv_event_t * e)
{
lv_obj_t * obj = lv_event_get_target(e);
/*Add the faded area before the lines are drawn*/
lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
if(dsc->part == LV_PART_ITEMS) {
if(!dsc->p1 || !dsc->p2)
return;
/*Add a line mask that keeps the area below the line*/
lv_draw_mask_line_param_t line_mask_param;
lv_draw_mask_line_points_init(&line_mask_param, dsc->p1->x, dsc->p1->y, dsc->p2->x, dsc->p2->y,
LV_DRAW_MASK_LINE_SIDE_BOTTOM);
int16_t line_mask_id = lv_draw_mask_add(&line_mask_param, NULL);
/*Draw a rectangle that will be affected by the mask*/
lv_draw_rect_dsc_t draw_rect_dsc;
lv_draw_rect_dsc_init(&draw_rect_dsc);
draw_rect_dsc.bg_opa = LV_OPA_COVER;
draw_rect_dsc.bg_color = dsc->line_dsc->color;
lv_area_t a;
a.x1 = dsc->p1->x;
a.x2 = dsc->p2->x;
a.y1 = LV_MIN(dsc->p1->y, dsc->p2->y);
a.y2 = obj->coords.y2 -
13; /* -13 cuts off where the rectangle draws over the chart margin. Without this an area of 0 doesn't look like 0 */
lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);
/*Remove the mask*/
lv_draw_mask_free_param(&line_mask_param);
lv_draw_mask_remove_id(line_mask_id);
}
}
/**
* Helper function to round a fixed point number
**/
static int32_t round_fixed_point(int32_t n, int8_t shift)
{
/* Create a bitmask to isolates the decimal part of the fixed point number */
int32_t mask = 1;
for(int32_t bit_pos = 0; bit_pos < shift; bit_pos++) {
mask = (mask << 1) + 1;
}
int32_t decimal_part = n & mask;
/* Get 0.5 as fixed point */
int32_t rounding_boundary = 1 << (shift - 1);
/* Return either the integer part of n or the integer part + 1 */
return (decimal_part < rounding_boundary) ? (n & ~mask) : ((n >> shift) + 1) << shift;
}
/**
* Stacked area chart
*/
void lv_example_chart_8(void)
{
/*Create a stacked_area_chart.obj*/
stacked_area_chart.obj = lv_chart_create(lv_scr_act());
lv_obj_set_size(stacked_area_chart.obj, 200, 150);
lv_obj_center(stacked_area_chart.obj);
lv_chart_set_type(stacked_area_chart.obj, LV_CHART_TYPE_LINE);
lv_chart_set_div_line_count(stacked_area_chart.obj, 5, 7);
lv_obj_add_event_cb(stacked_area_chart.obj, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
/* Set range to 0 to 100 for percentages. Draw ticks */
lv_chart_set_range(stacked_area_chart.obj, LV_CHART_AXIS_PRIMARY_Y, 0, 100);
lv_chart_set_axis_tick(stacked_area_chart.obj, LV_CHART_AXIS_PRIMARY_Y, 3, 0, 5, 1, true, 30);
/*Set point size to 0 so the lines are smooth */
lv_obj_set_style_size(stacked_area_chart.obj, 0, LV_PART_INDICATOR);
/*Add some data series*/
stacked_area_chart.series_list[0] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_RED),
LV_CHART_AXIS_PRIMARY_Y);
stacked_area_chart.series_list[1] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_BLUE),
LV_CHART_AXIS_PRIMARY_Y);
stacked_area_chart.series_list[2] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_GREEN),
LV_CHART_AXIS_PRIMARY_Y);
for(int point = 0; point < 10; point++) {
/* Make some random data */
uint32_t vals[3] = {lv_rand(10, 20), lv_rand(20, 30), lv_rand(20, 30)};
int8_t fixed_point_shift = 5;
uint32_t total = vals[0] + vals[1] + vals[2];
uint32_t draw_heights[3];
uint32_t int_sum = 0;
uint32_t decimal_sum = 0;
/* Fixed point cascade rounding ensures percentages add to 100 */
for(int32_t series_index = 0; series_index < 3; series_index++) {
decimal_sum += (((vals[series_index] * 100) << fixed_point_shift) / total);
int_sum += (vals[series_index] * 100) / total;
int32_t modifier = (round_fixed_point(decimal_sum, fixed_point_shift) >> fixed_point_shift) - int_sum;
/* The draw heights are equal to the percentage of the total each value is + the cumulative sum of the previous percentages.
The accumulation is how the values get "stacked" */
draw_heights[series_index] = int_sum + modifier;
/* Draw to the series in the reverse order to which they were initialised.
Without this the higher values will draw on top of the lower ones.
This is because the Z-height of a series matches the order it was initialised */
lv_chart_set_next_value(stacked_area_chart.obj, stacked_area_chart.series_list[3 - series_index - 1],
draw_heights[series_index]);
}
}
lv_chart_refresh(stacked_area_chart.obj);
}
#endif
import display_driver
import lvgl as lv
# A class is used to keep track of the series list because later we
# need to draw to the series in the reverse order to which they were initialised.
class StackedAreaChart:
def __init__(self):
self.obj = None
self.series_list = [None, None, None]
stacked_area_chart = StackedAreaChart()
#
# Callback which draws the blocks of colour under the lines
#
def draw_event_cb(e):
obj = e.get_target()
cont_a = lv.area_t()
obj.get_coords(cont_a)
#Add the faded area before the lines are drawn
dsc = e.get_draw_part_dsc()
if dsc.part == lv.PART.ITEMS:
if not dsc.p1 or not dsc.p2:
return
# Add a line mask that keeps the area below the line
line_mask_param = lv.draw_mask_line_param_t()
line_mask_param.points_init(dsc.p1.x, dsc.p1.y, dsc.p2.x, dsc.p2.y, lv.DRAW_MASK_LINE_SIDE.BOTTOM)
line_mask_id = lv.draw_mask_add(line_mask_param, None)
#Draw a rectangle that will be affected by the mask
draw_rect_dsc = lv.draw_rect_dsc_t()
draw_rect_dsc.init()
draw_rect_dsc.bg_opa = lv.OPA.COVER
draw_rect_dsc.bg_color = dsc.line_dsc.color
a = lv.area_t()
a.x1 = dsc.p1.x
a.x2 = dsc.p2.x
a.y1 = min(dsc.p1.y, dsc.p2.y)
a.y2 = cont_a.y2 - 13 # -13 cuts off where the rectangle draws over the chart margin. Without this an area of 0 doesn't look like 0
dsc.draw_ctx.rect(draw_rect_dsc, a)
# Remove the mask
lv.draw_mask_free_param(line_mask_param)
lv.draw_mask_remove_id(line_mask_id)
#
# Helper function to round a fixed point number
#
def round_fixed_point(n, shift):
# Create a bitmask to isolates the decimal part of the fixed point number
mask = 1
for bit_pos in range(shift):
mask = (mask << 1) + 1
decimal_part = n & mask
# Get 0.5 as fixed point
rounding_boundary = 1 << (shift - 1)
# Return either the integer part of n or the integer part + 1
if decimal_part < rounding_boundary:
return (n & ~mask)
return ((n >> shift) + 1) << shift
#
# Stacked area chart
#
def lv_example_chart_8():
#Create a stacked_area_chart.obj
stacked_area_chart.obj = lv.chart(lv.scr_act())
stacked_area_chart.obj.set_size(200, 150)
stacked_area_chart.obj.center()
stacked_area_chart.obj.set_type( lv.chart.TYPE.LINE)
stacked_area_chart.obj.set_div_line_count(5, 7)
stacked_area_chart.obj.add_event_cb( draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
# Set range to 0 to 100 for percentages. Draw ticks
stacked_area_chart.obj.set_range(lv.chart.AXIS.PRIMARY_Y,0,100)
stacked_area_chart.obj.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 3, 0, 5, 1, True, 30)
#Set point size to 0 so the lines are smooth
stacked_area_chart.obj.set_style_size(0, lv.PART.INDICATOR)
# Add some data series
stacked_area_chart.series_list[0] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
stacked_area_chart.series_list[1] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.BLUE), lv.chart.AXIS.PRIMARY_Y)
stacked_area_chart.series_list[2] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.PRIMARY_Y)
for point in range(10):
# Make some random data
vals = [lv.rand(10, 20), lv.rand(20, 30), lv.rand(20, 30)]
fixed_point_shift = 5
total = vals[0] + vals[1] + vals[2]
draw_heights = [0, 0, 0]
int_sum = 0
decimal_sum = 0
# Fixed point cascade rounding ensures percentages add to 100
for series_index in range(3):
decimal_sum += int(((vals[series_index] * 100) << fixed_point_shift) // total)
int_sum += int((vals[series_index] * 100) / total)
modifier = (round_fixed_point(decimal_sum, fixed_point_shift) >> fixed_point_shift) - int_sum
# The draw heights are equal to the percentage of the total each value is + the cumulative sum of the previous percentages.
# The accumulation is how the values get "stacked"
draw_heights[series_index] = int(int_sum + modifier)
# Draw to the series in the reverse order to which they were initialised.
# Without this the higher values will draw on top of the lower ones.
# This is because the Z-height of a series matches the order it was initialised
stacked_area_chart.obj.set_next_value( stacked_area_chart.series_list[3 - series_index - 1], draw_heights[series_index])
stacked_area_chart.obj.refresh()
lv_example_chart_8()
API¶
Typedefs
-
typedef uint8_t lv_chart_type_t¶
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typedef uint8_t lv_chart_update_mode_t¶
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typedef uint8_t lv_chart_axis_t¶
Enums
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enum [anonymous]¶
Chart types
Values:
-
enumerator LV_CHART_TYPE_NONE¶
Don't draw the series
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enumerator LV_CHART_TYPE_LINE¶
Connect the points with lines
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enumerator LV_CHART_TYPE_BAR¶
Draw columns
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enumerator LV_CHART_TYPE_SCATTER¶
Draw points and lines in 2D (x,y coordinates)
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enumerator LV_CHART_TYPE_NONE¶
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enum [anonymous]¶
Chart update mode for
lv_chart_set_nextValues:
-
enumerator LV_CHART_UPDATE_MODE_SHIFT¶
Shift old data to the left and add the new one the right
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enumerator LV_CHART_UPDATE_MODE_CIRCULAR¶
Add the new data in a circular way
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enumerator LV_CHART_UPDATE_MODE_SHIFT¶
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enum [anonymous]¶
Enumeration of the axis'
Values:
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enumerator LV_CHART_AXIS_PRIMARY_Y¶
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enumerator LV_CHART_AXIS_SECONDARY_Y¶
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enumerator LV_CHART_AXIS_PRIMARY_X¶
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enumerator LV_CHART_AXIS_SECONDARY_X¶
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enumerator _LV_CHART_AXIS_LAST¶
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enumerator LV_CHART_AXIS_PRIMARY_Y¶
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enum lv_chart_draw_part_type_t¶
typefield inlv_obj_draw_part_dsc_tifclass_p = lv_chart_classUsed inLV_EVENT_DRAW_PART_BEGINandLV_EVENT_DRAW_PART_ENDValues:
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enumerator LV_CHART_DRAW_PART_DIV_LINE_INIT¶
Used before/after drawn the div lines
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enumerator LV_CHART_DRAW_PART_DIV_LINE_HOR¶
Used for each horizontal division lines
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enumerator LV_CHART_DRAW_PART_DIV_LINE_VER¶
Used for each vertical division lines
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enumerator LV_CHART_DRAW_PART_LINE_AND_POINT¶
Used on line and scatter charts for lines and points
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enumerator LV_CHART_DRAW_PART_BAR¶
Used on bar charts for the rectangles
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enumerator LV_CHART_DRAW_PART_CURSOR¶
Used on cursor lines and points
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enumerator LV_CHART_DRAW_PART_TICK_LABEL¶
Used on tick lines and labels
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enumerator LV_CHART_DRAW_PART_DIV_LINE_INIT¶
Functions
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LV_EXPORT_CONST_INT(LV_CHART_POINT_NONE)¶
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lv_obj_t *lv_chart_create(lv_obj_t *parent)¶
Create a chart object
- Parameters
parent -- pointer to an object, it will be the parent of the new chart
- Returns
pointer to the created chart
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void lv_chart_set_type(lv_obj_t *obj, lv_chart_type_t type)¶
Set a new type for a chart
- Parameters
obj -- pointer to a chart object
type -- new type of the chart (from 'lv_chart_type_t' enum)
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void lv_chart_set_point_count(lv_obj_t *obj, uint16_t cnt)¶
Set the number of points on a data line on a chart
- Parameters
obj -- pointer to a chart object
cnt -- new number of points on the data lines
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void lv_chart_set_range(lv_obj_t *obj, lv_chart_axis_t axis, lv_coord_t min, lv_coord_t max)¶
Set the minimal and maximal y values on an axis
- Parameters
obj -- pointer to a chart object
axis --
LV_CHART_AXIS_PRIMARY_YorLV_CHART_AXIS_SECONDARY_Ymin -- minimum value of the y axis
max -- maximum value of the y axis
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void lv_chart_set_update_mode(lv_obj_t *obj, lv_chart_update_mode_t update_mode)¶
Set update mode of the chart object. Affects
- Parameters
obj -- pointer to a chart object
mode -- the update mode
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void lv_chart_set_div_line_count(lv_obj_t *obj, uint8_t hdiv, uint8_t vdiv)¶
Set the number of horizontal and vertical division lines
- Parameters
obj -- pointer to a chart object
hdiv -- number of horizontal division lines
vdiv -- number of vertical division lines
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void lv_chart_set_zoom_x(lv_obj_t *obj, uint16_t zoom_x)¶
Zoom into the chart in X direction
- Parameters
obj -- pointer to a chart object
zoom_x -- zoom in x direction. LV_ZOOM_NONE or 256 for no zoom, 512 double zoom
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void lv_chart_set_zoom_y(lv_obj_t *obj, uint16_t zoom_y)¶
Zoom into the chart in Y direction
- Parameters
obj -- pointer to a chart object
zoom_y -- zoom in y direction. LV_ZOOM_NONE or 256 for no zoom, 512 double zoom
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uint16_t lv_chart_get_zoom_x(const lv_obj_t *obj)¶
Get X zoom of a chart
- Parameters
obj -- pointer to a chart object
- Returns
the X zoom value
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uint16_t lv_chart_get_zoom_y(const lv_obj_t *obj)¶
Get Y zoom of a chart
- Parameters
obj -- pointer to a chart object
- Returns
the Y zoom value
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void lv_chart_set_axis_tick(lv_obj_t *obj, lv_chart_axis_t axis, lv_coord_t major_len, lv_coord_t minor_len, lv_coord_t major_cnt, lv_coord_t minor_cnt, bool label_en, lv_coord_t draw_size)¶
Set the number of tick lines on an axis
- Parameters
obj -- pointer to a chart object
axis -- an axis which ticks count should be set
major_len -- length of major ticks
minor_len -- length of minor ticks
major_cnt -- number of major ticks on the axis
minor_cnt -- number of minor ticks between two major ticks
label_en -- true: enable label drawing on major ticks
draw_size -- extra size required to draw the tick and labels (start with 20 px and increase if the ticks/labels are clipped)
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lv_chart_type_t lv_chart_get_type(const lv_obj_t *obj)¶
Get the type of a chart
- Parameters
obj -- pointer to chart object
- Returns
type of the chart (from 'lv_chart_t' enum)
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uint16_t lv_chart_get_point_count(const lv_obj_t *obj)¶
Get the data point number per data line on chart
- Parameters
chart -- pointer to chart object
- Returns
point number on each data line
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uint16_t lv_chart_get_x_start_point(const lv_obj_t *obj, lv_chart_series_t *ser)¶
Get the current index of the x-axis start point in the data array
- Parameters
chart -- pointer to a chart object
ser -- pointer to a data series on 'chart'
- Returns
the index of the current x start point in the data array
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void lv_chart_get_point_pos_by_id(lv_obj_t *obj, lv_chart_series_t *ser, uint16_t id, lv_point_t *p_out)¶
Get the position of a point to the chart.
- Parameters
chart -- pointer to a chart object
ser -- pointer to series
id -- the index.
p_out -- store the result position here
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void lv_chart_refresh(lv_obj_t *obj)¶
Refresh a chart if its data line has changed
- Parameters
chart -- pointer to chart object
-
lv_chart_series_t *lv_chart_add_series(lv_obj_t *obj, lv_color_t color, lv_chart_axis_t axis)¶
Allocate and add a data series to the chart
- Parameters
obj -- pointer to a chart object
color -- color of the data series
axis -- the y axis to which the series should be attached (::LV_CHART_AXIS_PRIMARY_Y or ::LV_CHART_AXIS_SECONDARY_Y)
- Returns
pointer to the allocated data series
-
void lv_chart_remove_series(lv_obj_t *obj, lv_chart_series_t *series)¶
Deallocate and remove a data series from a chart
- Parameters
chart -- pointer to a chart object
series -- pointer to a data series on 'chart'
-
void lv_chart_hide_series(lv_obj_t *chart, lv_chart_series_t *series, bool hide)¶
Hide/Unhide a single series of a chart.
- Parameters
obj -- pointer to a chart object.
series -- pointer to a series object
hide -- true: hide the series
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void lv_chart_set_series_color(lv_obj_t *chart, lv_chart_series_t *series, lv_color_t color)¶
Change the color of a series
- Parameters
obj -- pointer to a chart object.
series -- pointer to a series object
color -- the new color of the series
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void lv_chart_set_x_start_point(lv_obj_t *obj, lv_chart_series_t *ser, uint16_t id)¶
Set the index of the x-axis start point in the data array. This point will be considers the first (left) point and the other points will be drawn after it.
- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
id -- the index of the x point in the data array
-
lv_chart_series_t *lv_chart_get_series_next(const lv_obj_t *chart, const lv_chart_series_t *ser)¶
Get the next series.
- Parameters
chart -- pointer to a chart
ser -- the previous series or NULL to get the first
- Returns
the next series or NULL if there is no more.
-
lv_chart_cursor_t *lv_chart_add_cursor(lv_obj_t *obj, lv_color_t color, lv_dir_t dir)¶
Add a cursor with a given color
- Parameters
obj -- pointer to chart object
color -- color of the cursor
dir -- direction of the cursor.
LV_DIR_RIGHT/LEFT/TOP/DOWN/HOR/VER/ALL. OR-ed values are possible
- Returns
pointer to the created cursor
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void lv_chart_set_cursor_pos(lv_obj_t *chart, lv_chart_cursor_t *cursor, lv_point_t *pos)¶
Set the coordinate of the cursor with respect to the paddings
- Parameters
obj -- pointer to a chart object
cursor -- pointer to the cursor
pos -- the new coordinate of cursor relative to the chart
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void lv_chart_set_cursor_point(lv_obj_t *chart, lv_chart_cursor_t *cursor, lv_chart_series_t *ser, uint16_t point_id)¶
Stick the cursor to a point
- Parameters
obj -- pointer to a chart object
cursor -- pointer to the cursor
ser -- pointer to a series
point_id -- the point's index or
LV_CHART_POINT_NONEto not assign to any points.
-
lv_point_t lv_chart_get_cursor_point(lv_obj_t *chart, lv_chart_cursor_t *cursor)¶
Get the coordinate of the cursor with respect to the paddings
- Parameters
obj -- pointer to a chart object
cursor -- pointer to cursor
- Returns
coordinate of the cursor as lv_point_t
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void lv_chart_set_all_value(lv_obj_t *obj, lv_chart_series_t *ser, lv_coord_t value)¶
Initialize all data points of a series with a value
- Parameters
obj -- pointer to chart object
ser -- pointer to a data series on 'chart'
value -- the new value for all points.
LV_CHART_POINT_NONEcan be used to hide the points.
-
void lv_chart_set_next_value(lv_obj_t *obj, lv_chart_series_t *ser, lv_coord_t value)¶
Set the next point's Y value according to the update mode policy.
- Parameters
obj -- pointer to chart object
ser -- pointer to a data series on 'chart'
value -- the new value of the next data
-
void lv_chart_set_next_value2(lv_obj_t *obj, lv_chart_series_t *ser, lv_coord_t x_value, lv_coord_t y_value)¶
Set the next point's X and Y value according to the update mode policy.
- Parameters
obj -- pointer to chart object
ser -- pointer to a data series on 'chart'
x_value -- the new X value of the next data
y_value -- the new Y value of the next data
-
void lv_chart_set_value_by_id(lv_obj_t *obj, lv_chart_series_t *ser, uint16_t id, lv_coord_t value)¶
Set an individual point's y value of a chart's series directly based on its index
- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
id -- the index of the x point in the array
value -- value to assign to array point
-
void lv_chart_set_value_by_id2(lv_obj_t *obj, lv_chart_series_t *ser, uint16_t id, lv_coord_t x_value, lv_coord_t y_value)¶
Set an individual point's x and y value of a chart's series directly based on its index Can be used only with
LV_CHART_TYPE_SCATTER.- Parameters
obj -- pointer to chart object
ser -- pointer to a data series on 'chart'
id -- the index of the x point in the array
x_value -- the new X value of the next data
y_value -- the new Y value of the next data
-
void lv_chart_set_ext_y_array(lv_obj_t *obj, lv_chart_series_t *ser, lv_coord_t array[])¶
Set an external array for the y data points to use for the chart NOTE: It is the users responsibility to make sure the
point_cntmatches the external array size.- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
array -- external array of points for chart
-
void lv_chart_set_ext_x_array(lv_obj_t *obj, lv_chart_series_t *ser, lv_coord_t array[])¶
Set an external array for the x data points to use for the chart NOTE: It is the users responsibility to make sure the
point_cntmatches the external array size.- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
array -- external array of points for chart
-
lv_coord_t *lv_chart_get_y_array(const lv_obj_t *obj, lv_chart_series_t *ser)¶
Get the array of y values of a series
- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
- Returns
the array of values with 'point_count' elements
-
lv_coord_t *lv_chart_get_x_array(const lv_obj_t *obj, lv_chart_series_t *ser)¶
Get the array of x values of a series
- Parameters
obj -- pointer to a chart object
ser -- pointer to a data series on 'chart'
- Returns
the array of values with 'point_count' elements
Variables
-
const lv_obj_class_t lv_chart_class¶
-
struct lv_chart_series_t¶
- #include <lv_chart.h>
Descriptor a chart series
-
struct lv_chart_cursor_t¶
-
struct lv_chart_tick_dsc_t¶
-
struct lv_chart_t¶
Public Members
-
lv_ll_t series_ll¶
Linked list for the series (stores lv_chart_series_t)
-
lv_ll_t cursor_ll¶
Linked list for the cursors (stores lv_chart_cursor_t)
-
lv_chart_tick_dsc_t tick[4]¶
-
lv_coord_t ymin[2]¶
-
lv_coord_t ymax[2]¶
-
lv_coord_t xmin[2]¶
-
lv_coord_t xmax[2]¶
-
lv_coord_t pressed_point_id¶
-
uint16_t hdiv_cnt¶
Number of horizontal division lines
-
uint16_t vdiv_cnt¶
Number of vertical division lines
-
uint16_t point_cnt¶
Point number in a data line
-
uint16_t zoom_x¶
-
uint16_t zoom_y¶
-
lv_chart_type_t type¶
Line or column chart
-
lv_chart_update_mode_t update_mode¶
-
lv_ll_t series_ll¶