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fix(chart) various scatter chart related fixes

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Gabor Kiss-Vamosi
2021-05-24 15:37:27 +02:00
parent 7522f4e2f0
commit 5b9329fd5d
4 changed files with 143 additions and 105 deletions
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docs/widgets/extra/chart.md
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@@ -27,26 +27,37 @@ Charts also support:
## Usage
### Data series
You can add any number of series to the charts by `lv_chart_add_series(chart, color, LV_CHART_AXIS_PRIMARY/SECONDARY)`.
It allocates data for a `lv_chart_series_t` structure which contains the chosen `color` and an array for the data points.
`LV_CHART_AXIS_PRIMARY/SECONDARY` tells series should use the range of the `LV_CHART_AXIS_PRIMARY` (left) or `LV_CHART_AXIS_SECONDARY` (right) Y axis.
With `lv_chart_set_ext_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 get by `lv_chart_get_array(chart, ser)`. It can be use with `ext_array` or *normal array*s.
### Series' type
### Chart type
The following data display types exist:
- `LV_CHART_TYPE_NONE` Do not display any data. It can be used to hide the series.
- `LV_CHART_TYPE_LINE` Draw 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_...)`. The types can be 'OR'ed (like `LV_CHART_TYPE_LINE`).
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)`.
It allocates data for a `lv_chart_series_t` structure which contains the chosen `color` and an array for the data points.
`axis` can ha the following values:
- `LV_CHART_AXIS_PRIMARY_Y` Left axis
- `LV_CHART_AXIS_SECONDARY_Y` Right axis
- `LV_CHART_AXIS_PRIMARY_X` Bottom axis
- `LV_CHART_AXIS_SECONDARY_X` Top axis
`axis` tells which axis's range should be used te scale the values.
With `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 get by `lv_chart_get_y_array(chart, ser)`. It can be use with `ext_array` or *normal array*s.
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:
@@ -57,6 +68,9 @@ You have several options to set the data of series:
Use `LV_CHART_POINT_DEF` 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_SHIFT` Shift old data to the left and add the new one to the right.