80 lines
4.0 KiB
Markdown
80 lines
4.0 KiB
Markdown
# ChartSetDouble
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Sets a value for a corresponding property of the specified chart. Chart property should be of a [double](/en/docs/basis/types/double) type. The command is added to chart messages queue and will be executed after processing of all previous commands.
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```
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bool ChartSetDouble(
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long chart_id, // Chart ID
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ENUM_CHART_PROPERTY_DOUBLE prop_id, // Property ID
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double value // Value
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);
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```
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Parameters
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chart_id
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[in] Chart ID. 0 means the current chart.
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prop_id
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[in] Chart property ID. Can be one of the [ENUM_CHART_PROPERTY_DOUBLE](/en/docs/constants/chartconstants/enum_chart_property#enum_chart_property_double) values (except the read-only properties).
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value
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[in] Property value.
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Return Value
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Returns true if the command has been added to chart queue, otherwise false. To get an information about the [error](/en/docs/constants/errorswarnings/errorcodes), call the [GetLastError()](/en/docs/check/getlasterror) function.
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Note
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The function is asynchronous, which means that the function does not wait for the execution of the command, which has been successfully added to the queue of specified the chart. Instead, it immediately returns control. The property will only change after the handling of the appropriate command from the chart queue. To immediately execute commands from the chart queue, call the [ChartRedraw](/en/docs/chart_operations/chartredraw) function.
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If you want to immediately change several chart properties at once, then the corresponding functions ([ChartSetString](/en/docs/chart_operations/chartsetstring), [ChartSetDouble](/en/docs/chart_operations/chartsetdouble), [ChartSetString](/en/docs/chart_operations/chartsetstring)) should be executed in one code block, after which you should call [ChartRedraw](/en/docs/chart_operations/chartredraw) once.
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To check the command execution result, you can use a function, which requests the specified chart property ([ChartGetInteger](/en/docs/chart_operations/chartgetinteger), [ChartGetDouble](/en/docs/chart_operations/chartgetdouble), [ChartSetString](/en/docs/chart_operations/chartsetstring)). However, note that these functions are synchronous and wait for execution results.
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Example:
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```
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//+------------------------------------------------------------------+
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//| Script program start function |
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//+------------------------------------------------------------------+
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void OnStart()
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{
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//--- get the current chart ID
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long chart_id = ChartID();
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//--- save the initial offset of the zero bar from the right edge in percentage and the auto scroll flag
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double shift = ChartGetDouble(chart_id, CHART_SHIFT_SIZE);
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bool scroll= ChartGetInteger(chart_id,CHART_AUTOSCROLL);
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//--- reset the auto scroll chart flag
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ChartSetInteger(chart_id, CHART_AUTOSCROLL, true);
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PrintFormat("Initial chart shift size: %.2f", shift);
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//--- in the loop from 2.0% to 50.0% with the step of 0.5%
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for(int i=20; i<=500; i+=5)
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{
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//--- set the shift size as i / 10 and print the specified value in the journal
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ChartSetDouble(chart_id, CHART_SHIFT_SIZE, i/10.0);
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PrintFormat("Set chart shift size to %.1f%%", i/10.0);
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//--- keep the chart zero bar at the specified shift distance
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ChartNavigate(chart_id, CHART_END, 0);
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//--- wait a bit
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Sleep(16);
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}
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//--- set the initial chart shift and auto scroll
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Print("Set the chart shift size to the initial value of ", shift);
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ChartSetDouble(ChartID(), CHART_SHIFT_SIZE, shift);
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ChartSetInteger(chart_id, CHART_AUTOSCROLL, scroll);
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}
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```
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