Discussion of article "Graphical Interfaces X: The Standard Chart Control (build 4)"
For OBJ_CHART scrolling, why use a timer? And for interaction with the interface - a similar question. It seems that mouse events should always suffice.
For OBJ_CHART scrolling, why use a timer? And for interaction with the interface - a similar question. After all, it seems that mouse events should always suffice.
What you quoted refers not to OBJ_CHART, but to the timer of the library engine as a whole. That's why the solution of this problem was put in a separate section of the article "Optimisation of the timer and event handler of the library engine" as an addition to the main topic.
The timer is used to change the colour of controls on mouseover, as well as accelerated scrolling of lists, tables, calendar and values in input fields.
//---
P.S. And OBJ_CHART scrolling is just carried out by the mouse cursor movement event - CHARTEVENT_MOUSE_MOVE. In the listing below is the code of the handler (shortened version) of events of the "Standard Chart" element (class CStandardChart):
//+------------------------------------------------------------------+ //| Event handling| //+------------------------------------------------------------------+ void CStandardChart::OnEvent(const int id,const long &lparam,const double &dparam,const string &sparam) { //--- Handling of cursor movement event if(id==CHARTEVENT_MOUSE_MOVE) { //--- Exit if the item is hidden if(!CElement::IsVisible()) return; //--- Exit if in subwindow resizing mode if(CheckDragBorderWindowMode()) return; //--- Exit if subwindow numbers do not match if(CElement::m_subwin!=CElement::m_mouse.SubWindowNumber()) return; //--- Exit if the form is blocked by another element if(m_wnd.IsLocked() && m_wnd.IdActivatedElement()!=CElement::Id()) return; //--- Focus check CElement::MouseFocus(m_mouse.X()>X() && m_mouse.X()<X2() && m_mouse.Y()>Y() && m_mouse.Y()<Y2()); //--- If there is a focus if(CElement::MouseFocus()) //--- Horizontal scrolling of the graph HorizontalScroll(); //--- If there is no focus and the left mouse button is released else if(!m_mouse.LeftButtonState()) { //--- Hide horizontal scroll pointer m_x_scroll.Hide(); //--- Unlock the form if(m_wnd.IdActivatedElement()==CElement::Id()) { m_wnd.IsLocked(false); m_wnd.IdActivatedElement(WRONG_VALUE); } } //--- return; } //... }
Timer-based colour change of control elements on mouseover is arranged
Why can't I use the mouse here?
Because there is a smooth colour change (the number of steps is set by the user).
This also applies to the scrolling of lists. If you use the method as it is implemented in SB, you will have jagged (uneven) scrolling.
In what case (relative to the test Expert Advisor from the article) ?
- In the case when scrolling through the calendar is performed?
- In case of manual scrolling by CHARTEVENT_MOUSE_MOVE event in the item event handler(CStandardChart) ?
If the former, then the chart scrolling is timed, as the calendar scrolling is timed. That is, generation of the calendar date change event(ON_CHANGE_DATE) is timed at 16 ms interval.
If the second, the shift is calculated and is not always equal to 1 bar. So it only seems that manual scrolling by CHARTEVENT_MOUSE_MOVE event is smooth.
If the second, the shift is calculated and is not always equal to 1 bar. So it just seems that scrolling manually by CHARTEVENT_MOUSE_MOVE event is smooth.
Got it, thanks!
Anatoly, tell me what the cause of the error is
Everything worked fine before this update. Now when building the CTable table this error pops up.
Please tell me where it is wrong - I have already printed every line - the interface is built, but after somewhere stumbles, and .... error.
File with an example in the archive.
Found it.
Take your example from MQL4\Experts\Article07\TestLibrary02\TestLibrary02.mq4.
From your example above:
Make the number of columns and the number of visible columns the same , compile, run, and get an error.
//|| Creates a table|
//+------------------------------------------------------------------+
bool CProgram::CreateTable(void)
{
//#define COLUMNS1_TOTAL (100)
//#define ROWS1_TOTAL (1000)
#define COLUMNS1_TOTAL (6)
#define ROWS1_TOTAL (1000)
//--- Save the pointer to the form
m_table.WindowPointer(m_window1);
//--- Coordinates
int x=m_window1.X()+TABLE1_GAP_X;
int y=m_window1.Y()+TABLE1_GAP_Y;
//--- Number of visible columns and rows
int visible_columns_total =6;
int visible_rows_total =15;
//--- Set properties before creation
m_table.XSize(600);
m_table.RowYSize(20);
m_table.FixFirstRow(true);
m_table.FixFirstColumn(true);
m_table.LightsHover(true);
m_table.SelectableRow(true);
m_table.TextAlign(ALIGN_CENTER);
m_table.HeadersColor(C'255,244,213');
m_table.HeadersTextColor(clrBlack);
m_table.CellColorHover(clrGold);
m_table.TableSize(COLUMNS1_TOTAL,ROWS1_TOTAL);
m_table.VisibleTableSize(visible_columns_total,visible_rows_total);
//--- Create a control
if(!m_table.CreateTable(m_chart_id,m_subwin,x,y))
return(false);
//--- Let's fill in the table:
// The first cell is empty
m_table.SetValue(0,0,"-");
//--- Headings for columns
for(int c=1; c<COLUMNS1_TOTAL; c++)
{
for(int r=0; r<1; r++)
m_table.SetValue(c,r,"SYMBOL "+string(c));
}
//--- Headings for rows, text alignment method - to the right
for(int c=0; c<1; c++)
{
for(int r=1; r<ROWS1_TOTAL; r++)
{
m_table.SetValue(c,r,"PARAMETER "+string(r));
m_table.TextAlign(c,r,ALIGN_RIGHT);
}
}
//--- Data and table formatting (background colour and cell colour)
for(int c=1; c<COLUMNS1_TOTAL; c++)
{
for(int r=1; r<ROWS1_TOTAL; r++)
{
m_table.SetValue(c,r,string(c)+":"+string(r));
m_table.TextColor(c,r,(c%2==0)? clrRed : clrRoyalBlue);
m_table.CellColor(c,r,(r%2==0)? clrWhiteSmoke : clrWhite);
}
}
//--- Refresh the table to show changes
m_table.UpdateTable();
//--- Add the object to the common array of object groups
CWndContainer::AddToElementsArray(0,m_table);
return(true);
}
//+------------------------------------------------------------------+
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New article Graphical Interfaces X: The Standard Chart Control (build 4) has been published:
This time we will consider the Standard chart control. It will allow to create arrays of subcharts with the ability to synchronize horizontal scrolling. In addition, we will continue to optimize the library code to reduce the CPU load.
The library for creating graphical interfaces at the current stage of development looks like in the schematic below.
Author: Anatoli Kazharski