MQL5 Cookbook: Indicator Subwindow Controls - Scrollbar
Anatoli Kazharski | 7 November, 2013
Introduction
Let's continue exploring various controls and this time turn our attention to scrollbar. Just like in the previous article "MQL5 Cookbook: Indicator Subwindow Controls - Buttons", we will work in the indicator subwindow. Take a moment to read the above mentioned article as it provides a detailed description of working with events in the OnChartEvent() function, while this point will only be casually touched upon in this article. For illustrative purposes, this time around we will create a vertical scrollbar for a large list of all financial instrument properties that can be obtained using MQL5 resources.
In the previous articles on MQL5 programming we used the graphical object OBJ_LABEL (Text Label) to create lists. In this article, we will use a canvas to display text. The convenience of such approach lies in that instead of a great number of OBJ_LABEL objects, we will only use one - OBJ_BITMAP_LABEL (Bitmap Label). You can draw any interface elements on a canvas but this time we will limit ourselves to text only.
The scrollbar will be very simple. It usually has arrow buttons but they will not be features in our case. The scrollbar will only consist of the background and scroll box. The scroll box will change its color when the cursor goes over it. When clicked, it will also change color suggesting to the user that the scroll box is now selected and can be dragged. In creating scrolling objects, we will use graphical objects of the OBJ_RECTANGLE_LABEL (Rectangle Label) type.
Indicator Development
Let's start programming. Create a template of the indicator as it was done in the previous article. At the very beginning we, as usual, need to declare variables and arrays. To be able to work with the canvas, we include the CCanvas class from the Standard Library.
#define LIST_SIZE 71 // Number of strings in the list of financial instrument properties //--- Include the class for working with the canvas #include <Canvas\Canvas.mqh> CCanvas canvas; //+------------------------------------------------------------------+ //| Global variables | //+------------------------------------------------------------------+ //--- Indicator subwindow properties int subwindow_number =WRONG_VALUE; // Subwindow number int subwindow_height =0; // Subwindow height string subwindow_shortname ="TestScrollbar"; // Short name of the indicator string prefix =subwindow_shortname+"_"; // Prefix for objects int chart_width =0; // Chart width int chart_height =0; // Chart height int chart_y_offset =0; // Distance from the chart top to the subwindow //--- Canvas properties string canvas_name =prefix+"canvas"; // Canvas name color canvas_background_color =C'20,20,20'; // Canvas background color ENUM_COLOR_FORMAT color_format =COLOR_FORMAT_XRGB_NOALPHA; // Alpha channel component is ignored //--- List properties int list_height =0; // List height int text_height =0; // Text height int font_size =15; // Font size string font_name ="Calibri"; // Font double line_size =100/LIST_SIZE; // Size of a single string on the list, expressed as percentage //--- Scrollbar properties: scroll box string scrollbar_thumb_name =prefix+"scrollbar_thumb"; // Scroll box object name int scrollbar_thumb_x1 =0; // x1 coordinate int scrollbar_thumb_y1 =0; // y1 coordinate int scrollbar_thumb_x2 =0; // x2 coordinate int scrollbar_thumb_y2 =0; // y2 coordinate double scrollbar_thumb_y_percent =0.0; // Y-coordinate expressed as percentage int scrollbar_thumb_width =9; // Width int scrollbar_thumb_height =0; // Height bool scrollbar_thumb_clicked =false; // State (whether or not the scroll box is clicked) color scrollbar_thumb_color =clrSilver; // Scroll box color color scrollbar_thumb_color_on_hover=clrDimGray; // Scroll box color when the cursor hovers over it color scrollbar_thumb_color_on_click=clrSlateGray; // Scroll box color when clicked //--- Scrollbar properties: background string scrollbar_background_name =prefix+"scrollbar_background"; // Background object name int scrollbar_background_width =9; // Background width color scrollbar_background_color =C'50,50,50'; // Background color //--- Scrollbar properties: other int scrollbar_fix_point =0; // Y-coordinate of the fix point upon clicking int scrollbar_fix_point_y_offest =0; // Distance along the Y-axis from the scrollbar top to the fix point //--- Mouse button state (pressed/released) bool mouse_button_state=false; //--- Arrays for financial instrument properties color symbol_property_colors[]; // Colors of values string symbol_property_values[]; // Values //--- Financial instrument property names string symbol_propety_names[LIST_SIZE]= { "Number of deals in the current session", "Total number of Buy orders at the moment", "Total number of Sell orders at the moment", "Volume of the last deal", "Maximum daily volume", "Minimum daily volume", "Time of the last quote", "Number of decimal places", "Spread in points", "Floating spread indication", "Maximum number of requests displayed in the Depth of Market", "Contract price calculation mode", "Order execution type", "Trading start date for an instrument (usually used for futures)", "Trading end date for an instrument (usually used for futures)", "Minimum distance in points from the current closing price for the purpose of setting Stop orders", "Freeze distance for trading operations (in points)", "Deal execution mode", "Swap calculation model", "Day of the week when triple swap is charged", "Flags of allowed order expiration modes", "Flags of allowed order filling modes", //--- "Bid - best price at which an instrument can be sold", "Maximum Bid of the day", "Minimum Bid of the day", "Ask - best price at which an instrument can be bought", "Maximum Ask of the day", "Minimum Ask of the day", "Last - last deal price", "Maximum Last of the day", "Minimum Last of the day", "Point value", "Calculated tick value for a winning position", "Calculated tick value for a losing position", "Minimum price change", "Trade contract size", "Minimum volume for deal execution", "Maximum volume for deal execution", "Minimum step of volume change for deal execution", "Maximum allowable total volume of an open position and pending orders in the same direction", "Long swap value", "Short swap value", "Initial margin - amount in the margin currency required for opening a position (1 lot)", "Maintenance margin for an instrument", "Margin requirement applicable to long positions", "Margin requirement applicable to short positions", "Margin requirement applicable to Limit orders", "Margin requirement applicable to Stop orders", "Margin requirement applicable to Stop Limit orders", "Total volume of deals in the current session", "Total turnover in the current session", "Total volume of open positions", "Total volume of buy orders at the moment", "Total volume of sell orders at the moment", "Open price of the session", "Close price of the session", "Average weighted price of the session", "Settlement price of the current session", "Minimum allowable price value for the session", "Maximum allowable price value for the session", //--- "Base currency of an instrument", "Profit currency", "Margin currency", "Current quote source", "String description of a symbol", "Name of a trading symbol in the international system of securities identification numbers (ISIN)", "Location in the symbol tree", //--- "Current number of bars for a symbol on a selected time frame", "The very first date for a symbol on a selected time frame", "The very first date in the history for a symbol on a selected time frame", "Symbol data synchronized" };
Let's first write all the functions required for displaying the list of properties on the canvas. As soon as this is done, we will proceed to creating the scrollbar.
To create the canvas, we write the AddCanvas() function and use the second variant of the CreateBitmapLabel() method of the CCanvas class:
//+------------------------------------------------------------------+ //| Adding canvas | //+------------------------------------------------------------------+ void AddCanvas() { //--- If there is no canvas, add it if(ObjectFind(0,canvas_name)<0) canvas.CreateBitmapLabel(0,subwindow_number,canvas_name,0,0,chart_width,subwindow_height,color_format); }
We will also need a method for changing the canvas size to adjust it to the size of the indicator subwindow. For this purpose, we will write the ResizeCanvas() function that uses the Resize() method in the CCanvas class:
//+------------------------------------------------------------------+ //| Resizing canvas | //+------------------------------------------------------------------+ void ResizeCanvas() { //--- If the canvas has already been added to the indicator subwindow, set the new size if(ObjectFind(0,canvas_name)==subwindow_number) canvas.Resize(chart_width,subwindow_height); //--- If there is no canvas, add it else canvas.CreateBitmapLabel(0,subwindow_number,canvas_name,0,0,chart_width,subwindow_height,color_format); }
To delete the canvas, we use the Destroy() method:
//+------------------------------------------------------------------+ //| Deleting canvas | //+------------------------------------------------------------------+ void DeleteCanvas() { if(ObjectFind(0,canvas_name)>0) canvas.Destroy(); }
In this article, we are also going to use other methods of the CCanvas class, such as FontSet() for setting fonts, TextHeight() for determining the text height, TextOut() for printing text to the canvas, Erase() for clearing the canvas and Update() for redrawing. Further below, we are going to see where in the program the above methods are used.
During the initialization in the OnInit() function, we need to pave the way for the program operation. The below code shows what needs to be done. The comments provided in each string will help you better understand the actions. The FontSet() and TextHeight() methods of the CCanvas class are only used in this part of the program.
//+------------------------------------------------------------------+ //| Custom indicator initialization function | //+------------------------------------------------------------------+ int OnInit() { //--- Enable tracking of mouse events ChartSetInteger(0,CHART_EVENT_MOUSE_MOVE,true); //--- Set the short name IndicatorSetString(INDICATOR_SHORTNAME,subwindow_shortname); //--- Set sizes of arrays of symbol properties and their colors ArrayResize(symbol_property_colors,LIST_SIZE); ArrayResize(symbol_property_values,LIST_SIZE); //--- Set subwindow properties SetSubwindowProperties(); //--- Set the font for displaying on the canvas canvas.FontSet(font_name,font_size,FW_NORMAL); //--- Save the text size (height) for calculations text_height=canvas.TextHeight("A")-1; //--- Calculate the height of the entire list list_height=text_height*LIST_SIZE; //--- Add the canvas to the chart AddCanvas(); //--- Display the list of symbol properties ShowSymbolInfo(); //--- Refresh the chart ChartRedraw(); //--- Everything completed successfully return(INIT_SUCCEEDED); }
The SetSubwindowProperties() function has been taken from the previous article as is: it assigns the indicator subwindow number and its size to the global variables. Let's proceed straight to the ShowSymbolInfo() function:
//+------------------------------------------------------------------+ //| Displaying current symbol information | //+------------------------------------------------------------------+ void ShowSymbolInfo(double current_thumb_position=0.0) { int list_lines =0; // Counter of strings displayed in the canvas double thumb_position =0.0; // Position of the scroll box expressed as percentage for determining the first displayed string int y_distance =0; // For determining the coordinate of the next string in the list int line_number =0; // Number of the string starting from which the list will be displayed //--- Determine the string starting from which the list will be displayed for(int i=0; i<LIST_SIZE; i++) { //--- Count strings until you reach the one starting from which the list will be displayed if(thumb_position>=current_thumb_position) break; //--- thumb_position+=line_size; line_number++; } //--- Initialize list arrays from the specified string InitializePropertyArrays(line_number); //--- Clear the canvas canvas.Erase(canvas_background_color); //--- Show the list on the canvas for(int i=line_number; i<LIST_SIZE; i++) { //--- Property name canvas.TextOut(655,y_distance,symbol_propety_names[i]+" :",ColorToARGB(clrWhite),TA_RIGHT|TA_TOP); //--- Property value canvas.TextOut(665,y_distance,symbol_property_values[i],ColorToARGB(symbol_property_colors[i]),TA_LEFT|TA_TOP); //--- Calculate the coordinate for the next string y_distance+=text_height; //--- Count the number of displayed strings list_lines++; //--- If you go beyond the subwindow boundaries, terminate the loop if(list_lines*text_height>subwindow_height) break; } //--- Refresh the canvas canvas.Update(); }
The ShowSymbolInfo() function has one parameter, current_thumb_position, that by default is equal to zero (in case you need to use the default value, there is no need to pass the value to the function). This parameter determines the string starting from which the list should be displayed. In other words, the zero value will mean that the list should be displayed from the very beginning.
At the very beginning, we determine the number of the string starting from which the list should be displayed. Then arrays of values and colors (highlighted string in the above code) are initialized in the InitializePropertyArrays() function. The initialization is performed starting from the string determined in the previous loop. After that the canvas is cleared using the Erase() method - in practice, the entire canvas is filled with the color specified. In the last loop, the text is printed to the canvas using the TextOut() method. At the end, the canvas is refreshed using the Update() method.
The InitializePropertyArrays() function code is provided below:
//+-----------------------------------------------------------------------+ //| Initializing arrays of values and their colors for the current symbol | //+-----------------------------------------------------------------------+ void InitializePropertyArrays(int line_number) { int lines_count=0; //--- for(int i=line_number; i<LIST_SIZE; i++) { //--- Determine the value and color of the symbol property symbol_property_values[i]=GetStringSymbolInfoByIndex(i); symbol_property_colors[i]=GetColorSymbolInfoByIndex(i); //--- Increase the counter lines_count++; //--- If the number of strings exceeds the subwindow height, exit if(lines_count*text_height>subwindow_height) break; } }
The above code suggests that values of symbol properties and their colors are determined using two functions operating under similar principles, GetStringSymbolInfoByIndex() and GetColorSymbolInfoByIndex().
The GetStringSymbolInfoByIndex() function is simple, yet quite massive due to the large number of properties. Besides, in order to get some properties, we need auxiliary functions (strings highlighted in the code below).
//+------------------------------------------------------------------+ //| Returning the string value of the symbol property by index | //+------------------------------------------------------------------+ string GetStringSymbolInfoByIndex(int index) { string str ="-"; long l_check_value =0; double d_check_value =0.0; string s_check_value =""; //--- switch(index) { case 0 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_SESSION_DEALS); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 1 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_SESSION_BUY_ORDERS); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 2 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_SESSION_SELL_ORDERS); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 3 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_VOLUME); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 4 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_VOLUMEHIGH); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 5 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_VOLUMELOW); str=(l_check_value==0) ? "-" : IntegerToString(l_check_value); break; case 6 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_TIME); str=(l_check_value==0) ? "-" : TimeToString(l_check_value); break; case 7 : str=IntegerToString(SymbolInfoInteger(_Symbol,SYMBOL_DIGITS)); break; case 8 : str=IntegerToString(SymbolInfoInteger(_Symbol,SYMBOL_SPREAD)); break; case 9 : str=(!SymbolInfoInteger(_Symbol,SYMBOL_SPREAD_FLOAT)) ? "false" : "true"; break; case 10 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_TICKS_BOOKDEPTH); str=(l_check_value==0) ? "-" : DoubleToString(l_check_value,_Digits); break; case 11 : str=TradeCalcModeToString(SymbolInfoInteger(_Symbol,SYMBOL_TRADE_CALC_MODE)); break; case 12 : str=TradeModeToString(SymbolInfoInteger(_Symbol,SYMBOL_TRADE_MODE)); break; case 13 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_START_TIME); str=(l_check_value==0) ? "-" : TimeToString(l_check_value); break; case 14 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_EXPIRATION_TIME); str=(l_check_value==0) ? "-" : TimeToString(l_check_value); break; case 15 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_TRADE_STOPS_LEVEL); str=(l_check_value==0) ? "false" : IntegerToString(l_check_value); break; case 16 : l_check_value=SymbolInfoInteger(_Symbol,SYMBOL_TRADE_FREEZE_LEVEL); str=(l_check_value==0) ? "false" : IntegerToString(l_check_value); break; case 17 : str=TradeExeModeToString(SymbolInfoInteger(_Symbol,SYMBOL_TRADE_EXEMODE)); break; case 18 : str=SwapModeToString(SymbolInfoInteger(_Symbol,SYMBOL_SWAP_MODE)); break; case 19 : str=WeekdayToString(SymbolInfoInteger(_Symbol,SYMBOL_SWAP_ROLLOVER3DAYS)); break; case 20 : str=ExpirationModeToString(); break; case 21 : str=FillingModeToString(); break; //--- case 22 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_BID); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 23 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_BIDHIGH); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 24 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_BIDLOW); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 25 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_ASK); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 26 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_ASKHIGH); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 27 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_ASKLOW); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 28 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_LAST); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 29 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_LASTHIGH); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 30 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_LASTLOW); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,_Digits); break; case 31 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_POINT),_Digits); break; case 32 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_TRADE_TICK_VALUE_PROFIT),2); break; case 33 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_TRADE_TICK_VALUE_LOSS),2); break; case 34 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_TRADE_TICK_SIZE),_Digits); break; case 35 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_TRADE_CONTRACT_SIZE),2); break; case 36 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_MIN),2); break; case 37 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_MAX),2); break; case 38 : str=DoubleToString(SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_STEP),2); break; case 39 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_LIMIT); str=(d_check_value==0) ? "Unlimited" : DoubleToString(d_check_value,2); break; case 40 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SWAP_LONG); str=(d_check_value==0) ? "false" : DoubleToString(d_check_value,2); break; case 41 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SWAP_SHORT); str=(d_check_value==0) ? "false" : DoubleToString(d_check_value,2); break; case 42 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_INITIAL); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 43 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_MAINTENANCE); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 44 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_LONG); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 45 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_SHORT); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 46 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_LIMIT); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 47 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_STOP); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 48 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_MARGIN_STOPLIMIT); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 49 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_VOLUME); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 50 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_TURNOVER); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 51 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_INTEREST); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 52 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_BUY_ORDERS_VOLUME); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 53 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_SELL_ORDERS_VOLUME); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 54 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_OPEN); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 55 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_CLOSE); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 56 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_AW); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 57 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_PRICE_SETTLEMENT); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 58 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_PRICE_LIMIT_MIN); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; case 59 : d_check_value=SymbolInfoDouble(_Symbol,SYMBOL_SESSION_PRICE_LIMIT_MAX); str=(d_check_value==0) ? "-" : DoubleToString(d_check_value,2); break; //--- case 60 : str=SymbolInfoString(_Symbol,SYMBOL_CURRENCY_BASE); break; case 61 : str=SymbolInfoString(_Symbol,SYMBOL_CURRENCY_PROFIT); break; case 62 : str=SymbolInfoString(_Symbol,SYMBOL_CURRENCY_MARGIN); break; case 63 : s_check_value=SymbolInfoString(_Symbol,SYMBOL_BANK); str=(s_check_value!="") ? s_check_value : "-"; break; case 64 : str=SymbolInfoString(_Symbol,SYMBOL_DESCRIPTION); break; case 65 : s_check_value=SymbolInfoString(_Symbol,SYMBOL_ISIN); str=(s_check_value!="") ? s_check_value : "-"; break; case 66 : str=SymbolInfoString(_Symbol,SYMBOL_PATH); break; //--- case 67 : str=IntegerToString(SeriesInfoInteger(_Symbol,_Period,SERIES_BARS_COUNT)); break; case 68 : str=TimeToString((datetime)SeriesInfoInteger(_Symbol,_Period,SERIES_FIRSTDATE)); break; case 69 : str=TimeToString((datetime)SeriesInfoInteger(_Symbol,_Period,SERIES_SERVER_FIRSTDATE)); break; case 70 : str=(!(bool)SeriesInfoInteger(_Symbol,_Period,SERIES_SYNCHRONIZED)) ? "false" : "true"; break; } //--- return(str); }
The functions highlighted above: TradeCalcModeToString(), TradeModeToString(), TradeExeModeToString(), SwapModeToString() and WeekdayToString() simply return string representation of properties depending on the value passed.
//+------------------------------------------------------------------+ //| Returning string representation of the margin calculation | //| method for an instrument | //+------------------------------------------------------------------+ string TradeCalcModeToString(long mode) { string str="?"; //--- switch((ENUM_SYMBOL_CALC_MODE)mode) { case SYMBOL_CALC_MODE_FOREX : str="Forex mode"; break; case SYMBOL_CALC_MODE_FUTURES : str="Futures mode"; break; case SYMBOL_CALC_MODE_CFD : str="CFD mode"; break; case SYMBOL_CALC_MODE_CFDINDEX : str="CFD index mode"; break; case SYMBOL_CALC_MODE_CFDLEVERAGE : str="CFD Leverage mode"; break; case SYMBOL_CALC_MODE_EXCH_STOCKS : str="Exchange mode"; break; case SYMBOL_CALC_MODE_EXCH_FUTURES : str="Futures mode"; break; case SYMBOL_CALC_MODE_EXCH_FUTURES_FORTS : str="FORTS Futures mode"; break; } //--- return(str); } //+------------------------------------------------------------------+ //| Returning string representation of the trade mode | //+------------------------------------------------------------------+ string TradeModeToString(long mode) { string str="-"; //--- switch((ENUM_SYMBOL_TRADE_MODE)mode) { case SYMBOL_TRADE_MODE_DISABLED : str="Trade is disabled for a given symbol"; break; case SYMBOL_TRADE_MODE_LONGONLY : str="Only long positions are allowed"; break; case SYMBOL_TRADE_MODE_SHORTONLY : str="Only short positions are allowed"; break; case SYMBOL_TRADE_MODE_CLOSEONLY : str="Only position closing operations are allowed"; break; case SYMBOL_TRADE_MODE_FULL : str="No trade restrictions"; break; } //--- return(str); } //+------------------------------------------------------------------+ //| Returning string representation of the deal execution mode | //+------------------------------------------------------------------+ string TradeExeModeToString(long mode) { string str="-"; //--- switch((ENUM_SYMBOL_TRADE_EXECUTION)mode) { case SYMBOL_TRADE_EXECUTION_REQUEST : str="Request execution"; break; case SYMBOL_TRADE_EXECUTION_INSTANT : str="Instant execution"; break; case SYMBOL_TRADE_EXECUTION_MARKET : str="Market execution"; break; case SYMBOL_TRADE_EXECUTION_EXCHANGE : str="Exchange execution"; break; } //--- return(str); } //+------------------------------------------------------------------+ //| Returning string representation of the swap calculation model | //+------------------------------------------------------------------+ string SwapModeToString(long mode) { string str="-"; //--- switch((ENUM_SYMBOL_SWAP_MODE)mode) { case SYMBOL_SWAP_MODE_DISABLED : str="No swaps"; break; case SYMBOL_SWAP_MODE_POINTS : str="Swaps calculated in points"; break; case SYMBOL_SWAP_MODE_CURRENCY_SYMBOL : str="Swaps calculated in base currency of the symbol"; break; case SYMBOL_SWAP_MODE_CURRENCY_MARGIN : str="Swaps calculated in margin currency of the symbol"; break; case SYMBOL_SWAP_MODE_CURRENCY_DEPOSIT : str="Swaps calculated in the client's deposit currency"; break; case SYMBOL_SWAP_MODE_INTEREST_CURRENT : str="Swaps expressed as a percent per annum of the instrument price"; break; case SYMBOL_SWAP_MODE_INTEREST_OPEN : str="Swaps expressed as a percent per annum of the position opening price"; break; case SYMBOL_SWAP_MODE_REOPEN_CURRENT : str="Swaps based on position reopening (close price +/-)"; break; case SYMBOL_SWAP_MODE_REOPEN_BID : str="Swaps based on position reopening (bid price +/-)"; break; } //--- return(str); } //+------------------------------------------------------------------+ //| Returning string representation of the day of the week | //+------------------------------------------------------------------+ string WeekdayToString(long day) { string str="-"; //--- switch((ENUM_DAY_OF_WEEK)day) { case SUNDAY : str="Sunday"; break; case MONDAY : str="Monday"; break; case TUESDAY : str="Tuesday"; break; case WEDNESDAY : str="Wednesday"; break; case THURSDAY : str="Thursday"; break; case FRIDAY : str="Friday"; break; case SATURDAY : str="Saturday"; break; } //--- return(str); }
In the GetStringExpirationMode() and GetStringFillingMode() functions, the string representation is generated depending on the order expiration and volume filling modes available for the current symbol.
//+------------------------------------------------------------------+ //| Returning string representation of the order expiration modes | //+------------------------------------------------------------------+ string ExpirationModeToString() { string str=""; // For string generation //--- Variables for checking the modes bool gtc =false; // The order is valid for an unlimited time until explicitly canceled bool day =false; // The order is valid until the end of the day bool specified =false; // The expiration time is specified in the order bool specified_day =false; // The expiration date is specified in the order //--- Check the modes gtc =IsExpirationTypeAllowed(_Symbol,SYMBOL_EXPIRATION_GTC); day =IsExpirationTypeAllowed(_Symbol,SYMBOL_EXPIRATION_DAY); specified =IsExpirationTypeAllowed(_Symbol,SYMBOL_EXPIRATION_SPECIFIED); specified_day =IsExpirationTypeAllowed(_Symbol,SYMBOL_EXPIRATION_SPECIFIED_DAY); //--- Generate a string of the modes available if(gtc) { StringAdd(str,"GTC"); if(day || specified || specified_day) StringAdd(str," / "); } //--- if(day) { StringAdd(str,"Day"); if(specified || specified_day) StringAdd(str," / "); } //--- if(specified) { StringAdd(str,"Specified"); if(specified_day) StringAdd(str," / "); } //--- if(specified_day) StringAdd(str,"Specified Day"); //--- return(str); } //+------------------------------------------------------------------+ //| Returning string representation of the volume filling modes | //+------------------------------------------------------------------+ string FillingModeToString() { //--- Variable for string generation string str=""; //--- Variables for checking the modes: // "Fill or Kill" - if the required order volume cannot be filled at the specified price, // the order is canceled and the deal is not executed bool fok=false; // "Immediate or Cancel" - if the deal volume can only be partially filled at the price specified in the order, // the deal is executed to the extent of the volume available. The remaining volume of the order is canceled // and the new order is not placed bool ioc=false; // "Return" - The deal is executed to the extent of the volume available at the price specified in the order. // A new order is placed for the remaining volume at the same price bool return_remainder=false; //--- Check the modes fok =IsFillingTypeAllowed(_Symbol,SYMBOL_FILLING_FOK); ioc =IsFillingTypeAllowed(_Symbol,SYMBOL_FILLING_IOC); //--- For "Market execution" and "Exchange execution" modes ENUM_SYMBOL_TRADE_EXECUTION symbol_trade_exemode=(ENUM_SYMBOL_TRADE_EXECUTION)SymbolInfoInteger(_Symbol,SYMBOL_TRADE_EXEMODE); return_remainder=(symbol_trade_exemode==SYMBOL_TRADE_EXECUTION_MARKET || symbol_trade_exemode==SYMBOL_TRADE_EXECUTION_EXCHANGE) ? true : false; //--- Generate a string of the modes available if(fok) { StringAdd(str,"Fill or Kill"); if(ioc || return_remainder) StringAdd(str," / "); } //--- if(ioc) { StringAdd(str,"Immediate or Cancel"); if(return_remainder) StringAdd(str," / "); } //--- if(return_remainder) StringAdd(str,"Return"); //--- return(str); }
Since each mode availability needs to be checked separately, we, for convenience, use the auxiliary functions IsExpirationTypeAllowed() and IsFillingTypeAllowed(), provided in the documentation examples:
//+------------------------------------------------------------------+ //| Checking if a given expiration mode is allowed | //+------------------------------------------------------------------+ bool IsExpirationTypeAllowed(string symbol, int exp_type) { //--- Get the value of the property describing the allowable expiration modes int expiration=(int)SymbolInfoInteger(symbol,SYMBOL_EXPIRATION_MODE); //--- Return true if the exp_type mode is allowed return((expiration&exp_type)==exp_type); } //+------------------------------------------------------------------+ //| Checking if a given filling mode is allowed | //+------------------------------------------------------------------+ bool IsFillingTypeAllowed(string symbol, int fill_type) { //--- Get the value of the property describing the filling mode int filling=(int)SymbolInfoInteger(symbol,SYMBOL_FILLING_MODE); //--- Return true if the fill_type mode is allowed return((filling&fill_type)==fill_type); }
So, we have reviewed the string values of the symbol properties. Let's now take a look at the GetColorSymbolInfoByIndex() function. The code of this function is much simpler due to the fact that not all properties depend on the value displayed:
//+------------------------------------------------------------------+ //| Returning the symbol property color by index | //+------------------------------------------------------------------+ color GetColorSymbolInfoByIndex(int index) { double check_value =0.0; color clr =clrWhiteSmoke; //--- switch(index) { case 6 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_TIME)>0) ? clrCornflowerBlue : clrWhiteSmoke; break; //--- case 9 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_SPREAD_FLOAT)>0) ? clrGold : clrRed; break; //--- case 13 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_START_TIME)>0) ? clrCornflowerBlue : clrWhiteSmoke; break; case 14 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_EXPIRATION_TIME)>0) ? clrCornflowerBlue : clrWhiteSmoke; break; //--- case 15 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_TRADE_STOPS_LEVEL)>0) ? clrWhiteSmoke : clrRed; break; case 16 : clr=(SymbolInfoInteger(_Symbol,SYMBOL_TRADE_FREEZE_LEVEL)>0) ? clrWhiteSmoke : clrRed; break; //--- case 20 : clr=clrGold; break; case 21 : clr=clrGold; break; //--- case 39 : clr=(SymbolInfoDouble(_Symbol,SYMBOL_VOLUME_LIMIT)>0) ? clrWhiteSmoke : clrGold; break; case 40 : clr=(SymbolInfoDouble(_Symbol,SYMBOL_SWAP_LONG)>0) ? clrLime : clrRed; break; case 41 : clr=(SymbolInfoDouble(_Symbol,SYMBOL_SWAP_SHORT)>0) ? clrLime : clrRed; break; //--- case 60 : clr=clrGold; break; case 61 : clr=clrGold; break; case 62 : clr=clrGold; break; //--- case 68 : clr=(SeriesInfoInteger(_Symbol,_Period,SERIES_FIRSTDATE)>0) ? clrCornflowerBlue : clrWhiteSmoke; break; case 69 : clr=(SeriesInfoInteger(_Symbol,_Period,SERIES_SERVER_FIRSTDATE)>0) ? clrCornflowerBlue : clrWhiteSmoke; break; case 70 : clr=(!(bool)SeriesInfoInteger(_Symbol,_Period,SERIES_SYNCHRONIZED)) ? clrRed : clrGold; break; } //--- return(clr); }
If we now compile the indicator and add it to the chart, we will be able to see the list of the symbol properties in the subwindow as shown in screenshot below:
Fig. 1. Indicator attached to the chart without the scrollbar
All of this is one single object!
Further, we will write functions for working with the vertical scrollbar. As already mentioned at the beginning of the article, the scrollbar will be created using two graphical objects OBJ_RECTANGLE_LABEL (Rectangle Label). One is going to be used as a background and the other one will be the scroll box. The scrollbar will be situated on the right of the indicator subwindow.
CreateRectangleLable() - the function for creating a rectangle label:
//+------------------------------------------------------------------+ //| Creating a rectangle | //+------------------------------------------------------------------+ void CreateRectangleLable(long chart_id, // chart id int sub_window, // window number string object_name, // object name int x_distance, // X-coordinate int y_distance, // Y-coordinate int x_size, // width int y_size, // height ENUM_BASE_CORNER corner, // chart corner color border_color, // border color color background_color, // background color bool selectable, // cannot select the object if FALSE bool is_on_background) // background position { //--- If the object has been created successfully if(ObjectCreate(chart_id,object_name,OBJ_RECTANGLE_LABEL,sub_window,0,0)) { // set its properties ObjectSetInteger(chart_id,object_name,OBJPROP_XDISTANCE,x_distance); ObjectSetInteger(chart_id,object_name,OBJPROP_YDISTANCE,y_distance); ObjectSetInteger(chart_id,object_name,OBJPROP_XSIZE,x_size); ObjectSetInteger(chart_id,object_name,OBJPROP_YSIZE,y_size); ObjectSetInteger(chart_id,object_name,OBJPROP_BORDER_TYPE,BORDER_FLAT); // set the flat border style ObjectSetInteger(chart_id,object_name,OBJPROP_COLOR,border_color); ObjectSetInteger(chart_id,object_name,OBJPROP_CORNER,corner); ObjectSetInteger(chart_id,object_name,OBJPROP_BGCOLOR,background_color); ObjectSetInteger(chart_id,object_name,OBJPROP_SELECTABLE,selectable); ObjectSetInteger(chart_id,object_name,OBJPROP_BACK,is_on_background); // it will be used as a background if true ObjectSetString(chart_id,object_name,OBJPROP_TOOLTIP,"\n"); // no tooltip if "\n" } }
Let's write functions for creating and modifying the scroll box and scrollbar background sizes: AdjustScrollbarThumb() and AdjustScrollbarBackground():
//+------------------------------------------------------------------+ //| Adding scroll box or adjusting its size | //+------------------------------------------------------------------+ void AdjustScrollbarThumb() { //--- Calculate the scroll box size relative to the subwindow height CalculateScrollbarThumbHeight(); //--- If the scroll box is already available in the chart, adjust its properties if(ObjectFind(0,scrollbar_thumb_name)>0) { //--- Set the height and X-coordinate ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_YSIZE,scrollbar_thumb_height); ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_XDISTANCE,chart_width-scrollbar_thumb_width); //--- Adjust the scroll box position along the Y-axis if you go below the subwindow bottom boundary if(scrollbar_thumb_y1+scrollbar_thumb_height>subwindow_height) ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_YDISTANCE,subwindow_height-scrollbar_thumb_height); } //--- Create the scroll box if it does not exist else { CreateRectangleLable(0,subwindow_number,scrollbar_thumb_name, chart_width-scrollbar_thumb_width,0,scrollbar_thumb_width,scrollbar_thumb_height, CORNER_LEFT_UPPER,clrSilver,clrSilver,false,false); } } //+------------------------------------------------------------------+ //| Adding the scrollbar background or adjusting its size | //+------------------------------------------------------------------+ void AdjustScrollbarBackground() { //--- If the scrollbar background is already available in the chart, adjust its properties if(ObjectFind(0,scrollbar_background_name)>0) { //--- Set the background size ObjectSetInteger(0,scrollbar_background_name,OBJPROP_YDISTANCE,0); ObjectSetInteger(0,scrollbar_background_name,OBJPROP_XDISTANCE,chart_width-scrollbar_background_width); ObjectSetInteger(0,scrollbar_background_name,OBJPROP_YSIZE,subwindow_height); } //--- If there is no background, create it else { CreateRectangleLable(0,subwindow_number,scrollbar_background_name, chart_width-scrollbar_background_width,0,scrollbar_background_width,subwindow_height, CORNER_LEFT_UPPER,scrollbar_background_color,scrollbar_background_color,false,false); } }
The scroll box height is calculated at the very beginning of the AdjustScrollbarThumb() function, in the highlighted string:
//+------------------------------------------------------------------+ //| Calculating the scroll box size relative to the subwindow height | //+------------------------------------------------------------------+ void CalculateScrollbarThumbHeight() { //--- If the subwindow height is greater than the list size, save the subwindow size if(subwindow_height>=list_height) scrollbar_thumb_height=subwindow_height-1; //--- Otherwise calculate the scroll box size else { double height_temp=0.0; //--- Calculate the scroll box size relative to the subwindow height height_temp=subwindow_height-(((double)subwindow_height/100)*(100-((double)subwindow_height/list_height)*100)); //--- Set the minimum size at 25% of the subwindow height if(height_temp/subwindow_height<0.25) height_temp=subwindow_height/4; //--- Save to the global variable scrollbar_thumb_height=(int)height_temp; } }
Remember to delete the graphical objects:
//+------------------------------------------------------------------+ //| Deleting the scrollbar | //+------------------------------------------------------------------+ void DeleteScrollbar() { DeleteObjectByName(scrollbar_thumb_name); DeleteObjectByName(scrollbar_background_name); } //+------------------------------------------------------------------+ //| Deleting the object by name | //+------------------------------------------------------------------+ void DeleteObjectByName(string object_name) { //--- If such object exists if(ObjectFind(0,object_name)>=0) { //--- If an error occurred when deleting, print the relevant message if(!ObjectDelete(0,object_name)) Print("Error ("+IntegerToString(GetLastError())+") when deleting the object!"); } }
Let's now proceed to the most interesting part: we need to write functions that will allow for dragging the scroll box, thus causing the list to move, too. We also need to implement the change in the color of the scroll box when the cursor hovers over it and when the scroll box is clicked to indicate that the control has been passed to the scroll box and the latter can now be dragged. For this purpose, the scroll box color will additionally be changed upon clicking.
The scroll box is quite narrow in width, so when it is moved up/down you may experience sideways shifting of the cursor. To fix this issue, we will pass the control to the scroll box while the left mouse button is being pressed.
Below are the codes of the above described functions:
//+------------------------------------------------------------------+ //| Setting the scroll box color | //+------------------------------------------------------------------+ void SetScrollbarThumbColor(color thumb_color) { ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_COLOR,thumb_color); ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_BGCOLOR,thumb_color); } //+------------------------------------------------------------------+ //| Setting the scroll box boundaries | //+------------------------------------------------------------------+ void SetScrollbarThumbBoundaries() { scrollbar_thumb_x1=(int)ObjectGetInteger(0,scrollbar_thumb_name,OBJPROP_XDISTANCE); scrollbar_thumb_y1=(int)ObjectGetInteger(0,scrollbar_thumb_name,OBJPROP_YDISTANCE); scrollbar_thumb_x2=scrollbar_thumb_x1+scrollbar_thumb_width; scrollbar_thumb_y2=scrollbar_thumb_y1+scrollbar_thumb_height; } //+------------------------------------------------------------------+ //| Changing the color of the scroll box when the cursor hovers over | //+------------------------------------------------------------------+ void ChangeScrollbarThumbColorOnHover(int x,int y) { //--- If the cursor is within the scroll box area, make the color darker if(x>scrollbar_thumb_x1 && x<scrollbar_thumb_x2 && y>scrollbar_thumb_y1 && y<scrollbar_thumb_x2) SetScrollbarThumbColor(scrollbar_thumb_color_on_hover); //--- If the cursor is outside the scroll box boundaries else { //--- If the mouse button is released, set the standard scroll box color if(!mouse_button_state) SetScrollbarThumbColor(scrollbar_thumb_color); } } //+------------------------------------------------------------------+ //| Determining the scroll box state | //+------------------------------------------------------------------+ void SetScrollbarThumbState(int x,int y) { //--- If the mouse cursor is within the scroll box boundaries if(x>scrollbar_thumb_x1 && x<scrollbar_thumb_x2 && y>scrollbar_thumb_y1 && y<scrollbar_thumb_x2) { //--- If the mouse button is pressed, save it if(mouse_button_state) scrollbar_thumb_clicked=true; } //--- If the cursor is outside the scroll box boundaries else { //--- If the mouse button is released, disable the scroll box control if(!mouse_button_state) ZeroScrollbarThumbVariables(); } } //+------------------------------------------------------------------+ //| Zeroing out variables related to scroll box movement | //+------------------------------------------------------------------+ void ZeroScrollbarThumbVariables() { scrollbar_thumb_clicked =false; scrollbar_fix_point =0; scrollbar_fix_point_y_offest =0; }
Those are not all functions required to cause the scroll box to move. As a matter of fact, the scroll box mobility is based on events. In other words, a certain action would be triggered if the mouse button was pressed with the cursor being in the tracked chart area, followed by a shift of the cursor by the specified number of pixels with the mouse button still pressed. In our case, this would be the change in the scroll box position and, consequently, the list of the symbol properties. It is quite simple.
Below you can see the MoveThumb(), UpdateListAndScrollbarThumb() and ThumbYCoordinateToPercent() functions that are used to implement the above actions:
//+------------------------------------------------------------------+ //| Moving the scroll box vertically to the specified coordinate | //+------------------------------------------------------------------+ void MoveThumb(int y) { int threshold =1; // Threshold in pixels for recalculation int new_y_point =0; // New Y-coordinate //--- If the mouse button is pressed if(mouse_button_state) { //--- Set the clicked scroll box color SetScrollbarThumbColor(scrollbar_thumb_color_on_click); //--- Save the current Y-coordinate of the cursor if(scrollbar_fix_point==0) scrollbar_fix_point=y; //--- Save the distance from the scroll box top to the cursor if(scrollbar_fix_point_y_offest==0) scrollbar_fix_point_y_offest=scrollbar_thumb_y1-scrollbar_fix_point; } //--- If you scrolled down below the threshold value, while keeping the button pressed if(y-scrollbar_fix_point>=threshold) { //--- If you are still within the subwindow boundaries if(scrollbar_thumb_y1+scrollbar_thumb_height+threshold<subwindow_height) new_y_point=y+scrollbar_fix_point_y_offest; else { scrollbar_fix_point_y_offest=0; new_y_point=int(subwindow_height-scrollbar_thumb_height)-1; } //--- Refresh the list and the scroll box UpdateListAndScrollbarThumb(new_y_point); return; } //--- If you scrolled up above the threshold value, while keeping the button pressed if(y-scrollbar_fix_point<=-(threshold)) { //--- If you are still within the subwindow boundaries if(y-fabs(scrollbar_fix_point_y_offest)>=0) new_y_point=y-fabs(scrollbar_fix_point_y_offest); else { new_y_point=0; scrollbar_fix_point_y_offest=0; } //--- Refresh the list and the scroll box UpdateListAndScrollbarThumb(new_y_point); return; } } //+------------------------------------------------------------------+ //| Refreshing the list and the scroll box position | //+------------------------------------------------------------------+ void UpdateListAndScrollbarThumb(int new_point) { //--- Set the new Y-coordinate for the scroll box ObjectSetInteger(0,scrollbar_thumb_name,OBJPROP_YDISTANCE,new_point); //--- Refresh the list of the symbol properties relative to the current scroll box position ShowSymbolInfo(ThumbYCoordinateToPercent(new_point)); //--- Zero out the fix point scrollbar_fix_point=0; } //+------------------------------------------------------------------+ //| Converting the Y-coordinate of the scroll box to percentage | //+------------------------------------------------------------------+ double ThumbYCoordinateToPercent(long y) { if(subwindow_height<=0) subwindow_height=1; //--- return(((double)y/subwindow_height)*100); }
Now, all the functions should be put in a certain order to allow the program to work as initially conceived. In the OnChartEvent() function, we need to handle the events that help the user to interact with the indicator subwindow, as well as the list and scrollbar situated in the subwindow:
//+------------------------------------------------------------------+ //| ChartEvent function | //+------------------------------------------------------------------+ void OnChartEvent(const int id, const long &lparam, const double &dparam, const string &sparam) { //--- Track mouse clicks on the chart if(id==CHARTEVENT_CLICK) { //--- Zero out variables related to the scroll box movement ZeroScrollbarThumbVariables(); //--- Refresh the chart ChartRedraw(); return; } //--- Track the cursor movement and the state of the left mouse button if(id==CHARTEVENT_MOUSE_MOVE) { int x =(int)lparam; // X-coordinate int y =(int)dparam; // Y-coordinate int window =WRONG_VALUE; // Number of the window where the cursor is located datetime time =NULL; // Time corresponding to the X-coordinate double price =0.0; // Price corresponding to the Y-coordinate //--- Set subwindow properties SetSubwindowProperties(); //--- Check and save the state of the mouse button CheckMouseButtonState(sparam); //--- Get the position of the cursor if(ChartXYToTimePrice(0,x,y,window,time,price)) { //--- If the cursor is within the subwindow boundaries if(window==subwindow_number) { //--- Disable scrolling of the price chart ChartSetInteger(0,CHART_MOUSE_SCROLL,false); //--- Recalculate the Y coordinate relative to the indicator subwindow ChartYToSubwindowY(y); //--- Determine the scroll box boundaries SetScrollbarThumbBoundaries(); //--- Change the scroll box color when the cursor moves over it ChangeScrollbarThumbColorOnHover(x,y); //--- Determine the scroll box state SetScrollbarThumbState(x,y); //--- If the control is passed to the scroll box, drag it and refresh the list if(scrollbar_thumb_clicked) MoveThumb(y); } //--- If the cursor is outside the subwindow boundaries else { //--- Enable scrolling of the price chart ChartSetInteger(0,CHART_MOUSE_SCROLL,true); //--- If the mouse button is released, set the standard scroll box color if(!scrollbar_thumb_clicked) SetScrollbarThumbColor(scrollbar_thumb_color); } } //--- If the position of the cursor could not be determined else { //--- If the control has not been passed to the scroll box, set the standard scroll box color if(!scrollbar_thumb_clicked) SetScrollbarThumbColor(scrollbar_thumb_color); } //--- Refresh the chart ChartRedraw(); return; } //--- Track the change of properties and size of the chart if(id==CHARTEVENT_CHART_CHANGE) { //--- Set subwindow properties SetSubwindowProperties(); //--- Get the Y-coordinate of the scroll box scrollbar_thumb_y1=(int)ObjectGetInteger(0,scrollbar_thumb_name,OBJPROP_YDISTANCE); //--- If the subwindow size is zero, exit if(subwindow_height<=0) return; //--- Set the new canvas size ResizeCanvas(); //--- Refresh the scrollbar background AdjustScrollbarBackground(); //--- Refresh the scroll box AdjustScrollbarThumb(); //--- Refresh the data on the canvas ShowSymbolInfo(ThumbYCoordinateToPercent(scrollbar_thumb_y1)); //--- return; } }
The functions highlighted in the above code are auxiliary. You can easily understand their purpose from the comments provided.
//+-------------------------------------------------------------------+ //| Checking the mouse button state | //+-------------------------------------------------------------------+ void CheckMouseButtonState(string state) { //--- Left mouse button is pressed if(state=="1") mouse_button_state=true; //--- Left mouse button is released if(state=="0") { //--- Zero out variables ZeroScrollbarThumbVariables(); mouse_button_state=false; } } //+-------------------------------------------------------------------+ //| Recalculating the Y-coordinate relative to the indicator subwindow| //+-------------------------------------------------------------------+ void ChartYToSubwindowY(int &y) { //--- Get the distance from the chart top to the indicator subwindow chart_y_offset=(int)ChartGetInteger(0,CHART_WINDOW_YDISTANCE,subwindow_number); //--- Recalculate the Y-coordinate relative to the indicator subwindow y-=chart_y_offset; }
Like the canvas, the scrollbar should be added to the indicator subwindow during the initialization.
//+------------------------------------------------------------------+ //| Custom indicator initialization function | //+------------------------------------------------------------------+ int OnInit() { //--- Enable tracking of mouse events ChartSetInteger(0,CHART_EVENT_MOUSE_MOVE,true); //--- Set the short name IndicatorSetString(INDICATOR_SHORTNAME,subwindow_shortname); //--- Set sizes of arrays of symbol properties and their colors ArrayResize(symbol_property_colors,LIST_SIZE); ArrayResize(symbol_property_values,LIST_SIZE); //--- Set subwindow properties SetSubwindowProperties(); //--- Set the font for displaying on the canvas canvas.FontSet(font_name,font_size,FW_NORMAL); //--- Save the text size (height) for calculations text_height=canvas.TextHeight("A")-1; //--- Calculate the height of the entire list list_height=text_height*LIST_SIZE; //--- Add the canvas to the chart AddCanvas(); //--- Add the scrollbar: background and scroll box AdjustScrollbarBackground(); AdjustScrollbarThumb(); //--- Display the list of symbol properties ShowSymbolInfo(); //--- Refresh the chart ChartRedraw(); //--- Everything completed successfully return(INIT_SUCCEEDED); }
Don't forget to "clean up" in the OnDeinit() function. Depending on the deinitialization reason, the program can be set up more accurately.
//+------------------------------------------------------------------+ //| Deinitialization | //+------------------------------------------------------------------+ void OnDeinit(const int reason) { if(reason==REASON_REMOVE || // If the indicator has been removed from the chart or reason==REASON_CHARTCHANGE || // the symbol or time frame has been modified or reason==REASON_RECOMPILE || // the program has been recompiled or reason==REASON_CHARTCLOSE || // the chart has been closed or reason==REASON_CLOSE) // the terminal has been closed { //--- Delete the scrollbar DeleteScrollbar(); //--- Delete the canvas DeleteCanvas(); //--- Enable scrolling of the price chart ChartSetInteger(0,CHART_MOUSE_SCROLL,true); //--- Disable cursor tracking ChartSetInteger(0,CHART_EVENT_MOUSE_MOVE,false); //--- Refresh the chart ChartRedraw(); } }
And finally, to allow for some symbol properties to be refreshed in real-time mode, we need to add a couple of strings of code to the OnCalculate() function:
Now, everything is ready. The source code is attached to the article for your consideration in MetaEditor 5 and is available for download. The operation of the functions dealt with in this article is shown in the video provided below.
Conclusion
We have just completed the review of the scrollbar control. The article demonstrated how a scrollbar can be made of separate graphical objects which are located on a canvas. In one of the future articles, we will try to implement the entire functionality using methods of this class.