Programmatically equaling time on chart?

pangit68 · 2024-07-29T13:59:37.0000000Z

Greetings, Below I have a function intended to determine the intersection of 2 ('Object Trend') lines drawn on a chart. The issue is that the 'intersection time' being reported does not seem to equal what I am seeing visually on the chart. In the function the 'time' of the intersection is set as the variable for "x", while the 'price' at the intersection is set as the variable for "y". The 'intersection time' is set as the variable "intersectionTime". This problem might possibly be caused by some conversion error involving 'double' and 'datetime' variables in the MQL5 language...however I'm not exactly sure. There also appear to be issues involving the comparison of "intersectionTime" and "lastTime" (is a direct comparison as I have written it possible in MQL5?) and possibly the display of the "y" variable for price. Any suggestions greatly appreciated. // Function to check if two lines intersect bool DoLinesIntersect( double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4, int primary, int secondary) { // Get the index of the first visible bar on the chart long firstVisibleBar = ChartGetInteger ( 0 , CHART_FIRST_VISIBLE_BAR ); // Get the number of visible bars on the chart long visibleBars = ChartGetInteger ( 0 , CHART_VISIBLE_BARS ); // Calculate the index of the last visible bar long lastVisibleBar = MathAbs (firstVisibleBar - visibleBars) - 1 ; // Get the time of the last visible bar datetime lastTime = iTime ( NULL , 0 , lastVisibleBar); // Calculate slopes double m1 = (y2 - y1) / (x2 - x1); double m2 = (y4 - y3) / (x4 - x3); // Check if lines are parallel if (m1 == m2) { return false ; } // Calculate intersection point double x = (-m2 * x3 + y3 + m1 * x1 - y1) / (m1 - m2); double y = m1 * (x - x1) + y1; // Cast 'x' to datetime datetime intersectionTime = ( datetime )x; Print ( "intersectionTime is: " , intersectionTime); if ((intersectionTime <= lastTime) && (y >= MIN_PRICE) && (y <= MAX_PRICE)) { Print ( "Line Intersections Points Detected: X=" , intersectionTime, " , Y=" , ( double )y, "...BAR #" , primary, " intersects with BAR#" , secondary); return true ; } //'x' is BEFORE the TIME ENTRY of the LAST BAR ON THE RIGHT SIDE OF THE CHART...AND //'y' lies WITHIN the MAXIMUM and MINIMUM price values plotted on the chart. //Therefore the 'intersection' occurs within the visible area of the chart. return false ; } I thank you in advance for any assistance.

pangit68 2024.07.26 12:39 #11

Thanks for the post Yashar,

Your code looks much like mine for the most part, except you are running directly on a minute (M1) chart it seems...

pangit68 2024.07.29 13:45 #12

Well after some additional testing I have determined part of my earlier confusion, it seems MQL5 calculates intersection points when there is no actual line intersection...as illustrated in the image attached below.

I have indicated the two lines in question labelled as "First Line" and "Second Line". The reported intersection time reads 2024.7.26 22:57:00, however this time occurs before the bar where the "Second Line" originates. In my image I have drawn a dotted blue line (labelled "Extended Line") which extends from the origin of the "Second Line" to the left ('back in time') to the indicated intersection point. I didn't realize before that MQL5 would create an intersection by 'extending' projections of lines on the chart, and that these 'extensions' could 'reach back' to a time period before the line was actually drawn on the chart. Obviously I will have to modify my code to ignore any reported intersections that are placed at a time before the creation of the "Second Line". I am only interested in intersections of lines that actually take place on the chart.

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pangit68 2024.07.29 13:58 #13

Another thing I have noticed after some additional testing...

In the attached image (with labels added as I did in my previous post) there is an intersection reported at 2024.4.20 17:37:51 (as before, extending 'back in time' to a point not only before the "Second Line", but before the "First Line" as well). I am a bit confused by this reported intersection time, because 2024.4.20 was a Saturday. This chart is a Daily ("D1") rather than a Minute ("M1") as in my previous post.

I thought non-trading days such as Saturday would not be reported on a MQL5 chart? I would have thought the previous trading day (Friday) should have been reported, which would have been 2024.4.19...???

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