Drawing of the arrowhead on the end of drown Line.
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Category: For Users of the Library
Forum Name: I need help - I can help
Forum Description: Problems and solutions while programming with the Debenu Quick PDF Library and Debenu PDF Viewer SDK
URL: http://www.quickpdf.org/forum/forum_posts.asp?TID=3155
Printed Date: 30 Apr 24 at 7:30AM
Software Version: Web Wiz Forums 11.01 - http://www.webwizforums.com
Topic: Drawing of the arrowhead on the end of drown Line.
Posted By: Michael_67
Subject: Drawing of the arrowhead on the end of drown Line.
Date Posted: 07 Aug 15 at 8:54AM
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Hello. What's the easiest way, to draw an arrowhead (two short lines or a triangle does not matter) at the end of with DrawLine(double StartX, double StartY, double EndX, double EndY) drawn line? A snippet, best in C #, would be nice. |
Replies:
Posted By: mLipok
Date Posted: 07 Aug 15 at 1:33PM
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You must calculate the angle of slope of the line. Then determine the opening angle and length arrowhead. Calculate endpoints for each edge arrowhead and draw a triangle. Interesting task. Currently I am on vacation. I am happy to take care of this deeply when I come back, and maybe a little earlier. ------------- Here you can find description how to test my examples: http://www.quickpdf.org/forum/forum_posts.asp?TID=2932&PID=12600&title=drawcapturedpagematrix-matrix-howto#12600 |
Posted By: Michael_67
Date Posted: 07 Aug 15 at 2:38PM
Thank you. That is my idea too. This should be possible with the trigonometric functions. I was just hoping someone already has a ready-made solution. |
mLipok wrote:Posted By: mLipok
Date Posted: 10 Aug 15 at 6:44AM
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maybe this way: #Region TESTING _QPDF_Arrow(10, 10, 100, 10, 10, 10, 0.1, 1) ; #FUNCTION# ==================================================================================================================== ; Name ..........: _QPDF_Arrow ; Description ...: Draw Arrow with ArrowHeads ; Syntax ........: _QPDF_Arrow($iX1, $iY1, $iX2, $iY2[, $iArrowHeadLenPercent = 10[, $iArrowHeadAngleDegree = 10[, ; $iArrowThickness = 0.1[, $iArrowHeadThickness = 0.1]]]]) ; Parameters ....: $iX1 - an integer value. ; $iY1 - an integer value. ; $iX2 - an integer value. ; $iY2 - an integer value. ; $iArrowHeadLenPercent - [optional] an integer value. Default is 10. In relation to the length of the arrows. ; $iArrowHeadAngleDegree - [optional] an integer value. Default is 10. ; $iArrowThickness - [optional] an integer value. Default is 0.1. ; $iArrowHeadThickness - [optional] an integer value. Default is 0.1. ; Return values .: None ; Author ........: mLipok ; Modified ......: ; Remarks .......: ; Related .......: ; Link ..........: http://www.quickpdf.org/forum/drawing-of-the-arrowhead-on-the-end-of-drown-line_topic3155.html ; Example .......: No ; =============================================================================================================================== Func _QPDF_Arrow($iX1, $iY1, $iX2, $iY2, $iArrowHeadLenPercent = 10, $iArrowHeadAngleDegree = 10, $iArrowThickness = 0.1, $iArrowHeadThickness = 0.1) Local $oQP If _QPDF_CreateObjectAndUnlock($oQP) = 1 Then $oQP.SetOrigin($__eQPDF_SORIGIN_TopLeft); $oQP.SetMeasurementUnits($__eQPDF_MUNITS_Milimeters) $oQP.SetLineWidth($iArrowThickness) $oQP.SetLineCap(1) $oQP.Drawline($iX1, $iY1, $iX2, $iY2) Local $iX12 = $iX2 - $iX1 Local $iY12 = $iY2 - $iY1 ; Assign a Local constant variable the approximate PI number. Local Const $PI = _Radian(180) $iArrowHeadAngleRadian = _Radian($iArrowHeadAngleDegree) ; Tan(angle) = Y / X ; Atan(X / Y) = angle Local $iArrowRadian = ATan($iY12 / $iX12) Local $iReverseArrowRadian = $iArrowRadian + $PI Local $iArrowLength If $iY12 = 0 Then $iArrowLength = $iX12 Else ; Sin(angle) = Y / Len $iArrowLength = $iY12 / Sin($iArrowRadian) EndIf Local $iArrowHeadLength = $iArrowLength * $iArrowHeadLenPercent / 100 Local $iRadianTiltedToTheRight = $iReverseArrowRadian + $iArrowHeadAngleRadian Local $iRadianTiltedToTheLeft = $iReverseArrowRadian - $iArrowHeadAngleRadian ; tg(angle) = Y / X ; ctg(angle) = X / Y ; sin(angle) = Y / $iArrowHeadLength ; cos(angle) = X / $iArrowHeadLength $oQP.SetLineWidth($iArrowHeadThickness) $oQP.Drawline($iX2, $iY2, $iX2 + Cos($iRadianTiltedToTheRight) * $iArrowHeadLength, $iY2 + Sin($iRadianTiltedToTheRight) * $iArrowHeadLength) $oQP.Drawline($iX2, $iY2, $iX2 + Cos($iRadianTiltedToTheLeft) * $iArrowHeadLength, $iY2 + Sin($iRadianTiltedToTheLeft) * $iArrowHeadLength) _QPDF_Display($oQP) EndIf EndFunc ;==>_QPDF_Arrow #EndRegion TESTING ------------- Here you can find description how to test my examples: http://www.quickpdf.org/forum/forum_posts.asp?TID=2932&PID=12600&title=drawcapturedpagematrix-matrix-howto#12600 |
Posted By: Michael_67
Date Posted: 11 Aug 15 at 8:01AM
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Thank you very much! That looks pretty good. I'll translate it in C #, if I have the time. However, if the arrow direction is right to left, arrow head direction is false. And in case of a vertical line, it will lead to error in the line |
Posted By: Michael_67
Date Posted: 11 Aug 15 at 5:26PM
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My Function in C# (simplified, arrow head only, fix angle and length): private static void DrawArrowHead(double startX, double startY, double endX, double endY) { double headAngleDegree = 15; double headLength = 10; var headAngle = headAngleDegree * (Math.PI / 180); var deltaX = endX - startX; var deltaY = endY - startY; double lineSlopeAngle; if (deltaX == 0) { if (endY > endX) { lineSlopeAngle = Math.PI / 2; } else { lineSlopeAngle = -Math.PI / 2; } } else { lineSlopeAngle = Math.Atan(deltaY / deltaX); } if(deltaX >= 0) { lineSlopeAngle += Math.PI; } var rightLineAngle = lineSlopeAngle + headAngle; var leftLineAngle = lineSlopeAngle - headAngle; var rightLineEndX = endX + Math.Cos(rightLineAngle) * headLength; var rightLineEndY = endY + Math.Sin(rightLineAngle) * headLength; var leftLineEndX = endX + Math.Cos(leftLineAngle) * headLength; var leftLineEndY = endY + Math.Sin(leftLineAngle) * headLength; pdfLibrary.DrawLine(endX, endY, rightLineEndX, rightLineEndY); pdfLibrary.DrawLine(endX, endY, leftLineEndX, leftLineEndY); } |
Posted By: mLipok
Date Posted: 12 Aug 15 at 12:37PM
Can you show example of parameters, for my function ? ------------- Here you can find description how to test my examples: http://www.quickpdf.org/forum/forum_posts.asp?TID=2932&PID=12600&title=drawcapturedpagematrix-matrix-howto#12600 |
Posted By: Michael_67
Date Posted: 12 Aug 15 at 12:53PM
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Vertical line:
_QPDF_Arrow(100, 20, 100, 200 ... $iX12 = $iX2 - $iX1 is in this case 0, $iY12 / $iX12 - division by zero Right to left: _QPDF_Arrow(100, 20, 10, 200 ... X2 < X1 draws not <--- but >--- Best Regards Michael |
Posted By: mLipok
Date Posted: 12 Aug 15 at 1:31PM
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ah I see. You have right. But I do not worry about this as my dev.environment take care about that, and all works properly :) ------------- Here you can find description how to test my examples: http://www.quickpdf.org/forum/forum_posts.asp?TID=2932&PID=12600&title=drawcapturedpagematrix-matrix-howto#12600 |
Posted By: Michael_67
Date Posted: 12 Aug 15 at 4:03PM
C # is much more restrictive in this case :) Thank you again. You have helped me a lot with your algorithm. |