Algorithm to Draw a Line of Arbitrary Thickness

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HoboBen	Created : 04 September 2010 Edited : 04 September 2010 Language : Cobra Algorithm to Draw a Line of Arbitrary Thickness
By modifying Bresenham's line algorithm to plot rectangles instead of pixels, it is possible to draw lines of any thickness. Program Uses pure2d, keyset Procedure BLine(x0: Integer, y0: Integer, x1: Integer, y1: Integer, color: Integer, canvas: Element, xthickness: Integer, ythickness: Integer) Var steep: Boolean iTmp: Integer deltax, deltay: Integer error: Integer ystep: Integer x, y: Integer xthickOver2, ythickOver2: Integer Begin steep = abs(y1 - y0) > abs(x1 - x0) If steep then // swap(x0, y0) iTmp = x0 x0 = y0 y0 = iTmp // swap(x1, y1) iTmp = x1 x1 = y1 y1 = iTmp Endif If x0 > x1 then // swap(x0, x1) iTmp = x0 x0 = x1 x1 = iTmp // swap(y0, y1) iTmp = y0 y0 = y1 y1 = iTmp Endif deltax = x1 - x0 deltay = abs(y1 - y0) error = deltax / 2 ystep = 0 y = y0 If y0 < y1 then ystep = 1 else ystep = -1 For x = x0 to x1 xthickOver2 = xthickness/2 ythickOver2 = ythickness/2 If steep then Rect(y-ythickOver2, x-xthickOver2, xthickness, ythickness, color, TRUE, canvas) Else Rect(x-xthickOver2, y-ythickOver2, xthickness, ythickness, color, TRUE, canvas) Endif error = error - deltay If error < 0 then y = y + ystep error = error + deltax Endif Next End Begin OpenScreen(640, 480, 32, FALSE) While (KeyHits(VK_ESCAPE) = 0) Cls BLine(320, 240, MouseX, MouseY, ToRGBA(0,0,255), ScreenBuffer, 5, 5) Flip Pause(1) Wend End --v Syntax highlighting: Algorithm to Draw a Line of Arbitrary Thickness

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Monday, 20 September 2010, 18:01
Andy_A	I did a similar function for Blitz2D, B+, B3D. https://blitzmax.com/codearcs/codearcs.php?code=803 It looks like we both used a similar version of the Bresenham's algo.

Algorithm to Draw a Line of Arbitrary Thickness

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