1 files changed, 119 insertions, 0 deletions
diff --git a/Master/texmf-dist/doc/latex/luatikz/example/radon1.lua b/Master/texmf-dist/doc/latex/luatikz/example/radon1.lua
new file mode 100644
index 00000000000..166c44c7635
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/luatikz/example/radon1.lua
@@ -0,0 +1,119 @@
+tikz.within( '*' )
+
+local cos = math.cos
+local sin = math.sin
+local pi  = math.pi
+
+-- granularity of calculation
+local fine = 10
+
+-- factor the projection length is reduced
+local fproj = 0.35
+
+-- strength of the ellipse mediums
+local s1 = 1.00
+local s2 = 1.50
+local s3 = 1.75
+
+local e1 = ellipse{ at=p{ 0.00,  0.00 }, xradius=3.00, yradius=3.00 }
+local e2 = ellipse{ at=p{ 0.40,  1.20 }, xradius=0.85, yradius=0.50 }
+local e3 = ellipse{ at=p{ 0.00, -0.89 }, xradius=1.00, yradius=0.60 }
+
+draw{ fill='black!08!white', line_width=1, e1 }
+draw{ fill='black!16!white', line_width=1, e2 }
+draw{ fill='black!24!white', line_width=1, e3 }
+
+-- list of projection angles
+local listphi =
+{
+	-1/4 * pi,
+	 2/4 * pi,
+	 5/4 * pi,
+}
+
+-- length of projection lines
+local lenmaintop = 5.0
+local lenmainbot = 6.5
+
+for proji, phimain in ipairs( listphi )
+do
+	local lmain =
+		line{
+			p{ cos( phimain ), sin( phimain ) } * -lenmaintop,
+			p{ cos( phimain ), sin( phimain ) } *  lenmainbot,
+		}
+	local phinorm = phimain - pi/2
+
+	-- gets a point on the projection.
+	-- dp: distance from projection center
+	-- dv: projection value
+	function getpproj( dp, dv )
+		return(
+			lmain.p2
+			+ p{ cos( phinorm ) * dp,         sin( phinorm ) * dp         }
+			+ p{ cos( phimain ) * dv * fproj, sin( phimain ) * dv * fproj }
+		)
+	end
+
+	-- distance of projection line
+	local ddis = 1 / fine
+
+	-- list of all projection points
+	local listp = { }
+
+	for i = -3.5 * fine, 3.5 * fine
+	do
+		local p1i =
+			lmain.p1
+			+ p{ cos( phinorm ) * ddis * i, sin( phinorm ) * ddis * i }
+		local li = line{ p1i, p1i + ( lmain.p2 - lmain.p1 ) }
+		local lv = 0
+		local is1 = e1.intersectLine( li )
+
+		if is1 and #is1 > 1
+		then
+			local lis = line{ is1[ 1 ], is1[ 2 ] }
+			lv = lv + lis.length * s1
+		end
+
+		local is2 = e2.intersectLine( li )
+		if is2 and #is2 > 1
+		then
+			local lis = line{ is2[ 1 ], is2[ 2 ] }
+			lv = lv + lis.length * s2
+		end
+
+		local is3 = e3.intersectLine( li )
+		if is3 and #is3 > 1
+		then
+			local lis = line{ is3[ 1 ], is3[ 2 ] }
+			lv = lv + lis.length * s3
+		end
+
+		local pproj = getpproj( ddis * i, lv    )
+		if i % ( 0.7 * fine ) == 0
+		then
+			draw{
+				dotted, arrow, line_width=0.5,
+				line{ li.p1, getpproj( ddis * i, -0.20 ) },
+			}
+			draw{
+				dotted, line_width=0.5,
+				line{ li.p1, pproj },
+			}
+		end
+		table.insert( listp, pproj )
+	end
+
+	-- draws the projection screen
+	local lenlproj = 8
+	draw{
+		line{
+			getpproj(  lenlproj / 2, 0 ),
+			getpproj( -lenlproj / 2, 0 ),
+		}
+	}
+
+	-- draws the projection curve
+	draw{ line_width=1, polyline{ table.unpack( listp ) } }
+end