diff options
Diffstat (limited to 'draw/draw.go')
-rw-r--r-- | draw/draw.go | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/draw/draw.go b/draw/draw.go index cfde776..9af3ad9 100644 --- a/draw/draw.go +++ b/draw/draw.go @@ -27,6 +27,66 @@ func initializePlot() *gg.Context { return dc } +// saveImages saves the given context to a png at the given path +func saveImage(dc *gg.Context, path string) { + dc.SavePNG(path) +} + +// drawStar draws the given stars to the given context +func drawStar(dc *gg.Context, star structs.Star) { + dc.DrawPoint(star.C.X, star.C.Y, 1) + dc.Fill() + dc.Stroke() +} + +// vectorLength calculates the length of the given vector +func vectorLength(force structs.Force) float64 { + return math.Sqrt(math.Pow(force.X, 2) + math.Pow(force.Y, 2)) +} + +func drawForce(dc *gg.Context, star structs.Star) { + // controll the length of the vector + var scalingFactor float64 = 10 + + // Move the "cursor" to the start position of the vector + dc.MoveTo(star.C.X, star.C.Y) + + // calculate the length of the vector + vecLength := vectorLength(star.F) + + // Use a sigmoid function to generate useful values for coloring the vectors according to their + // strength + var val = 1.0 / (1.0 + math.Exp(-vecLength/100000)) + + // Set the color to a blue / red + dc.SetRGB(val, 0, 1-val) + + // trace the Vector + FxUnit := star.F.X / math.Abs(vecLength) + FyUnit := star.F.Y / math.Abs(vecLength) + dc.LineTo(star.C.X+(FxUnit*scalingFactor), star.C.Y+(FyUnit*scalingFactor)) + + // css + dc.SetLineWidth(2) + + // And finally: DRAW (stroke) the vector + dc.Stroke() +} + +// drawStars draws all the stars in the given slice to the given context +func drawStars(dc *gg.Context, slice []structs.Star) { + dc.SetRGB(1, 1, 1) + + for _, star := range slice { + drawForce(dc, star) + } + + for _, star := range slice { + drawStar(dc, star) + } +} + +// Slice draws the stars and the forces acting on them and saves the result to the given path func Slice(slice []structs.Star, path string) { dc := initializePlot() dc.SetRGB(1, 1, 1) |