Mercurial > gemma
changeset 4541:53b55f811666 iso-areas
Dump generated polygons as SVG.
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Thu, 26 Sep 2019 15:37:56 +0200 |
| parents | e01b6e7cbe7d |
| children | 56f4e8cbfab7 |
| files | cmd/isoareas/main.go go.mod go.sum |
| diffstat | 3 files changed, 65 insertions(+), 3 deletions(-) [+] |
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--- a/cmd/isoareas/main.go Thu Sep 26 13:08:56 2019 +0200 +++ b/cmd/isoareas/main.go Thu Sep 26 15:37:56 2019 +0200 @@ -15,15 +15,19 @@ import ( "bufio" + "fmt" "io" "log" "math" "math/bits" + "math/rand" "os" "strconv" "strings" "time" + svg "github.com/ajstarks/svgo" + "gemma.intevation.de/gemma/pkg/octree" ) @@ -219,17 +223,73 @@ return mask } +func linear(x1, y1, x2, y2 float64) func(float64) float64 { + // f(x1) = y1 + // f(x2) = y2 + // y1 = x1*a + b <=> b = y1 - x1*a + // y2 = x2*a + b + + // y1 - y2 = a*(x1 - x2) + // a = (y1-y2)/(x1 - x2) for x1 != x2 + + if x1 == x2 { + return func(float64) float64 { + return 0.5 * (y1 + y2) + } + } + a := (y1 - y2) / (x1 - x2) + b := y1 - x1*a + return func(x float64) float64 { + return x*a + b + } +} + func dumpPolygonsSVG( w io.Writer, min, max octree.Vertex, - polygons [][]octree.LineStringZ, -) error { + classPolygons [][]octree.LineStringZ, +) (err error) { ratio := (max.X - min.X) / (max.Y - min.Y) log.Printf("ratio: %.2f\n", ratio) - // TODO: Implement me! + const width = 1000 + height := int(math.Ceil(width * ratio)) + + px := linear(min.X, 0, max.X, width) + py := linear(min.Y, float64(height), max.Y, 0) + + out := bufio.NewWriter(w) + defer func() { err = out.Flush() }() + + canvas := svg.New(out) + canvas.Start(width, height) + + rnd := rand.New(rand.NewSource(42)) + + for _, polygons := range classPolygons { + + r := byte(rnd.Intn(256)) + g := byte(rnd.Intn(256)) + b := byte(rnd.Intn(256)) + style := fmt.Sprintf("fill:#%02x%02x%02x", r, g, b) + + for _, polygon := range polygons { + + x := make([]int, len(polygon)) + y := make([]int, len(polygon)) + for i, p := range polygon { + x[i] = int(math.Round(px(p.X))) + y[i] = int(math.Round(py(p.Y))) + } + + canvas.Polygon(x, y, style) + } + + } + + canvas.End() return nil }
--- a/go.mod Thu Sep 26 13:08:56 2019 +0200 +++ b/go.mod Thu Sep 26 15:37:56 2019 +0200 @@ -3,6 +3,7 @@ go 1.13 require ( + github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af github.com/cockroachdb/apd v1.1.0 // indirect github.com/etcd-io/bbolt v1.3.3 github.com/gofrs/uuid v3.2.0+incompatible // indirect
--- a/go.sum Thu Sep 26 13:08:56 2019 +0200 +++ b/go.sum Thu Sep 26 15:37:56 2019 +0200 @@ -2,6 +2,7 @@ github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ= github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU= github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU= +github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af h1:wVe6/Ea46ZMeNkQjjBW6xcqyQA/j5e0D6GytH95g0gQ= github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw= github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc= github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=