Mercurial > gemma
view pkg/models/colors.go @ 4969:5621586e7a54 fairway-marks-import
Avoid checking the same condition twice
An entry should either be UPDATEd or INSERTed, if it's not already
in the database. Thus simply INSERT if there was no UPDATE.
author | Tom Gottfried <tom@intevation.de> |
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date | Fri, 28 Feb 2020 17:55:55 +0100 |
parents | 18d5461bec5d |
children |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2019 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> // * Markus Kottländer <markus.kottlaender@intevation.de> package models import ( "fmt" "image/color" "math" "sort" "strconv" "strings" ) type ( // ColorValue models a tuple of a floating point value and a color. ColorValue struct { Value float64 Color color.RGBA } // ColorValues are a list of color values. // Colors between the given ones are linear interpolated. ColorValues []ColorValue // ClassBreak is a potential open interval of values associated // with a color. ClassBreak struct { High float64 HasHigh bool Low float64 HasLow bool Col color.RGBA } ) // Color gives a HTML compatible string representation of the color // of the class break. func (cb *ClassBreak) Color() string { return fmt.Sprintf("#%02x%02x%02x", cb.Col.R, cb.Col.G, cb.Col.B, ) } // ClassBreaks converts a list of colors to a list of class breaks. // The first an the last class break are open on the respective end. func (cc ColorValues) ClassBreaks() []ClassBreak { cbs := make([]ClassBreak, len(cc), len(cc)+1) for i := range cc { if i > 0 { cbs[i].Low = cc[i-1].Value cbs[i].HasLow = true } cbs[i].High = cc[i].Value cbs[i].HasHigh = true cbs[i].Col = cc[i].Color } if len(cc) > 0 { cbs = append(cbs, ClassBreak{ Col: cc[len(cc)-1].Color, Low: cc[len(cc)-1].Value, HasLow: true, }) } return cbs } // Heights extracts the values friom the color value pairs. func (cc ColorValues) Heights() []float64 { heights := make([]float64, len(cc)) for i := range cc { heights[i] = cc[i].Value } return heights } // Clip does the same as Interpolate // but if the value is out of bounds the value of the nearest border // is returned. func (cc ColorValues) Clip(v float64) color.RGBA { if len(cc) == 0 { return color.RGBA{} } if v < cc[0].Value { return cc[0].Color } if v > cc[len(cc)-1].Value { return cc[len(cc)-1].Color } c, _ := cc.Interpolate(v) return c } // Interpolate interpolates the color linearly between the // given values of the color values. // If the value is out of bounds false is returned. func (cc ColorValues) Interpolate(v float64) (color.RGBA, bool) { if len(cc) == 0 || v < cc[0].Value || v > cc[len(cc)-1].Value { return color.RGBA{}, false } if len(cc) == 1 { return cc[0].Color, cc[0].Value == v } for i := 0; i < len(cc)-1; i++ { v1 := cc[i].Value v2 := cc[i+1].Value if v1 <= v && v <= v2 { // f(v1) = 0 // f(v2) = 1 // 0 = m*v1 + c <=> c = -m*v1 // 1 = m*v2 + c // (1 - 0) = m*(v2 - v1) // m = 1/(v2 - v1) for v2 != v1 if v1 == v2 { return color.RGBA{ R: uint8((uint16(cc[i].Color.R) + uint16(cc[i+1].Color.R)) / 2), G: uint8((uint16(cc[i].Color.G) + uint16(cc[i+1].Color.G)) / 2), B: uint8((uint16(cc[i].Color.B) + uint16(cc[i+1].Color.B)) / 2), A: 0xff, }, true } m := 1 / (v2 - v1) c := -m * v1 s := v*m + c interpolate := func(a, b uint8) uint8 { v := math.Round(float64(a) + (float64(b)-float64(a))*s) if v < 0 { return 0 } if v > 255 { return 255 } return uint8(v) } return color.RGBA{ R: interpolate(cc[i].Color.R, cc[i+1].Color.R), G: interpolate(cc[i].Color.G, cc[i+1].Color.G), B: interpolate(cc[i].Color.B, cc[i+1].Color.B), A: 0xff, }, true } } return color.RGBA{}, false } // ParseColorValues parses a string to a list of color values. // The value/color pairs are separated by ','. // A color/value pair is separated with ':'. // f ':' is missing it is assumed that only the value is given. // The missing color is interpolated from fore and aftermost // value/colors pairs. func ParseColorValues(s string) (ColorValues, error) { var err error parseFloat := func(s string) float64 { var v float64 if err == nil { v, err = strconv.ParseFloat(s, 64) } return v } parseColor := func(s string) color.RGBA { if err != nil { return color.RGBA{} } s = strings.Map(func(r rune) rune { if ('0' <= r && r <= '9') || ('a' <= r && r <= 'f') || ('A' <= r && r <= 'F') { return r } return -1 }, s) var v int64 v, err = strconv.ParseInt(s, 16, 64) return color.RGBA{ R: uint8(v >> 16), G: uint8(v >> 8), B: uint8(v >> 0), A: 0xff, } } lines := strings.Split(s, ",") // first pass: find defined colors var defined ColorValues for _, line := range lines { // ignore the lines w/o a color. if !strings.ContainsRune(line, ':') { continue } parts := strings.SplitN(line, ":", 2) if len(parts) < 2 { continue } value := parseFloat(parts[0]) color := parseColor(parts[1]) defined = append(defined, ColorValue{ Value: value, Color: color, }) } if err != nil { return nil, err } sort.Slice(defined, func(i, j int) bool { return defined[i].Value < defined[j].Value }) // second pass: interpolate the rest var final ColorValues for _, line := range lines { if idx := strings.IndexRune(line, ':'); idx >= 0 { line = line[:idx] } value := parseFloat(line) if color, ok := defined.Interpolate(value); ok { final = append(final, ColorValue{ Value: value, Color: color, }) } } return final, err }