grokify/mogo

package colors

import (
    "fmt"
    "image/color"
    "sort"
)

func MatrixColumn(m [][]color.Color, colIdx uint) ([]color.Color, error) {
    colIdxInt := int(colIdx)
    clrs := []color.Color{}
    for i, row := range m {
        if colIdxInt >= len(row) {
            return clrs, fmt.Errorf("col [%d] not found on row [%d]", colIdx, i)
        }
        clrs = append(clrs, row[colIdxInt])
    }
    return clrs, nil
}

func MatrixUnique(c [][]color.Color) []color.Color {
    if len(c) == 0 {
        return []color.Color{}
    }
    uniques := map[string]color.Color{}
    keys := []string{}
    for _, row := range c {
        for _, cx := range row {
            cxs := ColorString(cx)
            if _, ok := uniques[cxs]; !ok {
                uniques[cxs] = cx
                keys = append(keys, cxs)
            }
        }
    }
    return uniqueColorsToSlice(keys, uniques)
}

func SliceUnique(c []color.Color) []color.Color {
    if len(c) == 0 {
        return c
    }
    uniques := map[string]color.Color{}
    keys := []string{}
    for _, cx := range c {
        cxs := ColorString(cx)
        if _, ok := uniques[cxs]; !ok {
            uniques[cxs] = cx
            keys = append(keys, cxs)
        }
    }
    return uniqueColorsToSlice(keys, uniques)
}

func uniqueColorsToSlice(keys []string, uniques map[string]color.Color) []color.Color {
    sort.Strings(keys)
    cslice := []color.Color{}
    for _, cxs := range keys {
        if c, ok := uniques[cxs]; ok {
            cslice = append(cslice, c)
        } else {
            panic(fmt.Sprintf("color [%s] not found", cxs))
        }
    }
    return cslice
}