mirror of https://github.com/mum4k/termdash.git
125 lines
3.2 KiB
Go
125 lines
3.2 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package draw
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import (
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"fmt"
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runewidth "github.com/mattn/go-runewidth"
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)
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// line_style.go contains the Unicode characters used for drawing lines of
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// different styles.
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// lineStyleChars maps the line styles to the corresponding component characters.
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// Source: http://en.wikipedia.org/wiki/Box-drawing_character.
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var lineStyleChars = map[LineStyle]map[linePart]rune{
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LineStyleLight: {
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hLine: '─',
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vLine: '│',
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topLeftCorner: '┌',
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topRightCorner: '┐',
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bottomLeftCorner: '└',
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bottomRightCorner: '┘',
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hAndUp: '┴',
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hAndDown: '┬',
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vAndLeft: '┤',
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vAndRight: '├',
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vAndH: '┼',
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},
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}
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// init verifies that all line parts are half-width runes (occupy only one
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// cell).
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func init() {
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for ls, parts := range lineStyleChars {
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for part, r := range parts {
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if got := runewidth.RuneWidth(r); got > 1 {
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panic(fmt.Errorf("line style %v line part %v is a rune %c with width %v, all parts must be half-width runes (width of one)", ls, part, r, got))
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}
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}
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}
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}
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// lineParts returns the line component characters for the provided line style.
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func lineParts(ls LineStyle) (map[linePart]rune, error) {
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parts, ok := lineStyleChars[ls]
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if !ok {
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return nil, fmt.Errorf("unsupported line style %d", ls)
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}
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return parts, nil
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}
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// LineStyle defines the supported line styles.Q
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type LineStyle int
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// String implements fmt.Stringer()
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func (ls LineStyle) String() string {
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if n, ok := lineStyleNames[ls]; ok {
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return n
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}
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return "LineStyleUnknown"
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}
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// lineStyleNames maps LineStyle values to human readable names.
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var lineStyleNames = map[LineStyle]string{
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LineStyleLight: "LineStyleLight",
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}
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// Supported line styles.
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const (
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LineStyleNone LineStyle = iota
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LineStyleLight
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)
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// linePart identifies individual line parts.
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type linePart int
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// String implements fmt.Stringer()
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func (lp linePart) String() string {
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if n, ok := linePartNames[lp]; ok {
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return n
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}
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return "linePartUnknown"
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}
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// linePartNames maps linePart values to human readable names.
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var linePartNames = map[linePart]string{
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vLine: "linePartVLine",
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topLeftCorner: "linePartTopLeftCorner",
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topRightCorner: "linePartTopRightCorner",
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bottomLeftCorner: "linePartBottomLeftCorner",
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bottomRightCorner: "linePartBottomRightCorner",
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hAndUp: "linePartHAndUp",
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hAndDown: "linePartHAndDown",
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vAndLeft: "linePartVAndLeft",
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vAndRight: "linePartVAndRight",
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vAndH: "linePartVAndH",
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}
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const (
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hLine linePart = iota
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vLine
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topLeftCorner
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topRightCorner
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bottomLeftCorner
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bottomRightCorner
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hAndUp
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hAndDown
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vAndLeft
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vAndRight
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vAndH
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)
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