render.go

Documentation: github.com/jedib0t/go-pretty/v6/list

     1  package list
     2  
     3  import (
     4  	"strings"
     5  	"unicode/utf8"
     6  )
     7  
     8  // Render renders the List in a human-readable "pretty" format. Example:
     9  //  * Game Of Thrones
    10  //    * Winter
    11  //    * Is
    12  //    * Coming
    13  //      * This
    14  //      * Is
    15  //      * Known
    16  //  * The Dark Tower
    17  //    * The Gunslinger
    18  func (l *List) Render() string {
    19  	l.initForRender()
    20  
    21  	var out strings.Builder
    22  	out.Grow(l.approxSize)
    23  	for idx, item := range l.items {
    24  		hint := renderHint{
    25  			isTopItem:    bool(idx == 0),
    26  			isFirstItem:  bool(idx == 0 || item.Level > l.items[idx-1].Level),
    27  			isLastItem:   !l.hasMoreItemsInLevel(item.Level, idx),
    28  			isBottomItem: bool(idx == len(l.items)-1),
    29  		}
    30  		if hint.isFirstItem && hint.isLastItem {
    31  			hint.isOnlyItem = true
    32  		}
    33  		l.renderItem(&out, idx, item, hint)
    34  	}
    35  	return l.render(&out)
    36  }
    37  
    38  func (l *List) renderItem(out *strings.Builder, idx int, item *listItem, hint renderHint) {
    39  	// when working on item number 2 or more, render a newline first
    40  	if idx > 0 {
    41  		out.WriteRune('\n')
    42  	}
    43  
    44  	// format item.Text as directed in l.style
    45  	itemStr := l.style.Format.Apply(item.Text)
    46  
    47  	// convert newlines if newlines are not "\n" in l.style
    48  	if strings.Contains(itemStr, "\n") && l.style.CharNewline != "\n" {
    49  		itemStr = strings.Replace(itemStr, "\n", l.style.CharNewline, -1)
    50  	}
    51  
    52  	// render the item.Text line by line
    53  	for lineIdx, lineStr := range strings.Split(itemStr, "\n") {
    54  		if lineIdx > 0 {
    55  			out.WriteRune('\n')
    56  		}
    57  
    58  		// render the prefix or the leading text before the actual item
    59  		l.renderItemBulletPrefix(out, idx, item.Level, lineIdx, hint)
    60  		l.renderItemBullet(out, lineIdx, hint)
    61  
    62  		// render the actual item
    63  		out.WriteString(lineStr)
    64  	}
    65  }
    66  
    67  func (l *List) renderItemBullet(out *strings.Builder, lineIdx int, hint renderHint) {
    68  	if lineIdx > 0 {
    69  		// multi-line item.Text
    70  		if hint.isLastItem {
    71  			out.WriteString(strings.Repeat(" ", utf8.RuneCountInString(l.style.CharItemVertical)))
    72  		} else {
    73  			out.WriteString(l.style.CharItemVertical)
    74  		}
    75  	} else {
    76  		l.renderItemBulletSingleLine(out, lineIdx, hint)
    77  	}
    78  }
    79  
    80  func (l *List) renderItemBulletSingleLine(out *strings.Builder, lineIdx int, hint renderHint) {
    81  	// single-line item.Text (or first line of a multi-line item.Text)
    82  	if hint.isOnlyItem {
    83  		if hint.isTopItem {
    84  			out.WriteString(l.style.CharItemSingle)
    85  		} else {
    86  			out.WriteString(l.style.CharItemBottom)
    87  		}
    88  	} else if hint.isTopItem {
    89  		out.WriteString(l.style.CharItemTop)
    90  	} else if hint.isFirstItem {
    91  		out.WriteString(l.style.CharItemFirst)
    92  	} else if hint.isBottomItem || hint.isLastItem {
    93  		out.WriteString(l.style.CharItemBottom)
    94  	} else {
    95  		out.WriteString(l.style.CharItemMiddle)
    96  	}
    97  	out.WriteRune(' ')
    98  }
    99  
   100  func (l *List) renderItemBulletPrefix(out *strings.Builder, itemIdx int, itemLevel int, lineIdx int, hint renderHint) {
   101  	// write a prefix if one has been set in l.style
   102  	if l.style.LinePrefix != "" {
   103  		out.WriteString(l.style.LinePrefix)
   104  	}
   105  
   106  	// render spaces and connectors until the item's position
   107  	for levelIdx := 0; levelIdx < itemLevel; levelIdx++ {
   108  		if l.hasMoreItemsInLevel(levelIdx, itemIdx) {
   109  			out.WriteString(l.style.CharItemVertical)
   110  		} else {
   111  			out.WriteString(strings.Repeat(" ", utf8.RuneCountInString(l.style.CharItemVertical)))
   112  		}
   113  	}
   114  }
   115
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