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|
// Copyright 2021 Graham Clark. All rights reserved. Use of this source
// code is governed by the MIT license that can be found in the LICENSE
// file.
// Package paragraph provides a simple text widget that neatly splits
// over multiple lines.
package paragraph
import (
"strings"
"github.com/gcla/gowid"
"github.com/gcla/gowid/gwutil"
)
//======================================================================
// Widget can be used to display text on the screen, with words broken
// cleanly as the output width changes.
type Widget struct {
words []string
lastcols int
lastrows int
gowid.RejectUserInput
gowid.NotSelectable
}
var _ gowid.IWidget = (*Widget)(nil)
func New(text string) *Widget {
return &Widget{
words: strings.Fields(text),
}
}
func NewWithWords(words ...string) *Widget {
return &Widget{
words: words,
}
}
func (w *Widget) Render(size gowid.IRenderSize, focus gowid.Selector, app gowid.IApp) gowid.ICanvas {
switch size := size.(type) {
case gowid.IRenderFlowWith:
res := gowid.NewCanvas()
var lc gowid.ICanvas
var pos int
var curWord string
i := 0
space := false
for {
if i >= len(w.words) {
if lc != nil {
res.AppendBelow(lc, false, false)
}
break
}
if curWord == "" {
curWord = w.words[i]
}
if lc == nil {
lc = gowid.NewCanvasOfSize(size.FlowColumns(), 1)
pos = 0
}
if space {
if pos < size.FlowColumns()-1 {
pos++
} else {
if lc != nil {
res.AppendBelow(lc, false, false)
lc = gowid.NewCanvasOfSize(size.FlowColumns(), 1)
pos = 0
}
}
space = false
} else {
// No space left in current line
if len(curWord) > size.FlowColumns()-pos {
// No space on this line, but it will fit on next line. If it
// doesn't even fit on a line by itself, well just split it
if pos > 0 && lc != nil && len(curWord) <= size.FlowColumns() {
res.AppendBelow(lc, false, false)
lc = gowid.NewCanvasOfSize(size.FlowColumns(), 1)
pos = 0
}
take := gwutil.Min(size.FlowColumns()-pos, len(curWord))
for j := 0; j < take; j++ {
lc.SetCellAt(pos, 0, gowid.CellFromRune(rune(curWord[j])))
pos++
}
if pos >= size.FlowColumns() {
res.AppendBelow(lc, false, false)
lc = nil
}
if take == len(curWord) {
i++
curWord = ""
space = true
} else {
// Must be less
curWord = curWord[take:]
}
} else {
for j := 0; j < len(curWord); j++ {
lc.SetCellAt(pos, 0, gowid.CellFromRune(rune(curWord[j])))
pos++
}
i++
curWord = ""
space = true
}
}
}
return res
default:
panic(gowid.WidgetSizeError{Widget: w, Size: size, Required: "gowid.IRenderFlow"})
}
}
func (w *Widget) RenderSize(size gowid.IRenderSize, focus gowid.Selector, app gowid.IApp) gowid.IRenderBox {
if w.lastcols != 0 {
return gowid.RenderBox{C: w.lastcols, R: w.lastrows}
}
res := gowid.CalculateRenderSizeFallback(w, size, focus, app)
w.lastcols = res.C
w.lastrows = res.R
return res
}
//======================================================================
// Local Variables:
// mode: Go
// fill-column: 110
// End:
|
