termdash/widgets/text/write_options.go

118 lines
2.8 KiB
Go

// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package text
// write_options.go contains options used when writing content to the Text widget.
import (
"sort"
"github.com/mum4k/termdash/cell"
)
// WriteOption is used to provide options to Write().
type WriteOption interface {
// set sets the provided option.
set(*writeOptions)
}
// writeOptions stores the provided options.
type writeOptions struct {
cellOpts *cell.Options
}
// newWriteOptions returns new writeOptions instance.
func newWriteOptions(wOpts ...WriteOption) *writeOptions {
wo := &writeOptions{
cellOpts: cell.NewOptions(),
}
for _, o := range wOpts {
o.set(wo)
}
return wo
}
// writeOption implements WriteOption.
type writeOption func(*writeOptions)
// set implements WriteOption.set.
func (wo writeOption) set(wOpts *writeOptions) {
wo(wOpts)
}
// WriteCellOpts sets options on the cells that contain the text.
func WriteCellOpts(opts ...cell.Option) WriteOption {
return writeOption(func(wOpts *writeOptions) {
wOpts.cellOpts = cell.NewOptions(opts...)
})
}
// optsRange are write options that apply to a range of bytes in the text.
type optsRange struct {
// low is the first byte where these options apply.
low int
// high is the end of the range. The opts apply to all bytes in range low
// <= b < high.
high int
// opts are the options provided at a call to Write().
opts *writeOptions
}
// newOptsRange returns a new optsRange.
func newOptsRange(low, high int, opts *writeOptions) *optsRange {
return &optsRange{
low: low,
high: high,
opts: opts,
}
}
// givenWOpts stores the write options provided on all the calls to Write().
// The options are keyed by their low indices.
type givenWOpts map[int]*optsRange
// newGivenWOpts returns a new givenWOpts instance.
func newGivenWOpts() givenWOpts {
return givenWOpts{}
}
// forPosition returns write options that apply to character at the specified
// byte position.
func (g givenWOpts) forPosition(pos int) *optsRange {
if or, ok := g[pos]; ok {
return or
}
var keys []int
for k := range g {
keys = append(keys, k)
}
sort.Ints(keys)
res := newOptsRange(0, 0, newWriteOptions())
for _, k := range keys {
or := g[k]
if or.low > pos {
break
}
if or.high > pos {
res = or
}
}
return res
}