piframe-go/vendor/github.com/gdamore/tcell/style.go

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2020-08-28 19:19:36 +00:00
// Copyright 2015 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use 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 tcell
// Style represents a complete text style, including both foreground
// and background color. We encode it in a 64-bit int for efficiency.
// The coding is (MSB): <7b flags><1b><24b fgcolor><7b attr><1b><24b bgcolor>.
// The <1b> is set true to indicate that the color is an RGB color, rather
// than a named index.
//
// This gives 24bit color options, if it ever becomes truly necessary.
// However, applications must not rely on this encoding.
//
// Note that not all terminals can display all colors or attributes, and
// many might have specific incompatibilities between specific attributes
// and color combinations.
//
// The intention is to extend styles to support paletting, in which case
// some flag bit(s) would be set, and the foreground and background colors
// would be replaced with a palette number and palette index.
//
// To use Style, just declare a variable of its type.
type Style int64
// StyleDefault represents a default style, based upon the context.
// It is the zero value.
const StyleDefault Style = 0
// styleFlags -- used internally for now.
const (
styleBgSet = 1 << (iota + 57)
styleFgSet
stylePalette
)
// Foreground returns a new style based on s, with the foreground color set
// as requested. ColorDefault can be used to select the global default.
func (s Style) Foreground(c Color) Style {
if c == ColorDefault {
return (s &^ (0x1ffffff00000000 | styleFgSet))
}
return (s &^ Style(0x1ffffff00000000)) |
((Style(c) & 0x1ffffff) << 32) | styleFgSet
}
// Background returns a new style based on s, with the background color set
// as requested. ColorDefault can be used to select the global default.
func (s Style) Background(c Color) Style {
if c == ColorDefault {
return (s &^ (0x1ffffff | styleBgSet))
}
return (s &^ (0x1ffffff)) | (Style(c) & 0x1ffffff) | styleBgSet
}
// Decompose breaks a style up, returning the foreground, background,
// and other attributes.
func (s Style) Decompose() (fg Color, bg Color, attr AttrMask) {
if s&styleFgSet != 0 {
fg = Color(s>>32) & 0x1ffffff
} else {
fg = ColorDefault
}
if s&styleBgSet != 0 {
bg = Color(s & 0x1ffffff)
} else {
bg = ColorDefault
}
attr = AttrMask(s) & attrAll
return fg, bg, attr
}
func (s Style) setAttrs(attrs Style, on bool) Style {
if on {
return s | attrs
}
return s &^ attrs
}
// Normal returns the style with all attributes disabled.
func (s Style) Normal() Style {
return s &^ Style(attrAll)
}
// Bold returns a new style based on s, with the bold attribute set
// as requested.
func (s Style) Bold(on bool) Style {
return s.setAttrs(Style(AttrBold), on)
}
// Blink returns a new style based on s, with the blink attribute set
// as requested.
func (s Style) Blink(on bool) Style {
return s.setAttrs(Style(AttrBlink), on)
}
// Dim returns a new style based on s, with the dim attribute set
// as requested.
func (s Style) Dim(on bool) Style {
return s.setAttrs(Style(AttrDim), on)
}
// Italic returns a new style based on s, with the italic attribute set
// as requested.
func (s Style) Italic(on bool) Style {
return s.setAttrs(Style(AttrItalic), on)
}
// Reverse returns a new style based on s, with the reverse attribute set
// as requested. (Reverse usually changes the foreground and background
// colors.)
func (s Style) Reverse(on bool) Style {
return s.setAttrs(Style(AttrReverse), on)
}
// Underline returns a new style based on s, with the underline attribute set
// as requested.
func (s Style) Underline(on bool) Style {
return s.setAttrs(Style(AttrUnderline), on)
}