96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
// Copyright 2016 Canonical Ltd.
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// Licensed under the LGPLv3, see LICENCE file for details.
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package ansiterm
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import (
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"fmt"
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"io"
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)
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// Context provides a way to specify both foreground and background colors
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// along with other styles and write text to a Writer with those colors and
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// styles.
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type Context struct {
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Foreground Color
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Background Color
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Styles []Style
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}
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// Foreground is a convenience function that creates a Context with the
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// specified color as the foreground color.
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func Foreground(color Color) *Context {
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return &Context{Foreground: color}
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}
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// Background is a convenience function that creates a Context with the
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// specified color as the background color.
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func Background(color Color) *Context {
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return &Context{Background: color}
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}
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// Styles is a convenience function that creates a Context with the
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// specified styles set.
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func Styles(styles ...Style) *Context {
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return &Context{Styles: styles}
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}
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// SetForeground sets the foreground to the specified color.
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func (c *Context) SetForeground(color Color) *Context {
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c.Foreground = color
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return c
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}
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// SetBackground sets the background to the specified color.
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func (c *Context) SetBackground(color Color) *Context {
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c.Background = color
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return c
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}
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// SetStyle replaces the styles with the new values.
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func (c *Context) SetStyle(styles ...Style) *Context {
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c.Styles = styles
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return c
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}
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type sgrWriter interface {
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io.Writer
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writeSGR(value sgr)
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}
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// Fprintf will set the sgr values of the writer to the specified
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// foreground, background and styles, then write the formatted string,
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// then reset the writer.
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func (c *Context) Fprintf(w sgrWriter, format string, args ...interface{}) {
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w.writeSGR(c)
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fmt.Fprintf(w, format, args...)
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w.writeSGR(reset)
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}
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// Fprint will set the sgr values of the writer to the specified foreground,
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// background and styles, then formats using the default formats for its
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// operands and writes to w. Spaces are added between operands when neither is
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// a string. It returns the number of bytes written and any write error
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// encountered.
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func (c *Context) Fprint(w sgrWriter, args ...interface{}) {
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w.writeSGR(c)
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fmt.Fprint(w, args...)
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w.writeSGR(reset)
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}
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func (c *Context) sgr() string {
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var values attributes
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if foreground := c.Foreground.foreground(); foreground != unknownAttribute {
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values = append(values, foreground)
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}
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if background := c.Background.background(); background != unknownAttribute {
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values = append(values, background)
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}
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for _, style := range c.Styles {
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if value := style.enable(); value != unknownAttribute {
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values = append(values, value)
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}
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}
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return values.sgr()
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}
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