element-ios/Riot/Categories/NSAttributedString+Theme.swift

56 lines
2.3 KiB
Swift

//
// Copyright 2023, 2024 New Vector Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only
// Please see LICENSE in the repository root for full details.
//
import Foundation
/// Custom NSAttributedString.Key to specify the theme
let themeIdentifierAttributeName = NSAttributedString.Key("ThemeIdentifier")
/// Custom NSAttributedString.Key to specify a theme color by its name
let themeColorNameAttributeName = NSAttributedString.Key("ThemeColorName")
extension NSAttributedString {
/// Fix foreground color attributes if this attributed string contains the `themeIdentifierAttributeName` and `foregroundColorNameAttributeName` attributes
/// - Returns: a new attributed string with updated colors
@objc func fixForegroundColor() -> NSAttributedString {
let activeTheme = ThemeService.shared().theme
// Check if a theme is defined for this attributed string
var needUpdate = false
self.vc_enumerateAttribute(themeIdentifierAttributeName) { (themeIdentifier: String, range: NSRange, _) in
needUpdate = themeIdentifier != activeTheme.identifier
}
guard needUpdate else {
return self
}
// Build a new attributedString with the proper colors if possible
let mutableAttributedString = NSMutableAttributedString(attributedString: self)
mutableAttributedString.vc_enumerateAttribute(themeColorNameAttributeName) { (colorName: String, range: NSRange, _) in
if let color = ThemeColorResolver.getColorByName(colorName) {
mutableAttributedString.addAttribute(.foregroundColor, value: color, range: range)
}
}
return mutableAttributedString
}
}
extension NSMutableAttributedString {
/// Adds a theme color name attribute
/// - Parameters:
/// - colorName: color name
/// - range:range for this attribute
@objc func addThemeColorNameAttribute(_ colorName: String, range: NSRange) {
self.addAttribute(themeColorNameAttributeName, value: colorName, range: range)
}
/// Adds a theme identifier attribute
@objc func addThemeIdentifierAttribute() {
self.addAttribute(themeIdentifierAttributeName, value: ThemeService.shared().theme.identifier, range: .init(location: 0, length: length))
}
}