kitepdf-core/io.github.yuroyami.kitepdf.core.render/ReaderTheme

ReaderTheme

class ReaderTheme(val background: RgbColor, val mapColor: (RgbColor) -> RgbColor, val images: ReaderImages)(source)

A reading theme: a page background plus a mapColor transform applied to every text / vector / border / CSS-background colour a page paints. Images and gradients pass through untouched, so photos never invert. withImages lets the theme recolour the images that are line art too.

Dark and Sepia keep text readable: a colour with a contrast of 4.5 or more on white paper keeps at least 4.5 on the theme's paper, and a weaker colour keeps the contrast it had (WCAG 2.2, 1.4.3).

Format-neutral: it themes any KiteCanvas (PDF or EPUB). Hand a theme to a rasterizer, or wrap a canvas yourself:

page.renderTo(ReaderTheme.Dark.wrap(canvas), ctm)   // paint background yourself

Two themes are equal when they share the paper colour and the same colour function, so a theme built inline with a lambda that captures nothing stays one cache key across recompositions.

Constructors

ReaderTheme

constructor(background: RgbColor, mapColor: (RgbColor) -> RgbColor, images: ReaderImages)

constructor(background: RgbColor, mapColor: (RgbColor) -> RgbColor)

Types

Companion

object Companion

Properties

background

val background: RgbColor

Paper colour behind the page content.

images

val images: ReaderImages

What the theme does to images: ReaderImages.Unchanged unless withImages says otherwise (#458).

mapColor

val mapColor: (RgbColor) -> RgbColor

Maps each content colour a page draws. Identity for Light.

Functions

equals

open operator override fun equals(other: Any?): Boolean

hashCode

open override fun hashCode(): Int

toString

open override fun toString(): String

withImages

fun withImages(images: ReaderImages): ReaderTheme

This theme, doing images to the images of a page. With ReaderImages.LineArt, a black symbol on white turns as light as the text on dark paper, and a photo keeps its colours:

wrap

fun wrap(canvas: KiteCanvas): KiteCanvas

Decorate canvas so its content colours are themed. Returns it unchanged for Light.