diff options
Diffstat (limited to 'js')
| -rw-r--r-- | js/reveal.js | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/js/reveal.js b/js/reveal.js index 637ea63..4cf43f7 100644 --- a/js/reveal.js +++ b/js/reveal.js @@ -1131,18 +1131,27 @@ if( data.backgroundPosition ) contentElement.style.backgroundPosition = data.backgroundPosition; if( data.backgroundOpacity ) contentElement.style.opacity = data.backgroundOpacity; - // If this slide has a background color, add a class that + // If this slide has a background color, we add a class that // signals if it is light or dark. If the slide has no background - // color, no class will be set - var computedBackgroundStyle = window.getComputedStyle( element ); - if( computedBackgroundStyle && computedBackgroundStyle.backgroundColor ) { - var rgb = colorToRgb( computedBackgroundStyle.backgroundColor ); + // color, no class will be added + var contrastColor = data.backgroundColor; + + // If no bg color was found, check the computed background + if( !contrastColor ) { + var computedBackgroundStyle = window.getComputedStyle( element ); + if( computedBackgroundStyle && computedBackgroundStyle.backgroundColor ) { + contrastColor = computedBackgroundStyle.backgroundColor; + } + } + + if( contrastColor ) { + var rgb = colorToRgb( contrastColor ); // Ignore fully transparent backgrounds. Some browsers return // rgba(0,0,0,0) when reading the computed background color of // an element with no background if( rgb && rgb.a !== 0 ) { - if( colorBrightness( computedBackgroundStyle.backgroundColor ) < 128 ) { + if( colorBrightness( contrastColor ) < 128 ) { slide.classList.add( 'has-dark-background' ); } else { |