cell renderings, light and dark

a filter to detect e.g. renderings: [light, dark]

retain any cell content before the first cell-output-display
then any div.cell-output-display are given the rendering names

formats choose what to do with these in the filter
currently HTML uses light and dark and classes them .light-content and .dark-content
and the other formats just use light rendering

applies body.quarto-light or body.quarto-dark based on default theme
for a decent NoJS experience

Author: gordonwoodhull

news/changelog-1.7.md

@@ -43,6 +43,7 @@ All changes included in 1.7:
 
 ## `html` format
 
+- ([#12277](https://github.com/quarto-dev/quarto-cli/pull/12277)): Provide light and dark plot and table renderings with `renderings: [light,dark]`
 - ([#11860](https://github.com/quarto-dev/quarto-cli/issues/11860)): ES6 modules that import other local JS modules in documents with `embed-resources: true` are now correctly embedded.
 
 ## `pdf` format

src/format/html/format-html-bootstrap.ts

@@ -1060,6 +1060,18 @@ function bootstrapHtmlFinalizer(format: Format, flags: PandocFlags) {
       }
     }
 
+    // start body with light or dark class for proper display when JS is disabled
+    let initialLightDarkClass = "quarto-light";
+    // some logic duplicated from resolveThemeLayer
+    const theme = format.metadata.theme;
+    if (theme && !Array.isArray(theme) && typeof theme === "object") {
+      const keys = Object.keys(theme);
+      if(keys.length > 1 && keys[0] === "dark") {
+        initialLightDarkClass = "quarto-dark";
+      }
+    }
+    doc.body.classList.add(initialLightDarkClass);
+
     // If there is no margin content and no toc in the right margin
     // then lower the z-order so everything else can get on top
     // of the sidebar

src/resources/filters/main.lua

@@ -61,6 +61,7 @@ import("./quarto-init/knitr-fixup.lua")
 import("./quarto-post/render-asciidoc.lua")
 import("./quarto-post/book.lua")
 import("./quarto-post/cites.lua")
+import("./quarto-post/cell-renderings.lua")
 import("./quarto-post/delink.lua")
 import("./quarto-post/docx.lua")
 import("./quarto-post/fig-cleanup.lua")
@@ -393,6 +394,10 @@ local quarto_post_filters = {
     },
     traverser = 'jog',
   },
+  { name = "post-choose-cell_renderings",
+    filter = choose_cell_renderings(),
+    flags = { "has_renderings" },
+  },
   { name = "post-landscape-div",
     filter = landscape_div(),
     flags = { "has_landscape" },

src/resources/filters/normalize/flags.lua

@@ -109,6 +109,11 @@ function compute_flags()
             flags.needs_output_unrolling = true
           end
         end
+
+        -- cell-renderings.lua
+        if node.attributes["renderings"] then
+          flags.has_renderings = true
+        end
       end
     end,
     CodeBlock = function(node)

src/resources/filters/quarto-post/cell-renderings.lua

@@ -0,0 +1,57 @@
+function choose_cell_renderings()
+  function jsonDecodeArray(json)
+    if json:sub(1, 1) == '[' then
+      return quarto.json.decode(json)
+    elseif json:sub(1, 1) == '{' then
+      quarto.log.warning('expected array or scalar', json)
+    else
+      return {json}
+    end
+  end
+  
+  return {
+    Div = function(div)
+      -- Only process cell div with renderings attr
+      if not div.classes:includes("cell") or not div.attributes["renderings"] then
+        return nil
+      end
+      local renderingsJson = div.attributes['renderings']
+      local renderings = jsonDecodeArray(renderingsJson)
+      if not type(renderings) == "table" or #renderings == 0 then
+        quarto.log.warning("renderings expected array of rendering names, got", renderings)
+        return nil
+      end
+      local cods = {}
+      local firstCODIndex = nil
+      for i, cellOutput in ipairs(div.content) do
+        if cellOutput.classes:includes("cell-output-display") then
+          if not firstCODIndex then
+            firstCODIndex = i
+          end
+          table.insert(cods, cellOutput)
+        end
+      end
+    
+      if #cods ~= #renderings then
+        quarto.log.warning("need", #renderings, "cell-output-display for renderings", table.concat(renderings, ",") .. ";", "got", #cods)
+        return nil
+      end
+    
+      local outputs = {}
+      for i, r in ipairs(renderings) do
+        outputs[r] = cods[i]
+      end
+      local lightDiv = outputs['light']
+      local darkDiv = outputs['dark']
+      local blocks = pandoc.Blocks({table.unpack(div.content, 1, firstCODIndex - 1)})
+      if quarto.format.isHtmlOutput() and lightDiv and darkDiv then
+        blocks:insert(pandoc.Div(lightDiv.content, pandoc.Attr("", {'light-content'}, {})))
+        blocks:insert(pandoc.Div(darkDiv.content, pandoc.Attr("", {'dark-content'}, {})))
+      else
+        blocks:insert(lightDiv or darkDiv)
+      end
+      div.content = blocks
+      return div
+    end
+  }
+end

src/resources/formats/html/bootstrap/dist/scss/_light-dark.scss

@@ -0,0 +1,7 @@
+body.quarto-light .dark-content {
+  display: none;
+}
+
+body.quarto-dark .light-content {
+  display: none;
+}

src/resources/formats/html/bootstrap/dist/scss/bootstrap.scss

@@ -1,7 +1,6 @@
 @import "mixins/banner";
 @include bsBanner("");
 
-
 // scss-docs-start import-stack
 // Configuration
 @import "variables-dark";
@@ -14,6 +13,7 @@
 @import "type";
 @import "images";
 @import "containers";
+@import "light-dark";
 @import "grid";
 @import "tables";
 @import "forms";

src/resources/schema/cell-attributes.yml

@@ -10,6 +10,11 @@
   schema: string
   description: "Classes to apply to cell container"
 
+- name: renderings
+  schema:
+    arrayOf: string
+  description: "Array of rendering names"
+
 - name: tags
   tags:
     engine: jupyter

tests/docs/smoke-all/dark-mode/ggplot-brandless.qmd

@@ -0,0 +1,116 @@
+---
+title: "knitr dark mode - thematic"
+format:
+  html:
+    theme:
+      light: united
+      dark: slate
+    keep-md: true
+execute:
+  echo: false
+  warning: false
+_quarto:
+  tests:
+    html:
+      ensureHtmlElements:
+        -
+          - 'body.quarto-light'
+          - 'div.cell div.light-content'
+          - 'div.cell div.dark-content'
+          - 'div.cell div.cell-code pre.code-with-copy'
+        - []
+---
+
+```{r}
+#| echo: false
+#| warning: false
+library(ggplot2)
+
+ggplot_theme <- function(bgcolor, fgcolor) {
+  theme_minimal(base_size = 11) %+%
+  theme(
+    panel.border = element_blank(),
+    panel.grid.major.y = element_blank(),
+    panel.grid.minor.y = element_blank(),
+    panel.grid.major.x = element_blank(),
+    panel.grid.minor.x = element_blank(),
+    text = element_text(colour = fgcolor),
+    axis.text = element_text(colour = fgcolor),
+    rect = element_rect(colour = bgcolor, fill = bgcolor),
+    plot.background = element_rect(fill = bgcolor, colour = NA),
+    axis.line = element_line(colour = fgcolor),
+    axis.ticks = element_line(colour = fgcolor)
+  )
+}
+
+united_theme <- ggplot_theme("#ffffff", "#333333")
+slate_theme <- ggplot_theme("#282B30", "#aaaaaa")
+
+colour_scale <- scale_colour_manual(values = c("darkorange", "purple", "cyan4"))
+```
+
+### no crossref, no caption
+
+```{r}
+#| renderings: [light, dark]
+theme_set(united_theme)
+ggplot(mtcars, aes(mpg, wt)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+theme_set(slate_theme)
+ggplot(mtcars, aes(mpg, wt)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+```
+
+### with crossref but no caption
+
+::: {#fig-thematic-ggplot}
+```{r}
+#| echo: true
+#| renderings:
+#|   - dark
+#|   - light
+theme_set(slate_theme)
+ggplot(mtcars, aes(mpg, disp)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+theme_set(united_theme)
+ggplot(mtcars, aes(mpg, disp)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+```
+:::
+
+### with caption but no crossref
+
+<div>
+
+```{r}
+#| renderings: [dark]
+theme_set(slate_theme)
+ggplot(mtcars, aes(mpg, disp)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+```
+
+thematic - base r graphics
+
+</div>
+
+## patchwork
+
+### with crossref and caption
+
+::: {#fig-thematic-patchwork}
+```{r}
+#| renderings: [light, dark]
+theme_set(united_theme)
+ggplot(mtcars, aes(mpg, hp)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+theme_set(slate_theme)
+ggplot(mtcars, aes(mpg, hp)) +
+  geom_point(aes(colour = factor(cyl))) + colour_scale
+```
+
+mtcars - mpg vs hp
+:::
+
+Here's a [link](https://example.com).
+
+{{< lipsum 3 >}}