Preprocess certain CSS values before PDF rendering to fix html2canvas limitations

packages/client/src/components/ClientApp.svelte

@@ -57,12 +57,6 @@
   let permissionError = false
   let embedNoScreens = false
 
-  // Get theme class names, which is always lightest for LDFs
-  $: isPDFScreen = $screenStore.activeScreen?.variant === ScreenVariant.PDF
-  $: themeClassNames = isPDFScreen
-    ? "spectrum--light"
-    : getThemeClassNames($themeStore.theme)
-
   // Determine if we should show devtools or not
   $: showDevTools = $devToolsEnabled && !$routeStore.queryParams?.peek
 
@@ -164,7 +158,7 @@
     id="spectrum-root"
     lang="en"
     dir="ltr"
-    class="spectrum spectrum--medium {themeClassNames}"
+    class="spectrum spectrum--medium {getThemeClassNames($themeStore.theme)}"
     class:builder={$builderStore.inBuilder}
     class:show={fontsLoaded && dataLoaded}
   >

packages/client/src/components/CustomThemeWrapper.svelte

@@ -1,12 +1,18 @@
 <script>
   import { themeStore } from "@/stores"
   import { setContext } from "svelte"
-  import { Context } from "@budibase/bbui"
+  import { Context, Helpers } from "@budibase/bbui"
 
-  setContext(Context.PopoverRoot, "#theme-root")
+  export let popoverRoot = true
+
+  const id = Helpers.uuid()
+
+  if (popoverRoot) {
+    setContext(Context.PopoverRoot, `#id`)
+  }
 </script>
 
-<div style={$themeStore.customThemeCss} id="theme-root">
+<div style={$themeStore.customThemeCss} {id}>
   <slot />
 </div>
 

packages/client/src/components/app/pdf/PDF.svelte

@@ -3,6 +3,7 @@
   import { Heading, Button } from "@budibase/bbui"
   import { htmlToPdf, pxToPt, A4HeightPx, type PDFOptions } from "./pdf"
   import { GridRowHeight } from "@/constants"
+  import CustomThemeWrapper from "@/components/CustomThemeWrapper.svelte"
 
   const component = getContext("component")
   const { styleable, Block, BlockComponent } = getContext("sdk")
@@ -30,6 +31,7 @@
   const generatePDF = async () => {
     rendering = true
     await tick()
+    preprocessCSS()
     try {
       const opts: PDFOptions = {
         fileName: safeName,
@@ -43,6 +45,16 @@
     rendering = false
   }
 
+  const preprocessCSS = () => {
+    const els = document.getElementsByClassName(
+      "grid-child"
+    ) as unknown as HTMLElement[]
+    for (let el of els) {
+      const styles = window.getComputedStyle(el)
+      el.style.setProperty("grid-column-end", styles.gridColumnEnd, "important")
+    }
+  }
+
   const getDividerStyle = (idx: number) => {
     const top = (idx + 1) * innerPageHeightPx + doubleMarginPx / 2
     return `--idx:"${idx + 1}"; --top:${top}px;`
@@ -90,19 +102,24 @@
             />
           {/each}
         {/if}
-        <div class="pageContent" bind:this={ref}>
-          <BlockComponent
-            type="container"
-            props={{ layout: "grid" }}
-            styles={{
-              normal: {
-                height: `${gridMinHeight}px`,
-              },
-            }}
-            context="grid"
-          >
-            <slot />
-          </BlockComponent>
+        <div
+          class="spectrum spectrum--medium spectrum--lightest pageContent"
+          bind:this={ref}
+        >
+          <CustomThemeWrapper popoverRoot={false}>
+            <BlockComponent
+              type="container"
+              props={{ layout: "grid" }}
+              styles={{
+                normal: {
+                  height: `${gridMinHeight}px`,
+                },
+              }}
+              context="grid"
+            >
+              <slot />
+            </BlockComponent>
+          </CustomThemeWrapper>
         </div>
       </div>
     </div>

packages/client/src/utils/grid.ts

@@ -116,6 +116,9 @@ export const gridLayout = (node: HTMLDivElement, metadata: GridMetadata) => {
       return
     }
 
+    // Add a unique class to elements we mutate so we can easily find them later
+    node.classList.add("grid-child")
+
     // Callback to select the component when clicking on the wrapper
     selectComponent = (e: Event) => {
       e.stopPropagation()