RMD Preview: font-size setting (#1333)

* preview: font-size

* fallback size

* Use zoom instead of fontSize (#1348)

---------

Co-authored-by: Kun Ren <renkun@outlook.com>

Author: ElianHugh

package.json

@@ -1544,6 +1544,11 @@
           "default": true,
           "markdownDescription": "Enable automatic refresh of R Markdown preview on file update."
         },
+        "r.rmarkdown.preview.zoom": {
+          "type": "number",
+          "default": 1,
+          "markdownDescription": "Controls the zoom of the R Markdown preview."
+        },
         "r.rmarkdown.knit.useBackgroundProcess": {
           "type": "boolean",
           "default": true,

src/rmarkdown/preview.ts

@@ -87,8 +87,11 @@ class RMarkdownPreview extends vscode.Disposable {
         const $ = cheerio.load(content);
         this.htmlLightContent = $.html();
 
+        const zoom = config().get<number>('rmarkdown.preview.zoom', 1);
+
         // make the output chunks a little lighter to stand out
         let chunkCol = String(config().get('rmarkdown.chunkBackgroundColor'));
+
         let outCol: string;
         if (chunkCol) {
             const colReg = /[0-9.]+/g;
@@ -106,6 +109,7 @@ class RMarkdownPreview extends vscode.Disposable {
         const style =
             `<style>
             body {
+                zoom: ${zoom};
                 color: var(--vscode-editor-foreground);
                 background: var(--vscode-editor-background);
             }