Add an option in scrollIntoView and goToXY in order to be able to center vertically or horizontally the point XY in the viewer container

Author: calixteman

test/integration/viewer_spec.mjs

@@ -17,6 +17,7 @@ import {
   awaitPromise,
   closePages,
   createPromise,
+  getRect,
   getSpanRectFromText,
   loadAndWait,
   scrollIntoView,
@@ -1416,4 +1417,49 @@ describe("PDF viewer", () => {
       );
     });
   });
+
+  describe("Scroll into view", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait(
+        "tracemonkey_annotation_on_page_8.pdf",
+        `.page[data-page-number = "1"] .endOfContent`
+      );
+    });
+
+    it("Check that the top right corner of the annotation is centered vertically", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          const handle = await page.evaluateHandle(() => [
+            new Promise(resolve => {
+              const container = document.getElementById("viewerContainer");
+              container.addEventListener("scrollend", resolve, {
+                once: true,
+              });
+              window.PDFViewerApplication.pdfLinkService.goToXY(
+                8,
+                43.55,
+                198.36,
+                {
+                  center: "vertical",
+                }
+              );
+            }),
+          ]);
+          await awaitPromise(handle);
+          const annotationSelector =
+            ".page[data-page-number='8'] .stampAnnotation";
+          await page.waitForSelector(annotationSelector, { visible: true });
+          const rect = await getRect(page, annotationSelector);
+          const containerRect = await getRect(page, "#viewerContainer");
+          expect(
+            Math.abs(2 * (rect.y - containerRect.y) - containerRect.height)
+          )
+            .withContext(`In ${browserName}`)
+            .toBeLessThan(1);
+        })
+      );
+    });
+  });
 });

test/pdfs/.gitignore

@@ -742,3 +742,4 @@
 !tracemonkey_with_annotations.pdf
 !tracemonkey_with_editable_annotations.pdf
 !bug1980958.pdf
+!tracemonkey_annotation_on_page_8.pdf

test/pdfs/tracemonkey_annotation_on_page_8.pdf

@@ -244,12 +244,14 @@ class PDFLinkService {
    * @param {number} pageNumber - The page number to scroll to.
    * @param {number} x - The x-coordinate to scroll to in page coordinates.
    * @param {number} y - The y-coordinate to scroll to in page coordinates.
+   * @param {Object} [options]
    */
-  goToXY(pageNumber, x, y) {
+  goToXY(pageNumber, x, y, options = {}) {
     this.pdfViewer.scrollPageIntoView({
       pageNumber,
       destArray: [null, { name: "XYZ" }, x, y],
       ignoreDestinationZoom: true,
+      ...options,
     });
   }
 

web/pdf_link_service.js

@@ -1554,6 +1554,9 @@ class PDFViewer {
    *   The default value is `false`.
    * @property {boolean} [ignoreDestinationZoom] - Ignore the zoom argument in
    *   the destination array. The default value is `false`.
+   * @property {string} [center] - Center the view on the specified coordinates.
+   *   The default value is `null`. Possible values are: `null` (don't center),
+   *  `horizontal`, `vertical` and `both`.
    */
 
   /**
@@ -1565,6 +1568,7 @@ class PDFViewer {
     destArray = null,
     allowNegativeOffset = false,
     ignoreDestinationZoom = false,
+    center = null,
   }) {
     if (!this.pdfDocument) {
       return;
@@ -1687,7 +1691,20 @@ class PDFViewer {
     let left = Math.min(boundingRect[0][0], boundingRect[1][0]);
     let top = Math.min(boundingRect[0][1], boundingRect[1][1]);
 
-    if (!allowNegativeOffset) {
+    if (center) {
+      if (center === "both" || center === "vertical") {
+        top -=
+          (this.container.clientHeight -
+            Math.abs(boundingRect[1][1] - boundingRect[0][1])) /
+          2;
+      }
+      if (center === "both" || center === "horizontal") {
+        left -=
+          (this.container.clientWidth -
+            Math.abs(boundingRect[1][0] - boundingRect[0][0])) /
+          2;
+      }
+    } else if (!allowNegativeOffset) {
       // Some bad PDF generators will create destinations with e.g. top values
       // that exceeds the page height. Ensure that offsets are not negative,
       // to prevent a previous page from becoming visible (fixes bug 874482).