From 0987a2affeae693f5cbe07207b52e5c9ac892bf0 Mon Sep 17 00:00:00 2001
From: xiangyu <3170102889@zju.edu.cn>
Date: Thu, 14 Jul 2022 10:42:18 +0800
Subject: [PATCH] fix: preview resize bug

---
 addon/chrome/content/previewPDF.html | 61 ++++++++++++----------------
 package.json                         |  2 +-
 src/events.ts                        |  2 +-
 src/preview.ts                       | 35 ++++++++++------
 4 files changed, 52 insertions(+), 48 deletions(-)

diff --git a/addon/chrome/content/previewPDF.html b/addon/chrome/content/previewPDF.html
index 4584fbb..c1f67fa 100644
--- a/addon/chrome/content/previewPDF.html
+++ b/addon/chrome/content/previewPDF.html
@@ -35,9 +35,11 @@
 
     <script>
       var itemID = -1;
-      function renderPage(pdf, pageNumber, canvas, width) {
-        pdf.getPage(pageNumber).then(function (page) {
-          viewport = page.getViewport({ scale: 1 });
+      var pdf;
+      function renderPage(currentPdf, pageNumber, canvas, width) {
+        currentPdf.getPage(pageNumber).then(function (page) {
+          const W = page.view[2];
+          viewport = page.getViewport({ scale: width / W });
           const ctx = canvas.getContext("2d");
           const dpr = window.devicePixelRatio || 1;
           const bsr =
@@ -48,21 +50,11 @@
             ctx.backingStorePixelRatio ||
             1;
           const ratio = dpr / bsr;
-          const resizeRatio = width / viewport.width;
-          viewport.width *= resizeRatio;
-          viewport.height *= resizeRatio;
           canvas.width = viewport.width * ratio;
           canvas.height = viewport.height * ratio;
           canvas.style.width = viewport.width + "px";
           canvas.style.height = viewport.height + "px";
-          ctx.setTransform(
-            ratio * resizeRatio,
-            0,
-            0,
-            ratio * resizeRatio,
-            0,
-            0
-          );
+          ctx.setTransform(ratio, 0, 0, ratio, 0, 0);
           console.log("Rendering", pageNumber);
           page.render({
             canvasContext: ctx,
@@ -71,40 +63,41 @@
         });
       }
 
-      async function renderPreview(buf, id, width) {
+      async function renderPreview(id, width) {
         // let item = Zotero.PDFPreview.preview.item;
         // Block other possible renders
         Zotero.PDFPreview.preview._loadingPromise = Zotero.Promise.defer();
 
         try {
-          pdfjsLib.getDocument(buf).promise.then((pdf) => {
-            viewer = document.getElementById("pdf-viewer");
-            viewer.innerHTML = "";
-            let lastNumber = pdf.numPages > 10 ? 10 : pdf.numPages;
-            for (i = 1; i <= lastNumber; i++) {
-              if (id !== itemID) {
-                // Stop current render if there is a new item
-                console.log(id, itemID, "Eraly stop rendering");
-                break;
-              }
-              canvas = document.createElement("canvas");
-              canvas.className = "pdf-page-canvas flexPage";
-              viewer.appendChild(canvas);
-              renderPage(pdf, i, canvas, width);
+          viewer = document.getElementById("pdf-viewer");
+          viewer.innerHTML = "";
+          let lastNumber = pdf.numPages > 10 ? 10 : pdf.numPages;
+          for (i = 1; i <= lastNumber; i++) {
+            if (id !== itemID) {
+              // Stop current render if there is a new item
+              console.log(id, itemID, "Eraly stop rendering");
+              break;
             }
-            Zotero.PDFPreview.preview._loadingPromise.resolve();
-          });
+            canvas = document.createElement("canvas");
+            canvas.className = "pdf-page-canvas flexPage";
+            viewer.appendChild(canvas);
+            renderPage(pdf, i, canvas, width);
+          }
+          Zotero.PDFPreview.preview._loadingPromise.resolve();
         } catch (e) {
           Zotero.PDFPreview.preview._loadingPromise.resolve();
           throw e;
         }
       }
 
-      function handler(e) {
+      async function handler(e) {
         console.log(e);
         if (e.data.type === "renderPreview") {
-          itemID = e.data.itemID;
-          renderPreview(e.data.buffer, e.data.itemID, e.data.width);
+          if (itemID !== e.data.itemID) {
+            pdf = await pdfjsLib.getDocument(e.data.buffer).promise;
+            itemID = e.data.itemID;
+          }
+          renderPreview(e.data.itemID, e.data.width);
         }
       }
 
diff --git a/package.json b/package.json
index a3041c6..76b880d 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,7 @@
   "bugs": {
     "url": "https://github.com/windingwind/zotero-pdf-preview/issues"
   },
-  "homepage": "https://github.com/windingwind/zotero-pdf-previews#readme",
+  "homepage": "https://github.com/windingwind/zotero-pdf-preview#readme",
   "dependencies": {
     "compressing": "^1.5.1",
     "esbuild": "^0.14.34",
diff --git a/src/events.ts b/src/events.ts
index e02dd08..6a1ff43 100644
--- a/src/events.ts
+++ b/src/events.ts
@@ -19,7 +19,7 @@ class AddonEvents extends AddonBase {
   private initPreviewResizeListener() {
     const splitter = window.document.getElementById("zotero-items-splitter");
     splitter.addEventListener("mouseup", (e) => {
-      this._Addon.preview.preview();
+      this._Addon.preview.preview(true);
     });
   }
 
diff --git a/src/preview.ts b/src/preview.ts
index 31be491..bb01805 100644
--- a/src/preview.ts
+++ b/src/preview.ts
@@ -10,18 +10,26 @@ class AddonPreview extends AddonBase {
     if (!items.length) {
       return false;
     }
-    items = items
-      .filter((e) => e.isRegularItem())
-      .map((e) =>
-        (Zotero.Items.get(e.getAttachments()) as ZoteroItem[]).filter((att) =>
-          att.isPDFAttachment()
-        )
-      )
-      .find((e) => e.length);
-    if (!items) {
+    let item: ZoteroItem;
+    for (const _item of items) {
+      if (false && _item.isPDFAttachment()) {
+        // Disable for now. The PDF doesn't have a side bar
+        item = _item;
+        break;
+      } else if (_item.isRegularItem()) {
+        const attachment = (
+          Zotero.Items.get(_item.getAttachments()) as ZoteroItem[]
+        ).find((att) => att.isPDFAttachment());
+        if (attachment) {
+          item = attachment;
+          break;
+        }
+      }
+    }
+    if (!item || (this.item && item.id === this.item.id)) {
       return false;
     }
-    this.item = items[0];
+    this.item = item;
     return this.item;
   }
 
@@ -32,9 +40,12 @@ class AddonPreview extends AddonBase {
     return new Uint8Array(buf).buffer;
   }
 
-  public async preview() {
-    const item = this.updatePreviewItem();
+  public async preview(force: boolean = false) {
+    let item = this.updatePreviewItem();
     console.log(item);
+    if (force && !item) {
+      item = this.item;
+    }
     if (item) {
       if (this._loadingPromise) {
         await this._loadingPromise.promise;