Merge pull request #20085 from calixteman/bug1975719

Handle the case where all the image data are in the alpha channel (bug 1975719)

l10n/en-US/viewer.ftl

@@ -614,6 +614,8 @@ pdfjs-editor-add-signature-save-checkbox = Save signature
 pdfjs-editor-add-signature-save-warning-message = You’ve reached the limit of 5 saved signatures. Remove one to save more.
 pdfjs-editor-add-signature-image-upload-error-title = Couldn’t upload image
 pdfjs-editor-add-signature-image-upload-error-description = Check your network connection or try another image.
+pdfjs-editor-add-signature-image-no-data-error-title = Can’t convert this image into a signature
+pdfjs-editor-add-signature-image-no-data-error-description = Please try uploading a different image.
 pdfjs-editor-add-signature-error-close-button = Close
 
 ## Dialog buttons

src/display/editor/drawers/signaturedraw.js

@@ -366,21 +366,12 @@ class SignatureExtractor {
     let max = -Infinity;
     let min = Infinity;
     for (let i = 0, ii = out.length; i < ii; i++) {
-      const A = buf[(i << 2) + 3];
-      if (A === 0) {
-        max = out[i] = 0xff;
-        continue;
-      }
       const pix = (out[i] = buf[i << 2]);
-      if (pix > max) {
-        max = pix;
-      }
-      if (pix < min) {
-        min = pix;
-      }
+      max = Math.max(max, pix);
+      min = Math.min(min, pix);
     }
     const ratio = 255 / (max - min);
-    for (let i = 0; i < N; i++) {
+    for (let i = 0, ii = out.length; i < ii; i++) {
       out[i] = (out[i] - min) * ratio;
     }
 
@@ -468,6 +459,8 @@ class SignatureExtractor {
     }
     const offscreen = new OffscreenCanvas(newWidth, newHeight);
     const ctx = offscreen.getContext("2d", { willReadFrequently: true });
+    ctx.fillStyle = "white";
+    ctx.fillRect(0, 0, newWidth, newHeight);
     ctx.filter = "grayscale(1)";
     ctx.drawImage(
       bitmap,

test/integration/signature_editor_spec.mjs

@@ -727,4 +727,47 @@ describe("Signature Editor", () => {
       );
     });
   });
+
+  describe("Bug 1975719", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait("empty.pdf", ".annotationEditorLayer");
+    });
+
+    afterEach(async () => {
+      await closePages(pages);
+    });
+
+    it("must check that an error is displayed with a monochrome image", async () => {
+      await Promise.all(
+        pages.map(async ([_, page]) => {
+          await switchToSignature(page);
+
+          await page.click("#editorSignatureAddSignature");
+
+          await page.waitForSelector("#addSignatureDialog", {
+            visible: true,
+          });
+          await page.click("#addSignatureImageButton");
+          await page.waitForSelector("#addSignatureImagePlaceholder", {
+            visible: true,
+          });
+          const input = await page.$("#addSignatureFilePicker");
+          await input.uploadFile(
+            `${path.join(__dirname, "../images/red.png")}`
+          );
+          await page.waitForSelector("#addSignatureError", { visible: true });
+          await page.waitForSelector(
+            "#addSignatureErrorTitle[data-l10n-id='pdfjs-editor-add-signature-image-no-data-error-title']"
+          );
+          await page.waitForSelector(
+            "#addSignatureErrorDescription[data-l10n-id='pdfjs-editor-add-signature-image-no-data-error-description']"
+          );
+          await page.click("#addSignatureErrorCloseButton");
+          await page.waitForSelector("#addSignatureError", { visible: false });
+        })
+      );
+    });
+  });
 });

web/signature_manager.js

@@ -56,6 +56,10 @@ class SignatureManager {
 
   #errorBar;
 
+  #errorDescription;
+
+  #errorTitle;
+
   #extractedSignatureData = null;
 
   #imagePath = null;
@@ -123,6 +127,8 @@ class SignatureManager {
       addButton,
       errorCloseButton,
       errorBar,
+      errorTitle,
+      errorDescription,
       saveCheckbox,
       saveContainer,
     },
@@ -142,6 +148,8 @@ class SignatureManager {
     this.#drawPlaceholder = drawPlaceholder;
     this.#drawThickness = drawThickness;
     this.#errorBar = errorBar;
+    this.#errorTitle = errorTitle;
+    this.#errorDescription = errorDescription;
     this.#imageSVG = imageSVG;
     this.#imagePlaceholder = imagePlaceholder;
     this.#imagePicker = imagePicker;
@@ -161,6 +169,12 @@ class SignatureManager {
 
     SignatureManager.#l10nDescription ||= Object.freeze({
       signature: "pdfjs-editor-add-signature-description-default-when-drawing",
+      errorUploadTitle: "pdfjs-editor-add-signature-image-upload-error-title",
+      errorUploadDescription:
+        "pdfjs-editor-add-signature-image-upload-error-description",
+      errorNoDataTitle: "pdfjs-editor-add-signature-image-no-data-error-title",
+      errorNoDataDescription:
+        "pdfjs-editor-add-signature-image-no-data-error-description",
     });
 
     dialog.addEventListener("close", this.#close.bind(this));
@@ -506,6 +520,18 @@ class SignatureManager {
     );
   }
 
+  #showError(type) {
+    this.#errorTitle.setAttribute(
+      "data-l10n-id",
+      SignatureManager.#l10nDescription[`error${type}Title`]
+    );
+    this.#errorDescription.setAttribute(
+      "data-l10n-id",
+      SignatureManager.#l10nDescription[`error${type}Description`]
+    );
+    this.#errorBar.hidden = false;
+  }
+
   #initImageTab(reset) {
     if (reset) {
       this.#resetTab("image");
@@ -539,7 +565,7 @@ class SignatureManager {
       async () => {
         const file = this.#imagePicker.files?.[0];
         if (!file || !SupportedImageMimeTypes.includes(file.type)) {
-          this.#errorBar.hidden = false;
+          this.#showError("Upload");
           this.#dialog.classList.toggle("waiting", false);
           return;
         }
@@ -601,18 +627,19 @@ class SignatureManager {
       console.error("SignatureManager.#extractSignature.", e);
     }
     if (!data) {
-      this.#errorBar.hidden = false;
+      this.#showError("Upload");
       this.#dialog.classList.toggle("waiting", false);
       return;
     }
 
-    const { outline } = (this.#extractedSignatureData =
+    const lineData = (this.#extractedSignatureData =
       this.#currentEditor.getFromImage(data.bitmap));
-
-    if (!outline) {
+    if (!lineData) {
+      this.#showError("NoData");
       this.#dialog.classList.toggle("waiting", false);
       return;
     }
+    const { outline } = lineData;
 
     this.#imagePlaceholder.hidden = true;
     this.#disableButtons(true);

web/viewer.html

@@ -735,8 +735,8 @@ See https://github.com/adobe-type-tools/cmap-resources
               <div id="addSignatureError" hidden="true" class="messageBar">
                 <div>
                   <div>
-                    <span class="title" data-l10n-id="pdfjs-editor-add-signature-image-upload-error-title"></span>
-                    <span class="description" data-l10n-id="pdfjs-editor-add-signature-image-upload-error-description"></span>
+                    <span id="addSignatureErrorTitle" class="title" data-l10n-id="pdfjs-editor-add-signature-image-upload-error-title"></span>
+                    <span id="addSignatureErrorDescription" class="description" data-l10n-id="pdfjs-editor-add-signature-image-upload-error-description"></span>
                   </div>
                   <button id="addSignatureErrorCloseButton" class="closeButton" type="button" tabindex="0"><span data-l10n-id="pdfjs-editor-add-signature-error-close-button"></span></button>
                 </div>

web/viewer.js

@@ -227,6 +227,8 @@ function getViewerConfiguration() {
       saveContainer: document.getElementById("addSignatureSaveContainer"),
       saveCheckbox: document.getElementById("addSignatureSaveCheckbox"),
       errorBar: document.getElementById("addSignatureError"),
+      errorTitle: document.getElementById("addSignatureErrorTitle"),
+      errorDescription: document.getElementById("addSignatureErrorDescription"),
       errorCloseButton: document.getElementById("addSignatureErrorCloseButton"),
       cancelButton: document.getElementById("addSignatureCancelButton"),
       addButton: document.getElementById("addSignatureAddButton"),