Add PDF preview support in attachment dialog using Poppler

share/translations/keepassxc_en.ts

@@ -7178,6 +7178,26 @@ Do you want to overwrite it?</source>
         <source>Image format not supported</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Failed to load the PDF</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Failed to read the PDF: The file is locked</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Failed to read the PDF: No pages found</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Failed to read the PDF: Unable to create a page</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Failed to render the PDF page</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>QMessageBox</name>

src/CMakeLists.txt

@@ -388,6 +388,12 @@ target_link_libraries(keepassxc_gui
         ${keeshare_LIB}
         ${sshagent_LIB})
 
+# Find Poppler
+find_package(PkgConfig)
+pkg_check_modules(POPPLER_CPP REQUIRED IMPORTED_TARGET poppler-cpp)
+
+target_link_libraries(keepassxc_gui PkgConfig::POPPLER_CPP)
+
 if(APPLE)
     target_link_libraries(keepassxc_gui "-framework Foundation -framework AppKit -framework Carbon -framework Security -framework LocalAuthentication -framework ScreenCaptureKit")
     if(Qt5MacExtras_FOUND)

src/gui/entry/PreviewEntryAttachmentsDialog.cpp

@@ -24,6 +24,12 @@
 #include <QTextCursor>
 #include <QtDebug>
 
+#include <memory>
+
+#include <poppler-document.h>
+#include <poppler-page-renderer.h>
+#include <poppler-page.h>
+
 PreviewEntryAttachmentsDialog::PreviewEntryAttachmentsDialog(QWidget* parent)
     : QDialog(parent)
     , m_ui(new Ui::EntryAttachmentsDialog)
@@ -84,7 +90,58 @@ void PreviewEntryAttachmentsDialog::update()
 void PreviewEntryAttachmentsDialog::updatePdfAttachment(const QByteArray& data)
 {
     // To preview a PDF as an image, you need to install the qt5-image-formats-plugin-pdf
-    updateImageAttachment(data);
+    poppler::byte_array array{std::cbegin(data), std::cend(data)};
+
+    auto doc = std::unique_ptr<poppler::document>(poppler::document::load_from_data(&array));
+    if (!doc) {
+        updateTextAttachment(tr("Failed to load the PDF").toUtf8());
+        return;
+    }
+
+    // Locked PDF files are not supported
+    if (doc->is_locked()) {
+        updateTextAttachment(tr("Failed to read the PDF: The file is locked").toUtf8());
+        return;
+    }
+
+    if (!doc->pages()) {
+        updateTextAttachment(tr("Failed to read the PDF: No pages found").toUtf8());
+        return;
+    }
+
+    // Preview the first page of the document.
+    auto page = std::unique_ptr<poppler::page>(doc->create_page(0));
+    if (!page) {
+        updateTextAttachment(tr("Failed to read the PDF: Unable to create a page").toUtf8());
+        return;
+    }
+
+    poppler::page_renderer renderer{};
+    auto popplerImage = renderer.render_page(page.get());
+
+    QImage image(reinterpret_cast<const uchar*>(popplerImage.const_data()),
+                 popplerImage.width(),
+                 popplerImage.height(),
+                 popplerImage.bytes_per_row(),
+                 QImage::Format_ARGB32);
+
+    if (image.isNull()) {
+        updateTextAttachment(tr("Failed to render the PDF page").toUtf8());
+        return;
+    }
+
+    updateImageAttachment(image);
+}
+
+QSize PreviewEntryAttachmentsDialog::calcucateImageSize()
+{
+    // Scale the image to the contents rect minus another set of margins to avoid scrollbars
+    auto margins = m_ui->attachmentTextEdit->contentsMargins();
+    auto size = m_ui->attachmentTextEdit->contentsRect().size();
+    size.setWidth(size.width() - margins.left() - margins.right());
+    size.setHeight(size.height() - margins.top() - margins.bottom());
+
+    return size;
 }
 
 void PreviewEntryAttachmentsDialog::updateTextAttachment(const QByteArray& data)
@@ -100,17 +157,15 @@ void PreviewEntryAttachmentsDialog::updateImageAttachment(const QByteArray& data
         return;
     }
 
+    updateImageAttachment(image);
+}
+
+void PreviewEntryAttachmentsDialog::updateImageAttachment(const QImage& image)
+{
     m_ui->attachmentTextEdit->clear();
     auto cursor = m_ui->attachmentTextEdit->textCursor();
 
-    // Scale the image to the contents rect minus another set of margins to avoid scrollbars
-    auto margins = m_ui->attachmentTextEdit->contentsMargins();
-    auto size = m_ui->attachmentTextEdit->contentsRect().size();
-    size.setWidth(size.width() - margins.left() - margins.right());
-    size.setHeight(size.height() - margins.top() - margins.bottom());
-    image = image.scaled(size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
-
-    cursor.insertImage(image);
+    cursor.insertImage(image.scaled(calcucateImageSize(), Qt::KeepAspectRatio, Qt::SmoothTransformation));
 }
 
 Tools::MimeType PreviewEntryAttachmentsDialog::attachmentType(const QByteArray& data) const

src/gui/entry/PreviewEntryAttachmentsDialog.h

@@ -51,6 +51,9 @@ private:
     void updateTextAttachment(const QByteArray& data);
     void updateImageAttachment(const QByteArray& data);
     void updatePdfAttachment(const QByteArray& data);
+    void updateImageAttachment(const QImage& image);
+
+    QSize calcucateImageSize();
 
     QScopedPointer<Ui::EntryAttachmentsDialog> m_ui;
 

tests/TestTools.cpp

@@ -301,10 +301,13 @@ void TestTools::testMimeTypes()
         "image/svg+xml" // SVG images
     };
 
+    const QStringList pdfMimeType = {
+        "application/pdf", // PDF documents
+    };
+
     const QStringList UnknownMimeTypes = {
         "audio/mpeg", // MPEG audio files
         "video/mp4", // MP4 video files
-        "application/pdf", // PDF documents
         "application/zip", // ZIP archives
         "application/x-tar", // TAR archives
         "application/x-rar-compressed", // RAR archives
@@ -327,15 +330,15 @@ void TestTools::testMimeTypes()
         "application/x-shellscript", // Shell scripts
     };
 
-    for (const auto& mime : TextMimeTypes) {
-        QCOMPARE(Tools::toMimeType(mime), Tools::MimeType::PlainText);
+    auto compare = [](const QStringList& mimeList, Tools::MimeType exptectedType) {
+        for (const auto& mime : mimeList) {
+            QCOMPARE(Tools::toMimeType(mime), exptectedType);
         }
+    };
 
-    for (const auto& mime : ImageMimeTypes) {
-        QCOMPARE(Tools::toMimeType(mime), Tools::MimeType::Image);
-    }
+    compare(TextMimeTypes, Tools::MimeType::PlainText);
+    compare(ImageMimeTypes, Tools::MimeType::Image);
+    compare(pdfMimeType, Tools::MimeType::Pdf);
 
-    for (const auto& mime : UnknownMimeTypes) {
-        QCOMPARE(Tools::toMimeType(mime), Tools::MimeType::Unknown);
-    }
+    compare(UnknownMimeTypes, Tools::MimeType::Unknown);
 }

vcpkg.json

@@ -76,6 +76,10 @@
     {
       "name": "zlib",
       "version>=": "1.3"
+    },
+    {
+      "name": "poppler",
+      "version>=": "23.1.0"
     }
   ]
 }