Thumbnail books, documents, 3D parts, drawings and fonts

src/embedded.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <QImage>
+#include <QString>
+
+// Thumbnails from a file's own bytes: the picture an EPUB, comic book, OpenDocument, Office Open XML, 3MF, FreeCAD, Krita or OpenRaster file keeps in its zip, or a font's own letters.
+namespace Embedded {
+
+bool handles(const QString &mime, const QString &path);
+
+// The kept picture, upright and at most `pixels` on its longer side, or the font's letters on a square of `pixels`; null when there is none.
+QImage thumbnail(const QString &path, const QString &mime, int pixels);
+
+} // namespace Embedded

src/foldermodel.cpp

@@ -212,6 +212,8 @@ QString FolderModel::kindForMime(const QString &mime) {
     if (mime.startsWith("image/")) return "image";
     if (mime.startsWith("video/")) return "video";
     if (mime.startsWith("audio/")) return "audio";
+    // A Type 1 font is PostScript, and so text, to the MIME database; it is shown as the font it is.
+    if (mime == "application/x-font-type1") return "other";
     // Anything readable as text (source code, config, JSON, Ruby, ...) is
     // text, whatever its own type is called.
     static const QMimeDatabase types;

src/previewer.cpp

@@ -36,6 +36,9 @@ QString Previewer::viewerFor(const QString &mime, bool isDir) {
     }
     if (mime == "text/markdown")
         return "markdown";
+    // A Type 1 font is PostScript, and so text, to the MIME database; it shows its sample like every other font, never its source.
+    if (mime == "application/x-font-type1")
+        return "other";
     const QMimeType type = QMimeDatabase().mimeTypeForName(mime);
     if (mime.startsWith("text/") || type.inherits("text/plain"))
         return "text";

src/rawembed.cpp

@@ -31,8 +31,7 @@ constexpr quint64 kEntryLength = 12;
 constexpr quint64 kMaxValue = 65536;
 // SubIFD fan-out is capped, so one count cannot queue unbounded work.
 constexpr quint32 kMaxPointers = 64;
-// No camera's preview holds more pixels than this; a frame header that claims more would cost a vast decode for nothing.
-constexpr quint64 kMaxPixels = 250000000;
+using RawEmbed::kMaxPixels;
 // The largest embedded JPEG read into memory; a real one is a few MiB.
 constexpr quint64 kMaxJpeg = 64 * 1048576;
 // SOI plus one frame header: anything shorter is no picture.

src/rawembed.h

@@ -8,6 +8,9 @@ namespace RawEmbed {
 
 bool handles(const QString &mime);
 
+// No camera's preview holds more pixels than this; a frame header that claims more would cost a vast decode for nothing.
+inline constexpr quint64 kMaxPixels = 250000000;
+
 // The largest valid embedded JPEG, upright and at most `pixels` on its longer side; null when the file holds none.
 QImage thumbnail(const QString &path, int pixels);
 

src/thumbnails.cpp

@@ -1,4 +1,5 @@
 #include "thumbnails.h"
+#include "embedded.h"
 #include "rawembed.h"
 
 #include <QBuffer>
@@ -321,9 +322,9 @@ Thumbnails::Thumbnails(const QString &cacheDirectory, const QStringList &thumbna
 }
 
 QString Thumbnails::missingPackage(const QString &mime) const {
-    // Qt draws its own pictures in-process, an installed thumbnailer needs nothing more, and pdftoppm draws a PDF without one.
+    // Qt draws its own pictures in-process, as Folio draws a picture a file keeps, an installed thumbnailer needs nothing more, and pdftoppm draws a PDF without one.
     if ((mime.startsWith("image/") && QImageReader::supportedMimeTypes().contains(mime.toLatin1()))
-        || m_thumbnailers.contains(mime)
+        || Embedded::handles(mime, {}) || m_thumbnailers.contains(mime)
         || (mime == "application/pdf" && !QStandardPaths::findExecutable("pdftoppm").isEmpty()))
         return {};
     return packageFor().value(mime);
@@ -403,10 +404,11 @@ QImage Thumbnails::load(const QString &path, const QString &mime, int size) cons
 }
 
 QImage Thumbnails::generate(const QString &path, const QString &mime, int pixels, bool &attempted) const {
-    // A camera RAW with no installed thumbnailer, the desktop's own answer, shows the JPEG the camera embedded.
-    if (RawEmbed::handles(mime) && !m_thumbnailers.contains(mime)) {
+    // A camera RAW, a file that keeps its picture in a zip, or a font, with no installed thumbnailer, the desktop's own answer, is drawn from its own bytes.
+    if ((RawEmbed::handles(mime) || Embedded::handles(mime, path)) && !m_thumbnailers.contains(mime)) {
         attempted = true;
-        if (const QImage image = RawEmbed::thumbnail(path, pixels); !image.isNull())
+        const QImage image = RawEmbed::handles(mime) ? RawEmbed::thumbnail(path, pixels) : Embedded::thumbnail(path, mime, pixels);
+        if (!image.isNull())
             return image;
     }
     // Common photo formats decode fastest in-process; anything Qt can't read

src/thumbnails.h

@@ -34,8 +34,9 @@ class Thumbnails : public QObject {
 
     static QString cacheKey(const QString &path);
     // The spec's fail/<program>-<version>: the number is raised when Folio learns to draw more, so old failures are tried
-    // again. 3: names with a thumbnailer's codes in them, and PDFs whose thumbnailer couldn't start, are drawn now.
-    static inline const QString failures = QStringLiteral("fail/folio-3");
+    // again. 3: names with a thumbnailer's codes in them, and PDFs whose thumbnailer couldn't start, are drawn now. 4: the
+    // picture a zip keeps inside, as an EPUB or an OpenDocument does.
+    static inline const QString failures = QStringLiteral("fail/folio-4");
     static QString bucketFor(int size);
     // A text file's first lines set on a page in the given colors. Made
     // fresh each time rather than cached, since the colors follow the theme.