Add support for multipage TIFF images to QTiffHandlerv5.9.0-alpha1

Allows multipage TIFF images to be read via QImageReader::jumpToImage
and QImageReader::jumpNextToImage.

[ChangeLog][QtGui][QImageReader] Support multipage TIFF images through
QImageReader

Change-Id: Id6ac68b75500148e51be11eff3d296c929d2d95c
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

5 files changed, 137 insertions, 10 deletions

diff --git a/src/plugins/imageformats/tiff/qtiffhandler.cpp b/src/plugins/imageformats/tiff/qtiffhandler.cpp
index 6fcf2a7..b5d80f9 100644
--- a/src/plugins/imageformats/tiff/qtiffhandler.cpp
+++ b/src/plugins/imageformats/tiff/qtiffhandler.cpp
@@ -116,6 +116,8 @@ public:
     uint16 photometric;
     bool grayscale;
     bool headersRead;
+    int currentDirectory;
+    int directoryCount;
 };
 
 static QImageIOHandler::Transformations exif2Qt(int exifOrientation)
@@ -174,6 +176,8 @@ QTiffHandlerPrivate::QTiffHandlerPrivate()
     , photometric(false)
     , grayscale(false)
     , headersRead(false)
+    , currentDirectory(0)
+    , directoryCount(0)
 {
 }
 
@@ -225,6 +229,19 @@ bool QTiffHandlerPrivate::openForRead(QIODevice *device)
     if (!tiff) {
         return false;
     }
+    return true;
+}
+
+bool QTiffHandlerPrivate::readHeaders(QIODevice *device)
+{
+    if (headersRead)
+        return true;
+
+    if (!openForRead(device))
+        return false;
+
+    TIFFSetDirectory(tiff, currentDirectory);
+
     uint32 width;
     uint32 height;
     if (!TIFFGetField(tiff, TIFFTAG_IMAGEWIDTH, &width)
@@ -275,14 +292,6 @@ bool QTiffHandlerPrivate::openForRead(QIODevice *device)
     return true;
 }
 
-bool QTiffHandlerPrivate::readHeaders(QIODevice *device)
-{
-    if (headersRead)
-        return true;
-
-    return openForRead(device);
-}
-
 QTiffHandler::QTiffHandler()
     : QImageIOHandler()
     , d(new QTiffHandlerPrivate)
@@ -308,7 +317,7 @@ bool QTiffHandler::canRead(QIODevice *device)
 bool QTiffHandler::read(QImage *image)
 {
     // Open file and read headers if it hasn't already been done.
-    if (!d->openForRead(device()))
+    if (!d->readHeaders(device()))
         return false;
 
     QImage::Format format = d->format;
@@ -438,7 +447,6 @@ bool QTiffHandler::read(QImage *image)
         }
     }
 
-    d->close();
     return true;
 }
 
@@ -739,6 +747,45 @@ bool QTiffHandler::supportsOption(ImageOption option) const
             || option == TransformedByDefault;
 }
 
+bool QTiffHandler::jumpToNextImage()
+{
+    if (!ensureHaveDirectoryCount())
+        return false;
+    if (d->currentDirectory >= d->directoryCount - 1)
+        return false;
+
+    d->headersRead = false;
+    ++d->currentDirectory;
+    return true;
+}
+
+bool QTiffHandler::jumpToImage(int imageNumber)
+{
+    if (!ensureHaveDirectoryCount())
+        return false;
+    if (imageNumber < 0 || imageNumber >= d->directoryCount)
+        return false;
+
+    if (d->currentDirectory != imageNumber) {
+        d->headersRead = false;
+        d->currentDirectory = imageNumber;
+    }
+    return true;
+}
+
+int QTiffHandler::imageCount() const
+{
+    if (!ensureHaveDirectoryCount())
+        return 1;
+
+    return d->directoryCount;
+}
+
+int QTiffHandler::currentImageNumber() const
+{
+    return d->currentDirectory;
+}
+
 void QTiffHandler::convert32BitOrder(void *buffer, int width)
 {
     uint32 *target = reinterpret_cast<uint32 *>(buffer);
@@ -751,4 +798,33 @@ void QTiffHandler::convert32BitOrder(void *buffer, int width)
                     | ((p & 0x000000ff) << 16);
     }
 }
+
+bool QTiffHandler::ensureHaveDirectoryCount() const
+{
+    if (d->directoryCount > 0)
+        return true;
+
+    TIFF *tiff = TIFFClientOpen("foo",
+                                "r",
+                                device(),
+                                qtiffReadProc,
+                                qtiffWriteProc,
+                                qtiffSeekProc,
+                                qtiffCloseProc,
+                                qtiffSizeProc,
+                                qtiffMapProc,
+                                qtiffUnmapProc);
+    if (!tiff) {
+        device()->reset();
+        return false;
+    }
+
+    do {
+        ++d->directoryCount;
+    } while (TIFFReadDirectory(tiff));
+    TIFFClose(tiff);
+    device()->reset();
+    return true;
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/imageformats/tiff/qtiffhandler_p.h b/src/plugins/imageformats/tiff/qtiffhandler_p.h
index f362a90..311ae46 100644
--- a/src/plugins/imageformats/tiff/qtiffhandler_p.h
+++ b/src/plugins/imageformats/tiff/qtiffhandler_p.h
@@ -63,6 +63,11 @@ public:
     void setOption(ImageOption option, const QVariant &value) override;
     bool supportsOption(ImageOption option) const override;
 
+    bool jumpToNextImage() Q_DECL_OVERRIDE;
+    bool jumpToImage(int imageNumber) Q_DECL_OVERRIDE;
+    int imageCount() const Q_DECL_OVERRIDE;
+    int currentImageNumber() const Q_DECL_OVERRIDE;
+
     enum Compression {
         NoCompression = 0,
         LzwCompression = 1
@@ -70,6 +75,7 @@ public:
 private:
     void convert32BitOrder(void *buffer, int width);
     const QScopedPointer<QTiffHandlerPrivate> d;
+    bool ensureHaveDirectoryCount() const;
 };
 
 QT_END_NAMESPACE
diff --git a/tests/auto/tiff/tst_qtiff.cpp b/tests/auto/tiff/tst_qtiff.cpp
index 8e3d0c9..65cc56c 100644
--- a/tests/auto/tiff/tst_qtiff.cpp
+++ b/tests/auto/tiff/tst_qtiff.cpp
@@ -78,6 +78,9 @@ private slots:
     void resolution_data();
     void resolution();
 
+    void multipage_data();
+    void multipage();
+
 private:
     QString prefix;
 };
@@ -513,5 +516,46 @@ void tst_qtiff::resolution()
     QCOMPARE(expectedDotsPerMeterY, generatedImage.dotsPerMeterY());
 }
 
+void tst_qtiff::multipage_data()
+{
+    QTest::addColumn<QString>("filename");
+    QTest::addColumn<int>("expectedNumPages");
+    QTest::addColumn<QVector<QSize>>("expectedSizes");
+
+    QVector<QSize> sizes = QVector<QSize>() << QSize(640, 480) << QSize(800, 600) << QSize(320, 240);
+    QTest::newRow("3 page TIFF") << ("multipage.tiff") << 3 << sizes;
+}
+
+void tst_qtiff::multipage()
+{
+    QFETCH(QString, filename);
+    QFETCH(int, expectedNumPages);
+    QFETCH(QVector<QSize>, expectedSizes);
+
+    QImageReader reader(prefix + filename);
+    QCOMPARE(reader.imageCount(), expectedNumPages);
+
+    // Test jumpToImage, currentImageNumber and whether the actual image is correct
+    QCOMPARE(reader.jumpToImage(-1), false);
+    for (int i = 0; i < expectedNumPages; ++i) {
+        reader.jumpToImage(i);
+        QCOMPARE(reader.currentImageNumber(), i);
+        QSize size = reader.size();
+        QCOMPARE(size.width(), expectedSizes[i].width());
+        QCOMPARE(size.height(), expectedSizes[i].height());
+        QImage image = reader.read();
+        QVERIFY2(!image.isNull(), qPrintable(reader.errorString()));
+    }
+    QCOMPARE(reader.jumpToImage(expectedNumPages), false);
+
+    // Test jumpToNextImage
+    reader.jumpToImage(0);
+    QCOMPARE(reader.currentImageNumber(), 0);
+    for (int i = 0; i < expectedNumPages - 1; ++i) {
+        QCOMPARE(reader.jumpToNextImage(), true);
+    }
+    QCOMPARE(reader.jumpToNextImage(), false);
+}
+
 QTEST_MAIN(tst_qtiff)
 #include "tst_qtiff.moc"
diff --git a/tests/shared/images/tiff.qrc b/tests/shared/images/tiff.qrc
index 8fcab8b..c98a72c 100644
--- a/tests/shared/images/tiff.qrc
+++ b/tests/shared/images/tiff.qrc
@@ -21,6 +21,7 @@
         <file>tiff/mono_orientation_6.tiff</file>
         <file>tiff/mono_orientation_7.tiff</file>
         <file>tiff/mono_orientation_8.tiff</file>
+        <file>tiff/multipage.tiff</file>
         <file>tiff/original_indexed.tiff</file>
         <file>tiff/original_mono.tiff</file>
         <file>tiff/original_rgb.tiff</file>
diff --git a/tests/shared/images/tiff/multipage.tiff b/tests/shared/images/tiff/multipage.tiff
new file mode 100644
index 0000000..0c2f266
--- /dev/null
+++ b/tests/shared/images/tiff/multipage.tiff