Add Farbfeld read only support

README.md

@@ -16,6 +16,7 @@ The following image formats have read-only support:
 
 - Animated Windows cursors (ani)
 - Camera RAW images (arw, cr2, cr3, dcs, dng, ...)
+- Farbfeld (ff)
 - Gimp (xcf)
 - Interchange Format Files (iff, ilbm, lbm)
 - Krita (kra)
@@ -256,6 +257,7 @@ limit depends on the format encoding).
 - DDS: 300,000 x 300,000 pixels
 - EXR: 300,000 x 300,000 pixels
 - EPS: same size as Qt's JPG plugin
+- FF: 300,000 x 300,000 pixels
 - HDR: 300,000 x 300,000 pixels
 - HEIF: n/a
 - IFF: 65,535 x 65,535 pixels

autotests/CMakeLists.txt

@@ -76,6 +76,7 @@ endmacro()
 # Loads each <format> image in read/<format>/, and compares the
 # result against the data read from the corresponding png file
 kimageformats_read_tests(
+    ff
     hdr
     iff
     pcx

autotests/ossfuzz/build_fuzzers.sh

@@ -162,6 +162,7 @@ HANDLER_TYPES="ANIHandler ani
         QAVIFHandler avif
         QDDSHandler dds
         EXRHandler exr
+        FFHandler ff
         HDRHandler hdr
         HEIFHandler heif
         IFFHandler iff

autotests/ossfuzz/kimgio_fuzzer.cc

@@ -23,7 +23,7 @@
   Usage:
     python infra/helper.py build_image kimageformats
     python infra/helper.py build_fuzzers --sanitizer undefined|address|memory kimageformats
-    python infra/helper.py run_fuzzer kimageformats kimgio_[ani|avif|dds|exr|hdr|heif|iff|jp2|jxl|jxr|kra|ora|pcx|pfm|pic|psd|pxr|qoi|ras|raw|rgb|sct|tim|tga|xcf]_fuzzer
+    python infra/helper.py run_fuzzer kimageformats kimgio_[ani|avif|dds|exr|ff|hdr|heif|iff|jp2|jxl|jxr|kra|ora|pcx|pfm|pic|psd|pxr|qoi|ras|raw|rgb|sct|tim|tga|xcf]_fuzzer
 */
 
 #include <QBuffer>
@@ -34,6 +34,7 @@
 #include "avif_p.h"
 #include "dds_p.h"
 #include "exr_p.h"
+#include "ff_p.h"
 #include "hdr_p.h"
 #include "heif_p.h"
 #include "iff_p.h"

src/imageformats/CMakeLists.txt

@@ -73,6 +73,10 @@ endif()
 
 ##################################
 
+kimageformats_add_plugin(kimg_ff SOURCES ff.cpp)
+
+##################################
+
 kimageformats_add_plugin(kimg_hdr SOURCES hdr.cpp)
 
 ##################################

src/imageformats/ff.cpp

@@ -0,0 +1,259 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2026 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+// Specs: https://tools.suckless.org/farbfeld/
+
+#include "ff_p.h"
+#include "util_p.h"
+
+#include <QColorSpace>
+#include <QIODevice>
+#include <QImage>
+#include <QLoggingCategory>
+#include <QtEndian>
+
+Q_DECLARE_LOGGING_CATEGORY(LOG_FFPLUGIN)
+
+#ifdef QT_DEBUG
+Q_LOGGING_CATEGORY(LOG_FFPLUGIN, "kf.imageformats.plugins.ff", QtDebugMsg)
+#else
+Q_LOGGING_CATEGORY(LOG_FFPLUGIN, "kf.imageformats.plugins.ff", QtWarningMsg)
+#endif
+
+/* *** FF_MAX_IMAGE_WIDTH and FF_MAX_IMAGE_HEIGHT ***
+ * The maximum size in pixel allowed by the plugin.
+ */
+#ifndef FF_MAX_IMAGE_WIDTH
+#define FF_MAX_IMAGE_WIDTH KIF_LARGE_IMAGE_PIXEL_LIMIT
+#endif
+#ifndef FF_MAX_IMAGE_HEIGHT
+#define FF_MAX_IMAGE_HEIGHT FF_MAX_IMAGE_WIDTH
+#endif
+
+#define HEADER_SIZE 16
+
+class FFHeader
+{
+private:
+    QByteArray m_rawHeader;
+
+public:
+    FFHeader()
+    {
+
+    }
+
+    bool isValid() const
+    {
+        if (m_rawHeader.size() < HEADER_SIZE) {
+            return false;
+        }
+        return m_rawHeader.startsWith(QByteArray::fromRawData("farbfeld", 8));
+    }
+
+    bool isSupported() const
+    {
+        auto w = width();
+        auto h = height();
+        if (w < 1 || w > FF_MAX_IMAGE_WIDTH || h < 1 || h > FF_MAX_IMAGE_HEIGHT) {
+            return false;
+        }
+        return format() != QImage::Format_Invalid;
+    }
+
+    qint32 width() const
+    {
+        if (!isValid()) {
+            return 0;
+        }
+        return qFromBigEndian<qint32>(m_rawHeader.data() + 8);
+    }
+
+    qint32 height() const
+    {
+        if (!isValid()) {
+            return 0;
+        }
+        return qFromBigEndian<qint32>(m_rawHeader.data() + 12);
+    }
+
+    QSize size() const
+    {
+        return QSize(width(), height());
+    }
+
+    QImage::Format format() const
+    {
+        if (!isValid()) {
+            return QImage::Format_Invalid;
+        }
+        return QImage::Format_RGBA64;
+    }
+
+    bool read(QIODevice *d)
+    {
+        m_rawHeader = d->read(HEADER_SIZE);
+        if (m_rawHeader.size() != HEADER_SIZE) {
+            return false;
+        }
+        return isValid();
+    }
+
+    bool peek(QIODevice *d)
+    {
+        m_rawHeader = d->peek(HEADER_SIZE);
+        if (m_rawHeader.size() != HEADER_SIZE) {
+            return false;
+        }
+        return isValid();
+    }
+};
+
+class FFHandlerPrivate
+{
+public:
+    FFHandlerPrivate() {}
+    ~FFHandlerPrivate() {}
+
+    FFHeader m_header;
+};
+
+FFHandler::FFHandler()
+    : QImageIOHandler()
+    , d(new FFHandlerPrivate)
+{
+}
+
+bool FFHandler::canRead() const
+{
+    if (canRead(device())) {
+        setFormat("ff");
+        return true;
+    }
+    return false;
+}
+
+bool FFHandler::canRead(QIODevice *device)
+{
+    if (!device) {
+        qCWarning(LOG_FFPLUGIN) << "FFHandler::canRead() called with no device";
+        return false;
+    }
+
+    FFHeader h;
+    if (!h.peek(device)) {
+        return false;
+    }
+
+    return h.isSupported();
+}
+
+bool FFHandler::read(QImage *image)
+{
+    auto&& header = d->m_header;
+
+    if (!header.read(device())) {
+        qCWarning(LOG_FFPLUGIN) << "FFHandler::read() invalid header";
+        return false;
+    }
+
+    auto img = imageAlloc(header.size(), header.format());
+    if (img.isNull()) {
+        qCWarning(LOG_FFPLUGIN) << "FFHandler::read() error while allocating the image";
+        return false;
+    }
+
+    auto d = device();
+
+    auto size = img.bytesPerLine();
+    for (auto y = 0, h = img.height(); y < h; ++y) {
+        auto line = reinterpret_cast<char*>(img.scanLine(y));
+        if (d->read(line, size) != size) {
+            qCWarning(LOG_FFPLUGIN) << "FFHandler::read() error while reading image scanline";
+            return false;
+        }
+#if Q_LITTLE_ENDIAN
+        for (auto i = 0; i < size; i += 2) {
+            std::swap(line[i], line[i + 1]);
+        }
+#endif
+    }
+
+    img.setColorSpace(QColorSpace(QColorSpace::SRgb));
+
+    *image = img;
+    return true;
+}
+
+bool FFHandler::supportsOption(ImageOption option) const
+{
+    if (option == QImageIOHandler::Size) {
+        return true;
+    }
+    if (option == QImageIOHandler::ImageFormat) {
+        return true;
+    }
+    return false;
+}
+
+QVariant FFHandler::option(ImageOption option) const
+{
+    QVariant v;
+
+    if (option == QImageIOHandler::Size) {
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.size());
+        } else if (auto d = device()) {
+            if (h.peek(d)) {
+                v = QVariant::fromValue(h.size());
+            }
+        }
+    }
+
+    if (option == QImageIOHandler::ImageFormat) {
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.format());
+        } else if (auto d = device()) {
+            if (h.peek(d)) {
+                v = QVariant::fromValue(h.format());
+            }
+        }
+    }
+
+    return v;
+}
+
+QImageIOPlugin::Capabilities FFPlugin::capabilities(QIODevice *device, const QByteArray &format) const
+{
+    if (format == "ff") {
+        return Capabilities(CanRead);
+    }
+    if (!format.isEmpty()) {
+        return {};
+    }
+    if (!device->isOpen()) {
+        return {};
+    }
+
+    Capabilities cap;
+    if (device->isReadable() && FFHandler::canRead(device)) {
+        cap |= CanRead;
+    }
+    return cap;
+}
+
+QImageIOHandler *FFPlugin::create(QIODevice *device, const QByteArray &format) const
+{
+    QImageIOHandler *handler = new FFHandler;
+    handler->setDevice(device);
+    handler->setFormat(format);
+    return handler;
+}
+
+#include "moc_ff_p.cpp"

src/imageformats/ff.json

@@ -0,0 +1,4 @@
+{
+    "Keys": [ "ff" ],
+    "MimeTypes": [ "image/x-farbfeld" ]
+}

src/imageformats/ff_p.h

@@ -0,0 +1,42 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2026 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#ifndef KIMG_FF_P_H
+#define KIMG_FF_P_H
+
+#include <QImageIOPlugin>
+#include <QScopedPointer>
+
+class FFHandlerPrivate;
+class FFHandler : public QImageIOHandler
+{
+public:
+    FFHandler();
+
+    bool canRead() const override;
+    bool read(QImage *image) override;
+
+    bool supportsOption(QImageIOHandler::ImageOption option) const override;
+    QVariant option(QImageIOHandler::ImageOption option) const override;
+
+    static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<FFHandlerPrivate> d;
+};
+
+class FFPlugin : public QImageIOPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "ff.json")
+
+public:
+    Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
+    QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
+};
+
+#endif // KIMG_FF_P_H