IFF: read only support to Interchange Format Files

Read-only support for most common Interchange Format Files (IFF). Supports IFF saved by Photoshop for the Amiga and Maya platform and HAM6 coded files.

Closes #29

src/imageformats/CMakeLists.txt

@@ -84,6 +84,10 @@ endif()
 
 ##################################
 
+kimageformats_add_plugin(kimg_iff SOURCES iff.cpp chunks.cpp)
+
+##################################
+
 if (LibJXL_FOUND AND LibJXLThreads_FOUND AND LibJXLCMS_FOUND)
     kimageformats_add_plugin(kimg_jxl SOURCES jxl.cpp microexif.cpp)
     target_link_libraries(kimg_jxl PRIVATE PkgConfig::LibJXL PkgConfig::LibJXLThreads PkgConfig::LibJXLCMS)

src/imageformats/chunks_p.h

@@ -0,0 +1,823 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2025 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+/*
+ * Format specifications:
+ * - https://wiki.amigaos.net/wiki/IFF_FORM_and_Chunk_Registry
+ * - https://www.fileformat.info/format/iff/egff.htm
+ */
+
+#ifndef KIMG_CHUNKS_P_H
+#define KIMG_CHUNKS_P_H
+
+#include <QByteArray>
+#include <QDateTime>
+#include <QImage>
+#include <QIODevice>
+#include <QPoint>
+#include <QSize>
+#include <QSharedPointer>
+
+// Main chunks (Standard)
+#define CAT__CHUNK QByteArray("CAT ")
+#define FILL_CHUNK QByteArray("    ")
+#define FORM_CHUNK QByteArray("FORM")
+#define LIST_CHUNK QByteArray("LIST")
+#define PROP_CHUNK QByteArray("PROP")
+
+// Main chuncks (Maya)
+#define FOR4_CHUNK QByteArray("FOR4")
+
+// FORM ILBM IFF
+#define BMHD_CHUNK QByteArray("BMHD")
+#define BODY_CHUNK QByteArray("BODY")
+#define CAMG_CHUNK QByteArray("CAMG")
+#define CMAP_CHUNK QByteArray("CMAP")
+#define DPI__CHUNK QByteArray("DPI ")
+#define SHAM_CHUNK QByteArray("SHAM") // undocumented
+
+// FOR4 CIMG IFF (Maya)
+#define RGBA_CHUNK QByteArray("RGBA")
+#define TBHD_CHUNK QByteArray("TBHD")
+
+// FORx IFF (found on some IFF format specs)
+#define AUTH_CHUNK QByteArray("AUTH")
+#define DATE_CHUNK QByteArray("DATE")
+#define FVER_CHUNK QByteArray("FVER")
+#define HIST_CHUNK QByteArray("HIST")
+#define VERS_CHUNK QByteArray("VERS")
+
+#define CHUNKID_DEFINE(a) static QByteArray defaultChunkId() { return a; }
+
+/*!
+ * \brief The IFFChunk class
+ */
+class IFFChunk
+{
+public:
+    using ChunkList = QList<QSharedPointer<IFFChunk>>;
+
+    virtual ~IFFChunk();
+
+    /*!
+     * \brief IFFChunk
+     * Creates invalid chunk.
+     * \sa isValid
+     */
+    IFFChunk();
+
+    IFFChunk(const IFFChunk& other) = default;
+    IFFChunk& operator =(const IFFChunk& other) = default;
+
+    bool operator ==(const IFFChunk& other) const;
+
+    /*!
+     * \brief isValid
+     * \return True if the chunk is valid, otherwise false.
+     * \note The default implementation checks that chunkId() contains only valid characters.
+     */
+    virtual bool isValid() const;
+
+    /*!
+     * \brief alignBytes
+     * \return The chunk alignment bytes. By default returns bytes set using setAlignBytes().
+     */
+    virtual qint32 alignBytes() const;
+
+    /*!
+     * \brief chunkId
+     * \return The chunk Id of this chunk.
+     */
+    QByteArray chunkId() const;
+
+    /*!
+     * \brief bytes
+     * \return The size (in bytes) of the chunck data.
+     */
+
+    quint32 bytes() const;
+
+    /*!
+     * \brief data
+     * \return The data stored inside the class. If no data present, use readRawData().
+     * \sa readRawData
+     */
+    const QByteArray& data() const;
+
+    /*!
+     * \brief chunks
+     * \return The chunks inside this chunk.
+     */
+    const ChunkList& chunks() const;
+
+    /*!
+     * \brief chunkVersion
+     * \param cid Chunk Id to extract the version from.
+     * \return The version of the chunk. Zero means no valid chunk data.
+     */
+    static quint8 chunkVersion(const QByteArray& cid);
+
+    /*!
+     * \brief isChunkType
+     * Check if the chunkId is of type of cid (any version).
+     * \param cid Chunk Id to check.
+     * \return True on success, otherwise false.
+     */
+    bool isChunkType(const QByteArray& cid) const;
+
+    /*!
+     * \brief readInfo
+     * Reads chunkID, size and set the data position.
+     * \param d The device.
+     * \return True on success, otherwise false.
+     */
+    bool readInfo(QIODevice *d);
+
+    /*!
+     * \brief readStructure
+     * Read the internal structure using innerReadStructure() of the Chunk and set device the position to the next chunks.
+     * \param d The device.
+     * \return True on success, otherwise false.
+     */
+    bool readStructure(QIODevice *d);
+
+    /*!
+     * \brief readRawData
+     * \param d The device.
+     * \param relPos The position to read relative to the chunk position.
+     * \param size The size of the data to read (-1 means all chunk).
+     * \return The data read or empty array on error.
+     * \note Ignores any data already read and available with data().
+     * \sa data
+     */
+    QByteArray readRawData(QIODevice *d, qint64 relPos = 0, qint64 size = -1) const;
+
+    /*!
+     * \brief seek
+     * \param d The device.
+     * \param relPos The position to read relative to the chunk position.
+     * \return True on success, otherwise false.
+     */
+    bool seek(QIODevice *d, qint64 relPos = 0) const;
+
+    /*!
+     * \brief fromDevice
+     * \param d The device.
+     * \param ok Set to false if errors occurred.
+     * \return The chunk list found.
+     */
+    static ChunkList fromDevice(QIODevice *d, bool *ok = nullptr);
+
+    /*!
+     * \brief search
+     * Search for a chunk in the list of chunks.
+     * \param cid The chunkId to search.
+     * \param chunks The list of chunks to search for the requested chunk.
+     * \return The list of chunks with the given chunkId.
+     */
+    static ChunkList search(const QByteArray &cid, const ChunkList& chunks);
+
+    /*!
+     * \brief search
+     */
+    static ChunkList search(const QByteArray &cid, const QSharedPointer<IFFChunk>& chunk);
+
+    /*!
+     * \brief searchT
+     * Convenient search function to avoid casts.
+     * \param chunk The chunk to search for the requested chunk type.
+     * \return The list of chunks of T type.
+     */
+    template <class T>
+    static QList<const T*> searchT(const IFFChunk *chunk) {
+        QList<const T*> list;
+        if (chunk == nullptr)
+            return list;
+        auto cid = T::defaultChunkId();
+        if (chunk->chunkId() == cid)
+            if (auto c = dynamic_cast<const T*>(chunk))
+                list << c;
+        auto tmp = chunk->chunks();
+        for (auto &&c : tmp)
+            list << searchT<T>(c.data());
+        return list;
+    }
+
+    /*!
+     * \brief searchT
+     * Convenient search function to avoid casts.
+     * \param chunks The list of chunks to search for the requested chunk.
+     * \return The list of chunks of T type.
+     */
+    template <class T>
+    static QList<const T*> searchT(const ChunkList& chunks) {
+        QList<const T*> list;
+        for (auto &&chunk : chunks)
+            list << searchT<T>(chunk.data());
+        return list;
+    }
+
+    CHUNKID_DEFINE(QByteArray())
+
+protected:
+    /*!
+     * \brief innerReadStructure
+     * Reads data structure. Default implementation does nothing.
+     * \param d The device.
+     * \return True on success, otherwise false.
+     */
+    virtual bool innerReadStructure(QIODevice *d);
+
+    /*!
+     * \brief setAlignBytes
+     * \param bytes
+     */
+    void setAlignBytes(qint32 bytes)
+    {
+        _align = bytes;
+    }
+
+
+    /*!
+     * \brief cacheData
+     * Read all chunk data and store it on _data.
+     * \return True on success, otherwise false.
+     * \warning This function does not load anything if the chunk size is larger than 8MiB. For larger chunks, use direct data access.
+     */
+    bool cacheData(QIODevice *d);
+
+    /*!
+     * \brief setChunks
+     * \param chunks
+     */
+    void setChunks(const ChunkList &chunks);
+
+    inline quint16 ui16(quint8 c1, quint8 c2) const {
+        return (quint16(c2) << 8) | quint16(c1);
+    }
+
+    inline qint16 i16(quint8 c1, quint8 c2) const {
+        return qint32(ui16(c1, c2));
+    }
+
+    inline quint32 ui32(quint8 c1, quint8 c2, quint8 c3, quint8 c4) const {
+        return (quint32(c4) << 24) | (quint32(c3) << 16) | (quint32(c2) << 8) | quint32(c1);
+    }
+
+    inline qint32 i32(quint8 c1, quint8 c2, quint8 c3, quint8 c4) const {
+        return qint32(ui32(c1, c2, c3, c4));
+    }
+
+    static ChunkList innerFromDevice(QIODevice *d, bool *ok, qint32 alignBytes);
+
+private:
+    char _chunkId[4];
+
+    quint32 _size;
+
+    qint32 _align;
+
+    qint64 _dataPos;
+
+    QByteArray _data;
+
+    ChunkList _chunks;
+
+
+};
+
+/*!
+ * \brief The IffBMHD class
+ * Bitmap Header
+ */
+class BMHDChunk: public IFFChunk
+{
+public:
+    enum Compression {
+        Uncompressed = 0,
+        Rle = 1
+    };
+
+    virtual ~BMHDChunk() override;
+
+    BMHDChunk();
+    BMHDChunk(const BMHDChunk& other) = default;
+    BMHDChunk& operator =(const BMHDChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    qint32 width() const;
+
+    qint32 height() const;
+
+    QSize size() const;
+
+    qint32 left() const;
+
+    qint32 top() const;
+
+    quint8 bitplanes() const;
+
+    quint8 masking() const;
+
+    Compression compression() const;
+
+    quint8 padding() const;
+
+    qint16 transparency() const;
+
+    quint8 xAspectRatio() const;
+
+    quint8 yAspectRatio() const;
+
+    quint16 pageWidth() const;
+
+    quint16 pageHeight() const;
+
+    quint32 rowLen() const;
+
+    CHUNKID_DEFINE(BMHD_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The CMAPChunk class
+ */
+class CMAPChunk : public IFFChunk
+{
+public:
+    virtual ~CMAPChunk() override;
+    CMAPChunk();
+    CMAPChunk(const CMAPChunk& other) = default;
+    CMAPChunk& operator =(const CMAPChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    QList<QRgb> palette() const;
+
+    CHUNKID_DEFINE(CMAP_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The CAMGChunk class
+ */
+class CAMGChunk : public IFFChunk
+{
+public:
+    enum ModeId {
+        LoResLace = 0x0004,
+        HalfBrite = 0x0080,
+        LoResDpf = 0x0400,
+        Ham = 0x0800,
+        HiRes = 0x8000
+    };
+
+    Q_DECLARE_FLAGS(ModeIds, ModeId)
+
+    virtual ~CAMGChunk() override;
+    CAMGChunk();
+    CAMGChunk(const CAMGChunk& other) = default;
+    CAMGChunk& operator =(const CAMGChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    ModeIds modeId() const;
+
+    CHUNKID_DEFINE(CAMG_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The DPIChunk class
+ */
+class DPIChunk : public IFFChunk
+{
+public:
+    virtual ~DPIChunk() override;
+    DPIChunk();
+    DPIChunk(const DPIChunk& other) = default;
+    DPIChunk& operator =(const DPIChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    /*!
+     * \brief dpiX
+     * \return The horizontal resolution in DPI.
+     */
+    quint16 dpiX() const;
+
+    /*!
+     * \brief dpiY
+     * \return The vertical resolution in DPI.
+     */
+    quint16 dpiY() const;
+
+    /*!
+     * \brief dotsPerMeterX
+     * \return X resolution as wanted by QImage.
+     */
+    qint32 dotsPerMeterX() const;
+
+    /*!
+     * \brief dotsPerMeterY
+     * \return Y resolution as wanted by QImage.
+     */
+    qint32 dotsPerMeterY() const;
+
+    CHUNKID_DEFINE(DPI__CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+
+/*!
+ * \brief The BODYChunk class
+ */
+class BODYChunk : public IFFChunk
+{
+public:
+    virtual ~BODYChunk() override;
+    BODYChunk();
+    BODYChunk(const BODYChunk& other) = default;
+    BODYChunk& operator =(const BODYChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    CHUNKID_DEFINE(BODY_CHUNK)
+
+    /*!
+     * \brief readStride
+     * \param d The device.
+     * \param header The bitmap header.
+     * \param camg The CAMG chunk (optional)
+     * \param cmap The CMAP chunk (optional)
+     * \return The scanline as requested for QImage.
+     * \warning Call resetStrideRead() once before this one.
+     */
+    QByteArray strideRead(QIODevice *d, const BMHDChunk *header, const CAMGChunk *camg = nullptr, const CMAPChunk *cmap = nullptr) const;
+
+    /*!
+     * \brief resetStrideRead
+     * Reset the stride read set the position at the beginning of the data and reset all buffers.
+     * \param d The device
+     * \param header The BMHDChunk chunk (mandatory)
+     * \param camg The CAMG chunk (optional)
+     * \return True on success, otherwise false.
+     * \sa strideRead
+     */
+    bool resetStrideRead(QIODevice *d) const;
+
+private:
+    static QByteArray deinterleave(const QByteArray &planes, const BMHDChunk *header, const CAMGChunk *camg = nullptr, const CMAPChunk *cmap = nullptr);
+
+    mutable QByteArray _readBuffer;
+};
+
+/*!
+ * \brief The FORMChunk class
+ */
+class FORMChunk : public IFFChunk
+{
+    QByteArray _type;
+
+public:
+    virtual ~FORMChunk() override;
+    FORMChunk();
+    FORMChunk(const FORMChunk& other) = default;
+    FORMChunk& operator =(const FORMChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    bool isSupported() const;
+
+    QByteArray formType() const;
+
+    QImage::Format format() const;
+
+    QSize size() const;
+
+    CHUNKID_DEFINE(FORM_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+
+/*!
+ * \brief The FOR4Chunk class
+ */
+class FOR4Chunk : public IFFChunk
+{
+    QByteArray _type;
+
+public:
+    virtual ~FOR4Chunk() override;
+    FOR4Chunk();
+    FOR4Chunk(const FOR4Chunk& other) = default;
+    FOR4Chunk& operator =(const FOR4Chunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    virtual qint32 alignBytes() const override;
+
+    bool isSupported() const;
+
+    QByteArray formType() const;
+
+    QImage::Format format() const;
+
+    QSize size() const;
+
+    CHUNKID_DEFINE(FOR4_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The TBHDChunk class
+ */
+class TBHDChunk : public IFFChunk
+{
+public:
+    enum Flag {
+        Rgb = 0x01,
+        Alpha = 0x02,
+        ZBuffer = 0x04,
+        Black = 0x10,
+
+        RgbA = Rgb | Alpha
+    };
+    Q_DECLARE_FLAGS(Flags, Flag)
+
+    enum Compression {
+        Uncompressed = 0,
+        Rle = 1
+    };
+
+    virtual ~TBHDChunk() override;
+
+    TBHDChunk();
+    TBHDChunk(const TBHDChunk& other) = default;
+    TBHDChunk& operator =(const TBHDChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    virtual qint32 alignBytes() const override;
+
+    /*!
+     * \brief width
+     * \return Image width in pixels.
+     */
+    qint32 width() const;
+
+    /*!
+     * \brief height
+     * \return Image height in pixels.
+     */
+    qint32 height() const;
+
+    /*!
+     * \brief size
+     * \return Image size in pixels.
+     */
+    QSize size() const;
+
+    /*!
+     * \brief left
+     * \return
+     */
+    qint32 left() const;
+
+    /*!
+     * \brief top
+     * \return
+     */
+    qint32 top() const;
+
+    /*!
+     * \brief flags
+     * \return Image flags.
+     */
+    Flags flags() const;
+
+    /*!
+     * \brief bpc
+     * \return Byte per channel (1 or 2)
+     */
+    qint32 bpc() const;
+
+    /*!
+     * \brief channels
+     * \return
+     */
+    qint32 channels() const;
+
+    /*!
+     * \brief tiles
+     * \return The number of tiles of the image.
+     */
+    quint16 tiles() const;
+
+    /*!
+     * \brief compression
+     * \return The data compression.
+     */
+    Compression compression() const;
+
+    /*!
+     * \brief format
+     * \return
+     */
+    QImage::Format format() const;
+
+    CHUNKID_DEFINE(TBHD_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The RGBAChunk class
+ */
+class RGBAChunk : public IFFChunk
+{
+public:
+    virtual ~RGBAChunk() override;
+    RGBAChunk();
+    RGBAChunk(const RGBAChunk& other) = default;
+    RGBAChunk& operator =(const RGBAChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    virtual qint32 alignBytes() const override;
+
+    /*!
+     * \brief isTileCompressed
+     * \param header The image header.
+     * \return True if the tile is compressed, otherwise false.
+     */
+    bool isTileCompressed(const TBHDChunk *header) const;
+
+    /*!
+     * \brief pos
+     * \return The tile position (top-left corner) in the final image.
+     */
+    QPoint pos() const;
+
+    /*!
+     * \brief size
+     * \return The tile size in pixels.
+     */
+    QSize size() const;
+
+    /*!
+     * \brief tile
+     * Create the tile by reading the data from the device.
+     * \param d The device.
+     * \param header The image header.
+     * \return The image tile.
+     */
+    QImage tile(QIODevice *d, const TBHDChunk *header) const;
+
+    CHUNKID_DEFINE(RGBA_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+
+private:
+    QImage compressedTile(QIODevice *d, const TBHDChunk *header) const;
+
+    QImage uncompressedTile(QIODevice *d, const TBHDChunk *header) const;
+
+    QByteArray readStride(QIODevice *d, const TBHDChunk *header) const;
+
+private:
+    QPoint _pos;
+
+    QSize _size;
+
+    mutable QByteArray _readBuffer;
+};
+
+
+/*!
+ * \brief The AUTHChunk class
+ */
+class AUTHChunk : public IFFChunk
+{
+public:
+    virtual ~AUTHChunk() override;
+    AUTHChunk();
+    AUTHChunk(const AUTHChunk& other) = default;
+    AUTHChunk& operator =(const AUTHChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    QString value() const;
+
+    CHUNKID_DEFINE(AUTH_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The DATEChunk class
+ */
+class DATEChunk : public IFFChunk
+{
+public:
+    virtual ~DATEChunk() override;
+    DATEChunk();
+    DATEChunk(const DATEChunk& other) = default;
+    DATEChunk& operator =(const DATEChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    QDateTime value() const;
+
+    CHUNKID_DEFINE(DATE_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+/*!
+ * \brief The FVERChunk class
+ *
+ * \warning The specifications on wiki.amigaos.net differ from what I see in a file saved in Maya format. I do not interpret the data for now.
+ */
+class FVERChunk : public IFFChunk
+{
+public:
+    virtual ~FVERChunk() override;
+    FVERChunk();
+    FVERChunk(const FVERChunk& other) = default;
+    FVERChunk& operator =(const FVERChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    CHUNKID_DEFINE(FVER_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+
+/*!
+ * \brief The HISTChunk class
+ */
+class HISTChunk : public IFFChunk
+{
+public:
+    virtual ~HISTChunk() override;
+    HISTChunk();
+    HISTChunk(const HISTChunk& other) = default;
+    HISTChunk& operator =(const HISTChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    QString value() const;
+
+    CHUNKID_DEFINE(HIST_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+
+/*!
+ * \brief The VERSChunk class
+ */
+class VERSChunk : public IFFChunk
+{
+public:
+    virtual ~VERSChunk() override;
+    VERSChunk();
+    VERSChunk(const VERSChunk& other) = default;
+    VERSChunk& operator =(const VERSChunk& other) = default;
+
+    virtual bool isValid() const override;
+
+    QString value() const;
+
+    CHUNKID_DEFINE(VERS_CHUNK)
+
+protected:
+    virtual bool innerReadStructure(QIODevice *d) override;
+};
+
+#endif // KIMG_CHUNKS_P_H

src/imageformats/iff.cpp

@@ -0,0 +1,362 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2025 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#include "chunks_p.h"
+#include "iff_p.h"
+#include "util_p.h"
+
+#include <QIODevice>
+#include <QImage>
+#include <QLoggingCategory>
+#include <QPainter>
+
+#ifdef QT_DEBUG
+Q_LOGGING_CATEGORY(LOG_IFFPLUGIN, "kf.imageformats.plugins.iff", QtInfoMsg)
+#else
+Q_LOGGING_CATEGORY(LOG_IFFPLUGIN, "kf.imageformats.plugins.iff", QtWarningMsg)
+#endif
+
+class IFFHandlerPrivate
+{
+public:
+    IFFHandlerPrivate() {}
+    ~IFFHandlerPrivate() {}
+
+    bool readStructure(QIODevice *d) {
+        if (d == nullptr) {
+            return {};
+        }
+
+        if (!_chunks.isEmpty()) {
+            return true;
+        }
+
+        auto ok = false;
+        auto chunks = IFFChunk::fromDevice(d, &ok);
+        if (ok) {
+            _chunks = chunks;
+        }
+        return ok;
+    }
+
+    template <class T>
+    static QList<const T*> searchForms(const IFFChunk::ChunkList &chunks, bool supportedOnly = true) {
+        QList<const T*> list;
+        auto cid = T::defaultChunkId();
+        auto forms = IFFChunk::search(cid, chunks);
+        for (auto &&form : forms) {
+            if (auto f = dynamic_cast<const T*>(form.data()))
+                if (!supportedOnly || f->isSupported())
+                    list << f;
+        }
+        return list;
+    }
+
+    template <class T>
+    QList<const T*> searchForms(bool supportedOnly = true) {
+        return searchForms<T>(_chunks, supportedOnly);
+    }
+
+    IFFChunk::ChunkList _chunks;
+};
+
+
+IFFHandler::IFFHandler()
+    : QImageIOHandler()
+    , d(new IFFHandlerPrivate)
+{
+}
+
+bool IFFHandler::canRead() const
+{
+    if (canRead(device())) {
+        setFormat("iff");
+        return true;
+    }
+    return false;
+}
+
+bool IFFHandler::canRead(QIODevice *device)
+{
+    if (!device) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::canRead() called with no device";
+        return false;
+    }
+
+    if (device->isSequential()) {
+        return false;
+    }
+
+    auto ok = false;
+    auto pos = device->pos();
+    auto chunks = IFFChunk::fromDevice(device, &ok);
+    if (!device->seek(pos)) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::canRead() unable to reset device position";
+    }
+    if (ok) {
+        auto forms = IFFHandlerPrivate::searchForms<FORMChunk>(chunks, true);
+        auto for4s = IFFHandlerPrivate::searchForms<FOR4Chunk>(chunks, true);
+        ok = !forms.isEmpty() || !for4s.isEmpty();
+    }
+    return ok;
+}
+
+void addMetadata(QImage& img, const IFFChunk *form)
+{
+    auto dates = IFFChunk::searchT<DATEChunk>(form);
+    if (!dates.isEmpty()) {
+        auto dt = dates.first()->value();
+        if (dt.isValid()) {
+            img.setText(QStringLiteral(META_KEY_CREATIONDATE), dt.toString(Qt::ISODate));
+        }
+    }
+    auto auths = IFFChunk::searchT<AUTHChunk>(form);
+    if (!auths.isEmpty()) {
+        auto auth = auths.first()->value();
+        if (!auth.isEmpty()) {
+            img.setText(QStringLiteral(META_KEY_AUTHOR), auth);
+        }
+    }
+    auto vers = IFFChunk::searchT<VERSChunk>(form);
+    if (!vers.isEmpty()) {
+        auto ver = vers.first()->value();
+        if (!vers.isEmpty()) {
+            img.setText(QStringLiteral(META_KEY_SOFTWARE), ver);
+        }
+    }
+}
+
+bool IFFHandler::readStandardImage(QImage *image)
+{
+    auto forms = d->searchForms<FORMChunk>();
+    if (forms.isEmpty()) {
+        return false;
+    }
+    auto &&form = forms.first();
+
+    // show the first one (I don't have a sample with many images)
+    auto headers = IFFChunk::searchT<BMHDChunk>(form);
+    if (headers.isEmpty()) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readStandardImage() no supported image found";
+        return false;
+    }
+
+    // create the image
+    auto &&header = headers.first();
+    auto img = imageAlloc(header->size(), form->format());
+    if (img.isNull()) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readStandardImage() error while allocating the image";
+        return false;
+    }
+
+    // resolution
+    auto dpis = IFFChunk::searchT<DPIChunk>(form);
+    if (!dpis.isEmpty()) {
+        auto &&dpi = dpis.first();
+        if (dpi->isValid()) {
+            img.setDotsPerMeterX(dpi->dotsPerMeterX());
+            img.setDotsPerMeterY(dpi->dotsPerMeterY());
+        }
+    }
+
+    // set color table
+    auto cmaps = IFFChunk::searchT<CMAPChunk>(form);
+    if (img.format() == QImage::Format_Indexed8) {
+        if (!cmaps.isEmpty())
+            if (auto &&cmap = cmaps.first())
+                img.setColorTable(cmap->palette());
+    }
+
+    auto bodies = IFFChunk::searchT<BODYChunk>(form);
+    if (bodies.isEmpty()) {
+        img.fill(0);
+    } else {
+        const CAMGChunk *camg = nullptr;
+        auto camgs = IFFChunk::searchT<CAMGChunk>(form);
+        if (!camgs.isEmpty()) {
+            camg = camgs.first();
+        }
+
+        const CMAPChunk *cmap = nullptr;
+        if (!cmaps.isEmpty())
+            cmap = cmaps.first();
+
+        auto &&body = bodies.first();
+        if (!body->resetStrideRead(device())) {
+            qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readStandardImage() error while reading image data";
+            return false;
+        }
+        for (auto y = 0, h = img.height(); y < h; ++y) {
+            auto line = reinterpret_cast<char*>(img.scanLine(y));
+            auto ba = body->strideRead(device(), header, camg, cmap);
+            if (ba.isEmpty()) {
+                qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readStandardImage() error while reading image scanline";
+                return false;
+            }
+            memcpy(line, ba.constData(), std::min(img.bytesPerLine(), ba.size()));
+        }
+    }
+
+    addMetadata(img, form);
+
+    *image = img;
+    return true;
+}
+
+bool IFFHandler::readMayaImage(QImage *image)
+{
+    auto forms = d->searchForms<FOR4Chunk>();
+    if (forms.isEmpty()) {
+        return false;
+    }
+    auto &&form = forms.first();
+
+    // show the first one (I don't have a sample with many images)
+    auto headers = IFFChunk::searchT<TBHDChunk>(form);
+    if (headers.isEmpty()) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() no supported image found";
+        return false;
+    }
+
+    // create the image
+    auto &&header = headers.first();
+    auto img = imageAlloc(header->size(), form->format());
+    if (img.isNull()) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() error while allocating the image";
+        return false;
+    }
+
+    auto &&tiles = IFFChunk::searchT<RGBAChunk>(form);
+    if ((tiles.size() & 0xFFFF) != header->tiles()) { // Photoshop, on large images saves more than 65535 tiles
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() tile number mismatch: found" << tiles.size() << "while expected" << header->tiles();
+        return false;
+    }
+    for (auto &&tile : tiles) {
+        auto tp = tile->pos();
+        auto ts = tile->size();
+        if (tp.x() < 0 || tp.x() + ts.width() > img.width()) {
+            qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() wrong tile position or size";
+            return false;
+        }
+        if (tp.y() < 0 || tp.y() + ts.height() > img.height()) {
+            qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() wrong tile position or size";
+            return false;
+        }
+        // For future releases: it might be a good idea not to use a QPainter
+        auto ti = tile->tile(device(), header);
+        if (ti.isNull()) {
+            qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readMayaImage() error while decoding the tile";
+            return false;
+        }
+        QPainter painter(&img);
+        painter.setCompositionMode(QPainter::CompositionMode_Source);
+        painter.drawImage(tp, ti);
+    }
+#if QT_VERSION < QT_VERSION_CHECK(6, 9, 0)
+    img.mirror(false, true);
+#else
+    img.flip(Qt::Orientation::Vertical);
+#endif
+    addMetadata(img, form);
+
+    *image = img;
+    return true;
+}
+
+bool IFFHandler::read(QImage *image)
+{
+    if (!d->readStructure(device())) {
+        qCWarning(LOG_IFFPLUGIN) << "IFFHandler::read() invalid IFF structure";
+        return false;
+    }
+
+    if (readStandardImage(image)) {
+        return true;
+    }
+
+    if (readMayaImage(image)) {
+        return true;
+    }
+
+    qCWarning(LOG_IFFPLUGIN) << "IFFHandler::read() no supported image found";
+    return false;
+}
+
+bool IFFHandler::supportsOption(ImageOption option) const
+{
+    if (option == QImageIOHandler::Size) {
+        return true;
+    }
+    if (option == QImageIOHandler::ImageFormat) {
+        return true;
+    }
+    return false;
+}
+
+QVariant IFFHandler::option(ImageOption option) const
+{
+    QVariant v;
+
+    if (option == QImageIOHandler::Size) {
+        if (d->readStructure(device())) {
+            auto forms = d->searchForms<FORMChunk>();
+            if (!forms.isEmpty())
+                if (auto &&form = forms.first())
+                    v = QVariant::fromValue(form->size());
+
+            auto for4s = d->searchForms<FOR4Chunk>();
+            if (!for4s.isEmpty())
+                if (auto &&form = for4s.first())
+                    v = QVariant::fromValue(form->size());
+        }
+    }
+
+    if (option == QImageIOHandler::ImageFormat) {
+        if (d->readStructure(device())) {
+            auto forms = d->searchForms<FORMChunk>();
+            if (!forms.isEmpty())
+                if (auto &&form = forms.first())
+                    v = QVariant::fromValue(form->format());
+
+            auto for4s = d->searchForms<FOR4Chunk>();
+            if (!for4s.isEmpty())
+                if (auto &&form = for4s.first())
+                    v = QVariant::fromValue(form->format());
+        }
+    }
+
+    return v;
+}
+
+QImageIOPlugin::Capabilities IFFPlugin::capabilities(QIODevice *device, const QByteArray &format) const
+{
+    if (format == "iff") {
+        return Capabilities(CanRead);
+    }
+    if (!format.isEmpty()) {
+        return {};
+    }
+    if (!device->isOpen()) {
+        return {};
+    }
+
+    Capabilities cap;
+    if (device->isReadable() && IFFHandler::canRead(device)) {
+        cap |= CanRead;
+    }
+    return cap;
+}
+
+QImageIOHandler *IFFPlugin::create(QIODevice *device, const QByteArray &format) const
+{
+    QImageIOHandler *handler = new IFFHandler;
+    handler->setDevice(device);
+    handler->setFormat(format);
+    return handler;
+}
+
+#include "moc_iff_p.cpp"

src/imageformats/iff.json

@@ -0,0 +1,4 @@
+{
+    "Keys": [ "iff" ],
+    "MimeTypes": [ "application/x-iff" ]
+}

src/imageformats/iff_p.h

@@ -0,0 +1,47 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2025 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#ifndef KIMG_IFF_P_H
+#define KIMG_IFF_P_H
+
+#include <QImageIOPlugin>
+#include <QScopedPointer>
+
+class IFFHandlerPrivate;
+class IFFHandler : public QImageIOHandler
+{
+public:
+    IFFHandler();
+
+    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:
+    bool readStandardImage(QImage *image);
+
+    bool readMayaImage(QImage *image);
+
+private:
+    const QScopedPointer<IFFHandlerPrivate> d;
+};
+
+class IFFPlugin : public QImageIOPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "iff.json")
+
+public:
+    Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
+    QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
+};
+
+#endif // KIMG_IFF_P_H

src/imageformats/packbits_p.h

@@ -0,0 +1,111 @@
+/*
+    Packbits compression used on many legacy formats (IFF, PSD, TIFF).
+
+    SPDX-FileCopyrightText: 2025 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+#ifndef PACKBITS_P_H
+#define PACKBITS_P_H
+
+#include <QIODevice>
+
+/*!
+ * \brief packbitsDecompress
+ * Fast PackBits decompression.
+ * \param input The compressed input buffer.
+ * \param ilen The input buffer size.
+ * \param output The uncompressed target buffer.
+ * \param olen The target buffer size.
+ * \param allowN128 If true, -128 is a valid run length size (false for PSD / TIFF, true for IFF) .
+ * \return The number of valid bytes in the target buffer.
+ */
+inline qint64 packbitsDecompress(const char *input, qint64 ilen, char *output, qint64 olen, bool allowN128 = false)
+{
+    qint64  j = 0;
+    for (qint64 ip = 0, rr = 0, available = olen; j < olen && ip < ilen; available = olen - j) {
+        signed char n = static_cast<signed char>(input[ip++]);
+        if (n == -128 && !allowN128)
+            continue;
+
+        if (n >= 0) {
+            rr = qint64(n) + 1;
+            if (available < rr) {
+                --ip;
+                break;
+            }
+
+            if (ip + rr > ilen)
+                return -1;
+            memcpy(output + j, input + ip, size_t(rr));
+            ip += rr;
+        } else if (ip < ilen) {
+            rr = qint64(1-n);
+            if (available < rr) {
+                --ip;
+                break;
+            }
+            memset(output + j, input[ip++], size_t(rr));
+        }
+
+        j += rr;
+    }
+    return j;
+}
+
+/*!
+ * \brief packbitsDecompress
+ * PackBits decompression.
+ * \param input The input device.
+ * \param output The uncompressed target buffer.
+ * \param olen The target buffer size.
+ * \param allowN128 If true, -128 is a valid run length size (false for PSD / TIFF, true for IFF) .
+ * \return The number of valid bytes in the target buffer.
+ */
+inline qint64 packbitsDecompress(QIODevice *input, char *output, qint64 olen, bool allowN128 = false)
+{
+    qint64  j = 0;
+    for (qint64 rr = 0, available = olen; j < olen; available = olen - j) {
+        char n;
+
+        // check the output buffer space for the next run
+        if (available < 129) {
+            if (input->peek(&n, 1) != 1) { // end of data (or error)
+                break;
+            }
+            if (static_cast<signed char>(n) != -128 || allowN128)
+                if ((static_cast<signed char>(n) >= 0 ? qint64(n) + 1 : qint64(1 - n)) > available)
+                    break;
+        }
+
+        // decompress
+        if (input->read(&n, 1) != 1) { // end of data (or error)
+            break;
+        }
+
+        if (static_cast<signed char>(n) == -128 && !allowN128) {
+            continue;
+        }
+
+        if (static_cast<signed char>(n) >= 0) {
+            rr = input->read(output + j, qint64(n) + 1);
+            if (rr == -1) {
+                return -1;
+            }
+        }
+        else {
+            char b;
+            if (input->read(&b, 1) != 1) {
+                break;
+            }
+            rr = qint64(1 - static_cast<signed char>(n));
+            std::memset(output + j, b, size_t(rr));
+        }
+
+        j += rr;
+    }
+    return j;
+}
+
+
+#endif // PACKBITS_P_H

src/imageformats/psd.cpp

@@ -28,6 +28,7 @@
 
 #include "fastmath_p.h"
 #include "microexif_p.h"
+#include "packbits_p.h"
 #include "psd_p.h"
 #include "scanlineconverter_p.h"
 #include "util_p.h"
@@ -712,48 +713,6 @@ static bool IsSupported(const PSDHeader &header)
     return true;
 }
 
-/*!
- * \brief decompress
- * Fast PackBits decompression.
- * \param input The compressed input buffer.
- * \param ilen The input buffer size.
- * \param output The uncompressed target buffer.
- * \param olen The target buffer size.
- * \return The number of valid bytes in the target buffer.
- */
-qint64 decompress(const char *input, qint64 ilen, char *output, qint64 olen)
-{
-    qint64  j = 0;
-    for (qint64 ip = 0, rr = 0, available = olen; j < olen && ip < ilen; available = olen - j) {
-        signed char n = static_cast<signed char>(input[ip++]);
-        if (n == -128)
-            continue;
-
-        if (n >= 0) {
-            rr = qint64(n) + 1;
-            if (available < rr) {
-                --ip;
-                break;
-            }
-
-            if (ip + rr > ilen)
-                return -1;
-            memcpy(output + j, input + ip, size_t(rr));
-            ip += rr;
-        } else if (ip < ilen) {
-            rr = qint64(1-n);
-            if (available < rr) {
-                --ip;
-                break;
-            }
-            memset(output + j, input[ip++], size_t(rr));
-        }
-
-        j += rr;
-    }
-    return j;
-}
-
 /*!
  * \brief imageFormat
  * \param header The PSD header.
@@ -1102,7 +1061,7 @@ bool readChannel(QByteArray &target, QDataStream &stream, quint32 compressedSize
         if (stream.readRawData(tmp.data(), tmp.size()) != tmp.size()) {
             return false;
         }
-        if (decompress(tmp.data(), tmp.size(), target.data(), target.size()) < 0) {
+        if (packbitsDecompress(tmp.data(), tmp.size(), target.data(), target.size()) < 0) {
             return false;
         }
     } else if (stream.readRawData(target.data(), target.size()) != target.size()) {