Add documentation for wxImageHandler derivations

This makes it possible to wrap these classes automatically

It also documents wxGIFHandler::SaveAnimation() which wasn't previously
documented at all, even implicitly and so closes #16424.

Closes https://github.com/wxWidgets/wxWidgets/pull/511

interface/wx/imaggif.h

@@ -0,0 +1,55 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imaggif.h 
+// Purpose:     interface of wxGIFHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+#define wxIMAGE_OPTION_GIF_COMMENT wxT("GifComment")
+
+/**
+    @class wxGIFHandler
+
+    This is the image handler for the GIF format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxGIFHandler : public wxImageHandler
+{
+public:
+    /**
+    Default constructor for wxGIFHandler
+    */
+    wxGIFHandler();
+
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose = true, 
+                            int index = -1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+    /**
+        Save the animated gif.
+        
+        @param images
+            The image array object which is to be affected by this operation.
+        @param stream
+            Opened output stream for writing the data.
+        @param verbose
+            If set to @true, errors reported by the image handler will produce wxLogMessages
+        @param delayMilliSecs
+            How long, in milliseconds, to wait between each frame.
+
+
+        @return @true if the operation succeeded, @false otherwise.
+
+    */
+    bool SaveAnimation(const wxImageArray& images, wxOutputStream *stream,
+                        bool verbose = true, int delayMilliSecs = 1000);
+
+protected:
+    // allow parent class documentation to overwrite.
+    virtual int DoGetImageCount(wxInputStream& stream);
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagiff.h

@@ -0,0 +1,31 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagiff.h 
+// Purpose:     interface of wxIFFHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxIFFHandler
+
+    This is the image handler for the IFF format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxIFFHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxIFFHandler
+    */
+    wxIFFHandler();
+
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagjpeg.h

@@ -0,0 +1,40 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagjpeg.h 
+// Purpose:     interface of wxJPEGHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxJPEGHandler
+
+    This is the image handler for the JPEG format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxJPEGHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxJPEGHandler
+    */
+    wxJPEGHandler();
+    
+    /**
+        Retrieve the version information about the JPEG library used by this
+        handler.
+
+        @since 2.9.2
+    */
+    static wxVersionInfo GetLibraryVersionInfo();
+
+    // allow the parent class's documentation through.
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagpcx.h

@@ -0,0 +1,32 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagpcx.h 
+// Purpose:     interface of wxPCXHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxPCXHandler
+
+    This is the image handler for the PCX format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxPCXHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxPCXHandler
+    */
+    wxPCXHandler();
+
+    // allow the parent class's documentation through.
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagpng.h

@@ -0,0 +1,52 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagpng.h 
+// Purpose:     interface of wxPNGHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+#define wxIMAGE_OPTION_PNG_FORMAT                   wxT("PngFormat")
+#define wxIMAGE_OPTION_PNG_BITDEPTH                 wxT("PngBitDepth")
+#define wxIMAGE_OPTION_PNG_FILTER                   wxT("PngF")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_LEVEL        wxT("PngZL")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_MEM_LEVEL    wxT("PngZM")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_STRATEGY     wxT("PngZS")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_BUFFER_SIZE  wxT("PngZB")
+
+/* These are already in interface/wx/image.h
+    They were likely put there as a stopgap, but they've been there long enough
+    that that location trumps moving them here.
+enum
+{
+    wxPNG_TYPE_COLOUR = 0,
+    wxPNG_TYPE_GREY = 2,
+    wxPNG_TYPE_GREY_RED = 3,
+    wxPNG_TYPE_PALETTE = 4
+};
+*/
+
+/**
+    @class wxPNGHandler
+
+    This is the image handler for the PNG format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxPNGHandler : public wxImageHandler
+{
+public:
+    /**
+    Default constructor for wxPNGHandler
+    */
+    wxPNGHandler();
+
+    // let parent class's documentation through.
+    virtual bool LoadFile( wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1 );
+    virtual bool SaveFile( wxImage *image, wxOutputStream& stream, bool verbose=true );
+
+protected:
+    virtual bool DoCanRead( wxInputStream& stream );
+};

interface/wx/imagpnm.h

@@ -0,0 +1,32 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagpnm.h 
+// Purpose:     interface of wxPNMHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxPNMHandler
+
+    This is the image handler for the PNM format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxPNMHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxPNMHandler
+    */
+    wxPNMHandler();
+
+    // allow the parent class's documentation through.
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagtga.h

@@ -0,0 +1,32 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagtga.h 
+// Purpose:     interface of wxTGAHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxTGAHandler
+
+    This is the image handler for the TGA format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxTGAHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxTGAHandler
+    */
+    wxTGAHandler();
+
+    // allow the parent class's documentation through.
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};

interface/wx/imagtiff.h

@@ -0,0 +1,48 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        imagtiff.h
+// Purpose:     interface of wxTIFFHandler
+// Author:      Samuel Dunn
+// Licence:     wxWindows licence
+////////////////////////////////////////////////////////////////////////////
+
+#define wxIMAGE_OPTION_TIFF_BITSPERSAMPLE           wxString("BitsPerSample")
+#define wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL         wxString("SamplesPerPixel")
+#define wxIMAGE_OPTION_TIFF_COMPRESSION             wxString("Compression")
+#define wxIMAGE_OPTION_TIFF_PHOTOMETRIC             wxString("Photometric")
+#define wxIMAGE_OPTION_TIFF_IMAGEDESCRIPTOR         wxString("ImageDescriptor")
+
+/**
+    @class wxTIFFHandler
+    
+    This is the image handler for the TIFF format.
+    
+    @library{wxcore}
+    @category{gdi}
+    
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxTIFFHandler : public wxImageHandler
+{
+public:
+    /**
+    Default constructor for wxTIFFHandler
+    */
+    wxTIFFHandler();
+    
+    /**
+        Retrieve the version information about the TIFF library used by this
+        handler.
+
+        @since 2.9.2
+    */
+    static wxVersionInfo GetLibraryVersionInfo();
+    
+    // let the parent class' (wxImageHandler) documentation through for these methods
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    
+protected:
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+    virtual int DoGetImageCount(wxInputStream& stream);
+    virtual bool DoCanRead(wxInputStream& stream);
+};
+

interface/wx/imagxpm.h

@@ -0,0 +1,32 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagxpm.h 
+// Purpose:     interface of wxXPMHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+/** 
+    @class wxXPMHandler
+
+    This is the image handler for the XPM format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxXPMHandler : public wxImageHandler
+{
+public:
+    /**
+        Default constructor for wxXPMHandler
+    */
+    wxXPMHandler();
+
+    // allow the parent class's documentation through.
+    virtual bool LoadFile(wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1);
+    virtual bool SaveFile(wxImage *image, wxOutputStream& stream, bool verbose=true);
+
+protected:
+    virtual bool DoCanRead(wxInputStream& stream);
+};