pcsx2/common/EmbeddedImage.h

/*  PCSX2 - PS2 Emulator for PCs
 *  Copyright (C) 2002-2010  PCSX2 Dev Team
 *
 *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU Lesser General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  PCSX2 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with PCSX2.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include <wx/image.h>
#include <wx/mstream.h>
#include <wx/gdicmn.h>

//////////////////////////////////////////////////////////////////////////////////////////
// Interface for loadable embedded images.  See EmbeddedImage description for details.
//
class IEmbeddedImage
{
public:
    virtual const wxImage &Get() = 0;
    virtual wxImage Scale(int width, int height) = 0;
};

//////////////////////////////////////////////////////////////////////////////////////////
// EmbeddedImage - Helper class for loading images which have been embedded into the binary
// manifest of the executable file.  Images are only loaded when Get() is called,
// which allows this type to be passed to functions as a fallback or default action without
// incurring an unnecessary memory footprint.
//
// Note: Get() only loads the image once.  All subsequent calls to Get will use the
// previously loaded image data.
//
template <typename ImageType>
class EmbeddedImage : public IEmbeddedImage
{
protected:
    wxImage m_Image;
    const wxSize m_ResampleTo;

protected:
    // ------------------------------------------------------------------------
    // Internal function used to ensure the image is loaded before returning the image
    // handle (called from all methods that return an image handle).
    //
    void _loadImage()
    {
        if (!m_Image.Ok()) {
            wxMemoryInputStream joe(ImageType::Data, ImageType::Length);
            m_Image.LoadFile(joe, ImageType::GetFormat());

            if (m_ResampleTo.IsFullySpecified() && (m_ResampleTo.GetWidth() != m_Image.GetWidth() || m_ResampleTo.GetHeight() != m_Image.GetHeight()))
                m_Image.Rescale(m_ResampleTo.GetWidth(), m_ResampleTo.GetHeight(), wxIMAGE_QUALITY_HIGH);
        }
    }

public:
    EmbeddedImage()
        : m_Image()
        , m_ResampleTo(wxDefaultSize)
    {
    }

    // ------------------------------------------------------------------------
    // Constructor for creating an embedded image that gets resampled to the specified size when
    // loaded.
    //
    // Implementation Note: This function uses wxWidgets ResamplBox method to resize the image.
    // wxWidgets ResampleBicubic appears to be buggy and produces fairly poor results when down-
    // sampling images (basically resembles a pixel resize).  ResampleBox produces much cleaner
    // results.
    //
    EmbeddedImage(int newWidth, int newHeight)
        : m_Image()
        , m_ResampleTo(newWidth, newHeight)
    {
    }

    // ------------------------------------------------------------------------
    // Loads and retrieves the embedded image.  The embedded image is only loaded from its em-
    // bedded format once.  Any subsequent calls to Get(), Rescale(), or Resample() will use
    // the pre-loaded copy.  Translation: the png/jpeg decoding overhead happens only once,
    // and only happens when the image is actually fetched.  Simply creating an instance
    // of an EmbeddedImage object uses no excess memory nor cpu overhead. :)
    //
    const wxImage &Get()
    {
        _loadImage();
        return m_Image;
    }

    wxIcon GetIcon()
    {
        wxIcon retval;
        retval.CopyFromBitmap(Get());
        return retval;
    }

    // ------------------------------------------------------------------------
    // Performs a pixel resize of the loaded image and returns a new image handle (EmbeddedImage
    // is left unmodified).
    //

    wxImage Scale(int width, int height)
    {
        _loadImage();
        // Not strictly necessary - wxWidgets does the dimensions check anyway.
        if (width != m_Image.GetWidth() || height != m_Image.GetHeight())
            return m_Image.Scale(width, height, wxIMAGE_QUALITY_HIGH);
        else
            return m_Image;
    }
};