image.cpp

A*算法 A*算法 A*算法 A*算法A*算法A*算法

                green = p;
                blue = hsv.value;
                break;

            default:    // case 5:
                red = hsv.value;
                green = p;
                blue = hsv.value * (1.0 - hsv.saturation * f);
                break;
        }
    }

    return RGBValue((unsigned char)(red * 255.0),
                    (unsigned char)(green * 255.0),
                    (unsigned char)(blue * 255.0));
}

/*
 * Rotates the hue of each pixel of the image. angle is a double in the range
 * -1.0..1.0 where -1.0 is -360 degrees and 1.0 is 360 degrees
 */
void wxImage::RotateHue(double angle)
{
    unsigned char *srcBytePtr;
    unsigned char *dstBytePtr;
    unsigned long count;
    wxImage::HSVValue hsv;
    wxImage::RGBValue rgb;

    wxASSERT (angle >= -1.0 && angle <= 1.0);
    count = M_IMGDATA->m_width * M_IMGDATA->m_height;
    if (count > 0 && angle != 0.0)
    {
        srcBytePtr = M_IMGDATA->m_data;
        dstBytePtr = srcBytePtr;
        do
        {
            rgb.red = *srcBytePtr++;
            rgb.green = *srcBytePtr++;
            rgb.blue = *srcBytePtr++;
            hsv = RGBtoHSV(rgb);

            hsv.hue = hsv.hue + angle;
            if (hsv.hue > 1.0)
                hsv.hue = hsv.hue - 1.0;
            else if (hsv.hue < 0.0)
                hsv.hue = hsv.hue + 1.0;

            rgb = HSVtoRGB(hsv);
            *dstBytePtr++ = rgb.red;
            *dstBytePtr++ = rgb.green;
            *dstBytePtr++ = rgb.blue;
        } while (--count != 0);
    }
}

//-----------------------------------------------------------------------------
// wxImageHandler
//-----------------------------------------------------------------------------

IMPLEMENT_ABSTRACT_CLASS(wxImageHandler,wxObject)

#if wxUSE_STREAMS
bool wxImageHandler::LoadFile( wxImage *WXUNUSED(image), wxInputStream& WXUNUSED(stream), bool WXUNUSED(verbose), int WXUNUSED(index) )
{
    return false;
}

bool wxImageHandler::SaveFile( wxImage *WXUNUSED(image), wxOutputStream& WXUNUSED(stream), bool WXUNUSED(verbose) )
{
    return false;
}

int wxImageHandler::GetImageCount( wxInputStream& WXUNUSED(stream) )
{
    return 1;
}

bool wxImageHandler::CanRead( const wxString& name )
{
    if (wxFileExists(name))
    {
        wxFileInputStream stream(name);
        return CanRead(stream);
    }

    wxLogError( _("Can't check image format of file '%s': file does not exist."), name.c_str() );

    return false;
}

bool wxImageHandler::CallDoCanRead(wxInputStream& stream)
{
    wxFileOffset posOld = stream.TellI();
    if ( posOld == wxInvalidOffset )
    {
        // can't test unseekable stream
        return false;
    }

    bool ok = DoCanRead(stream);

    // restore the old position to be able to test other formats and so on
    if ( stream.SeekI(posOld) == wxInvalidOffset )
    {
        wxLogDebug(_T("Failed to rewind the stream in wxImageHandler!"));

        // reading would fail anyhow as we're not at the right position
        return false;
    }

    return ok;
}

#endif // wxUSE_STREAMS

// ----------------------------------------------------------------------------
// image histogram stuff
// ----------------------------------------------------------------------------

bool
wxImageHistogram::FindFirstUnusedColour(unsigned char *r,
                                        unsigned char *g,
                                        unsigned char *b,
                                        unsigned char r2,
                                        unsigned char b2,
                                        unsigned char g2) const
{
    unsigned long key = MakeKey(r2, g2, b2);

    while ( find(key) != end() )
    {
        // color already used
        r2++;
        if ( r2 >= 255 )
        {
            r2 = 0;
            g2++;
            if ( g2 >= 255 )
            {
                g2 = 0;
                b2++;
                if ( b2 >= 255 )
                {
                    wxLogError(_("No unused colour in image.") );
                    return false;
                }
            }
        }

        key = MakeKey(r2, g2, b2);
    }

    if ( r )
        *r = r2;
    if ( g )
        *g = g2;
    if ( b )
        *b = b2;

    return true;
}

bool
wxImage::FindFirstUnusedColour(unsigned char *r,
                               unsigned char *g,
                               unsigned char *b,
                               unsigned char r2,
                               unsigned char b2,
                               unsigned char g2) const
{
    wxImageHistogram histogram;

    ComputeHistogram(histogram);

    return histogram.FindFirstUnusedColour(r, g, b, r2, g2, b2);
}



// GRG, Dic/99
// Counts and returns the number of different colours. Optionally stops
// when it exceeds 'stopafter' different colours. This is useful, for
// example, to see if the image can be saved as 8-bit (256 colour or
// less, in this case it would be invoked as CountColours(256)). Default
// value for stopafter is -1 (don't care).
//
unsigned long wxImage::CountColours( unsigned long stopafter ) const
{
    wxHashTable h;
    wxObject dummy;
    unsigned char r, g, b;
    unsigned char *p;
    unsigned long size, nentries, key;

    p = GetData();
    size = GetWidth() * GetHeight();
    nentries = 0;

    for (unsigned long j = 0; (j < size) && (nentries <= stopafter) ; j++)
    {
        r = *(p++);
        g = *(p++);
        b = *(p++);
        key = wxImageHistogram::MakeKey(r, g, b);

        if (h.Get(key) == NULL)
        {
            h.Put(key, &dummy);
            nentries++;
        }
    }

    return nentries;
}


unsigned long wxImage::ComputeHistogram( wxImageHistogram &h ) const
{
    unsigned char *p = GetData();
    unsigned long nentries = 0;

    h.clear();

    const unsigned long size = GetWidth() * GetHeight();

    unsigned char r, g, b;
    for ( unsigned long n = 0; n < size; n++ )
    {
        r = *p++;
        g = *p++;
        b = *p++;

        wxImageHistogramEntry& entry = h[wxImageHistogram::MakeKey(r, g, b)];

        if ( entry.value++ == 0 )
            entry.index = nentries++;
    }

    return nentries;
}

/*
 * Rotation code by Carlos Moreno
 */

// GRG: I've removed wxRotationPoint - we already have wxRealPoint which
//      does exactly the same thing. And I also got rid of wxRotationPixel
//      bacause of potential problems in architectures where alignment
//      is an issue, so I had to rewrite parts of the code.

static const double gs_Epsilon = 1e-10;

static inline int wxCint (double x)
{
    return (x > 0) ? (int) (x + 0.5) : (int) (x - 0.5);
}


// Auxiliary function to rotate a point (x,y) with respect to point p0
// make it inline and use a straight return to facilitate optimization
// also, the function receives the sine and cosine of the angle to avoid
// repeating the time-consuming calls to these functions -- sin/cos can
// be computed and stored in the calling function.

inline wxRealPoint rotated_point (const wxRealPoint & p, double cos_angle, double sin_angle, const wxRealPoint & p0)
{
    return wxRealPoint (p0.x + (p.x - p0.x) * cos_angle - (p.y - p0.y) * sin_angle,
                        p0.y + (p.y - p0.y) * cos_angle + (p.x - p0.x) * sin_angle);
}

inline wxRealPoint rotated_point (double x, double y, double cos_angle, double sin_angle, const wxRealPoint & p0)
{
    return rotated_point (wxRealPoint(x,y), cos_angle, sin_angle, p0);
}

wxImage wxImage::Rotate(double angle, const wxPoint & centre_of_rotation, bool interpolating, wxPoint * offset_after_rotation) const
{
    int i;
    angle = -angle;     // screen coordinates are a mirror image of "real" coordinates

    bool has_alpha = HasAlpha();

    // Create pointer-based array to accelerate access to wxImage's data
    unsigned char ** data = new unsigned char * [GetHeight()];
    data[0] = GetData();
    for (i = 1; i < GetHeight(); i++)
        data[i] = data[i - 1] + (3 * GetWidth());

    // Same for alpha channel
    unsigned char ** alpha = NULL;
    if (has_alpha)
    {
        alpha = new unsigned char * [GetHeight()];
        alpha[0] = GetAlpha();
        for (i = 1; i < GetHeight(); i++)
            alpha[i] = alpha[i - 1] + GetWidth();
    }

    // precompute coefficients for rotation formula
    // (sine and cosine of the angle)
    const double cos_angle = cos(angle);
    const double sin_angle = sin(angle);

    // Create new Image to store the result
    // First, find rectangle that covers the rotated image;  to do that,
    // rotate the four corners

    const wxRealPoint p0(centre_of_rotation.x, centre_of_rotation.y);

    wxRealPoint p1 = rotated_point (0, 0, cos_angle, sin_angle, p0);
    wxRealPoint p2 = rotated_point (0, GetHeight(), cos_angle, sin_angle, p0);
    wxRealPoint p3 = rotated_point (GetWidth(), 0, cos_angle, sin_angle, p0);
    wxRealPoint p4 = rotated_point (GetWidth(), GetHeight(), cos_angle, sin_angle, p0);

    int x1 = (int) floor (wxMin (wxMin(p1.x, p2.x), wxMin(p3.x, p4.x)));
    int y1 = (int) floor (wxMin (wxMin(p1.y, p2.y), wxMin(p3.y, p4.y)));
    int x2 = (int) ceil (wxMax (wxMax(p1.x, p2.x), wxMax(p3.x, p4.x)));
    int y2 = (int) ceil (wxMax (wxMax(p1.y, p2.y), wxMax(p3.y, p4.y)));

    // Create rotated image
    wxImage rotated (x2 - x1 + 1, y2 - y1 + 1, false);
    // With alpha channel
    if (has_alpha)
        rotated.SetAlpha();

    if (offset_after_rotation != NULL)
    {
        *offset_after_rotation = wxPoint (x1, y1);
    }

    // GRG: The rotated (destination) image is always accessed
    //      sequentially, so there is no need for a pointer-based
    //      array here (and in fact it would be slower).
    //
    unsigned char * dst = rotated.GetData();

    unsigned char * alpha_dst = NULL;
    if (has_alpha)
        alpha_dst = rotated.GetAlpha();

    // GRG: if the original image has a mask, use its RGB values
    //      as the blank pixel, else, fall back to default (black).
    //
    unsigned char blank_r = 0;
    unsigned char blank_g = 0;
    unsigned char blank_b = 0;

    if (HasMask())
    {
        blank_r = GetMaskRed();
        blank_g = GetMaskGreen();
        blank_b = GetMaskBlue();
        rotated.SetMaskColour( blank_r, blank_g, blank_b );
    }

    // Now, for each point of the rotated image, find where it came from, by
    // performing an inverse rotation (a rotation of -angle) and getting the
    // pixel at those coordinates

    // GRG: I've taken the (interpolating) test out of the loops, so that
    //      it is done only once, instead of repeating it for each pixel.

    int x;
    if (interpolating)
    {
        for (int y = 0; y < rotated.GetHeight(); y++)
        {
            for (x = 0; x < rotated.GetWidth(); x++)
            {
                wxRealPoint src = rotated_point (x + x1, y + y1, cos_angle, -sin_angle, p0);

                if (-0.25 < src.x && src.x < GetWidth() - 0.75 &&
                    -0.25 < src.y && src.y < GetHeight() - 0.75)
                {
                    // interpolate using the 4 enclosing grid-points.  Those
                    // points can be obtained using floor and ceiling of the
                    // exact coordinates of the point
                        // C.M. 2000-02-17:  when the point is near the border, special care is required.

                    int x1, y1, x2, y2;

                    if (0 < src.x && src.x < GetWidth() - 1)
                    {
                        x1 = wxCint(floor(src.x));
                        x2 = wxCint(ceil(src.x));
                    }
                    else    // else means that x is near one of the borders (0 or width-1)
                    {
                        x1 = x2 = wxCint (src.x);
                    }

                    if (0 < src.y && src.y < GetHeight() - 1)
                    {
                        y1 = wxCint(floor(src.y));
                        y2 = wxCint(ceil(src.y));
                    }
                    else
                    {
                        y1 = y2 = wxCint (src.y);
                    }

                    // get four points and the distances (square of the distance,
                    // for efficiency reasons) for the interpolation formula

                    // GRG: Do not calculate the points until they are
                    //      really needed -- this way we can calculate
                    //      just one, instead of four, if d1, d2, d3
                    //      or d4 are < gs_Epsilon

                    const double d1 = (src.x - x1) * (src.x - x1) + (src.y - y1) * (src.y - y1);
                    const double d2 = (src.x - x2) * (src.x - x2) + (src.y - y1) * (src.y - y1);
                    const double d3 = (src.x - x2) * (src.x - x2) + (src.y - y2) * (src.y - y2);
                    const double d4 = (src.x - x1) * (src.x - x1) + (src.y - y2) * (src.y - y2);

                    // Now interpolate as a weighted average of the four surrounding
                    // points, where the weights are the distances to each of those points

                    // If the point is exactly at one point of the grid of the source
                    // image, then don't interpolate -- just assign the pixel

                    if (d1 < gs_Epsilon)        // d1,d2,d3,d4 are positive -- no need for abs()
                    {
                        unsigned char *p = data[y1] + (3 * x1);
                        *(dst++) = *(p++);
                        *(dst++) = *(p++);
                        *(dst++) = *p;

                        if (has_alpha)
                        {
                            unsigned char *p = alpha[y1] + x1;
                            *(alpha_dst++) = *p;
                        }
                    }
                    else if (d2 < gs_Epsilon)
                    {
                        unsigned char *p = data[y1] + (3 * x2);
                        *(dst++) = *(p++);
                        *(dst++) = *(p++);
                        *(dst++) = *p;

                        if (has_alpha)
                        {
                            unsigned char *p = alpha[y1] + x2;
                            *(alpha_dst++) = *p;
                        }
                    }
                    else if (d3 < gs_Epsilon)
                    {
                        unsigned char *p = data[y2] + (3 * x2);
                        *(dst++) = *(p++);
                        *(dst++) = *(p++);
                        *(dst++) = *p;

                        if (has_alpha)
                        {
                            unsigned char *p = alpha[y2] + x2;
                            *(alpha_dst++) = *p;
                        }
                    }
                    else if (d4 < gs_Epsilon)
                    {
                        unsigned char *p = data[y2] + (3 * x1);
                        *(dst++) = *(p++);
                        *(dst++) = *(p++);
                        *(dst++) = *p;

                        if (h