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agg_trans_viewport.h
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agg_trans_viewport.h
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//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//----------------------------------------------------------------------------
//
// Viewport transformer - simple orthogonal conversions from world coordinates
// to screen (device) ones.
//
//----------------------------------------------------------------------------
#ifndef AGG_TRANS_VIEWPORT_INCLUDED
#define AGG_TRANS_VIEWPORT_INCLUDED
#include <string.h>
#include "agg_trans_affine.h"
namespace agg
{
enum aspect_ratio_e
{
aspect_ratio_stretch,
aspect_ratio_meet,
aspect_ratio_slice
};
//----------------------------------------------------------trans_viewport
class trans_viewport
{
public:
//-------------------------------------------------------------------
trans_viewport() :
m_world_x1(0.0),
m_world_y1(0.0),
m_world_x2(1.0),
m_world_y2(1.0),
m_device_x1(0.0),
m_device_y1(0.0),
m_device_x2(1.0),
m_device_y2(1.0),
m_aspect(aspect_ratio_stretch),
m_is_valid(true),
m_align_x(0.5),
m_align_y(0.5),
m_wx1(0.0),
m_wy1(0.0),
m_wx2(1.0),
m_wy2(1.0),
m_dx1(0.0),
m_dy1(0.0),
m_kx(1.0),
m_ky(1.0)
{}
//-------------------------------------------------------------------
void preserve_aspect_ratio(double alignx,
double aligny,
aspect_ratio_e aspect)
{
m_align_x = alignx;
m_align_y = aligny;
m_aspect = aspect;
update();
}
//-------------------------------------------------------------------
void device_viewport(double x1, double y1, double x2, double y2)
{
m_device_x1 = x1;
m_device_y1 = y1;
m_device_x2 = x2;
m_device_y2 = y2;
update();
}
//-------------------------------------------------------------------
void world_viewport(double x1, double y1, double x2, double y2)
{
m_world_x1 = x1;
m_world_y1 = y1;
m_world_x2 = x2;
m_world_y2 = y2;
update();
}
//-------------------------------------------------------------------
void device_viewport(double* x1, double* y1, double* x2, double* y2) const
{
*x1 = m_device_x1;
*y1 = m_device_y1;
*x2 = m_device_x2;
*y2 = m_device_y2;
}
//-------------------------------------------------------------------
void world_viewport(double* x1, double* y1, double* x2, double* y2) const
{
*x1 = m_world_x1;
*y1 = m_world_y1;
*x2 = m_world_x2;
*y2 = m_world_y2;
}
//-------------------------------------------------------------------
void world_viewport_actual(double* x1, double* y1,
double* x2, double* y2) const
{
*x1 = m_wx1;
*y1 = m_wy1;
*x2 = m_wx2;
*y2 = m_wy2;
}
//-------------------------------------------------------------------
bool is_valid() const { return m_is_valid; }
double align_x() const { return m_align_x; }
double align_y() const { return m_align_y; }
aspect_ratio_e aspect_ratio() const { return m_aspect; }
//-------------------------------------------------------------------
void transform(double* x, double* y) const
{
*x = (*x - m_wx1) * m_kx + m_dx1;
*y = (*y - m_wy1) * m_ky + m_dy1;
}
//-------------------------------------------------------------------
void transform_scale_only(double* x, double* y) const
{
*x *= m_kx;
*y *= m_ky;
}
//-------------------------------------------------------------------
void inverse_transform(double* x, double* y) const
{
*x = (*x - m_dx1) / m_kx + m_wx1;
*y = (*y - m_dy1) / m_ky + m_wy1;
}
//-------------------------------------------------------------------
void inverse_transform_scale_only(double* x, double* y) const
{
*x /= m_kx;
*y /= m_ky;
}
//-------------------------------------------------------------------
double device_dx() const { return m_dx1 - m_wx1 * m_kx; }
double device_dy() const { return m_dy1 - m_wy1 * m_ky; }
//-------------------------------------------------------------------
double scale_x() const
{
return m_kx;
}
//-------------------------------------------------------------------
double scale_y() const
{
return m_ky;
}
//-------------------------------------------------------------------
double scale() const
{
return (m_kx + m_ky) * 0.5;
}
//-------------------------------------------------------------------
trans_affine to_affine() const
{
trans_affine mtx = trans_affine_translation(-m_wx1, -m_wy1);
mtx *= trans_affine_scaling(m_kx, m_ky);
mtx *= trans_affine_translation(m_dx1, m_dy1);
return mtx;
}
//-------------------------------------------------------------------
trans_affine to_affine_scale_only() const
{
return trans_affine_scaling(m_kx, m_ky);
}
//-------------------------------------------------------------------
unsigned byte_size() const
{
return sizeof(*this);
}
void serialize(int8u* ptr) const
{
memcpy(ptr, this, sizeof(*this));
}
void deserialize(const int8u* ptr)
{
memcpy(this, ptr, sizeof(*this));
}
private:
void update();
double m_world_x1;
double m_world_y1;
double m_world_x2;
double m_world_y2;
double m_device_x1;
double m_device_y1;
double m_device_x2;
double m_device_y2;
aspect_ratio_e m_aspect;
bool m_is_valid;
double m_align_x;
double m_align_y;
double m_wx1;
double m_wy1;
double m_wx2;
double m_wy2;
double m_dx1;
double m_dy1;
double m_kx;
double m_ky;
};
//-----------------------------------------------------------------------
inline void trans_viewport::update()
{
const double epsilon = 1e-30;
if(fabs(m_world_x1 - m_world_x2) < epsilon ||
fabs(m_world_y1 - m_world_y2) < epsilon ||
fabs(m_device_x1 - m_device_x2) < epsilon ||
fabs(m_device_y1 - m_device_y2) < epsilon)
{
m_wx1 = m_world_x1;
m_wy1 = m_world_y1;
m_wx2 = m_world_x1 + 1.0;
m_wy2 = m_world_y2 + 1.0;
m_dx1 = m_device_x1;
m_dy1 = m_device_y1;
m_kx = 1.0;
m_ky = 1.0;
m_is_valid = false;
return;
}
double world_x1 = m_world_x1;
double world_y1 = m_world_y1;
double world_x2 = m_world_x2;
double world_y2 = m_world_y2;
double device_x1 = m_device_x1;
double device_y1 = m_device_y1;
double device_x2 = m_device_x2;
double device_y2 = m_device_y2;
if(m_aspect != aspect_ratio_stretch)
{
double d;
m_kx = (device_x2 - device_x1) / (world_x2 - world_x1);
m_ky = (device_y2 - device_y1) / (world_y2 - world_y1);
if((m_aspect == aspect_ratio_meet) == (m_kx < m_ky))
{
d = (world_y2 - world_y1) * m_ky / m_kx;
world_y1 += (world_y2 - world_y1 - d) * m_align_y;
world_y2 = world_y1 + d;
}
else
{
d = (world_x2 - world_x1) * m_kx / m_ky;
world_x1 += (world_x2 - world_x1 - d) * m_align_x;
world_x2 = world_x1 + d;
}
}
m_wx1 = world_x1;
m_wy1 = world_y1;
m_wx2 = world_x2;
m_wy2 = world_y2;
m_dx1 = device_x1;
m_dy1 = device_y1;
m_kx = (device_x2 - device_x1) / (world_x2 - world_x1);
m_ky = (device_y2 - device_y1) / (world_y2 - world_y1);
m_is_valid = true;
}
}
#endif