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