the_application(agg::pix_format_e format, bool flip_y)
: agg::platform_support(format, flip_y),
m_gamma(5.0, 5.0, 340.0, 12.0, !flip_y),
m_mouse_x(200),
m_mouse_y(200) {
m_gamma.range(0.5, 2.5);
m_gamma.value(1.0);
m_gamma.label("Gamma = %.3f");
add_ctrl(m_gamma);
m_gamma.no_transform();
m_gamma_lut.gamma(m_gamma.value());
m_old_gamma = m_gamma.value();
build_gradient_lut();
}
virtual void on_draw()
{
pixfmt pixf(rbuf_window());
renderer_base rb(pixf);
renderer_solid rs(rb);
rb.clear(agg::rgba(1, 1, 1));
// When Gamma changes rebuild the gamma and gradient LUTs
//------------------
if(m_old_gamma != m_gamma.value())
{
m_gamma_lut.gamma(m_gamma.value());
build_gradient_lut();
m_old_gamma = m_gamma.value();
}
// Gradient center. All gradient functions assume the
// center being in the origin (0,0) and you can't
// change it. But you can apply arbitrary transformations
// to the gradient (see below).
//------------------
double cx = initial_width() / 2;
double cy = initial_height() / 2;
double r = 100;
// Focal center. Defined in the gradient coordinates,
// that is, with respect to the origin (0,0)
//------------------
double fx = m_mouse_x - cx;
double fy = m_mouse_y - cy;
gradient_func_type gradient_func(r, fx, fy);
gradient_adaptor_type gradient_adaptor(gradient_func);
agg::trans_affine gradient_mtx;
// Making the affine matrix. Move to (cx,cy),
// apply the resizing transformations and invert
// the matrix. Gradients and images always assume the
// inverse transformations.
//------------------
gradient_mtx.translate(cx, cy);
gradient_mtx *= trans_affine_resizing();
gradient_mtx.invert();
interpolator_type span_interpolator(gradient_mtx);
span_gradient_type span_gradient(span_interpolator,
gradient_adaptor,
m_gradient_lut,
0, r);
// Form the simple rectangle
//------------------
m_rasterizer.reset();
m_rasterizer.move_to_d(0,0);
m_rasterizer.line_to_d(width(), 0);
m_rasterizer.line_to_d(width(), height());
m_rasterizer.line_to_d(0, height());
// Render the gradient to the whole screen and measure the time
//------------------
start_timer();
agg::render_scanlines_aa(m_rasterizer, m_scanline, rb, m_alloc, span_gradient);
double tm = elapsed_time();
// Draw the transformed circle that shows the gradient boundary
//------------------
agg::ellipse e(cx, cy, r, r);
agg::conv_stroke<agg::ellipse> estr(e);
agg::conv_transform<
agg::conv_stroke<
agg::ellipse> > etrans(estr, trans_affine_resizing());
m_rasterizer.add_path(etrans);
agg::render_scanlines_aa_solid(m_rasterizer, m_scanline, rb, agg::rgba(1,1,1));
// Show the gradient time
//------------------
char buf[64];
agg::gsv_text t;
t.size(10.0);
agg::conv_stroke<agg::gsv_text> pt(t);
pt.width(1.5);
sprintf(buf, "%3.2f ms", tm);
t.start_point(10.0, 35.0);
t.text(buf);
m_rasterizer.add_path(pt);
agg::render_scanlines_aa_solid(m_rasterizer, m_scanline, rb, agg::rgba(0,0,0));
#if !LINEAR_RGB
// Show the controls
//------------------
agg::render_ctrl(m_rasterizer, m_scanline, rb, m_gamma);
// Apply the inverse gamma to the whole buffer
// (transform the colors to the perceptually uniform space)
//------------------
pixf.apply_gamma_inv(m_gamma_lut);
#endif
}
