Function example_illusion

test/test.cpp:2047–2076

}

void example_illusion( canvas &that, float width, float height )
{
    that.set_color( fill_style, 0.0f, 0.4f, 1.0f, 1.0f );
    that.fill_rectangle( 0.0f, 0.0f, width, height );
    that.set_color( fill_style, 0.8f, 0.8f, 0.0f, 1.0f );
    that.set_line_width( 0.4f );
    for ( float spot = 0.0f; spot < 240.0f; spot += 1.0f )
    {
        float angle = fmodf( spot * 0.61803398875f, 1.0f ) * 6.28318531f;
        float radius = spot / 240.0f * 0.5f * hypotf( width, height );
        float size = min( width, height ) * sqrtf( spot ) / 240.0f;
        that.set_transform( 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f );
        that.translate( 0.5f * width + radius * cosf( angle ),
                        0.5f * height + radius * sinf( angle ) );
        that.rotate( angle - 1.3f );
        that.scale( 0.8f * size, 0.6f * size );
        that.rotate( 1.3f );
        that.begin_path();
        that.arc( 0.0f, 0.0f, 1.0f, 0.0f, 6.28318531f );
        that.fill();
        that.begin_path();
        that.arc( 0.0f, 0.0f, 1.0f, 0.0f, 3.14159265f );
        that.set_color( stroke_style, 1.0f, 1.0f, 1.0f, 1.0f );
        that.stroke();
        that.begin_path();
        that.arc( 0.0f, 0.0f, 1.0f, 3.14159265f, 6.28318531f );
        that.set_color( stroke_style, 0.0f, 0.0f, 0.0f, 1.0f );
        that.stroke();
    }
}

void example_star( canvas &that, float width, float height )
{