ft2-computations.html

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<p>The angle pi expressed in <a href="ft2-computations.html#FT_Angle">FT_Angle</a> units.</p>
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<h4><a name="FT_ANGLE_2PI">FT_ANGLE_2PI</a></h4>
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#define <b>FT_ANGLE_2PI</b>  ( <a href="ft2-computations.html#FT_ANGLE_PI">FT_ANGLE_PI</a> * 2 )

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<p>The angle 2*pi expressed in <a href="ft2-computations.html#FT_Angle">FT_Angle</a> units.</p>
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<h4><a name="FT_ANGLE_PI2">FT_ANGLE_PI2</a></h4>
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#define <b>FT_ANGLE_PI2</b>  ( <a href="ft2-computations.html#FT_ANGLE_PI">FT_ANGLE_PI</a> / 2 )

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<p>The angle pi/2 expressed in <a href="ft2-computations.html#FT_Angle">FT_Angle</a> units.</p>
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<h4><a name="FT_ANGLE_PI4">FT_ANGLE_PI4</a></h4>
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#define <b>FT_ANGLE_PI4</b>  ( <a href="ft2-computations.html#FT_ANGLE_PI">FT_ANGLE_PI</a> / 4 )

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<p>The angle pi/4 expressed in <a href="ft2-computations.html#FT_Angle">FT_Angle</a> units.</p>
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<h4><a name="FT_Sin">FT_Sin</a></h4>
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  FT_EXPORT( <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a> )
  <b>FT_Sin</b>( <a href="ft2-computations.html#FT_Angle">FT_Angle</a>  angle );

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<p>Return the sinus of a given angle in fixed point format.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>angle</b></td><td>
<p>The input angle.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>The sinus value.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>note</b></em></td></tr><tr><td>
<p>If you need both the sinus and cosinus for a given angle, use the function <a href="ft2-computations.html#FT_Vector_Unit">FT_Vector_Unit</a>.</p>
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<h4><a name="FT_Cos">FT_Cos</a></h4>
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  FT_EXPORT( <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a> )
  <b>FT_Cos</b>( <a href="ft2-computations.html#FT_Angle">FT_Angle</a>  angle );

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<p>Return the cosinus of a given angle in fixed point format.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>angle</b></td><td>
<p>The input angle.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>The cosinus value.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>note</b></em></td></tr><tr><td>
<p>If you need both the sinus and cosinus for a given angle, use the function <a href="ft2-computations.html#FT_Vector_Unit">FT_Vector_Unit</a>.</p>
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<h4><a name="FT_Tan">FT_Tan</a></h4>
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  FT_EXPORT( <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a> )
  <b>FT_Tan</b>( <a href="ft2-computations.html#FT_Angle">FT_Angle</a>  angle );

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<p>Return the tangent of a given angle in fixed point format.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>angle</b></td><td>
<p>The input angle.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>The tangent value.</p>
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<h4><a name="FT_Atan2">FT_Atan2</a></h4>
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  FT_EXPORT( <a href="ft2-computations.html#FT_Angle">FT_Angle</a> )
  <b>FT_Atan2</b>( <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a>  x,
            <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a>  y );

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<p>Return the arc-tangent corresponding to a given vector (x,y) in the 2d plane.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>x</b></td><td>
<p>The horizontal vector coordinate.</p>
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<tr valign=top><td><b>y</b></td><td>
<p>The vertical vector coordinate.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>The arc-tangent value (i.e. angle).</p>
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<h4><a name="FT_Angle_Diff">FT_Angle_Diff</a></h4>
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  FT_EXPORT( <a href="ft2-computations.html#FT_Angle">FT_Angle</a> )
  <b>FT_Angle_Diff</b>( <a href="ft2-computations.html#FT_Angle">FT_Angle</a>  angle1,
                 <a href="ft2-computations.html#FT_Angle">FT_Angle</a>  angle2 );

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<p>Return the difference between two angles. The result is always constrained to the ]-PI..PI] interval.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>angle1</b></td><td>
<p>First angle.</p>
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<tr valign=top><td><b>angle2</b></td><td>
<p>Second angle.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>Contrainted value of `value2-value1'.</p>
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<h4><a name="FT_Vector_Unit">FT_Vector_Unit</a></h4>
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  FT_EXPORT( <span class="keyword">void</span> )
  <b>FT_Vector_Unit</b>( <a href="ft2-basic_types.html#FT_Vector">FT_Vector</a>*  vec,
                  <a href="ft2-computations.html#FT_Angle">FT_Angle</a>    angle );

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<p>Return the unit vector corresponding to a given angle. After the call, the value of `vec.x' will be `sin(angle)', and the value of `vec.y' will be `cos(angle)'.</p>
<p>This function is useful to retrieve both the sinus and cosinus of a given angle quickly.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>output</b></em></td></tr><tr><td>
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<tr valign=top><td><b>vec</b></td><td>
<p>The address of target vector.</p>
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<tr valign=top><td><b>angle</b></td><td>
<p>The address of angle.</p>
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<h4><a name="FT_Vector_Rotate">FT_Vector_Rotate</a></h4>
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  FT_EXPORT( <span class="keyword">void</span> )
  <b>FT_Vector_Rotate</b>( <a href="ft2-basic_types.html#FT_Vector">FT_Vector</a>*  vec,
                    <a href="ft2-computations.html#FT_Angle">FT_Angle</a>    angle );

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<p>Rotate a vector by a given angle.</p>
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<tr valign=top><td><b>vec</b></td><td>
<p>The address of target vector.</p>
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<tr valign=top><td><b>angle</b></td><td>
<p>The address of angle.</p>
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<h4><a name="FT_Vector_Length">FT_Vector_Length</a></h4>
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  FT_EXPORT( <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a> )
  <b>FT_Vector_Length</b>( <a href="ft2-basic_types.html#FT_Vector">FT_Vector</a>*  vec );

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<p>Return the length of a given vector.</p>
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<tr valign=top><td><b>vec</b></td><td>
<p>The address of target vector.</p>
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<p>The vector length, expressed in the same units that the original vector coordinates.</p>
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<h4><a name="FT_Vector_Polarize">FT_Vector_Polarize</a></h4>
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  FT_EXPORT( <span class="keyword">void</span> )
  <b>FT_Vector_Polarize</b>( <a href="ft2-basic_types.html#FT_Vector">FT_Vector</a>*  vec,
                      <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a>   *length,
                      <a href="ft2-computations.html#FT_Angle">FT_Angle</a>   *angle );

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<p>Compute both the length and angle of a given vector.</p>
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<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>input</b></em></td></tr><tr><td>
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<tr valign=top><td><b>vec</b></td><td>
<p>The address of source vector.</p>
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<tr valign=top><td><b>length</b></td><td>
<p>The vector length.</p>
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<tr valign=top><td><b>angle</b></td><td>
<p>The vector angle.</p>
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<h4><a name="FT_Vector_From_Polar">FT_Vector_From_Polar</a></h4>
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  FT_EXPORT( <span class="keyword">void</span> )
  <b>FT_Vector_From_Polar</b>( <a href="ft2-basic_types.html#FT_Vector">FT_Vector</a>*  vec,
                        <a href="ft2-basic_types.html#FT_Fixed">FT_Fixed</a>    length,
                        <a href="ft2-computations.html#FT_Angle">FT_Angle</a>    angle );

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<p>Compute vector coordinates from a length and angle.</p>
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<tr valign=top><td><b>vec</b></td><td>
<p>The address of source vector.</p>
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<tr valign=top><td><b>length</b></td><td>
<p>The vector length.</p>
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<tr valign=top><td><b>angle</b></td><td>
<p>The vector angle.</p>
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