You know that the float point mathematics routines are very expensive. If you do not want precision mathematics result, you can use fixed point. MiniGUI uses a double word (32-bit) integer to represent a fixed point ranged from -32767.0 to 32767.0, and defines some fixed point mathematics routines for your application. Some GDI functions need fixed point math routines, like Arc. More...

Functions
MG_EXPORT fixed	fixsqrt (fixed x)
	Returns the non-negative square root of a fixed point value. More...

MG_EXPORT fixed	fixhypot (fixed x, fixed y)
	Returns the Euclidean distance from the origin. More...

MG_EXPORT fixed	fixatan (fixed x)
	Calculates the arc tangent of a fixed point value. More...

MG_EXPORT fixed	fixatan2 (fixed y, fixed x)
	Calculates the arc tangent of two fixed point variables. More...

static fixed	ftofix (double x)
	Converts a float point value to a fixed point value. More...

static double	fixtof (fixed x)
	Converts a fixed point value to a float point value. More...

static fixed	fixadd (fixed x, fixed y)
	Returns the sum of two fixed point values. More...

static fixed	fixsub (fixed x, fixed y)
	Subtract a fixed point value from another. More...

MG_EXPORT fixed	fixmul (fixed x, fixed y)
	Returns the product of two fixed point values. More...

MG_EXPORT fixed	fixdiv (fixed x, fixed y)
	Returns the quotient of two fixed point values. More...

static int	fixceil (fixed x)
	Rounds a fixed point value to the nearest integer. More...

static fixed	itofix (int x)
	Converts an integer to a fixed point value. More...

static int	fixtoi (fixed x)
	Converts an fixed point value to an integer. More...

static fixed	fixcos (fixed x)
	Returns the cosine of a fixed point. More...

static fixed	fixsin (fixed x)
	Returns the sine of a fixed point. More...

static fixed	fixtan (fixed x)
	Returns the tangent of a fixed point. More...

static fixed	fixacos (fixed x)
	Calculates and returns the arc cosine of a fixed point. More...

static fixed	fixasin (fixed x)
	Calculates and returns the arc sine of a fixed point. More...

Detailed Description

You know that the float point mathematics routines are very expensive. If you do not want precision mathematics result, you can use fixed point. MiniGUI uses a double word (32-bit) integer to represent a fixed point ranged from -32767.0 to 32767.0, and defines some fixed point mathematics routines for your application. Some GDI functions need fixed point math routines, like Arc.

Example 1:

    /* Draw an arc from 0 radians to 1 radians */
    Arc (hdc, 100, 100, 100, 0, itofix (1));
 
    /* Draw an arc from 0.5 radians to 1.5 radians */
    fixed radian1 = itofix (1);
    fixed radian2 = itofix (2);
    fixed radian05 = fixdiv (radian1, radian2);
    fixed radian15 = fixdiv (fadd (radian1, randian2), radian2);
 
    Arc (hdc, 100, 100, 100, radian05, radian15);

Example 2:

void draw_arc (HDC hdc, POINT* pts)
{
            int sx = pts [0].x, sy = pts [0].y;
            int dx = pts [1].x - sx, dy = pts [1].y - sy;
            int r = sqrt (dx * dx * 1.0 + dy * dy * 1.0);
            double cos_d = dx * 1.0 / r;
            fixed cos_f = ftofix (cos_d);
            fixed ang1 = fixacos (cos_f);
            int r2;
            fixed ang2;
 
            if (dy > 0) {
                ang1 = fixsub (0, ang1);
            }
 
            dx = pts [2].x - sx;
            dy = pts [2].y - sy;
            r2 = sqrt (dx * dx * 1.0 + dy * dy * 1.0);
            cos_d = dx * 1.0 / r2;
            cos_f = ftofix (cos_d);
            ang2 = fixacos (cos_f);
            if (dy > 0) {
                ang2 = fixsub (0, ang2);
            }
 
            Arc (hdc, sx, sy, r, ang1, ang2);
}

Function Documentation

◆ fixacos()

fixed fixacos ( fixed x )

inlinestatic

Calculates and returns the arc cosine of a fixed point.

This function calculates the arc cosine of the fixed point x; that is the value whose cosine is x. If x falls outside the range -1 to 1, this function fails and errno is set to EDOM.

Returns: Returns the arc cosine in radians and the value is mathematically defined to be between 0 and PI (inclusive).

See also: fixcos

Definition at line 423 of file fixedmath.h.

◆ fixadd()

fixed fixadd	(	fixed	x,
		fixed	y
	)

inlinestatic

Returns the sum of two fixed point values.

This function adds two fixed point values x and y, and returns the sum.

Parameters

x	x,y: Two addends.
y	x,y: Two addends.

Returns: The sum. If the result runs out of range of fixed point, this function sets errno to ERANGE.

See also: fixsub

Definition at line 229 of file fixedmath.h.

◆ fixasin()

fixed fixasin ( fixed x )

inlinestatic

Calculates and returns the arc sine of a fixed point.

This function calculates the arc sine of the fixed point x; that is the value whose sine is x. If x falls outside the range -1 to 1, this function fails and errno is set to EDOM.

Returns: Returns the arc sine in radians and the value is mathematically defined to be between -PI/2 and PI/2 (inclusive).

See also: fixsin

Definition at line 446 of file fixedmath.h.

◆ fixatan()

fixed fixatan ( fixed x )

Calculates the arc tangent of a fixed point value.

This function calculates the arc tangent of x; that is the value whose tangent is x.

Returns: Returns the arc tangent in radians and the value is mathematically defined to be between -PI/2 and PI/2 (inclusive).

See also: fixatan2

◆ fixatan2()

fixed fixatan2	(	fixed	y,
		fixed	x
	)

Calculates the arc tangent of two fixed point variables.

This function calculates the arc tangent of the two variables x and y. It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result.

Returns: Returns the result in radians, which is between -PI and PI (inclusive).

See also: fixatan

◆ fixceil()

int fixceil ( fixed x )

inlinestatic

Rounds a fixed point value to the nearest integer.

This function rounds the fixed point value x to the nearest integer and returns it.

Returns: The rounded integer value.

Definition at line 328 of file fixedmath.h.

◆ fixcos()

fixed fixcos ( fixed x )

inlinestatic

Returns the cosine of a fixed point.

This function returns the cosine of the fixed point x, where x is given in radians.

See also: fixacos

Definition at line 377 of file fixedmath.h.

◆ fixdiv()

fixed fixdiv	(	fixed	x,
		fixed	y
	)

Returns the quotient of two fixed point values.

This function returns the quotient of two fixed point values x and y.

Parameters

x	The dividend.
y	The divisor.

Returns: The quotient. If the result runs out of range of fixed point, this function sets errno to ERANGE.

See also: fixmul

◆ fixhypot()

fixed fixhypot	(	fixed	x,
		fixed	y
	)

Returns the Euclidean distance from the origin.

The function returns the sqrt(x*x+y*y). This is the length of the hypotenuse of a right-angle triangle with sides of length x and y, or the distance of the point (x,y) from the origin.

See also: fixsqrt

◆ fixmul()

fixed fixmul	(	fixed	x,
		fixed	y
	)

Returns the product of two fixed point values.

This function returns the product of two fixed point values x and y.

Parameters

x	The faciend.
y	The multiplicato.

Returns: The prodcut. If the result runs out of range of fixed point, this function sets errno to ERANGE.

See also: fixdiv

◆ fixsin()

fixed fixsin ( fixed x )

inlinestatic

Returns the sine of a fixed point.

This function returns the sine of the fixed point x, where x is given in radians.

See also: fixasin

Definition at line 391 of file fixedmath.h.

◆ fixsqrt()

fixed fixsqrt ( fixed x )

Returns the non-negative square root of a fixed point value.

This function returns the non-negative square root of x. It fails and sets errno to EDOM, if x is negative.

See also: fixhypot

◆ fixsub()

fixed fixsub	(	fixed	x,
		fixed	y
	)

inlinestatic

Subtract a fixed point value from another.

This function subtracts the fixed point values y from the fixed point value x, and returns the difference.

Parameters

x	The minuend.
y	The subtrahend.

Returns: The difference. If the result runs out of range of fixed point, this function sets errno to ERANGE.

See also: fixadd

Definition at line 266 of file fixedmath.h.

◆ fixtan()

fixed fixtan ( fixed x )

inlinestatic

Returns the tangent of a fixed point.

This function returns the tangent of the fixed point x, where x is given in radians.

See also: fixcos, fixsin

Definition at line 405 of file fixedmath.h.

◆ fixtof()

double fixtof ( fixed x )

inlinestatic

Converts a fixed point value to a float point value.

This function converts the specified fixed point value x to a float point value.

See also: ftofix

Definition at line 209 of file fixedmath.h.

◆ fixtoi()

int fixtoi ( fixed x )

inlinestatic

Converts an fixed point value to an integer.

This function converts the fixed point x to an integer.

See also: itofix

Definition at line 363 of file fixedmath.h.

◆ ftofix()

fixed ftofix ( double x )

inlinestatic

Converts a float point value to a fixed point value.

This function converts the specified float point value x to a fixed point value.

Note: The float point should be ranged from -32767.0 to 32767.0. If it runs out of the range, this function sets errno to ERANGE.

See also: fixtof

Definition at line 185 of file fixedmath.h.

◆ itofix()

fixed itofix ( int x )

inlinestatic

Converts an integer to a fixed point value.

This function converts the integer x to a fixed point value.

See also: fixtoi

Definition at line 350 of file fixedmath.h.

Functions

Detailed Description

Function Documentation

◆ fixacos()

◆ fixadd()

◆ fixasin()

◆ fixatan()

◆ fixatan2()

◆ fixceil()

◆ fixcos()

◆ fixdiv()

◆ fixhypot()

◆ fixmul()

◆ fixsin()

◆ fixsqrt()

◆ fixsub()

◆ fixtan()

◆ fixtof()

◆ fixtoi()

◆ ftofix()

◆ itofix()