path.h File Reference

Draw on Canvas using SVG-like path commands. More...

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Macros
#define	CMDFX_PATH_COMMAND_MOVETO_ABSOLUTE   'M'
#define	CMDFX_PATH_COMMAND_MOVETO_RELATIVE   'm'
#define	CMDFX_PATH_COMMAND_LINETO_ABSOLUTE   'L'
#define	CMDFX_PATH_COMMAND_LINETO_RELATIVE   'l'
#define	CMDFX_PATH_COMMAND_HLINETO_ABSOLUTE   'H'
#define	CMDFX_PATH_COMMAND_HLINETO_RELATIVE   'h'
#define	CMDFX_PATH_COMMAND_VLINETO_ABSOLUTE   'V'
#define	CMDFX_PATH_COMMAND_VLINETO_RELATIVE   'v'
#define	CMDFX_PATH_COMMAND_RECT_ABSOLUTE   'R'
#define	CMDFX_PATH_COMMAND_RECT_RELATIVE   'r'
#define	CMDFX_PATH_COMMAND_ELLIPSE_ABSOLUTE   'E'
#define	CMDFX_PATH_COMMAND_ELLIPSE_RELATIVE   'e'
#define	CMDFX_PATH_COMMAND_QUAD_ABSOLUTE   'Q'
#define	CMDFX_PATH_COMMAND_QUAD_RELATIVE   'q'
#define	CMDFX_PATH_COMMAND_CUBIC_ABSOLUTE   'C'
#define	CMDFX_PATH_COMMAND_CUBIC_RELATIVE   'c'
#define	CMDFX_PATH_COMMAND_ARC_ABSOLUTE   'A'
#define	CMDFX_PATH_COMMAND_ARC_RELATIVE   'a'

Functions
int	Canvas_path (const char *path, char ch)
	Draws a path on the canvas using the specified path string.

Detailed Description

Draw on Canvas using SVG-like path commands.

Author

Gregory Mitchell (me@gm.nosp@m.itch.nosp@m.215.x.nosp@m.yz)

Version

0.2.0

Date

2025-04-25

Copyright

Copyright (c) 2025

Macro Definition Documentation

CMDFX_PATH_COMMAND_ARC_ABSOLUTE

#define CMDFX_PATH_COMMAND_ARC_ABSOLUTE   'A'

Draws an elliptical arc from the current point to the specified coordinates.

Parameters

rx	The x radius of the ellipse
ry	The y radius of the ellipse
x_axis_rotation	The rotation of the ellipse in degrees
large_arc_flag	A flag indicating whether to use the large arc
sweep_flag	A flag indicating whether to use the positive angle
x2	The x coordinate of the end point
y2	The y coordinate of the end point

CMDFX_PATH_COMMAND_ARC_RELATIVE

#define CMDFX_PATH_COMMAND_ARC_RELATIVE   'a'

Draws an elliptical arc from the current point to the specified coordinates relative to the current point.

Parameters

rx	The x radius of the ellipse
ry	The y radius of the ellipse
x_axis_rotation	The rotation of the ellipse in degrees
large_arc_flag	A flag indicating whether to use the large arc
sweep_flag	A flag indicating whether to use the positive angle
dx2	The x coordinate of the end point relative to the current point
dy2	The y coordinate of the end point relative to the current point

CMDFX_PATH_COMMAND_CUBIC_ABSOLUTE

#define CMDFX_PATH_COMMAND_CUBIC_ABSOLUTE   'C'

Draws a cubic Bezier curve from the current point to the specified coordinates.

Parameters

x1	The x coordinate of the first control point
y1	The y coordinate of the first control point
x2	The x coordinate of the second control point
y2	The y coordinate of the second control point
x3	The x coordinate of the end point
y3	The y coordinate of the end point

CMDFX_PATH_COMMAND_CUBIC_RELATIVE

#define CMDFX_PATH_COMMAND_CUBIC_RELATIVE   'c'

Draws a cubic Bezier curve from the current point to the specified coordinates relative to the current point.

Parameters

dx1	The x coordinate of the first control point relative to the current point
dy1	The y coordinate of the first control point relative to the current point
dx2	The x coordinate of the second control point relative to the current point
dy2	The y coordinate of the second control point relative to the current point
dx3	The x coordinate of the end point relative to the current point
dy3	The y coordinate of the end point relative to the current point

CMDFX_PATH_COMMAND_ELLIPSE_ABSOLUTE

#define CMDFX_PATH_COMMAND_ELLIPSE_ABSOLUTE   'E'

Draws an ellipse with the specified coordinates.

Parameters

cx	The x coordinate of the center of the ellipse
cy	The y coordinate of the center of the ellipse
rx	The x radius of the ellipse
ry	The y radius of the ellipse
x_axis_rotation	The rotation of the ellipse in degrees

CMDFX_PATH_COMMAND_ELLIPSE_RELATIVE

#define CMDFX_PATH_COMMAND_ELLIPSE_RELATIVE   'e'

Draws an ellipse with the specified coordinates relative to the current point.

Parameters

dx	The x coordinate of the center of the ellipse relative to the current point
dy	The y coordinate of the center of the ellipse relative to the current point
rx	The x radius of the ellipse
ry	The y radius of the ellipse
x_axis_rotation	The rotation of the ellipse in degrees

CMDFX_PATH_COMMAND_HLINETO_ABSOLUTE

#define CMDFX_PATH_COMMAND_HLINETO_ABSOLUTE   'H'

Draws a horizontal line from the current point to the specified x coordinate.

Parameters

x	The x coordinate of the point

CMDFX_PATH_COMMAND_HLINETO_RELATIVE

#define CMDFX_PATH_COMMAND_HLINETO_RELATIVE   'h'

Draws a horizontal line from the current point to the specified x coordinate relative to the current point.

Parameters

dx	The x coordinate of the point relative to the current point

CMDFX_PATH_COMMAND_LINETO_ABSOLUTE

#define CMDFX_PATH_COMMAND_LINETO_ABSOLUTE   'L'

Draws a line from the current point to the specified coordinates.

Parameters

x	The x coordinate of the point
y	The y coordinate of the point

CMDFX_PATH_COMMAND_LINETO_RELATIVE

#define CMDFX_PATH_COMMAND_LINETO_RELATIVE   'l'

Draws a line from the current point to the specified coordinates relative to the current point.

Parameters

dx	The x coordinate of the point relative to the current point
dy	The y coordinate of the point relative to the current point

CMDFX_PATH_COMMAND_MOVETO_ABSOLUTE

#define CMDFX_PATH_COMMAND_MOVETO_ABSOLUTE   'M'

Moves the current point to the specified coordinates.

Parameters

x	The x coordinate of the point
y	The y coordinate of the point

CMDFX_PATH_COMMAND_MOVETO_RELATIVE

#define CMDFX_PATH_COMMAND_MOVETO_RELATIVE   'm'

Moves the current point to the specified coordinates relative to the current point.

Parameters

dx	The x coordinate of the point relative to the current point
dy	The y coordinate of the point relative to the current point

CMDFX_PATH_COMMAND_QUAD_ABSOLUTE

#define CMDFX_PATH_COMMAND_QUAD_ABSOLUTE   'Q'

Draws a quadratic Bezier curve from the current point to the specified coordinates.

Parameters

x1	The x coordinate of the control point
y1	The y coordinate of the control point
x2	The x coordinate of the end point
y2	The y coordinate of the end point

CMDFX_PATH_COMMAND_QUAD_RELATIVE

#define CMDFX_PATH_COMMAND_QUAD_RELATIVE   'q'

Draws a quadratic Bezier curve from the current point to the specified coordinates relative to the current point.

Parameters

dx1	The x coordinate of the control point relative to the current point
dy1	The y coordinate of the control point relative to the current point
dx2	The x coordinate of the end point relative to the current point
dy2	The y coordinate of the end point relative to the current point

CMDFX_PATH_COMMAND_RECT_ABSOLUTE

#define CMDFX_PATH_COMMAND_RECT_ABSOLUTE   'R'

Draws a rectangle with the specified coordinates.

Parameters

x1	The x coordinate of the top-left corner of the rectangle
y1	The y coordinate of the top-left corner of the rectangle
x2	The x coordinate of the bottom-right corner of the rectangle
y2	The y coordinate of the bottom-right corner of the rectangle

CMDFX_PATH_COMMAND_RECT_RELATIVE

#define CMDFX_PATH_COMMAND_RECT_RELATIVE   'r'

Draws a rectangle with the specified coordinates relative to the current point.

Parameters

dx1	The x coordinate of the top-left corner of the rectangle relative to the current point
dy1	The y coordinate of the top-left corner of the rectangle relative to the current point
dx2	The x coordinate of the bottom-right corner of the rectangle relative to the current point
dy2	The y coordinate of the bottom-right corner of the rectangle relative to the current point

CMDFX_PATH_COMMAND_VLINETO_ABSOLUTE

#define CMDFX_PATH_COMMAND_VLINETO_ABSOLUTE   'V'

Draws a vertical line from the current point to the specified y coordinate.

Parameters

y	The y coordinate of the point

CMDFX_PATH_COMMAND_VLINETO_RELATIVE

#define CMDFX_PATH_COMMAND_VLINETO_RELATIVE   'v'

Draws a vertical line from the current point to the specified y coordinate relative to the current point.

Parameters

dy	The y coordinate of the point relative to the current point

Function Documentation

Canvas_path()

int Canvas_path	(	const char *	path,
		char	ch )

Draws a path on the canvas using the specified path string.

This function interprets the path string as a series of SVG-like commands and draws the corresponding shapes on the canvas. The path string can contain commands for moving to a point, drawing lines, rectangles, ellipses, and curves, as well as closing the path.

The function will make no attempt to validate the path string, so it is the responsibility of the caller to ensure that the path string is well-formed and contains valid commands. The function will return -1 if the path string is NULL or if an error occurs while drawing the path.

Parameters

path	The path string to draw
ch	The character to draw

Returns

0 on success, -1 on error