pen.c File Reference

Vector drawing abstraction. More...

#include <stdio.h>
#include "pen.h"
#include "svd2x2.h"

Include dependency graph for pen.c:

Go to the source code of this file.

Macros
#define	FILE_BUFFER_CAPACITY   (1024*4)
	Buffer size to use for file output. More...
#define	SWAP(A, B)
	Swap A and B. More...

Functions
pen *	NewPen ()
	Create a new pen. More...
void	FreePen (pen *Pen)
	Free all memory associated with a pen. More...
FILE *	PenGetFile (pen *Pen)
	Get the stdio FILE* pointer associated with a pen. More...
int	PenDrawLine (pen *Pen, float x1, float y1, float x2, float y2)
	Draw a line. More...
int	PenDrawRectangle (pen *Pen, float x1, float y1, float x2, float y2)
	Draw a rectangle. More...
int	PenDrawQBezier (pen *Pen, float x1, float y1, float x2, float y2, float x3, float y3)
	Draw a quadratic Bezier curve. More...
int	PenDrawCircle (pen *Pen, float x, float y, float r)
	Draw a circle. More...
int	PenDrawEllipse (pen *Pen, float x, float y, float rx, float ry, float Theta)
	Draw an ellipse. More...
void	PenWriteDouble (FILE *File, double Value, int NumDigits)
	Write a floating-point value without trailing zeros. More...
int	PenGetNumDigits (pen *Pen)
	Get the number of digits used for writing floats. More...
void	PenSetNumDigits (pen *Pen, int NumDigits)
	Set the number of digits used for writing floats. More...
pentrans	PenGetTrans (pen *Pen)
	Get the pen canvas transformation. More...
void	PenSetTrans (pen *Pen, pentrans Trans)
	(Re)set the pen canvas transformation More...
void	PenTransformCanvas (pen *Pen, double a, double b, double c, double d, double e, double f)
	Transform the pen's canvas. More...
void	PenTranslateCanvas (pen *Pen, double tx, double ty)
	Translate the pen's canvas. More...
void	PenScaleCanvas (pen *Pen, double XScale, double YScale)
	Scale the pen's canvas. More...
void	PenRotateCanvas (pen *Pen, double Theta)
	Rotate the pen's canvas. More...
void	PenXSkewCanvas (pen *Pen, double Skew)
	Horizontally skew the pen's canvas. More...
void	PenYSkewCanvas (pen *Pen, double Skew)
	Vertically skew the pen's canvas. More...
int	PenColorToIndex (pen *Pen, const float *Color)
	Find the pen palette index of a color. More...
int	PenDefineColor (pen *Pen, const float *Color)
	Add a color to a pen's palette. More...
int	PenSetColor (pen *Pen, const float *Color)
	Set the current pen drawing color. More...
void	TransformEllipse (float *x, float *y, float *rx, float *ry, float *Theta, pentrans Trans)
	Compute canvas transformation for an ellipse. More...
float	EstArcLenQBezier (float x1, float y1, float x2, float y2, float x3, float y3, pentrans Trans)
	Estimate arc length of a quadratic Bezier curve. More...
float	EstArcLenEllipse (float x, float y, float rx, float ry, float Theta, pentrans Trans)
	Estimate the arc length of an ellipse. More...
int	PenRenderToImage (pen *Pen, float *Image, int Width, int Height)
	Set pen to render to a raster image. More...
void	EpsSetColor (pen *Pen, const float *Color)
	Set drawing color in an EPS. More...
int	EpsOpen (pen *Pen, const char *FileName, float Width, float Height)
	Start writing a new EPS file. More...
int	EpsClose (pen *Pen)
	Finish writing an EPS file. More...
int	WriteASCII85 (FILE *File, const uint8_t *Data, int NumBytes)
	Write ASCII85 encoded data. More...
int	EpsWriteGrayImage (FILE *File, const uint8_t *Image, int Width, int Height)
	Writes a grayscale image to an EPS file. More...
int	EpsWriteColorImage (FILE *File, const uint8_t *Image, int Width, int Height)
	Writes an RGB color image to an EPS file. More...
int	SvgOpen (pen *Pen, const char *FileName, float Width, float Height)
	Start writing a new SVG file. More...
int	SvgClose (pen *Pen)
	Finish writing an SVG file. More...

Variables
const pentrans	IdentityPenTrans = {1, 0, 0, 1, 0, 0}
	Identity transform. More...

Detailed Description

Vector drawing abstraction.

Author

Pascal Getreuer getre.nosp@m.uer@.nosp@m.gmail.nosp@m..com

Copyright (c) 2010-2011, Pascal Getreuer All rights reserved.

This program is free software: you can use, modify and/or redistribute it under the terms of the simplified BSD License. You should have received a copy of this license along this program. If not, see http://www.opensource.org/licenses/bsd-license.html.

Definition in file pen.c.

Macro Definition Documentation

#define FILE_BUFFER_CAPACITY   (1024*4)

Buffer size to use for file output.

Definition at line 21 of file pen.c.

#define SWAP	(		A,
			B
	)

Value:

Temp = A; \
    A = B; \
    B = Temp;

Swap A and B.

Definition at line 635 of file pen.c.

Function Documentation

int EpsClose

(

pen *

Pen

)

Finish writing an EPS file.

Parameters

Pen	the pen object

Returns

1 on success, 0 on failure

Definition at line 996 of file pen.c.

int EpsOpen	(	pen *	Pen,
		const char *	FileName,
		float	Width,
		float	Height
	)

Start writing a new EPS file.

Parameters

Pen	the pen object
FileName	the EPS file name
Width,Height	dimensions of the SVG canvas

Returns

1 on success, 0 on failure

Definition at line 933 of file pen.c.

void EpsSetColor	(	pen *	Pen,
		const float *	Color
	)

Set drawing color in an EPS.

Parameters

Pen	the pen object
Color	drawing color

Definition at line 798 of file pen.c.

int EpsWriteColorImage	(	FILE *	File,
		const uint8_t *	Image,
		int	Width,
		int	Height
	)

Writes an RGB color image to an EPS file.

Parameters

File	the stdio file handle to write to
Image	interleaved RGB color image data
Width,Height	the image dimensions

The image is plotted on the canvas in the rectangle [0,Width] x [0,Height] where the lower-left corner is at the origin.

This routine only writes the image data. EpsOpen should be called first, then this routine and other drawing commands, and finally EpsClose.

For relative simplicity, the image data is written uncompressed in ASCII85 encoding. The file size is approximately 25% larger than in the PGM file format.

Definition at line 1144 of file pen.c.

int EpsWriteGrayImage	(	FILE *	File,
		const uint8_t *	Image,
		int	Width,
		int	Height
	)

Writes a grayscale image to an EPS file.

Parameters

File	the stdio file handle to write to
Image	grayscale image data
Width,Height	the image dimensions

The image is plotted on the canvas in the rectangle [0,Width] x [0,Height] where the lower-left corner is at the origin.

This routine only writes the image data. EpsOpen should be called first, then this routine and other drawing commands, and finally EpsClose.

For relative simplicity, the image data is written uncompressed in ASCII85 encoding. The file size is approximately 25% larger than in the PGM file format.

Definition at line 1100 of file pen.c.

float EstArcLenEllipse	(	float	x,
		float	y,
		float	rx,
		float	ry,
		float	Theta,
		pentrans	Trans
	)

Estimate the arc length of an ellipse.

Parameters

x,y,rx,ry,Theta	parameters for pen::DrawEllipse
Trans	the canvas transformation

Returns

estimated arc length

Definition at line 616 of file pen.c.

float EstArcLenQBezier	(	float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	x3,
		float	y3,
		pentrans	Trans
	)

Estimate arc length of a quadratic Bezier curve.

Parameters

Pen	the pen object
x1,y1,x2,y2,x3,y3	starting point, control point, and endpoint

Returns

estimated arc length

Computes a crude overestimate of the arc length.

Definition at line 589 of file pen.c.

void FreePen

(

pen *

Pen

)

Free all memory associated with a pen.

Parameters

Pen	the pen object to free

Definition at line 139 of file pen.c.

pen* NewPen

(

)

Create a new pen.

Returns

a pen*, or NULL on allocation failure

Allocates a new pen object. The caller must call FreePen() to free the pen when done.

Definition at line 121 of file pen.c.

int PenColorToIndex	(	pen *	Pen,
		const float *	Color
	)

Find the pen palette index of a color.

Parameters

Pen	the pen object
Color	color to find

Returns

palette index, or -1 if not in palette

Definition at line 454 of file pen.c.

int PenDefineColor	(	pen *	Pen,
		const float *	Color
	)

Add a color to a pen's palette.

Parameters

Pen	the pen object
Color	color to add

Returns

1 on success, 0 on failure

Color is added to Pen->Palette if it is not already in the palette. The palette is reallocated if more space is needed.

Definition at line 480 of file pen.c.

int PenDrawCircle	(	pen *	Pen,
		float	x,
		float	y,
		float	r
	)

Draw a circle.

Parameters

Pen	the pen object
x,y	circle center
r	circle radius

Returns

1 on success, 0 on failure

This function is a wrapper for pen::DrawEllipse.

Definition at line 213 of file pen.c.

int PenDrawEllipse	(	pen *	Pen,
		float	x,
		float	y,
		float	rx,
		float	ry,
		float	Theta
	)

Draw an ellipse.

Parameters

Pen	the pen object
x,y	center of the ellipse
rx,ry	radii of the ellipse
Theta	ellipse rotation

Returns

1 on success, 0 on failure

This function is a wrapper for pen::DrawEllipse.

Definition at line 229 of file pen.c.

int PenDrawLine	(	pen *	Pen,
		float	x1,
		float	y1,
		float	x2,
		float	y2
	)

Draw a line.

Parameters

Pen	the pen object
x1,y1,x2,y2	endpoints of the line

Returns

1 on success, 0 on failure

This function is a wrapper for pen::DrawLine.

Definition at line 167 of file pen.c.

int PenDrawQBezier	(	pen *	Pen,
		float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	x3,
		float	y3
	)

Draw a quadratic Bezier curve.

Parameters

Pen	the pen object
x1,y1,x2,y2,x3,y3	starting point, control point, and endpoint

Returns

1 on success, 0 on failure

This function is a wrapper for pen::DrawQBezier.

Definition at line 197 of file pen.c.

int PenDrawRectangle	(	pen *	Pen,
		float	x1,
		float	y1,
		float	x2,
		float	y2
	)

Draw a rectangle.

Parameters

Pen	the pen object
x1,y1,x2,y2	corners of the rectangle

Returns

1 on success, 0 on failure

Definition at line 179 of file pen.c.

FILE* PenGetFile

(

pen *

Pen

)

Get the stdio FILE* pointer associated with a pen.

Parameters

Pen	the pen object

Definition at line 153 of file pen.c.

int PenGetNumDigits

(

pen *

Pen

)

Get the number of digits used for writing floats.

Parameters

Pen	the pen object

Returns

number of digits

Gets the number of digits used in PenWriteDouble().

Definition at line 301 of file pen.c.

pentrans PenGetTrans

(

pen *

Pen

)

Get the pen canvas transformation.

Parameters

Pen	the pen object

Returns

pentrans canvas transformation

Gets pen::Trans. This is useful in combination with PenSetTrans() to save and later restore the canvas transformation.

Definition at line 330 of file pen.c.

int PenRenderToImage	(	pen *	Pen,
		float *	Image,
		int	Width,
		int	Height
	)

Set pen to render to a raster image.

Parameters

Pen	the pen object
Image	the row-major interleaved RGB image to render to
Width,Height	dimensions of Image

Returns

1 on success, 0 on failure

Definition at line 774 of file pen.c.

void PenRotateCanvas	(	pen *	Pen,
		double	Theta
	)

Rotate the pen's canvas.

Parameters

Pen	the pen object
Theta	counter-clockwise rotation in radians

Definition at line 413 of file pen.c.

void PenScaleCanvas	(	pen *	Pen,
		double	XScale,
		double	YScale
	)

Scale the pen's canvas.

Parameters

Pen	the pen object
XScale,YScale	scale factors

Definition at line 401 of file pen.c.

int PenSetColor	(	pen *	Pen,
		const float *	Color
	)

Set the current pen drawing color.

Parameters

Pen	the pen object
Color	the drawing color

Returns

the color's palette index, or -1 if not in palette

Definition at line 520 of file pen.c.

void PenSetNumDigits	(	pen *	Pen,
		int	NumDigits
	)

Set the number of digits used for writing floats.

Parameters

Pen	the pen object
NumDigits	the number of digits

Sets the number of digits used in PenWriteDouble().

Definition at line 314 of file pen.c.

void PenSetTrans	(	pen *	Pen,
		pentrans	Trans
	)

(Re)set the pen canvas transformation

Parameters

Pen	the pen object
Trans	the pentrans canvas transformation

Sets pen::Trans to Trans. This is useful in combination with PenGetTrans() to save and later restore the canvas transformation.

Definition at line 344 of file pen.c.

void PenTransformCanvas	(	pen *	Pen,
		double	a,
		double	b,
		double	c,
		double	d,
		double	e,
		double	f
	)

Transform the pen's canvas.

Parameters

Pen	the pen object
Trans	the pentrans canvas transformation

Definition at line 356 of file pen.c.

void PenTranslateCanvas	(	pen *	Pen,
		double	tx,
		double	ty
	)

Translate the pen's canvas.

Parameters

Pen	the pen object
tx,ty	translation

Definition at line 389 of file pen.c.

void PenWriteDouble	(	FILE *	File,
		double	Value,
		int	NumDigits
	)

Write a floating-point value without trailing zeros.

Parameters

File	the file or stream
Value	floating-point value to write
NumDigits	Value is written in decimal notation using up to NumDigits digits after the decimal point. Trailing zeros are omitted.

Definition at line 245 of file pen.c.

void PenXSkewCanvas	(	pen *	Pen,
		double	Skew
	)

Horizontally skew the pen's canvas.

Parameters

Pen	the pen object
Skew	skew amount

Definition at line 429 of file pen.c.

void PenYSkewCanvas	(	pen *	Pen,
		double	Skew
	)

Vertically skew the pen's canvas.

Parameters

Pen	the pen object
Skew	skew amount

Definition at line 441 of file pen.c.

int SvgClose

(

pen *

Pen

)

Finish writing an SVG file.

Parameters

Pen	the pen object

Returns

1 on success, 0 on failure

Definition at line 1426 of file pen.c.

int SvgOpen	(	pen *	Pen,
		const char *	FileName,
		float	Width,
		float	Height
	)

Start writing a new SVG file.

Parameters

Pen	the pen object
FileName	the SVG file name
Width,Height	dimensions of the SVG canvas

Returns

1 on success, 0 on failure

Definition at line 1359 of file pen.c.

void TransformEllipse	(	float *	x,
		float *	y,
		float *	rx,
		float *	ry,
		float *	Theta,
		pentrans	Trans
	)

Compute canvas transformation for an ellipse.

Parameters

x,y,rx,ry,Theta	parameters for pen::DrawEllipse
Trans	the canvas transformation

The input values of the parameters x, y, rx, ry, Theta are the untransformed parameters as given to pen::DrawEllipse. They are replaced with transformed values.

Definition at line 545 of file pen.c.

int WriteASCII85	(	FILE *	File,
		const uint8_t *	Data,
		int	NumBytes
	)

Write ASCII85 encoded data.

Parameters

File	the destination stream or File
Data	binary data to encode
NumBytes	number of bytes in Data

Returns

1 on success, 0 on failure

Definition at line 1015 of file pen.c.

Variable Documentation

const pentrans IdentityPenTrans = {1, 0, 0, 1, 0, 0}

Identity transform.

Definition at line 25 of file pen.c.