net.codecrete.qrbill.canvas

Interface Canvas

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable

All Known Implementing Classes:

AbstractCanvas, PDFCanvas, PNGCanvas, SVGCanvas

public interface Canvas
extends java.io.Closeable

Common graphics interface for drawing

The coordinate system is initialized by setupPage. It's origin is initially in the bottom left corner of the pages and extends in x-direction to the right and in y-direction to the top.

All text has to be in the font Helvetica. Arial should also do as the font metrics are similar enough and advanced text placing such a justified text is not used.

A canvas may only be used to generate a single page. After the result has been retrieved, the instance must not be used anymore.

Method Summary

Modifier and Type	Method and Description
void	addRectangle(double x, double y, double width, double height) Adds a rectangle to the path
void	fillPath(int color) Fills the current path and ends it
byte[]	getResult() Returns the generated graphics as a byte array After this method was called, the page is no longer valid.
void	lineTo(double x, double y) Adds a line segment to the open path from the previous point to the speicifed position.
void	moveTo(double x, double y) Moves the current point of the open path to the specified position.
int	putMultilineText(java.lang.String text, double x, double y, int fontSize, double maxWidth, double leading) Adds several lines of text to the graphics.
void	putText(java.lang.String text, double x, double y, int fontSize, boolean isBold) Adds text to the graphics.
void	putTextLines(java.lang.String[] lines, double x, double y, int fontSize, double leading) Adds several lines of text to the graphics.
void	setTransformation(double translateX, double translateY, double scale) Sets a translation and a scale factor for the subsequent operations Before a new translation is applied, the coordinate system is reset to it's original state after page setup (see setupPage).
void	setupPage(double width, double height) Sets up the page The page (and graphics context) is not valid until this method has been called.
void	startPath() Starts a path that can be filled or stroked
void	strokePath(double strokeWidth, int color) Strokes the current path and ends it

Methods inherited from interface java.io.Closeable

close

Method Detail

setupPage

void setupPage(double width,
               double height)
        throws java.io.IOException

Sets up the page

The page (and graphics context) is not valid until this method has been called.

Parameters:

width - width of page (in mm)

height - height of page (in mm)

Throws:

java.io.IOException - thrown if graphics cannot be generated

setTransformation

void setTransformation(double translateX,
                       double translateY,
                       double scale)
                throws java.io.IOException

Sets a translation and a scale factor for the subsequent operations

Before a new translation is applied, the coordinate system is reset to it's original state after page setup (see setupPage).

Parameters:

translateX - translation in x direction (in mm)

translateY - translation in y direction (in mm)

scale - scale fator (1.0 = no scaling)

Throws:

java.io.IOException - thrown if the graphics cannot be generated

putText

void putText(java.lang.String text,
             double x,
             double y,
             int fontSize,
             boolean isBold)
      throws java.io.IOException

Adds text to the graphics.

The text position refers to the left most point on the text's baseline.

Parameters:

text - the text

x - x position of the text's start (in mm)

y - y position of the text's top (in mm)

fontSize - the font size (in pt)

isBold - indicates if the text is in bold or regular weight

Throws:

java.io.IOException - thrown if the graphics cannot be generated

putMultilineText

int putMultilineText(java.lang.String text,
                     double x,
                     double y,
                     int fontSize,
                     double maxWidth,
                     double leading)
              throws java.io.IOException

Adds several lines of text to the graphics.

The specified text is automatically broken into several lines if a text line would exceed the specified maximum length of a text line. Newlines can be used to force a line break.

The text position refers to the left most point on the baseline of the first text line. Additional lines then follow below.

Parameters:

text - the text

x - x position of the text's start (in mm)

y - y position of the text's top (in mm)

fontSize - the font size (in pt)

maxWidth - maximum length of text line / width of text block (in mm)

leading - additional vertical space between text lines (in mm)

Returns:

the number of text lines that were added

Throws:

java.io.IOException - thrown if the graphics cannot be generated

putTextLines

void putTextLines(java.lang.String[] lines,
                  double x,
                  double y,
                  int fontSize,
                  double leading)
           throws java.io.IOException

Adds several lines of text to the graphics.

The text position refers to the left most point on the baseline of the first text line. Additional lines then follow below.

Parameters:

lines - the text lines

x - x position of the text's start (in mm)

y - y position of the text's top (in mm)

fontSize - the font size (in pt)

leading - additional vertical space between text lines (in mm)

Throws:

java.io.IOException - thrown if the graphics cannot be generated

startPath

void startPath()
        throws java.io.IOException

Starts a path that can be filled or stroked

Throws:

java.io.IOException - thrown if the graphics cannot be generated

moveTo

void moveTo(double x,
            double y)
     throws java.io.IOException

Moves the current point of the open path to the specified position.

Parameters:

x - x-coordinate of position

y - y-coordinate of position

Throws:

java.io.IOException - thrown if the graphics cannot be generated

lineTo

void lineTo(double x,
            double y)
     throws java.io.IOException

Adds a line segment to the open path from the previous point to the speicifed position.

Parameters:

x - x-coordinate of position

y - y-coordinate of position

Throws:

java.io.IOException - thrown if the graphics cannot be generated

addRectangle

void addRectangle(double x,
                  double y,
                  double width,
                  double height)
           throws java.io.IOException

Adds a rectangle to the path

Parameters:

x - the rectangle's left position (in mm)

y - the rectangle's top position (in mm)

width - the rectangle's width (in mm)

height - rectangle's height (in mm)

Throws:

java.io.IOException - thrown if the graphics cannot be generated

fillPath

void fillPath(int color)
       throws java.io.IOException

Fills the current path and ends it

Parameters:

color - the fill color (expressed similar to HTML, e.g. 0xffffff for white)

Throws:

java.io.IOException - thrown if the graphics cannot be generated

strokePath

void strokePath(double strokeWidth,
                int color)
         throws java.io.IOException

Strokes the current path and ends it

Parameters:

strokeWidth - the stroke width (in pt)

color - the stroke color (expressed similar to HTML, e.g. 0xffffff for white)

Throws:

java.io.IOException - thrown if the graphics cannot be generated

getResult

byte[] getResult()
          throws java.io.IOException

Returns the generated graphics as a byte array

After this method was called, the page is no longer valid.

Returns:

the byte array

Throws:

java.io.IOException - thrown if the graphics cannot be generated