Package 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

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method 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
      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.
      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
      void setupPage​(double width, double height)
      Sets up the page
      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

      • 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