Method Description

GraphicImage.setPenStyle()

Set pen drawing style

Syntax

GraphicImage = GraphicImage.setPenStyle(point_colours)

Parameters

The 'GraphicImage.setPenStyle' method takes 1 parameter:

Results

The 'GraphicImage.setPenStyle' method returns GraphicImage:

Remarks

By default drawing operations such as drawRectangle, use a continuous line. This method allows this default behaviour to be modified to create dashed lines, lines of varying colour and other effects.

The style is specified as an array of 'colour values'. You can specify that particular pixels are not drawn in order to create dashed lines. Colours are specified as usual, with values returned from colourAlloc (or colourResolve). for pixels that are to remain transparent set the colour to the special value of GraphicImage.transparent.

To tell the drawing tool to use the defined style instead of a standard colour use the special colour value of GraphicImage.styled.

Example

To draw a rectangle using an long-dashed line with each dash being 10 pixels and a short gap of 5 pixels use the following style, alternate each dash between red and blue :

  // Create an empty 100x100 pixel palette based image
  var img = (new GraphicImage).create(100,100, false);

  var red   = img.colourResolve(255,  0,  0);
  var blue  = img.colourResolve(  0,  0,255);
  var t     = GraphicImage.transparent;

  // Define the style using an array of colours, using -1 to indicate transparent
  var style = [
    // Red dash
    red,red,red,red,red,red,red,red,red,red,

    // Transparent dot
    t, t, t, t, t, 

    // Blue dash
    blue,blue,blue,blue,blue,blue,blue,blue,blue,blue,

    // Transparent dot
    t, t, t, t, t, 
  ];
  // Set style
  img.setPenStyle(style);

  // Draw a dashed rectangle 75x50 pixels using the defined style. Style
  // is identified using the special colour value of '-1' (third parameter)
  img.drawRectangle({x:30,y:30},{x:80,y:80},-1);