GraphicImage Template

drawPixels()

Set the colour for specific pixels within an image

Syntax

GraphicImage = rb.GraphicImage.drawPixels(pointArray, defaultColour)

Parameters

The 'drawPixels' method takes 2 parameters:

Results

The 'drawPixels' method returns GraphicImage:

Remarks

'draw' one or more pixels at [x,y] co-ordinates within the image. The target pixels are specified in an array and so a single call can draw many pixels.

The colour with which pixels are drawn can be determined in one of two ways:

1. On a pixel-by-pixel basis within the array by specifying a colour attribute 'c' on each pixel
2. By alternatively specifying a 'defaultColour' second parameter

These two colour specifying methods are not mutually exclusive so you can specify a default colour and then over-ride that on a pixel by pixel basis as needed.

If a pixel does not have a specifically defined colour and there is no defaultColour parameter then : for true-colour (the default) pixels are set to black ; for palette based, to the colour index '0' within the palette (first colour specified).

Example

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

  // Draw the pixels {0,0},{1,1},{2,2} to red and the pixel at {3,3} to blue
  var red  = img.colourAlloc(255,0,0);
  var blue = img.colourAlloc(  0,0,255);

  var pixels = [
    {x:0, y:1},
    {x:1, y:1},
    {x:2, y:2},
    {x:3, y:3, c:blue}
  ];
  img.drawPixels(pixels,red);