Method Description

GraphicImage.colourResolve()

Allocate a colour for use in drawing methods

Syntax

number = GraphicImage.colourResolve(red, green, blue, alpha)

Parameters

The 'GraphicImage.colourResolve' method takes 4 parameters:

Results

The 'GraphicImage.colourResolve' method returns number:

Remarks

Allocate a colour for subsequent drawing operations. For true-colour images this method always returns the requested colour and is functionally identical to colourAlloc.

For palette images this method allocates colours from the available palette using the following palette :

1. A search is made of existing colours. If there is an exact match with the requested colour then that is returned to the application
2. If there is no exact match, but the palette is not full then a new palette slot is allocated for the requested colour and that is returned to the application
3. If there is no exact match and the palette is full then the set of existing colours is compared against the requested colour and the best match is returned to the application

Example

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

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