Newton Developer Technical Information: Newton Programmer's Guide: 2.1 OS Addendum /

Chapter 2 - Newton Works Draw Application / Using the Drawing Application Interface

Adding Patterns and Gray Tones to the Fill Tool

To add patterns or gray tones to the fill pattern palette, use the *RegPatterns method of the Draw application's viewDef. This method takes two arguments, a uniquely identifying symbol and an array of patterns. This array can contain any of the kRGB_GrayXX gray tone constants, a packed RGB integer (as returned by *PackRGB), or a pattern, gray pattern, or dithered pattern. For information on these values see "Specifying Shades of Gray" and "Using Patterns, Gray Patterns, and Dithered Patterns". The viewDef contains a *UnRegPatterns method to remove patterns from the fill palette.

Patterns are usually added in an auto part package. The sample code below shows the full content of a text file that creates such an auto part.

Listing 2-2 Adding to the Draw application's fill tool

 DefineGlobalConstant( 'kCheckeredPattern, 

   MakeBinaryFromHex ("F0F0F0F00F0F0F0F",'pattern)

 InstallScript := func (partFrame, removeFrame)

begin
   local viewDef := GetViewDefs('drawPaper).default;
   local sym   := EnsureInternal(kAppSymbol);
   local pats  := [  kRGB_Gray6,
                     vfGray,
                     kCheckeredPattern,
                     {  class    :'ditherPattern,
                        pattern  : vfLtGray,
                        foreground: kRGB_Gray2,
                        background: kRGB_GrayD,
                     }  
                  ];
   if viewDef then
      viewDef:RegPatterns(sym, pats)
end;

RemoveScript := func (removeFrame) 
begin
   local viewDef := GetViewDefs('drawPaper).default;
   if viewDef then
      viewDef:UnRegPatterns(kAppSymbol);
 end;