• Overview

  • a Graphic Layer as portion of DrawTool, accepts editing interactions and renders charts.
  • with a floating ToolBar containing choices of editable charts.

• Purpose

  • a Graphic Layer can attach to any chart view with a coordinate about Values and Dates.
  • the attached chart view as the background layer and the hosted window.
  • a Graphic Layer manages any number of independed chart graphs as sub layers. it is a connector between the hosted window and the sub chart graphs.
  • a chart graph is abstracted as DTAssistGraphisc for extending.
  • a Equation, some like x=0 is a line, 0<x<1 and y = 1 is a line segment, x*x + y*y = r*r is a cycle. a Equation alos respond to tranform coords. a chart graph can use Equations to render, move-to and hit-test.
  • edit, a chart graph has three anchor points for location and editting, this software code support a framework for editing a chart graph.

• Namings

  • files with prefix DrawTool
  • Classes with prefix DT
  • functions with prefix DTApi

• KeyRoles

  • DTAssistGraphiscs, a layer, a connector between window and sub layers.
  • DTAssistGraphisc, a sub layer, act as a chart graph
  • DTCoordinateTransform, between screen x-y-coord and view date-value-coord.
  • ENUM_ASSIST_EDIT_MODE, state machine for layer edting.