DrawGraph

Table of Contents

• Introduction
• Theory of operation
• DrawGraph Control
  • Property Pages
  • DrawGraph OCX
  • Example Applications

Common Vision Blox Foundation Package-Tool

Introduction

The DrawGraph Control provides a convenient and straightforward way of displaying data buffers of many different data types in form of a graph.

The DrawGraph Control was mainly designed to display the data computed by a LightMeter Control. Different from other tools on the market, which are designed to display buffer data created by programs like Excel in a variety of different chart styles, the DrawGraph Control is optimized for the belongings of image processing. The priority in the design of the tool was speed rather then a great variety of graph styles which would not be used in an image processing application anyway.

The DrawGraph Control which is shipped with the LightMeter Control can be used to display results generated by the LightMeter Control in a very straightforward way.

DrawGraph is available as part of the CVB Foundation Package.

Theory of operation

The DrawGraph Control's basic idea is to display the contents of any data buffer in form of a point chart or bar chart.

As an input the tool needs one ore more data buffers, the number of entries in each data buffer and the size of a single data buffer entry. When the control is executed it scales the included buffer entries to fit into the drawing window of the DrawGraph Control.

The scaling of the buffers is depending on the selected scale mode.

• If the linear mode is selected all buffers are scaled linear.
• If the logarithmic mode is selected the buffers a scaled with the natural logarithmic function. To scale the buffers correctly the control calculates the minimum and maximum value of a data buffer to determine the total range of the values. Depending on the selected scale mode this data is used to scale each buffer between his own minimum and maximum value or to use the minimum and maximum value of all buffers contained in the control to compute this scaling.

DrawGraph Control

DrawGraph is available as ActiveX Control only.

Property Pages

In addition to the standard properties dialog you can select and change most properties in the Property Pages of DrawGraph Control. This is a convenient way to setup the tool.

The General Property Page of a DrawGraph Control

The General page of the DrawGraph Control allows you to change the properties online and have a direct feedback of this changes.

• The Graph Style section allows you to select the different styles for the DrawGraph Control.
• The Graph Scaling section changes the scale and formatting of the graph.
• The Test Graph section allows you to show a test graph.
• The Grid Scale section changes the appearance and format of the grid.

DrawGraph OCX

The DrawGraph.ocx can be found here.

Example Applications

Tutorials using DrawGraph are to be found under %CVB%Tutorial\LightMeter.

The following image shows an example application the DrawGraph Control can be used for: