---------------------------------------------------------------- Knob VBX Control Copyright 1994 Northeast Data Corp. All Rights Reserved ---------------------------------------------------------------- Release 1.0 March 1994 This document describes the Knob Custom VBX Control. CONTENTS 1. Product Description 2. Legal Information 3. Installation 4. Usage 5. Ordering Information ---------------------------------------------------------------- 1. Product Description The Knob VBX Control is a Microsoft Windows DLL designed and implemented in compliance with Microsoft standards for interfacing with Visual Basic. The control appears to the end user as a knob similar to those used on audio/video equipment such as stereos, tuners, and amplifiers. To the application programmer, the interface to the knob is similar to the one for the MS Windows standard scroll bar. The programmer can set a range of values that will be fed back to the application as the end user adjusts the position of the knob. Being a VBX control, the programmer can add the Knob Control to the tool palette in Visual Basic. This allows use of the control in Visual Basic forms. Since Visual C++ supports use of VBX controls, the knob control can also be used in the Visual C++ environment. Use of the Knob Control in a finished application requires the Knob Control DLL (knob.vbx) to be installed with the application. This is true of all custom controls written for MS Windows. There are properties available that allow the programmer to control the behavior and appearance of the knob Control. The knob can use a dot or a line as a pointer. The knob can increment it's values in either a clockwise or counter clockwise direction. The knob can also specify the range of degrees used for rotation. This feature allows the knob to rotate several times before reaching it's stop. The range of the knob can be set to any range with low and high values varying from 0 to 32767. All communication between the Knob Control and the application is performed using the standard Windows message mechanism for controls. Design of the knob Control message mechanism allows the application to continuously monitor the setting of the control. ------------------------------------------------------------------- 2. Legal Information The purchaser of the Knob Control is allowed to use it and distribute it in applications without paying any royalty, and without printing or displaying a copyright notice for the control. This only includes distribution of the Knob Control DLL (KNOB.VBX). It does not include distribution of documentation that comes with the Knob Control. The purchaser of the Knob Control may distribute the control DLL with applications that are networked (multiple users accessing the DLL from a file server) without paying any license fees to Northeast Data Corp. ------------------------------------------------------------------- 3. Installation Create a "knob" directory on your hard disk and copy all files from the distribution disk to the directory. These files include: KNOB.VBX FORM1.FRM PROJECT1.MAK README.TXT VBTEST.EXE If you have downloaded the knob1.zip file from Compuserve, use PKUNZIP to extract the files into the directory. Start Visual Basic or the Visual C++ App Studio applications and use the custom control installation function to install the knob.vbx control. ------------------------------------------------------------------- 4. Usage PROPERTIES ---------- BackColor - Sets the background color. DegreeMax - The maximum degree value used during rotation (long). DegreeMin - The minimum degree value used during rotation (long). Delay - The number of milliseconds used for the delay while holding the left mouse button down. Direction - The direction used to increment the value of the knob. 0 - Normal (clockwise) 1 - Reversed (counter clockwise). FaceColor - Sets the color of the knob face. Height - Height of control. HighlightColor - Sets the outer bevel color. KnobType - 0 - Point, 1 - Line Left - Left position. Max - Maximum knob value. This must be greater than the minimum knob value. Min - Minimum knob value. This must be less than the maximum knob value. PointColor - Sets the color of the point or line. Pos - Current knob position. This must be a value between or including the current minimum and maximum values of the knob. ShadowColor - Sets the color of the focus bevel. TabStop - If this is turned on (1 instead of 0), the knob can be activated by tabbing to it with the TAB key. Tag - Control tag. Top - Top of control window. Visible - Visible/Invisible attribute. Width - Width of control. EVENTS ------ These events work the same way as for other VBX controls. DblClick DragDrop DragOver GotFocus KeyDown KeyUp LostFocus LMouseDown - Occurs when the left mouse button is pressed down LMouseUp - Occurs when the left mouse button is released ValueChanged - Occurs when the value of the knob has changed In order to update values in your application based on the current position of the knob control, you should handle the ValueChanged event. Ordering Information -------------------- To order the commercial version of the Knob Control, send a check to: Northeast Data Corp. 2117 Buffalo Rd., Suite 290 Rochester, NY 14624 The prices are: Knob VBX Control (for Visual Basic and Visual C++) - $55 Knob DLL Custom Control (for C) - $50 Both controls - $75 Source code (includes both controls) - $235 Include your phone number and Compuserve ID if applicable. In return for your check, you will get the software, a telephone number for support, and a Compuserve ID for support.