趋势图控件源代码

Trend Component - additional information. ----------------------------------------- The Trend component is a graphical component designed to show an animated plot of parameter values. As values are added old values scroll off the graph to the left. The trend can be viewed in a number of ways tsBar - Each value is represented as a rectangle tsLine - A line is drawn connecting each value tsScatter - A small rectangle is drawn at each value ts3D - Each value is represented by a 3D rectangle tsFilled - As tsLine with the area below the line filled A few options can be applied toValues - On tsBar and ts3D text values are added to each column. toTwin - Two values are displayed for each slot One area where the toTwin option is useful is when monitoring systems with demand and feedback values. Here it is important to know that a given command is tracked accuratley. Differences between command and feedback are especially well highlighted by using ts3D and toTwin as shown in the TrendTwinDemo program. Before you can compile the demo programs you need to install the component trend.pas in the usual way. To see what the component does without installing it just run the .exe demo files included in the demo archive. Two example programs are included with source. How to use it. -------------- Once installed the component appears on a new tab called 'Mark'. It is based on a standard TPanel component so inherits all of TPanel's properties. The new things it creates are as follows :- Methods. -------- Add( Integer ) - Adds the specified value to the graph on the right, shifting the previous values to the left. AddBase( Integer ) - Adds the specified value to the Base values on the right, shifting the previous values to the left. Base values are only used when the option toTwin is true. Clear - Set all values to zero. ClearBase - Set all Base values to zero. Get( Integer ) - Return the value at the specified position. GetBase( Integer ) - Return the specified base value at the specified position. Demo - Each time you invoke this a new random point is added to the graph. Properties. ----------- Divisions - The number of points in the graph. (2 to 100) ColorBase - The colour to use for Base values in toTwin mode. MinVal - The minimum value to display. MaxVal - The maximum value to display. Options - toValues to display text values of tsBar and ts3D toTwin to display twin data sets Style - tsBar to display as 2d barchart tsLine to display as lines ts3D to display as 3d barchart tsFilled to display as a line filled underneath tsScatter to display as points Archive file details. --------------------- trend.pas - Component source file trend.dcr - Component toolbar image trend.txt - This file A demo of the toTwin option TrendTwinDemo\TrendTwinDemoProj.exe - Ready built demo TrendTwinDemo\TrendTwinDemoProj.dpr - Project file for building demo TrendTwinDemo\TrendTwinDemo.pas - Source TrendTwinDemo\TrendTwinDemo.dfm - Form info A general demo of trend types TrendDemo\TrendDemoProj.exe - Ready built demo TrendDemo\TrendDemoProj.dpr - Project file for building demo TrendDemo\TrendDemo.pas - Source TrendDemo\TrendDemo.dfm - Form info --------------------------------------------------------------------------------- Author - Mark Dodson Date - 4th July 1997 email - MarkDodson@aol.com ---------------------------------------------------------------------------------