TxyGraph 2.10 Release Information.  8th August 1996

Introduction
------------------------------------------------

Welcome to the TxyGraph Version 2.2
TxyGraph is postcardware, although it's
probably good enough to be shareware now.
I've not received very many postcards...
(thanks to those who have sent me postcards). 


Contents:
1. legal stuff
2. Files in this package
3. Installation
4. What's new
5. Backwards compatibility notes
6. What's next


1. Legal Stuff
------------------------------------------------

This code is copyright  Grahame Grieve. (Kim 
Kirkpatrick also has copyright on the code for 
TxyGraph - Kim is at least as much responsible
for the improvements in TxyGraph as I am).
Thanks also to Paul Bailey.

Although we've done our best to make TxyGraph 
bug-free, we are not responsible for any mishaps
that may occur during proper or improper use of 
TxyGraph. The same applies to the other components
included in this package.

If you use TxyGraph, you should send me a postcard.
If you pass TxyGraph on, you must include all 
the files listed below, and this file as is.

If you improve TxyGraph, you might send me a copy.
Kim did, and everybody benefits.


2. Files Included
------------------------------------------------

Enclosed in this zip file is the following files:

xyGraph.txt  - this file

xydata.pas   - } source code
xyGraph.pas  - } for TxyGraph

xyGraph.dcr  - delphi 1 dcr file.
xyGraph.hlp  - documentation for TxyGraph

xyeditor.pas - } source for the runtime/designtime 
xyeditor.dfm - } editor

xyhist.pas   - } THistogram Source
xyhist.dcr   - } Delphi 1 dcr for THistogram

oldgraph.zip - source code for version 1

Grafdemo.dpr - }
graph.pas    - }
graph.dfm    - } Example program 1
statform.pas - }
statform.dfm - }

graphtst.dpr - }
graph_f.pas  - } Example Program 2
graph_f.dfm  - }


3. Installation
------------------------------------------------

To install TxyGraph, copy xydata.pas, xyeditor.pas,
xyeditor.dfm, xygraph.pas,  and xygraph.dcr into 
your standard component directory and install 
xygraph.pas.
To install THistogram, you need the files xyhist.pas, 
xydata.pas and xyhist.dcr. install the file xyhist.
If you are using Delphi 2.0, you'll need to open 
xygraph.dcr and or xyhist.dcr in the 32bit image 
editor and then save it. (xygraph FAQ no #1).
You may find that you need to add xydata to your uses
clause. If anyone can tell me how to get around this
requirement, I'd be grateful!


4. What's new
------------------------------------------------

Version 2.0
* it's now a lot more stable - no more crashes because
  of bad axes settings
* Much smarter axis scaling
* No limits to the amount of data
* Much improved data interface
* Plot functions and annotations on the graph
* Regression and general statistical analyses of data
  available
* proper printing routine
* automatic scaling and moving of the graph

Version 2.1:
* TDataseries - all the data handling capacity
  separated from TxyGraph
* Dates on Axes

Version 2.2  
* Second Y axis
* More Statistical analysis
* hooking foreign TSeries
* inclusion of THistogram and TxyzGraph
* designer


5. Backwards compatibility with version 1
       (or at least, where there is a lack thereof)
------------------------------------------------
General comment about backwards compatibility:
It's getting harder to maintain backwards compatibility
with version 1. I don't know how much longer I'm going
to bother. Backwards compatibility with version 2.0+
will obviously last a lot longer

* Notes for version 2.2:
 
-Gridlines has been split between the different Axes
-The creation of new font properties will probably
 cause you some trouble

* Notes for version 2.0 - 2.1:

Just about everything has changed one way or another
since version 1. Internally the structure has changed
so much that 99+% of the code is different.

However there have been few changes to the public and
published parts of TxyGraph. Changes are listed here

renamed:
 - GridColour to GridColor 
   and all other places where Colour occurred.
    (especially for the Americans)

changed:
 - get function  - to getpoint/getvalue
 - delete function - to deletepoint/deletevalue

    These changes were to allow multiple data points
   with the same x value. Refer to the help file for
   the syntax and use of these new functions.
    If you set the new property AllowDuplicates to
   false you can ignore the indexing parts of these
   functions and supply them with dummy variables
   It's probably better to change to use the new data
   interface, since you have to change things anyway.

You'll also find that the autoscaling scales differently 
now. But I hope you'll agree that it's heaps better!

Removed:
 - Text - graph always plots the axes now. The
          name of the graph will always be visible
          at design time, but not at all at runtime

 - OnNumericalError - Handling of invalid plotting has
          been completely changed. The 2 new events
          OnScaleError and OnLogError replace it

A whole host of properties have been moved out of the 
published section, to present a more structured interface
in the object inspector. You will receive a series of 
errors the first time you use the new version. Don't worry!
The old properties are available in the public section so that
they are still usable in your code. But you will have to 
use the new properties in the object inspector.

6. What's next.
------------------------------------------------

There is a few improvements to be made to TxyGraph:

* At present we are not able to provide printed lines that are
  both scaled to an appropriate thickness and also dotted or
  dashed - this is a limitation of the Windows API.
  Fixes welcomed with glee.
* I want a copy to clipboard method to copy a wmf. I can
  produce a metafile ok, but I haven't figured the scaling
  issues out. (again, I happily accept help)
 
However there is no time-scale associated with these changes.

Grahame Grieve
g.grieve@pgrad.unimelb.edu.au








