Graphing Data - Setting the stage

If I have a set of data for sales, or temperature, or mosquito populations, or anything at all and I want to plot it on an X/Y graph, what are my choices for layout?

Should our graphing library figure out what the ranges are and set its own scaling?  Should it require that we tell it up front what the X and Y scales are?  Maybe it can even be designed to allow for changing the scale on the fly?

It would be great if our data plotting graphics library could handle plotting to screen, saving that to a file as a bitmap, and also plotting to a printer.

How about data sources and formats?  Should we design it to accept one or more strings of delimited values?  In the graphing example at runbasic.com it allows you to upload a CSV file with data to plot.  Maybe as an interesting example I should find a downloadable file from a scientific website and the project should be to plot a graph from that?

Feedback welcome.  More to come.

GETCLIENTRECT - Gettting the dimensions of the inside of a window

Sometimes it comes in really handy to know exactly what the limits of the inside of a window are.  For example, if your Liberty BASIC program opens a window that is 500x400 pixels and you want to draw graphics that fit precisely or you are creating a game.. Think of Space Invaders where the aliens march back and forth on the screen!  You need to know the precise inner dimensions of the window so you need to know how thick the window frame is and also the title bar on top of the window.

The trouble is, these measurements are not going to be the same from one version of Windows to another, and they change if you modify your system font sizes.

So what to do?  Windows provides us a way to get the dimensions of the inside of the window by using the GETWINRECT function.

    WindowWidth = 500
    WindowHeight = 400
    open "get client rectangle" for window as #w
    'Get the window handle
    hndl = hwnd(#w)
    'Declare the struct which will be used to get the window client rectangle
    struct winRect, orgX as long, orgY as long, cornerX as long, cornerY as long
    'Make the GetClientRect call
    calldll #user32, "GetClientRect", hndl as ulong, winRect as struct, result as Boolean
    'Grab the width and height from the struct
    wide=winRect.cornerX.struct-winRect.orgX.struct
    high=winRect.cornerY.struct-winRect.orgY.struct
    notice "inside of window frame width = "; wide; " height = "; high

BASIC and CSS

One of the important aspects of integrating a programming language with web development is page layout. Until recently this would have meant inserting lots of HTML tags into your source code. You can do this with Run BASIC.

However there is a better way. It is called CSS (Cascading Style Sheets). This provides a way to wrap the things on your web page with tags that you give your own names to, and you defined the appearance of the stuff wrapped in those tags somewhere else. This way your program's code has very little extra stuff in it to clutter up your code. If there is too much clutter it can be very hard to understand what code means, and this can slow you down and lead to bugs.

So, Scott McLaughlin and I have begun to integrate CSS with Run BASIC. We added a CSSID statement (originally this blog entry had this as CSS, but we changed the command), a DIV statement, and an END DIV statement. Here's a very short example:

cssid #myTag, "{ background: #FFDDDD; font-family: tahoma }"

div myTag
print "count to ten"
for x = 1 to 10
print x
next x
end div

Okay, so this displays all the text printed between the DIV and the END DIV with a light red background, and using the tahoma font. The #myFont token isn't a handle like the ones used for files and GUI controls. The # is simply part of CSS syntax.

DIV statements can be nested, and the contents of one DIV block will be rendered on the page nested inside of each other.

There is a lot more that can be done with CSS, and we're trying to explore what are the simplest and most useful things to include in Run BASIC.

We will be posting a screencast in the next few days that shows how this works.