The LA Fox Developer Newsletter

February 1997

VFP Forms for Any

Screen Resolution

By Nelson M. Johnson, CCP

While I was learning MS Access, I saw a really cool demonstra-

tion of a form that would proportionally resize all the controls on

the form each time the form size was changed so that no matter

how small or large the form was, the user could still use all the

controls. I was stunned. This was the answer to my Windows-

client prayers. Now I could develop a form for one resolution and

regardless of what screen resolution the user had, my form

would always look right. I initially tried copying the code into the

forms I wanted to have this ability, but reality struck. Access

has this nasty requirement that ALL procedure names through-

out the application must be unique. This meant that if I really

wanted this to work, I would have to do some serious re-writing.

Along comes Visual FoxPro. I wrote a simplified procedure to

do this very trick and have included it below. There are four

properties you will need to add to your form: PrevHeight,

PrevWidth, BaseWidth, and BaseFontSize. You should manu-

ally set the BaseFontSize to whatever font size is your default

for the form. Then add these two procedures to your form and

you are off. There are a couple things you need to be aware of:

This will not handle container objects such as option groups and

page frames. Also, some controls have an AutoSize property

which this will set to .T., but the ones that don’t (like text boxes)

will have problems in the handling of the height property be-

cause rounding error will cause the size to “creep” if you resize

the form several times. I started to address this problem in fonts

by tracking the original base font size and then use an absolute

scaling factor, but I haven’t perfected it - I will leave that to you

to share with us. Unlike its Access cousin, this code should

allow you to drop it into many forms or classes and impress

your clients and coworkers, especially if they have been using

an FPW application.

Procedure Form.lnit()

this.prevHeight = this.height

this.prevWldth = this.width

this.BaseWidth = this.width

Procedure Form.Resize()

local InI && a loop counter

local lcName && the name of the object

local InScaleFactor && a relative scale factor

local InBaseScaleFactor && an absolute scale factor

local IcError

IcError = on(’error’)

InScaleFactor = this.width I this.prevWidth

this.prevWidth = this.width

this.height = this.prevHeight * InScaleFactor

&& the height of the form isa

&& fixed function of the width

this.prevHeight = this.height

InBaseScaleFactor = this.width / this.BaseWidth

on error * && some objects don’t have

&& FontSize or AutoSize Property

(Con't, next column)

Forum Hot Tip

Corrupted Table

/ have a small corrupted datebase which I’d like to fix and I

understand that! should use a Foxpro compatible program to

make the changes.

The Software program is Navcis 1.76, a Compusetve "offline

reader” The specific database which is couurpted is the

address book. It is about 70 kb in size and consists of 314

records. Each record is assigned a number. The numbers

should run from 1-314. Howe ver somehow the db got corru pted

and actually reads from 1 to about 150 and then starts over,

again running from about I - 150. I understand that I simply

need to open the db and manually change the numbering to I -

314. Any suggestions?

Bob

Hi Bob,

Try this-

First create a table with an exact structure like your

‘corrupted_table’.

Then-

SELECT ‘corrupted_table’

COPY TO ARRAY anyname

SELECT new_table’

APPEND FROM ARRAY anyname

VFP Forms (Con? from prey, column)

=amembers(laMembers,this,2) && get a list of object names

&& (ignore nested objects)

this.lockscreen = .t. && this will make form updates

&& wait until we are done

for InI = I to alen(laMembers)

IcName = laMembers[lnl]

with this.&lcName

.AutoSize .t.

.width .wldth * InScaleFactor

.height = height * lnScaleFactor

.top = .top * InScaleFactor

.left = .left * InScaleFactor

.FontSize int(this.BaseFontSize * lnBaseScaleFactor)

endwith

next

thls.lockscreen = .f. && allow form to udpate

on error &lcError

[Ed. Note: Nelson M. Johnson, Certified Computer Profes-

sional, is a member of the Potomac Area FoxPro Group. To

contact him, send e-mail to consult@i-t-works-inc.com. Copy-

right © 1996 i.t. Works, Inc.)

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