Pict1 = Pict2 Relationship ?

General
1

Somewhere in a project I have a bug. I resolved it when I reload a Picture from file.

An hour later I fall into another bug and I found it, but I am unsure why.

In the code below, what happens to Pict1 ?

[code]Pict2 = Pict1 // Initialized at the same size above

Pict2.Graphics.DrawString “Emile”,10,20[/code]

The REAL question is: WIll the “Emile” String appear too in Pict1 ?

2

Hi Emile,

A Object is Always referenced.

So keep in mind a picture is put in memoryspace and Pict1 is only a Ref to it (Link / shortcut) .
Pict2 = Pict1 means that also Pict2 now having the same reference to this picture…
So when you change the picture it’s seen by Pict1 and Pict2
Remark : Integers, and Strings doesn’t have this way of working.

Look at Picture.GetData to see how you can copy pictures.

3

Thanks Erwin for your reply.

So, in my code above, Pict2 is a simple “Alias” of Pict 1… (holds a reference to Pict1: everything I do to Pict2 is in fact done in Pict1…)

This explain my bug, a bug I do not found any explanation previously.

To be clear, think at Pict1 as a Template Pict and Pict2 is a place where I add other graphics to the Template.

I will now use:

Pict2.DrawPicture Pict1,0,0

Edit:
Unfortunately, it is not possible to lock a Picture.

4

My trouble (error above) certainly comes from:

Canvas1.Backdrop = Pict1

and

Pict1 = Canvas1.Backdrop

BTW: I do understand why there is no collateral error in these two above lines.

5

For your template picture and additional (overlay) graphics (I asume)

It’s better to play with the paint event of the Canvas object

My approach would be:

Create a new class (IDE Insert new class)
Set in Inspector supet to Canvas (superclass this Canvas object) .

add property for you template picture example : Pict_Template
add property for your adjustments perhaps a group2d object : pict_Overlay2D

Now Add event handler to your class
use g.drawpicture(Pict_Template,X,Y etc etc) (check help)

create methods in this object for drawing thing on your picture (Text, Ovals, Rect etc etc)

use g.drawobject(pict_Overlay2D)
See manual for examples of group2d

Place your new class on window and place a button to forced refresh of canvas (to play)
Paint event is called when user drags window / resize etc etc. .

If you want to do more funky stuff with your picture …(blending, collorchange etc)
Learn to copy your picture data into a memoryblock and recreate picture again and again .

I hope I give you a direction where to look for…

Kind regards,
Erwin

6

Thank you Erwin.