Canvas per Newbie

Getting Started
1

Salve. Ho una CANVAS (ImageMember) di 150x150 px con settato un BACKDROP (una immagine di 150x150 px). Ho un tasto “Add Image” con un Event Handler Action:
Dim f As FolderItem
Dim d As OpenDialog
d = New OpenDialog
f = d.ShowModal()
If f <> Nil Then
MyPic = Picture.Open(f)
ImageMember.Invalidate
End If

Sul CANVAS ho settato un Event Handler Paint :
If MyPic <> Nil Then
g.DrawPicture(MyPic, 0, 0, g.Width, g.Height, 0, 0, MyPic.Width, MyPic.Height)
End If

  1. domanda: come elimino l’immagine di BACKDROP?

Ho un tasto “Clear All” con una EH Action:
AddressField.Text = “”
CityField.Text = “”
EmailField.Text = “”
FirstNameField.Text = “”
LastNameField.Text = “”
GradeField.Text = “”
MobileField.Text = “”
PhoneField.Text = “”
ZipCodeField.Text = “”
//MyPic = Nil

  1. domanda: come elimino l’immagine caricata e ricarico l’immagine di BACKDROP?
2 
ImageMember.Backdrop = Nil

(If ImageMember is the Canvas name).

3

why not simple

If f <> Nil And f.Exists Then Canvas.Backdrop = Picture.Open(f)

4

Hi Axel. Danke für deine Hilfe. Ich habe das BACKDROP Imagedatei in einem Ordner in Xojo. Wie kann ich direkt die Datei laden ohne ein OpenDialog zu öffnen?

5

use the name that the image has in the IDE

Canvas.Backdrop = name_of_the_image

6

and to erase the image loaded into the canvas?

7 
Canvas.Backdrop =  NIL
8

I meant I want to erase the image I have uploaded after erasing the BACKDROP
I already have:
If f <> Nil Then
MyPic = Picture.Open(f)
ImageMember.Invalidate
ImageMember.Backdrop = Nil
End If

In the CLEAR Action I want: ImageMember.Clear or so…
and then I have already: ImageMember.Backdrop = photocamera

9

a new backdrop removes the old backdrop

10

But the IMAGE is not the BACKDROP. After this in the CLEAR Action:
ImageMember.Backdrop = Nil
ImageMember.Backdrop = photocamera

I have two images: the BACKDROP and the image that I loaded with OpenDialog

11

Have you read the intro to programming book and the Xojo manual?
These two things will greatly help you as a new developer.

12

remove Code in Canvas.Paint