Canvas1.Graphics help please

Targets macOS
21

This is exactly where your trouble comes from.

Adding Window1. as a prefix does change nothing to the matter (workse, read: Me vs. Self – Xojo Programming Blog).

In your project, using in the MouseUp Event:

Window1.Canvas1.Graphics. is the source of the evil.

At last: Window1.Canvas1.Graphics.DrawOval does not exists. I saw that at compile time.

22

I sent a post with what I did but I am not seeing it so I will send it again…

In MouseUP I have…
app.gMousedownXU = X
app.gMousedownYU = Y

MouseUp = true
Invalidate()

and in Paint I have…
if MouseUp = true Then
g.ForeColor = &cFF0000
g.DrawOval(app.gMousedownXD-3, app.gMousedownYD-3, app.gMousedownXU-app.gMousedownXD+6, app.gMousedownYU-app.gMousedownYD+6)
g.DrawOval(app.gMousedownXD, app.gMousedownYD, app.gMousedownXU-app.gMousedownXD, app.gMousedownYU-app.gMousedownYD)

else
end if
MouseUp = false

In Xojo 2018 Release 4, I can do single marquees, but when I try multiple marquees, the last one is displayed but the previous one is erased.

Thanks.

Lennox

24

Hi Emile,

I don’t have
Window1.Canvas1.Graphics

I have this…
app.gMousedownXU = X
app.gMousedownYU = Y

Canvas1.Graphics.ForeColor = &cFF0000
Canvas1.Graphics.DrawOval ( app.gMousedownXD-3, app.gMousedownYD-3, app.gMousedownXU-app.gMousedownXD+6, app.gMousedownYU-app.gMousedownYD+6 )
Canvas1.Graphics.DrawOval ( app.gMousedownXD, app.gMousedownYD, app.gMousedownXU-app.gMousedownXD, app.gMousedownYU-app.gMousedownYD )

and that works in Xojo 2018 Release 2.

This is what I have now

In MouseUP I have…
app.gMousedownXU = X
app.gMousedownYU = Y

MouseUp = true
Invalidate()

and in Paint I have…
if MouseUp = true Then
g.ForeColor = &cFF0000
g.DrawOval(app.gMousedownXD-3, app.gMousedownYD-3, app.gMousedownXU-app.gMousedownXD+6, app.gMousedownYU-app.gMousedownYD+6)
g.DrawOval(app.gMousedownXD, app.gMousedownYD, app.gMousedownXU-app.gMousedownXD, app.gMousedownYU-app.gMousedownYD)

else
end if

The project that works in Xojo 2018 Release 2 has been uploaded here… https://www.mediafire.com/file/4ngk8i7ha8aq2al/Multiple_Graphic_Marquee_2019_Feb_10'.xojo_binary_project/file

Thanks.

Lennox
MouseUp = false

25

Hi Lennox,
[I was talking about that example]

the shared project does not compile with Xojo 2018r4.

for example:

[code]Sub MouseUp(X As Integer, Y As Integer) Handles MouseUp
app.gMousedownXU = X
app.gMousedownYU = Y

Canvas1.Graphics.ForeColor = &cFF0000
Canvas1.Graphics.DrawOval ( app.gMousedownXD-3, app.gMousedownYD-3, app.gMousedownXU-app.gMousedownXD+6, app.gMousedownYU-app.gMousedownYD+6 )
Canvas1.Graphics.DrawOval ( app.gMousedownXD, app.gMousedownYD, app.gMousedownXU-app.gMousedownXD, app.gMousedownYU-app.gMousedownYD )

End Sub[/code]

You have to note the name of the event is MouseUp and you use Canvas1.Graphics in the 3 offended lines (these lines do not compile).

26

Yes Emile, I know that, it compiles and works in Xojo 2018r2 but not in Xojo 2018r4.

I have changed that to

In MouseUP I have…
app.gMousedownXU = X
app.gMousedownYU = Y

MouseUp = true
Invalidate()

and in Paint I have…
if MouseUp = true Then
g.ForeColor = &cFF0000
g.DrawOval(app.gMousedownXD-3, app.gMousedownYD-3, app.gMousedownXU-app.gMousedownXD+6, app.gMousedownYU-app.gMousedownYD+6)
g.DrawOval(app.gMousedownXD, app.gMousedownYD, app.gMousedownXU-app.gMousedownXD, app.gMousedownYU-app.gMousedownYD)

else
end if

That compiles in Xojo 2018r4 but I can only get one marquee…
In Xojo 2018 Release 4, I can do single marquees, but when I try multiple marquees, the last one is displayed but the previous one is erased.

Thanks.

Lennox

27

Isn’t it because you paint it in the Paint Event ?
(it disappears at the first refresh / Refresh happens when you Paint something in the Paint Event).

What about a Picture property (in App or Window) and Paint there ?
Doing so make no Paint disappearance(s).
Doing so will make the errors in Xojo 2018r4 to disappears.

Edit:
I trashed Xojo 2108r2 (as soon as r3 appears and do the same as soon as r4 appears).

I added to your project a Property, changed some bits in Paint, some others in mouseUp and I was able to compile/run the project.
But no marquee at all.

Now I have to go home.

28

Thanks for the info Emile, trust that someone would assist.

Thanks again.

Lennox

29

Here you go Lennox, not my best work as it was a bit quick, you’ll need to put in some error checking etc.

https://www.dropbox.com/s/2qlyc0ntkur8c5b/TestDropOval.xojo_binary_project?dl=1

30

Thanks Julian,

I can see the multiple marquees now, so I will have to implement that into my original project.

Thanks again.

Lennox

31

Thanks Julian,

Got it going the way I want.

Thanks again.

Lennox