Canvas with scrollbar example project?

Getting Started
1

Hi,

I need simple example project (that works on all three platforms) where is canvas and horizontal scrollbar.
I’ve tryed to figure it out for my own now for a week and now i have to give up.
I need to draw several pictures and text to canvas.

I’ve tryed to draw it directly to canvas (growing canvas.width) and scrolling vanvas inside rectangle:
canvas.paint

[code] Canvas2.Width = 0
If data <> Nil Then
While Not data.EOF
if data.Field(“ktype”).IntegerValue < 5 then
Canvas2.Width = Canvas2.Width + 90
g.DrawString(CStr(data.Field(“kid”).IntegerValue), Canvas2.Width-70, 370)
g.DrawPicture(p(data.Field(“ktype”).IntegerValue -1), Canvas2.Width-86, 0)
else
Canvas2.Width = Canvas2.Width + 140
g.DrawString(CStr(data.Field(“kid”).IntegerValue), Canvas2.Width-120, 370)
g.DrawPicture(p(data.Field(“ktype”).IntegerValue -1), Canvas2.Width-136, 0)
end if
data.MoveNext
if Canvas2.Width > Rectangle2.Width then
ScrollBar1.Enabled=True
ScrollBar1.Maximum=Canvas2.Width-Rectangle2.Width
ScrollBar1.Minimum=0

  Else
    ScrollBar1.Enabled=False
  End If
Wend
data.Close

End If[/code]
This won’t work at all in windows…

…and i’ve tryd to keep canvas still and moving only graphics:

If data <> Nil Then While Not data.EOF if data.Field("ktype").IntegerValue < 5 then g.DrawString(CStr(data.Field("kid").IntegerValue), (leveys + 90)-70-ScrollBar1.Value, 370) g.DrawPicture(p(data.Field("ktype").IntegerValue -1), (leveys + 90)-86-ScrollBar1.Value, 0) leveys=leveys+90 else g.DrawString(CStr(data.Field("kid").IntegerValue), (leveys + 140)-120-ScrollBar1.Value, 370) g.DrawPicture(p(data.Field("ktype").IntegerValue -1), (leveys + 140)-136-ScrollBar1.Value, 0) leveys=leveys+140 end if data.MoveNext if leveys > Canvas2.Width then ScrollBar1.Enabled=True ScrollBar1.Maximum=leveys-Canvas2.Width ScrollBar1.Minimum=0 Else ScrollBar1.Enabled=False End If Wend data.Close End If
This is closest I’ve get :slight_smile:

I think I need to draw a buffer first, but if I draw in another method to buffer, buffer.graphics it’s always NilException.

So, please someone make simple example project, I couldn’t find anything from xojo examples.

Thanks

Jukka

2

Here’s a simple example project that demonstrates horizontal and vertical scrolling of a picture in a resizable window.

3

Thanks. I made new method for drawing buffer pic. And paint just displays buffer.

Perfect!

Jukka