| function graphics curiosity? bug? [message #94925] |
Mon, 11 December 2017 17:44  |
Jonathan
Messages: 8
Registered: January 2011
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Junior Member |
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Have a look at the following code:
x = findgen(128)
y = 1.0 + 0.1*randomn(seed,128)
y2 = 1.0 + 0.2 randomn(seed,128)
b = widget_base( xsize=480, xoffset=940, ysize=360, yoffset=0 )
w = widget_window( b, x_scroll_size=470, y_scroll_size=350 )
widget_control, b, /realize
widget_control, w, get_value=d
p = plot( x, y, current=d, xstyle=2, ystyle=2 )
p2 = plot( x, y2, color='red', linestyle='', symbol='+', current=d, /overplot )
d.uvalue = { x:x, y:y, y2:y2, b:b, p:p, p2:p2 }
end
This creates a widget window, w, under a base, b, and then places two overlapping plots within that window. Now, if the data changes for the second plot, I would like to do the following steps:
y3 = 1.0 + 0.2 randomn(seed,128) ; new data
p2.delete ; erases the p2 data in the plot
p2 = plot( x, y3, color='red, , linestyle='', symbol='+', current=d, /overplot )
d.uvalue.p2 = p2 ; store the plot identifier in the window's uvalue structure
The last line generates the following error message:
% Attempt to store into an expression: Structure reference.
% Execution halted at: $MAIN$
What has happened is that IDL forgot the type of d.uvalue.p2, so when I try to put a new (identical) p2 there, it rejects the attempt.
This turns out to be a huge hassle for me.
My solution is a kludge, which is to create a new structure for d.uvalue and replace the whole thing, rather than just one element.
Is there a better, simpler way?
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| Re: function graphics curiosity? bug? [message #94926 is a reply to message #94925] |
Tue, 12 December 2017 02:37  |
Markus Schmassmann
Messages: 129
Registered: April 2016
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Senior Member |
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On 12/12/2017 02:44 AM, Jonathan wrote:
> Have a look at the following code:
>
> x = findgen(128)
> y = 1.0 + 0.1*randomn(seed,128)
> y2 = 1.0 + 0.2 randomn(seed,128)
> b = widget_base( xsize=480, xoffset=940, ysize=360, yoffset=0 )
> w = widget_window( b, x_scroll_size=470, y_scroll_size=350 )
> widget_control, b, /realize
> widget_control, w, get_value=d
> p = plot( x, y, current=d, xstyle=2, ystyle=2 )
> p2 = plot( x, y2, color='red', linestyle='', symbol='+', current=d, /overplot )
> d.uvalue = { x:x, y:y, y2:y2, b:b, p:p, p2:p2 }
> end
>
> This creates a widget window, w, under a base, b, and then places
> two overlapping plots within that window. Now, if the data changes for the
> second plot, I would like to do the following steps:
>
> y3 = 1.0 + 0.2 randomn(seed,128) ; new data
> p2.delete ; erases the p2 data in the plot
> p2 = plot( x, y3, color='red, , linestyle='', symbol='+', current=d, /overplot )
> d.uvalue.p2 = p2 ; store the plot identifier in the window's uvalue structure
>
> The last line generates the following error message:
> % Attempt to store into an expression: Structure reference.
> % Execution halted at: $MAIN$
> What has happened is that IDL forgot the type of d.uvalue.p2, so
> when I try to put a new (identical) p2 there, it rejects the attempt.
>
> This turns out to be a huge hassle for me.
> My solution is a kludge, which is to create a new structure for
> d.uvalue and replace the whole thing, rather than just one element.
>
> Is there a better, simpler way?
; a simpler way:
p2.putData, y3
; ps: a '*' is missing in the definition of y2 & y3
y2 = 1.0 + 0.2 * randomn(seed,128)
y3 = 1.0 + 0.2 * randomn(seed,128)
; |
Directly updating the values is also much faster than creating a new
plot. I hope this help,
Markus
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| Re: function graphics curiosity? bug? [message #94927 is a reply to message #94926] |
Tue, 12 December 2017 06:44 |
Jonathan
Messages: 8
Registered: January 2011
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Junior Member |
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On Tuesday, December 12, 2017 at 6:37:37 AM UTC-4, Markus Schmassmann wrote:
> On 12/12/2017 02:44 AM, Jonathan wrote:
>> Have a look at the following code:
>>
>> x = findgen(128)
>> y = 1.0 + 0.1*randomn(seed,128)
>> y2 = 1.0 + 0.2 randomn(seed,128)
>> b = widget_base( xsize=480, xoffset=940, ysize=360, yoffset=0 )
>> w = widget_window( b, x_scroll_size=470, y_scroll_size=350 )
>> widget_control, b, /realize
>> widget_control, w, get_value=d
>> p = plot( x, y, current=d, xstyle=2, ystyle=2 )
>> p2 = plot( x, y2, color='red', linestyle='', symbol='+', current=d, /overplot )
>> d.uvalue = { x:x, y:y, y2:y2, b:b, p:p, p2:p2 }
>> end
>>
>> This creates a widget window, w, under a base, b, and then places
>> two overlapping plots within that window. Now, if the data changes for the
>> second plot, I would like to do the following steps:
>>
>> y3 = 1.0 + 0.2 randomn(seed,128) ; new data
>> p2.delete ; erases the p2 data in the plot
>> p2 = plot( x, y3, color='red, , linestyle='', symbol='+', current=d, /overplot )
>> d.uvalue.p2 = p2 ; store the plot identifier in the window's uvalue structure
>>
>> The last line generates the following error message:
>> % Attempt to store into an expression: Structure reference.
>> % Execution halted at: $MAIN$
>> What has happened is that IDL forgot the type of d.uvalue.p2, so
>> when I try to put a new (identical) p2 there, it rejects the attempt.
>>
>> This turns out to be a huge hassle for me.
>> My solution is a kludge, which is to create a new structure for
>> d.uvalue and replace the whole thing, rather than just one element.
>>
>> Is there a better, simpler way?
>
> ; a simpler way:
> p2.putData, y3
>
> ; ps: a '*' is missing in the definition of y2 & y3
> y2 = 1.0 + 0.2 * randomn(seed,128)
> y3 = 1.0 + 0.2 * randomn(seed,128)
> ; |
>
> Directly updating the values is also much faster than creating a new
> plot. I hope this help,
>
> Markus
That answers my question. Thank you.
I don't know why this is not made clear in the documentation, nor are there examples.
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