[QGIS-Developer] Preview job and slow datasources

[Matthias Kuhn]

Hi Patrick,

This uses some memory (~ canvas width pixels * canvas height pixels * 8
preview images * 32 bit RGBA), so let's assume 50 MB to 100 MB.

This consumption is independent from the number or type of layers.

Matthias


On 11/16/2017 08:02 AM, Patrick Dunford wrote:
>
> So to put it another way this is the reason why Qgis wants to use a
> huge amount of memory (40 GB) when I have a lot of raster images
> loaded in the background.
>
>
> On 16/11/17 18:56, Tim Sutton wrote:
>> Hi
>>
>>> On 16 Nov 2017, at 04:35, Patrick Dunford <enzedrailmaps at gmail.com
>>> <mailto:enzedrailmaps at gmail.com>> wrote:
>>>
>>> What is this "preview job" function?
>>>
>>>
>>
>> Its application logic to prefetch / pre-render offscreen content in
>> anticipation of user panning the map.
>>
>> Regards
>>
>> Tim
>>>
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>> —
>>
>>
>>
>>
>>
>>
>> *Tim Sutton*
>>
>> *Co-founder:* Kartoza
>> *Project chair:* QGIS.org <http://QGIS.org>
>>
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>
>
>
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