Applies To:
  • CitectSCADA 3.00
Summary:
If Citect is running on a page with colour floods that are flooded and I switch to another windows application. if the other application is move so that it uncovers the colour flood, the colour flood redraws in its un-flooded state and not in the flooded state as it should. Why does this occur?

Solution:
Colour flooding is a feature which does not suit a windowed graphical environment. As discussed in some detail in knowledge base article Q1567 when a colour flood is on a page and a portion of the screen needs to be re-drawn the whole page must be re-drawn to guarantee that colour floods are drawn correctly. This type of behaviour would be unacceptable for most users so some optimisation code was added to limit the amount of redrawing that is required. However, for this optimisation to work Citect needs to know about all windows that are on top of it. Being aware In this context means that communication needs to take place between Citect and the other windows and visa-versa. The only windows that Citect is aware of are ones which are owned by Citect such as Tip Help, genies and popups. For other applications this communication is not possible. Thus when another application is on top of Citect and you move that application, uncovering a portion of the Citect page, flooded colour floods will not redraw correctly. However, when switching focus back to Citect the colour floods will repaint correctly.  
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