Re: Color question

[Peter Krueger <pkrueger appss de>]

On Wed, 31 Mar 2004, kadil wrote:
> I have an appthat is reading data from an odbc database and drawing the
> results on a drawing area. One line drawn per row returned. Table data as
> follows:
>
> Start_of_line         End_Of_Line     Color
> 0                     10                      565466
> 10                    17                      99094
> 17                    42                      255
>
> One of the columns returned is a color. So I want to draw the each rectangle
> colored as per the record. When I try to change the color, it changes the
> color of all the previous rectangles that I have drawn. Do I need to define a
> separate color for each possible color option?
Hi kadil,
it's not clear to me how you draw your rectangles in detail. What you
should do is:
- invalidate your drawing area when your data changes, so that an
  expose-event is generated (gtk_widget_queue_draw_area)
- in the expose-event handler:
  - set draw color
  - draw a rectangle
  - set next draw color
  - draw next rectangle
  and so on

You should decide yourself whether you read data from the database every
time an expose-event occurs or rather cache them in own data structures
inside your program.

Regards,
                         Peter
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