Re: [perl-win32-gui-users] flickering static-DC

[Jason P. <ma...@wa...>]

Hello Raphael,
I unfortunately do not have a breadth of experience with the DC object as
some on this list, but having seen this I can at least offer some tid-bit of
possible use. I would say that the one means I can come to think of is
ignoring repaint wherein there is no cause to redraw this particular
rectangle. Ok, this sounds a simple concept, but I realize this may not be
as easy to complete in reality. This of course, offers no help with the
issue of the bad flicker during dragging, but it offers some to the regular
usage flickering.


Jason  P

On Sun, Mar 8, 2009 at 7:54 PM, Raphael Stoeckli <win...@ra...>wrote:

> Hi @ all
>
> I try to plot a static DC-Object (means: the graphic is calculated uniquely
> at runtime, depending of several parameters, and does not change while
> displaying the window) in a window.
> The problem is that this object continuously needs to be redrawn, because
> it
> vanishes during moving the window around, or if an other window is moving
> over it.
> I thought, a repaint-routine like that would solve the problem:
> -------------------------------------
> use strict;
> use Win32::GUI();
> our $WIN;
> our %DC;
>
> &build_gui;
> Win32::GUI::Dialog();
>
> sub build_gui # Building the GUI
> {
> $WIN = new Win32::GUI::Window(
>      -left => 200, -top => 200, -width  => 300, -height => 300,
>      -name   => "WIN",
>      -text   => "Static-DC-Test",
>      #-noflicker => 1, # Useless/worse result
>      );
> $WIN->Show();
> $DC{'color'}{'white'} = [255,255,255];
> $DC{'color'}{'red'} = [255,0,0];
> $DC{'pen'} = new Win32::GUI::Pen( -color => $DC{'color'}{'red'}, -width =>
> 3, );
> $DC{'brush'} = new Win32::GUI::Brush( -color => $DC{'color'}{'white'},
> -width => 1, );
> &repaint;
> $DC{'timer'} = $WIN ->AddTimer("timer", 100);
> }
>
> sub ::timer_Timer # Repaint DC with interval of 'timer'
> { &repaint; }
>
> sub WIN_Terminate { return -1; }
>
> sub repaint # Create/rebuild DC-Object
> {
> $DC{'dc'}{'object'} = $WIN -> GetDC;
> $DC{'dc'}{'object'} -> FillRect(10, 10, 280, 260,$DC{'brush'});
> $DC{'dc'}{'object'} -> SelectObject($DC{'pen'});
> $DC{'dc'}{'object'} -> BeginPath();
> $DC{'dc'}{'object'} -> MoveTo(10, 10);
> $DC{'dc'}{'object'} -> LineTo(280, 260);
> $DC{'dc'}{'object'} -> EndPath();
> $DC{'dc'}{'object'} -> StrokePath();
> #$DC{'dc'}{'object'}   -> Save(); # ??? Save() --> Restore() ???
> }
> -------------------------------------
> But the result of the code above is a flickering, annoying graphic.
> So the next thought, was to generate a bitmap from the DC. There is, if I’m
> not wrong, a method with DIBitmap. But, I would like to refrain from
> binding
> in that module, only for converting a single graphic, because it’s bloating
> up the program/PAR-binary.
>
>
> Sadly, the DC-Documentation is frequent a sealed book for me.
> Does anyone know an easy method (I also like to take a complex solution
> :-))
> to convert a DC into a bitmap-object, without using DIBitmap? Or, even
> better, a way to prevent that flickering during the repaint?
>
> Thanks a lot.
>
> Regards,
> Raphael
>
>
>
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