Disclaimer

The content of this blog is my personal opinion only. Although I am an employee - currently of Imagination Technologies's MIPS group, in the past of other companies such as Intellectual Ventures, Intel, AMD, Motorola, and Gould - I reveal this only so that the reader may account for any possible bias I may have towards my employer's products. The statements I make here in no way represent my employer's position, nor am I authorized to speak on behalf of my employer. In fact, this posting may not even represent my personal opinion, since occasionally I play devil's advocate.

See http://docs.google.com/View?id=dcxddbtr_23cg5thdfj for photo credits.

Wednesday, October 24, 2012

How to capture a screen image with transient flyovers in VNC

I usually work in VNC, on a UNIX box, typically from a Windows PC latop.

I occasionally want to capture screen clippings of GUI applications running in VNC.   Problem: often they are transient - any key press, etc., causes what I want to capture to disappear.

Usually on Windows my scren capture tools (Windows 7's snipping tool, or SnagIt) have a keyboard or mouse shortcut that takes priority.  However, apparently VNC managed to install itself underneath, so all keyboard and input events get sent to VNC and Linux and the app.

So here's how to capture such a transient GUI popup or the like in VNC:

VNC has its own shortcut. On my machine, F8.

Press F8. Go to the VNC options menu. Unselect "send keyboard events to server" and "send mouse events to server".  Now enter the screen capture shortcut.  Undo so that VNC works again.

Not nice, but I can use it.  Will have to see whether AutoHotKey is underneath all of these so can shortcut.

GMake order dependent inconsistency

I dislike how GMake is inconsistent about ordering:

You can define rules out-of-order

top-rule: sub-rule1 sub-rule2
      @echo top-rule
sub-rule1:
      @echo sub-rule1

sub-rule2:
      @echo sub-rule2

but if you want to do something like collecting the sunb rules in a variable this breaks

top-rule: $(SUBRULES)
      @echo top-rule
SUBRULES+= sub-rule1
sub-rule1:
      @echo sub-rule1

SUBRULES+= sub-rule1
sub-rule2:
      @echo sub-rule2

because the variable is expanded when encountered

It must be fixed by rearranging

SUBRULES+= sub-rule1
sub-rule1:
      @echo sub-rule1

SUBRULES+= sub-rule1
sub-rule2:
      @echo sub-rule2
top-rule: $(SUBRULES)
      @echo top-rule

Darn! But I like being able write things out of order, top-down.

In general, I like languages that have relaxed order dependencies.  Like some RTL languages (notably Intel iHDL).  Even C++ has relaxed ordering in some places.

But the inconsistencies such as above are painful and confusing.

--

Single assignment is the easiest way to do non-order dependent.

But accumulation - += - is very much required.

Q: is the accumulation done order dependent, or not?

What is needed is accumulating += - probably order dependent.
And then expanding.

With an error if expanding results in changes to variables already being expanded.  ??

Or relaxation.