On Mon, 21 Mar 2011, Mattias Gaertner wrote:
On Mon, 21 Mar 2011 11:25:12 +0100 (CET)
[email protected] wrote:
[...]
Using widgetset is perhaps not the ideal solution, but the practical one,
given the contraints of existing tools.
Surely they may be improved, but that is not fast not easy to do.
Correct. Unfortunately, no-one seems to be willing to take on the task :(
Huh?
AFAIK you can do quite a lot with fpcanvas. You
can use fonts. But using fonts is not very comfortable because you have
to search and load it yourself.
None of "theme, screen color depths and sub pixel rendering parameters" are
necessary to create a bitmap. A bitmap is a matrix of pixels with a certain
color. No more, no less. Some of these parameters are needed when the bitmap
is being displayed, but definitely not when it is created.
I am not sure how you could create a bitmap without (at least implicitly)
specifying color depth.
There is no need for 'color depth'. A color is 4 words; that's it.
48bit for each pixel costs a lot of mem and speed.
But it is easy with fpimage to define a RGB 8bit image or RGBA or
grayscale.
[...]
I even suspect that in many cases widgetset drawing is faster than
pure FPCanvas.
Why?
AFAIK in cgi you can not use the hardware acceleration.
You don't need it, either.
When generating a bitmap, I don't see how hardware accelleration
of the graphics card comes into play ?
When generating a bitmap 'on screen', the double buffering mechanism
means that
a) you somehow create it in memory
b) it is then moved 'accelerated' to screen.
and in 95% of cases, even without double buffering, this is the mechanism
used.
Since CGI only needs step a), the 'acceleration' is not needed.
Now, the fact that a widgetset tries to access *screen* to create a bitmap
is a problem, I would even call it a bug, although I do not know if it
is in GTK or LCL.
I suppose the LCL, because most likely it asks some system metrics (DPI etc).
The widgetset can only get them from the display...
Since you are the second to blame the LCL, let's try the most simple
gtk program:
program test1;
uses gtk2;
begin
gtk_init(nil, nil);
end.
$ ./test1
(test1:3683): Gtk-WARNING **: cannot open display:
Obviously, but AFAIK it is the LCL that calls gtk_init ?
Simply linking to GTK doesn't open a display, I presume.
Michael.
--
_______________________________________________
Lazarus mailing list
[email protected]
http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
