Why does TPen not draw dotted lines?
lazarus / 39-Graphics

----------------------------------------------------------------------
eny · 2015-07-22 11:47

When setting the style of Canvas.Pen to psDot, no dotted lines are
drawn but dashed ones.
The 2nd line from the bottom is supposed to be a dotted line, but it
is a dashed line.
Only setting Cosmetic to false (bottom line) gives the expected
result.
Example:Code: [Select]  pbox.Canvas.Pen.Style := psSolid;            
                      pBox.Canvas.Line(10,10,100,10);
  pbox.Canvas.Pen.Style := psDash;                                   
 pBox.Canvas.Line(10,20,100,20);
  pbox.Canvas.Pen.Style := psDot;                                    
pBox.Canvas.Line(10,30,100,30);
  pbox.Canvas.Pen.Style := psDot;   pbox.Canvas.Pen.Cosmetic := false;
pBox.Canvas.Line(10,40,100,40);
This seems in contradiction with what is documented: "Cosmetic is to
draw 1-pixel wide lines fast"
LCL bug?
Underlying (Win-) API bug?
By design?

----------------------------------------------------------------------
rvk · 2015-07-22 13:39

Quote from: eny on July 22, 2015, 01:47:38 pmLCL bug?
Underlying (Win-) API bug?
By design?
A known WinAPI bug?
http://stackoverflow.com/questions/541166/winapi-how-to-draw-dotted-
line
http://www.experts-
exchange.com/Programming/Microsoft_Development/Q_10152035.html

----------------------------------------------------------------------
eny · 2015-07-22 14:25

Quote from: rvk on July 22, 2015, 03:39:47 pmA known WinAPI bug?
http://stackoverflow.com/questions/541166/winapi-how-to-draw-dotted-
line
Already saw that and many other examples with more or less the same
solution.
Creating a new pen does not work; the dotted line will be a 3-dot
dashed line except when Cosmetic is set to false.
In that case the example I gave already works.

>> http://www.experts-
exchange.com/Programming/Microsoft_Development/Q_10152035.html
Hardly anybody uses EE anymore after they started selling content
given to them for free by volunteers...

----------------------------------------------------------------------
rvk · 2015-07-22 14:51

Quote from: eny on July 22, 2015, 04:25:58 pm>> http://www.experts-
exchange.com/Programming/Microsoft_Development/Q_10152035.html
Hardly anybody uses EE anymore after they started selling content
given to them for free by volunteers...
I know. But they still come up in Google a lot.
I haven't got a subscription (and never had).
With script blockers they still show content/answers if gone through
Google.
(but clicking the link here I see it doesn't)