Using perfmon to analyze the performance and code of GDI +

How many times have the paint event been triggered? In a simple way, we can create a counter that can be used by perfmon. ViewCode:

1 Private   Void Button#click ( Object Sender, eventargs E)
2 {
3
4 If ( ! Performancecountercategory. exists ( " GDI + Monitor " ))
5 {
6 Countercreationdatacollection CCDC =   New Countercreationdatacollection ();
7
8 Countercreationdata totalpaint =   New Countercreationdata ();
9 Totalpaint. countername =   " # Operator executed " ;
10 Totalpaint. counterhelp =   " Counts of onpaint events called " ;
11 Totalpaint. countertype = Performancecountertype. numberofitems32;
12
13 CCDC. Add (totalpaint );
14
15 Performancecountercategory. Create ( " GDI + Monitor " , " Some counters for GDI + objects " , Performancecountercategorytype. multiinstance, CCDC );
16 }
17 }

Okay, click button1 and we can see the category of GDI + Monitor in perfmon. Then there is only one counter, that is, # Operator executed.

Then add the following section to winform: Paintcall =   New Performancecounter ();
Paintcall. categoryname =   " GDI + Monitor " ;
Paintcall. countername =   " # Operator executed " ;
Paintcall. machinename =   " . " ;
Paintcall. readonly =   False ;

Okay, you can use the paintcall variable in the code. Our current requirement is to monitor how many times the paint is triggered, so you can write it in the Code: 1 Graphics G2 = E. graphics;
2
3 Bitmap BMP =   New Bitmap ( This . Width, This . Height );
4 Graphics g = Graphics. fromimage (BMP );
5
6 Paintcall. increment ();
7
8 Rectangle R =   New Rectangle ( 0 , 0 , This . Width, This . Height );
9 G. fillrectangle ( New Lineargradientbrush (R, color. Red, color. Blue, lineargradientmode. backwarddiagonal), R );
10
11 G2.drawimage (BMP, New Point ( 0 , 0 ));
12
13 G. Dispose ();
14 G =   Null ;
15
16 BMP. Dispose ();
17 BMP =   Null ;

Look at the above 6th rows. This sentence will add a paint call. Of course, there are many other methods. I will not write them here.
Run perfmon and add the newly added counter. Well, we can see that when the window is invalid, the counter is increased.

There is a small detail. When the window size is slightly changed, you will find that the paint has been called many times, which is really depressing. So, do something: 1 Private   Bool Resize =   False ;
2 Private   Void Form1_resizeend ( Object Sender, eventargs E)
3 {
4Resize= False;
5This. Invalidate ();
6}
7
8 Private   Void Form1_resizebegin ( Object Sender, eventargs E)
9 {
10Resize= True;
11}

Then let's modify the code of the paint event as follows: 1 Private   Void Form1_paint ( Object Sender, painteventargs E)
2 {
3 If ( True   = Resize) Return ;
4
5 Graphics G2 = E. graphics;
6
7 Bitmap BMP =   New Bitmap ( This . Width, This . Height );
8 Graphics g = Graphics. fromimage (BMP );
9
10 Paintcall. increment ();
11
12 Rectangle R =   New Rectangle ( 0 , 0 , This . Width, This . Height );
13 G. fillrectangle ( New Lineargradientbrush (R, color. Red, color. Blue, lineargradientmode. backwarddiagonal), R );
14
15 G2.drawimage (BMP, New Point ( 0 , 0 ));
16
17 G. Dispose ();
18 G =   Null ;
19
20 BMP. Dispose ();
21 BMP =   Null ;
22 }

Note that in the third row, we determine that if the resize process is used, the system returns the result directly. In this way, although the interface is like a whiteboard, but a lot of painting operations are missing, the performance will be much better.