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Re: Transparent backgrounds for controls

Profox Jase13-Feb-02 5:38

Profox Jase

13-Feb-02 5:38

Hi Senkwe,

Thanks for taking the time to help me. I have tried your idea but nfortunately your suggestion does not solve the problem.

My polygon represents an irregular shape - actually, an asteroid.

The foreground is, say, red - yes, a red asteroid (and why not?).
The background which c# paints it on is the same colour as the form (grey).
It is possible to change the background colour to black, green etc etc. When you do this, you get a red asteroid in a black (or whatever) rectangle.

When two asteroids overlap slightly the rectangle from one blocks out (is on top of) the other asteroid - this is my problem. All asteroid need to be drawn on a transparent rectangle so that their canvasses do not obscure each other.

If you look at control.settype, it seems there may be a way to make the background colour transparent, in fact I have managed this, however, the asteroid is redrawn very slowly.... here is some of the code from the constructor of asteroid:control

public asteroid(int startX, int startY, int incX, int incY, Form theForm)
{
this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.backgroundColor = Color.FromArgb(1,Color.Gray);
...

I think I will tidy up my code and paste here for people to read. As an additional problem, when I am performing collision testing, I have a peculiar problem that seems to be inconsistent. When I create a rectangular region from my asteroid control, I can use region.isVisible(point) to test whether point is included in the region. This works. When I create an asteroid shaped region (instead of a rectangular shape), the call to region.isVisible(point) always seems to return false. Perhaps I am misunderstanding the region concept. Any ideas?

Jase

jason.king@profox.co.uk
Feel the love at www.profox.co.uk

Re: Transparent backgrounds for controls

James T. Johnson13-Feb-02 8:11

James T. Johnson

13-Feb-02 8:11

One thing that might speed up your drawing code is to enable double buffering, then all of your graphics drawing is done in system memory; then copied to video memory once; by passing the system->video bottle neck.

Hope that helps a little,

James

Sonork ID: 100.11138 - Hasaki
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

Re: Transparent backgrounds for controls

Profox Jase17-Feb-02 0:46

Profox Jase

17-Feb-02 0:46

Thanks to the 2 people that helped me out. Neither solution really helped that much, but I did learn, so that's a good thing.

In the end, to remove background rectangles, I made one big background rectangle and drew everything on that, in other words, I painted everything on one canvas (instead of one canvas per game character). This seems to have done the job nicely.

If anyone wants to see the finished code, drop me a mail.

Rose | [Rose]

Jase

Jason King

jason.king@profox.co.uk
Feel the love at www.profox.co.uk

C# and .NET books

Oyvind Bratland13-Feb-02 0:42

Oyvind Bratland

13-Feb-02 0:42

I want to buy two books:
One C# book, and one .NET book.

Which books should I choose?