who is good at maths?

[Heyt]

just tested zooming out and it will also work if with a slightly change in the code

Code:

double leftpos = current.X; //only first time when zoom is 1
double toppos = current.Y; //only first time when zoom is 1


double leftoff = (-1 * current.X) - leftpos;
double topoff = (-1 * current.Y) - toppos;

double oldWidth = current.Width;
double oldHeight = current.Height;

current.Width = current.OriginalWidth * current.Zoom;
current.Height = current.OriginalHeight * current.Zoom;

if (oldWidth <= ScreenWidth)
{
current.X -= ((current.Width - oldWidth) / 2);
}
else
{
current.X = (-1 * leftoff * current.Zoom / oldZoom) - (((ScreenWidth * current.Zoom / oldZoom) - ScreenWidth) / 2);
  if (current.X > 0)
  {
  current.X = current.X * -1;
  }
  else
  {
  current.X -= leftpos;
  }
}

if (oldHeight <= ScreenHeight)
{
current.Y -= ((current.Height - oldHeight) / 2);
}
else
{
current.Y = (-1 * topoff * current.Zoom / oldZoom) - (((ScreenHeight * current.Zoom / oldZoom) - ScreenHeight) / 2);
  if (current.Y > 0)
  {
  current.Y = current.Y * -1;
  }
  else
  {
  current.Y -= toppos;
  }
}

[smeghead]

I've done some testing and attached the whole project directory as a zip.

I had to comment out the re-centering code as I couldn't get it quite right. I also need to test the ratio settins with a more obscure image rectangle.

You will need to put a jpeg file as C:\temp\test.jpg but you can alter this in the code.

The executable should be in there as well

I'll keep testing with a more rectangular rectangle to make sure it works properly. When zoom is 1.0 then the image is shown as best fit in the screen. When Zoom is more than 1.0 then the whole screen area is used.

[reven]

hey smeghead whats the deal with the "@" here
c = new Class1(@"c:\temp\test.jpg");
ive seen it here and there, and have no idea what it does (if anything).

[smeghead]

It makes sure that the string is treated like a directory path and makes any changes necessary i.e. the \ parameter isn't taken as an escape sequence but as a directory seperator.

[reven]

oh, is there a way to reverse it? to escape all those characters? ie to prevent code injection (we covered this in uni, but only for php).

[smeghead]

Done another version that corrects the aspect ratio when zooming.

I'm probably about to stop doing this now if that's OK. The code to centre the image doesn't work (and is currently commented out) but i'm not convinced that it's needed anyway - let me know if you think it is and i'll have another go.

[smeghead]

oh, is there a way to reverse it? to escape all those characters? ie to prevent code injection (we covered this in uni, but only for php).

Can't remember - sorry

[reven]

Can't remember - sorry

thats cool, just curious.

thanks for the help, i should be able to put it all together now.

[reven]

sweet! its working! im so happy, thanks guys for all your help. all i go to do now is do some safety checks on moving/zooming out but thats no biggy.

really thank you guys, this one had me stumped.