Line Graph

I once did something similar to this in VB. But, if you play around a little and read up at MSDN I''m sure you can do the same in C++.

Basically what I did was this:
Since the pixel coorinate system is upside down compared to what we commonly use, you have to reverse the Y coorinate.

So, if you were to plot a pixel at (0, 123) then you would do this:

HDC your_window_hdc = GetDC(your_window); //Gets DC of the window int max_y = GetDeviceCaps(your_window_hdc, VERTRES); //Gets the number of pixels high COLORREF some_colorref = RBG(0, 0, 0); //Creates a black color SetPixel(your_window_hdc, 0, max_y - 123, some_colorref); //Sets the pixel to black

If that doesn''t work (which it should, unless I''ve forgotten something important), read around MSDN about DC''s, COLORREFS, and SetPixel.

To get back to the specifics of the graphing engine - my graphing engine made points that were 3 pixels by 3 pixels for visibility reasons. It also plotted every 3rd pixel to save time and because each plot was 3x3.

no no. I can draw a pixel, I can draw lines, I can figure out where to draw them, etc

I can even MAKE a line graph. my problem is how to figure out a USER friendly Y axis increment.

again, from my example, the increment would be 500. thus the y axis marks would go from 0 - 2000 at increments of 500

now, how do find those 3 numbers is what I''m asking (increment val, lowest val, highest val)

Hope this clears things up
~Shaun

OH! I''m sorry, I misread.

Well, what I did was ask the user to specify and upper bound, but another way is to round the highest value to the heightest hundred or thousand (whatever you choose), then divide that into 4 or 8 or however many equal parts works for you.

This is from the top of my head, and will give you an idea how to do this.

1st, find the min and max numbers of you''re samples (obviously)

2nd, find the resolution of each values (ie, find how many digits it has (10, 100, 1000, etc.))

3rd, use the lower resolution for the min value, and use the higher resolution for the max value.

That is just a thought off the top of my head. No algorithm written in C, but you can do that yourself.