Plotting graphs HQ

[Dhaann]

Hi all,

I am making a program to plot mathematical functions. I am using GDI+ graphics in C++ to plot graphs, but the quality isn't that good (I'm already using antialiasing). My solution is to plot the graph as a larger image (lets say 1500*1500) and then scale this image to a smaller one, to fit in the window (500*500). Is such a thing possible?

Thanks!

[Disch]

Yes it's possible, but I'm not so sure it would have the effect you're hoping for.

I'm not that familiar with GDI+, but in regular WinGDI you would just create an offscreen DC, draw to it, then blit that offscreen DC to the display. In GDI+ it's probably similar -- create an offscreen surface and draw to that first... then copy it over (and possibly scale it down) to the display.


But again.. not sure this will improve the image quality. It'll just make the lines and text thin and hard to see.

Can you upload an example pic of the low quality you're talking about? Like upload it to imgur or something?

[Dhaann]

http://i.imgur.com/qE4UgCS.gif

it doesn't seem that bad when I printscreen, but for some reason it looks worse in the application..

I did some research about your solution even before I posted here, but I couldn't really find a good explanation/code. Do you have an example code?

[Disch]

it doesn't seem that bad when I printscreen, but for some reason it looks worse in the application..

Yeah that doesn't look bad to me at all.

AFAIK there's no way printscreen would be modifying the image before capturing it... so if it looks good on a printscreen, maybe it's just in your head?

I know when I'm doing audio work, my ears are always finding the slightest, tiniest break in the sound... even when it sounds just fine to everyone else. I swear I imagine a lot of the issues.

I say put the printscreen version side by side from the actual app. See if you can spot any differences.

Do you have an example code?

Unfortunately, not for GDI+... sorry. =(

Like I say I'm not all that familiar with it.

[Dhaann]

I managed to create a much larger image and then scale it down, but it doesn't have any effect on the quality. There are math programs that are able to draw really smooth lines, how do they do it? I read about Anti-Grain, gnuplot and some other libraries, but I'm not sure wether those are going to help me..

Does anyone have a suggestion on how to tackle this?