Question

I want to make a control that acts as a time ruler with a wave form for sound wav files like that in movie maker or in camtasia studio video editor

• i have a method to parse the sound wav file
• i have a method to draw the wave of a specified time period

the problem is that the duration is long how to render all of it??one time or when the user is scrolling to a point if it isn’t rendered I’ll render it? what after its all rendered ? it will be so long user will zoom in and so on how to do it without effecting the performance

Answer 1

If you’re dealing with a big image and lots of data I would sugest this:

• render/display what user is currently looking at
• render rest of if in a background thread into a memory image

Once you have the whole image rendered in an image kept in memory, any scrolling and/or zooming would be just to position your display window.

Render your image in an unzoomed scale into a Bitmap object. When you need to display part of if use Bitmap.Clone to copy section of that bitmap into a picture displayed to user. A bit difficult part will be to render part of your base Bitmap which is currently demanded to be viewed.

This could be memory demanding. It is effectively a caching mechanism and as always in cases like that you get speed by using more memory.

Something similar to how google maps works.