Speed up loading an image from disk in a windows forms (c#.net) app

Question

I\'m currently working on an app that allows the user to play (automatically scroll) through a series of local images. Usually there will be five or six on screen at once.

Answer 1

I came across this page which describes how to use the GDI+ API directly to load images. Very simple to use:

ImageFast.FromFile(@"C:\MyPhoto.JPG");

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Added to show speed of ImageFast over Image From File method

This uses the source code found here. The code was copied and pasted and required no changes.

Stopwatch watch = Stopwatch.StartNew();

string filePath = @"C:\TestImage25k.png";

Image fromFile = Image.FromFile(filePath);

watch.Stop();

Console.WriteLine("Image.FromFile     Ticks = {0:n}", watch.ElapsedTicks);

long fromFileTicks = watch.ElapsedTicks;

watch.Reset();
watch.Start();

Image fastImage = ImageFast.FromFile(filePath);

watch.Stop();

long fastFileTicks = watch.ElapsedTicks;

Console.WriteLine("ImageFast.FromFile Ticks = {0:n}", watch.ElapsedTicks);

Console.WriteLine("fromFileTicks - fastFileTicks = {0:n}", fromFileTicks - fastFileTicks);

The console output was

Image.FromFile     Ticks = 19,281,605.00

ImageFast.FromFile Ticks = 7,557,403.00

fromFileTicks - fastFileTicks = 11,724,202.00

You can see the impact of the ImageFast. Over time those 11 million saved ticks will add up.

Answer 2

Easiest might be to put a 'next' and 'previous' button to limit the number of images and preload.

Answer 3

Check out the concept of double buffering. What you want to be doing is have a second thread that can be loading the next set of images while you are displaying the first set. Once the 1/6 time gate hits, you switch the one set of images out and start loading the next set.

Answer 4

i would probably create a background thread to continously fetch all the images from disk (keeps the ui responsive) and then publish each newly loaded image via an event

Answer 5

I think concept of double buffering will be useful. Set "Double Buffer" property of the form to True. This will help you little bit. Following links may be useful to you

• http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/f15ae586-b63f-4afb-90a7-d9067ccc19d5
• How to speed up .NET winforms rendering

Answer 6

If you have 6 images displayed at once, and you change them all every 1/6 of a second, you should be running into performance issues. Loading 150 kb from disk should be a trivial activity even without caching. It sounds like you may be overdoing the file loads. Are you sure you are only loading 6 images at a time? Are you reading images from disk that are not displayed?

If you can you provide a little more detail of the application flow, I may be able to be a little more helpful.