What image format can c# load fastest?

Question

this may seem like an odd question, and I don't know the formats of images so I'll just go ahead and ask...

I'm making a minesweeper game (relevant to different things too) which utilizes a grid of buttons, then I'm adding a sprite to the buttons using backgroundImage. If the grid is 9x9 it's fine. 15x15 it slows down and 30x30 you can visibly see each button being loaded.

That raises me to my question: Which image format would load fastest? Obviously, file size takes a part in the loading speed, however, I am enquiring as to if, say, a jpeg - with the same filesize as a gif - will load faster. or a bmp, png, etc.

I'm asking this as to see if I can get my grid to load faster using a different format.

Thanks!

Answer 1

You want an image format that paints faster. There's only one, the one whose pixel format directly matches the video adapter's setting so that the pixel data can be directly copied without needing format adjustments.

On most any modern machine, that's PixelFormat.Format32bppPArgb. It draws ten times faster than all the other ones.

You won't get that format when loading an image from a resource or a file, you have to create it.

Do note that this still won't give you stellar paint speed if every cell in the grid is a control. Particularly if it is a button, they are very expensive to draw since they support transparency effects. You'll only get ahead here if you draw the entire grid in one Paint event handler. Like the form's.

A completely different approach is to cover up the visible delays with this hack.

Answer 2

use the 8-bit PNG or GIF format and reduce the number of colors in the palette. Some image programs such as PhotoShop allow you to save the image for the web and fine-tune the image settings. By reducing the color palette from 256 to something like 32, you greatly reduce the size of the file. The less colors that the image has, the smaller the file size is going to be.

PNG has a similar feature called "Interlaced". You may want to turn this feature off so that the full image downloads quicker.

Because the 8-bit PNG and GIF formats have the potential to result in much smaller image files, try to keep this in mind when creating graphics and illustrations for your application. Try to keep the amount of colors to a minimum and use flat graphics instead of photographs. This way you can create images with palettes of 16 colors, keeping the file size extremely small and fast to load.

Best Regards

Answer 3

Are you reloading the image every time you paint a button? If so, there's your problem - solve it with a cache.

Are you painting the image at its native size? Runtime resampling can create a performance hit.