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CSS Spriting Tricks
For a project I'm having fun with, I have a tilemap that I want to use for sprites. Each tile is cleanly 16px by 16px.
Searching on the Interwebs, most people recommend making a background image and then using background-position in CSS to shift which image is being viewed.
There are a couple drawbacks to this:
1) You now have to put *something* in the element in order to make sure that it still exists on the page. So what usually happens here is a 10000px text-indent so that there's no chance that it will appear in the viewport.
2) You now have no option of scaling the image at all.
It turns out for option #2, there's some sort of magic scaling going into CSS3 called background-size, but it's not clear to me that it allow arbitrary aspect ratio changes.
I thought about it and came up with the following solution that seems to work well enough for me:
<!DOCTYPE html> <html> <head> <style> .wh-mapelement-image { position: absolute; } .wh-mapelement-container { position: absolute; height: 16px; width: 16px; overflow: hidden; display: block; } </style> </head> <body> <div class="element-container"> <img src="foo.png" class="element-image" width="640" height"432"> </div> </body> </html>
A .wh-mapelement-container:hover can be added here with left:-16px top:-16px to give the rollover effect to the sprite.
But wait! THAT'S NOT ALL!
If I double the width and the height on the image link, I can also double the width and the height in the container. That way, the browser's image size manipulations will work as expected and I can see my 16x16 pixel sprite on this reasonable DPI screen.
Searching on the Interwebs, most people recommend making a background image and then using background-position in CSS to shift which image is being viewed.
There are a couple drawbacks to this:
1) You now have to put *something* in the element in order to make sure that it still exists on the page. So what usually happens here is a 10000px text-indent so that there's no chance that it will appear in the viewport.
2) You now have no option of scaling the image at all.
It turns out for option #2, there's some sort of magic scaling going into CSS3 called background-size, but it's not clear to me that it allow arbitrary aspect ratio changes.
I thought about it and came up with the following solution that seems to work well enough for me:
<!DOCTYPE html> <html> <head> <style> .wh-mapelement-image { position: absolute; } .wh-mapelement-container { position: absolute; height: 16px; width: 16px; overflow: hidden; display: block; } </style> </head> <body> <div class="element-container"> <img src="foo.png" class="element-image" width="640" height"432"> </div> </body> </html>
A .wh-mapelement-container:hover can be added here with left:-16px top:-16px to give the rollover effect to the sprite.
But wait! THAT'S NOT ALL!
If I double the width and the height on the image link, I can also double the width and the height in the container. That way, the browser's image size manipulations will work as expected and I can see my 16x16 pixel sprite on this reasonable DPI screen.