cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   Cloov
   Member

   Hi,

   I've been looking into how to set the size of a sprite after creation. I want to set the dimensions of a few square sprites individually, but only after I create them. I'm now thinking this might have to be done by scale, but I want to set their widths and heights separately, and choose actual pixel values (so I might choose to make one square into a 40 by 5 rectangle, like a floor panel in a game).

   I couldn't see how to scale in both dimensions. If I could, I'd probably have created a method that takes the width and height and does a sort of reverse calculation using the sprite's contentSize and its scale.

   I then discovered that you can use the anchor point to affect the way the sprite scales.

   This whole process, though, sounds a bit lengthy just to resize a sprite on-screen. Is there an easier way?

   Posted 2 years ago #
2. 

   Cloov
   Member

   Okay, I've done something that works, but still, I'd like to know if there are any better examples.

   - (void) setSize : (int)newWidth : (int)newHeight {
   CGSize originalSize = [mySprite contentSize];
   float originalWidth = originalSize.width;
   float originalHeight = originalSize.height;
   float newScaleX = (float)(newWidth) / originalWidth;
   float newScaleY = (float)(newHeight) / originalHeight;
   [mySprite setScaleX:newScaleX];
   [mySprite setScaleY:newScaleY];
   }

   Posted 2 years ago #
3. 

   kalx
   Member

   I've always just used scale without questioning it lol, but your post got me curious. I took a look and don't see any properties/methods to directly set the width or height.

   I also took a look at how the Sprites (inherits CocosNode) implements scaling. It looks like it uses an Open GL function (glScalef) that directly accepts the scales to apply. Based on that, i suspect that even if a feature was implemented to take in new width/height pixel values, it would be implemented similarly to what you've done. However, I'm still learning the basics of OpenGL and I don't know enough about it to definitively say that's true :p

   - kalx

   Posted 2 years ago #
4. 

   kalx
   Member

   By the way, you probably did it for clarity, but I would simplify the function to two lines with:

   [mySprite setScaleX: newWidth/mySprite.contentSize.width];
   [mySprite setScaleY: newHeight/mySprite.contentSize.height];

   - kalx

   Posted 2 years ago #
5. 

   Codemattic
   Moderator

   Sounds like a job for categories!

   Posted 2 years ago #

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