How can I make an UIImage programmatically?

Question

This isn't what you probably thought it was to begin with. I know how to use UIImage's, but I now need to know how to create a "blank" UIImage using: `CGRect screenRect = [self.view bounds];` Well, those dimensions. Anyway, I want to know how I can create a UIImage with those dimensions colored all white. No actual images here. Is this even possible? I am sure it is, but maybe I am wrong. Edit This needs to be a "white" image. Not a blank one. :)

Accepted Answer

You need to use `CoreGraphics`, as follows.

```
CGSize size = CGSizeMake(desiredWidth, desiredHeight);
UIGraphicsBeginImageContextWithOptions(size, YES, 0);
[[UIColor whiteColor] setFill];
UIRectFill(CGRectMake(0, 0, size.width, size.height));
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
```

The code creates a new `CoreGraphics` image context with the options passed as parameters; size, opaqueness, and scale. By passing `0` for scale, iOS automatically chooses the appropriate value for the current device.

Then, the context fill colour is set to `[UIColor whiteColor]`. Immediately, the canvas is then actually filled with that color, by using `UIRectFill()` and passing a rectangle which fills the canvas.

A `UIImage` is then created of the current context, and the context is closed. Therefore, the image variable contains a `UIImage` of the desired size, filled white.

How can I make an UIImage programmatically?

Solution

Problem